All Things Motorcycle - Contrary Opinions

en-us Fri, 20 Nov 2009 16:50:38 -0500 ATM@msgroup.org 60 All Things Motorcycle - Contrary Opinions http://www.msgroup.org/forums/mtt/ All Things Motorcycle for Guest http://www.msgroup.org/forums/mtt/ http://www.msgroup.org/forums/mtt/rss_32.png All Things Motorcycle RSS Feed 144 47 Contrary Opinions - Tip 45 - Dragging a pegAndrew Dresselhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=8940&REPLY_ID=105972Contrary Opinions Tue, 22 Sep 2009 16:39:58 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=8940

quote:
Originally posted by whittlebeast

I was mostly looking at the unfiltered part of that trace (light blue/green). As the torque is climbing after the shift the vertical geez go positive (above 1) implying that the seat is rising as the power is coming back on.
I guess that it is possible that we are looking at tire shake or some other phenomenon but I doubt it as the acceleration numbers look as I would expect and there is very little filtering on that part of the trace.

I agree with your guess then: perhaps just bumps in the pavement. The oscillations at 492.5 seconds, with no obviously associated large change in forward acceleration, appear about as big as the spike just before 494 seconds, and so do not indicate to me any strong correlation with forward acceleration. If anything, the unfiltered trace still suggests a slight squat as forward acceleration peaks, and then a slight rise as you brake.

However, you obviously know you equipment better than I possibly can. I can only comment on how the graph looks.

In any case, it is fun to see some real data.

(edited to fix typos)]]>Contrary Opinions - Leather and hydrationHouse_of_Dexterhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=10295&REPLY_ID=105912Contrary Opinions Mon, 21 Sep 2009 08:55:22 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=10295 I've now gone 2 seasons in the heat 105F+ Texas Summer in stop and go traffic in Dallas. The first summer was with Joe Rocket Black Textile. This summer I wore perforated Leather. My ability to survive was 2 fold. First I hydrated wearing a camelback. On weather 95F+ I wore an evaporation vest under my armor. The evaporation vest is the most important equipment I wear during these conditions.]]>Contrary Opinions - Tip 258 - 'Advanced' or 'Performance' TrainingHouse_of_Dexterhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=10766&REPLY_ID=105611Contrary Opinions Fri, 11 Sep 2009 16:50:30 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=10766 I think one of the best arguments for track day...is to take it off the streets. Another forum that I frequent. We frown on riders showing risky behavior on the streets, they recommend track day so they can get it out of there system. These riders know there is a place for speeding and dragging a knee...and the public roadways are not that place.

]]>Contrary Opinions - Emergency Braking and Downshiftinghaithabuhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=9609&REPLY_ID=105304Contrary Opinions Wed, 02 Sep 2009 15:21:05 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=9609 Good enough. Thanks for your critique, James. I can't say it has changed my original conclusion but it has added to my store of knowledge, which I always welcome. We all want to survive out there!]]>Contrary Opinions - Tip #48: Contact Patch moves back not forwardAndrew Dresselhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=10500&REPLY_ID=103436Contrary Opinions Wed, 22 Jul 2009 15:22:00 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=10500

quote:
Originally posted by Proprioceptor
Foale provides an excellent diagram showing the front tire turned away from the direction of travel. See Fig. 5 at bottom. It matches the photos of actual high-speed cornering we see every day.

That figure, as the accompanying text explains, is for "speedway racing": that is "dirt track". On page 2-32 of his book, Motorcycle Handling and Chassis Design, he titles the same picture "Schematic for Drifting", clearly far beyond the realm of reasonable street riding.

On page 2-28 he explains that graph 2.25 for a hypothetical tire shows that "we would have to ... steer out of the corner" at lean angles less than 28", but I cannot tell if he is describing tires on pavement or gravel.

Cossalter limits his analysis to pavement and goes into much more detail on pages 125-130 of Motorcycle Dynamics (http://books.google.com/books?id=rJ...cle+Dynamics) with graphs of turning radius, velocity, steering angle, and roll angle for three different tire scenarios. Although he does state the need for negative front sideslip angles, he never shows a negative steering angle.

So far, I have yet to find an author that clearly states that a motorcycle will have to have a negative steering angle in a steady state turn on pavement.]]>Contrary Opinions - Tip 221James R. Davishttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=10549&REPLY_ID=102865Contrary Opinions Thu, 09 Jul 2009 15:58:10 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=10549 Fun to think with analogies, but yours are slightly wrong.

Horsepower is the amount of work done over time while Torque is the force doing that work.

As watts are a measurement of work being done over time (power), it is an apt analogy for horsepower.

If you apply a torque wrench to a lug nut and stand on it, torque exists (as a potential) but unless that nut turns there is NO horsepower. Thus, Volts is an apt analogy for torque.

Current is neither power not potential - it is the work being done. Current would be an apt analogy for the turning nut.

Despite these definitional differences it's clear that you actually understand the roles played by torque and horsepower.]]>Contrary Opinions - Counter-Steering (Oh-No)The Meromorphhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=8813&REPLY_ID=102492Contrary Opinions Tue, 30 Jun 2009 22:21:20 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=8813

quote:
Originally posted by Moses

How about a bike with "beach" style bars that wrap around almost to the rider's sides? You wouldn't push forward or downward on those grips, but almost outward. The idea is to steer the bike COUNTER to the direction you want to go, hence the name COUNTERsteering.

Actually you should still push forward on that grip. If you try pushing sideways, I think you will find yourself actually turning the bars much more than you should, The turning that is used for countersteering is usually very small, small enough to be hard to see. The proprioception of it (the feel of it) is more like pressing than pushing. I think if you tried to push 'beach bars' sideways on the road, you might find the steering input wildly over exaggerated. Maybe that's why they're called 'beach bars'? You need the exaggerated steering inputs riding in sand?]]>Contrary Opinions - Tip #086 - First Aid KitsNieborhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=10400&REPLY_ID=101681Contrary Opinions Sun, 14 Jun 2009 18:28:56 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=10400 Note to self: Add one large Roll 4" gauze to first aid kit. [;)]

I carry a dozen 3x3 pads, and now realize that's insufficient. It appears the elasticity of guaze would be very helpful in keeping other bandage material in place. I did add several triangular bandages awhile back, per James's well stated advice. Many legitimate uses for them came up. Though uses do seem to overlap, each has it's strengths. Carying both appears to be the best answer. LOL, I think it may be time to upsize my kit a bit. This one is beginning to burst at the seams.

I really wish the gal we hire to train us in first aid would cover topics like this. Against the rules though, we know how that goes...

Thanks Matt! [:D]]]>Contrary Opinions - Tip#254: A Case Against Counterbalancingrioguyhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=10341&REPLY_ID=101449Contrary Opinions Tue, 09 Jun 2009 19:54:12 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=10341 Sibemol,

Counter-steering is one of my pet subjects, so I read every post with interest. Thanks for posting the quote directly. I absolutely agree the quote leaves room for confusion.

If you are at the point where you can safely practice, go out and practice. Then it would be interesting if you would put your perceptions and see how it compares to what we have read.

Be sure to practice keeping a light grip on the hand grips.

]]>Contrary Opinions - Why do bars have parking lots?bkikkerthttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=8724&REPLY_ID=100618Contrary Opinions Mon, 25 May 2009 08:28:13 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=8724

quote:
Originally posted by Texasphotographer

Do not have to agree with it, the fact is the police have a limited amount of latitude in which to do their job. Sometimes the law gets in the way.[:x)]

I suppose the line has to be drawn somewhere between 'to serve and protect' and a police state.]]>Contrary Opinions - Putting it in neutral at stop lightsRobushttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=1331&REPLY_ID=100366Contrary Opinions Tue, 19 May 2009 23:03:30 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1331

quote:
Originally posted by raptor5618

Did you blink your brake lights? I try to do that when the approaching car was not following me into the light.

I don't recall if I did or not. This would have been around 1985 and I wasn't as safety-conscious back in those days. I do a lot of blinking now.

I think Hough makes the point in one of his books that eye-contact is no assurance that the driver is actually going to yield to you. It's one clue. He recommends that you watch what the front wheels are doing.]]>Contrary Opinions - Don`t get too close to the car, stopped too far ahead at a stop lightscottrnelsonhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=10236&REPLY_ID=100275Contrary Opinions Mon, 18 May 2009 07:09:36 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=10236 He should have been paying attention and realized that a car sticking out into the intersection might want to back up to the correct position.

That is one circumstance when I'll always stop where I would be if the car were in the correct position, in case they want to back up to where they should have been in the first place. Usually the driver remains sticking out, totally clueless, but occasionally they'll realize what they've done wrong and correct it.

In my opinion, the rider that stopped ten feet back made the first mistake in this example.]]>Contrary Opinions - Harleys the "safest" bikes?Robushttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=1387&REPLY_ID=100269Contrary Opinions Mon, 18 May 2009 01:16:47 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1387 Agree with what someone said, that people select bikes according to their personalities and riding styles, and that those dispositions have more impact on safety than do the different capabilities of the machines. I ride a Harley cruiser because I am not interested in doing the things that you buy a sportbike to do. When I was younger, I used to ride faster, but I was not a safer rider.

I don't see how "flickability" or the capacity to lean over farther in a corner are safety features. Realstically, those features aren't intended to help you swerve to avoid a pothole or a homicidal left-turner (alertness, proper speed, and braking are for coping with those situations). They are intended to let you negotiate twisty roads at speeds faster than we cruisers-riders tend to want to ride. Ridden within the limits of its design, by a rider who knows his own limitations, a Harley should be as safe as any bike can be.]]>Contrary Opinions - To "Cone" or not to "cone"kinninghamhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=8895&REPLY_ID=98410Contrary Opinions Mon, 13 Apr 2009 06:41:54 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=8895 With cones and without cones are both beneficial, just different training. One difference is psychological, like the difference between doing a Uturn between parking lot lines and doing them in an actual street with curbs.

I noticed recently my slow speed turns are more accurate if I lean back until the outboard arm is almost straight and I adjust steering by push and pull with my inside arm. I don't know why it helps. May be it's just a transitional technique as balance improves. Another thing I noticed recently is Uturns are easier when I'm expecting to tighten the turn as it progresses. The initial lean and turn of the wheel never seems like enough because it's not. When I plan to tighten the turn as it progresses things go better.]]>Contrary Opinions - Motorcycle Sales Foundationaidanspahttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=9346&REPLY_ID=98144Contrary Opinions Mon, 06 Apr 2009 19:21:17 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=9346 Allow me to welcome you to the site as well goatlocker95. We are glad to have you aboard, and look forward to your continued participation here.]]>Contrary Opinions - Motorcycle simulatrsAndrew Dresselhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=9707&REPLY_ID=96011Contrary Opinions Tue, 24 Feb 2009 14:33:18 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=9707

quote:
Originally posted by tusome
The CV on a PID controller is the Control Variable, bascially the output of the controller.

In that case, no. The confusion is probably caused by the way I've labeled the plots. Sorry about that. I use the titles for stuff such as parameters I need to record for comparing different plots. The y-axis label contains the information about what is actually plotted.

The output, the "CV", is steering torque in the lower right.
The inputs to the LQR controller are lean angle and steer angle.

On a real bike, I would do state estimating to calculate things that would be hard to measure, such as lean angle, from things that are easier to measure, such as steering angle.

These guys in the Netherlands are doing the only public instrumented bike testing that I know of: http://audiophile.tam.cornell.edu/~...le/index.htm]]>Contrary Opinions - Theoretical Cornering Question - counter-steeringcostoshttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=9677&REPLY_ID=95961Contrary Opinions Mon, 23 Feb 2009 00:44:38 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=9677 Thankyou gentlemen, now I have some reading, research, deep thinking and sleepless nights to contend with while I digest all that information.... On a lighter note here is a video of what my pit-bull thinks of some of your comments;-

http://www.youtube.com/watch?v=AKJ-u9US4CQ

I'm only joking of course.[88]]]>Contrary Opinions - HornsThe Meromorphhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=1677&REPLY_ID=92606Contrary Opinions Sun, 28 Dec 2008 20:47:40 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1677 I posted it under a different section, but it seems appropriate to mention it here. I have succeeded in mounting a WOLO horn (exactly similar to the Stebel) on my bike. It's as loud as any I've ever had.]]>Contrary Opinions - premium (high octane fuel) is bettercaponerdhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=4560&REPLY_ID=92588Contrary Opinions Sun, 28 Dec 2008 11:08:39 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=4560

quote:
Originally posted by bikerdave

I can't get the "experts" to agree on which fuel is better for a relatively low compression, small capacity V-TWIN engine with no real engine mods...
The dealerships say run premiun (95 - 98 octane) where as the manufacturer advises on a lower rating, as long as you dont get pinging (detonation).
Some even say that running a higher octane fuel than you need can lead to "incomplete combustion" as the fuel is much denser, and resulting carbon build up in the cylinder head (not a good thing I assume).

Anyone??

I run the lowest octane rating fuel that doesn't cause detonation. This is consistent with what every expert (as opposed to the "experts" in quotes) I've ever read or talked to has said.
High octane fuel is designed to burn more slowly in high-compression engines where lower octane fuel will detonate instantly rather than burn smoothly.
Havinge said that, you definately want to avoid detonation, as it drastically reduces power output, plus puts a lot of stress on internal engine components, and in extreme cases will result in a hole burning into a piston. (I've seen it happen)]]>Contrary Opinions - Stopping on yellow (not countersteering!)johncrosbyhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=5690&REPLY_ID=91005Contrary Opinions Mon, 17 Nov 2008 10:36:26 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=5690

quote:
Originally posted by Ballbarian

I am somewhat worried by the apparent lack of respect given to intersections controlled by lights in the US, as described in this thread.

I have to say I do disagree with the wonderfully named Ballbarian. The UK misuse of traffic signals and totally inept traffic management encourages an opportunistic approach to navigating intersections.

Having lived and driven in Continental Europe for many years (more than in the UK thankfully), my subjective experience is that on the contrary driving standards are only superficially worse (more overt letter of the law rule-breaking) but in actuality overall more predictable and less erratic than the UK.

Foreign truck drivers are far more influenced by being economically encouraged to overdrive without a tach. Tiredness combined with driving on the left in a bleak dreary grey landscape for hours on end, eating the most dreadful pigswill at UK eateries, isn't the best environment to maintain alertness etc.

On the traffic signals, in Germany the lights are often set up such that if you drive at or around the local speed limit, you will mostly often reach consecutive green lights, turning to amber shortly after you drive through. This is honestly the best piece of intelligent thinking to do with traffic lights I'd ever seen. In the UK it's the polar opposite. A punitive stupid counter-productive setting up of the lights to deliberately reduce the flow of traffic (in some crazy effort to make car use less attractive compared to the joys of buses etc). The previous Mayor of London admitted on numerous occasions that Transport for London did syncronise lights such that if you don't speed you'd hit every singly red all along your journey. Nothing frustrates road users more or encourages dangerous and illegal amber/red running of lights more than this nonsense policy.

The US/Europe is nirvana in comparison to the UK, but only from a cultural, aesthetic, culinary and driver/rider perspective! [:)]

]]>Contrary Opinions - Tip # 234 Wide Open Throttle PreventionTecpatl4http://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=7580&REPLY_ID=89303Contrary Opinions Fri, 10 Oct 2008 09:11:13 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=7580

quote:
Originally posted by Hazex3

In the MSF I had the problem. Once or twice while breaking a rev'd the engine. I had spent no time at all on a motorcycle or even dirt bike till I took the class. I do have plenty of time on mountain bikes though.

I had the same problem when I first started riding my bike. But then in the BRC class the instructor pointed out to me that I was only braking with two fingers and keeping the other two on the throttle. Once I started using all my fingers on the brake the problem seems to have mostly gone away. After reading this, since I have to replace the clutch lever this weekend I may reposition the brake lever while I'm at it, to see if helps with comfort and control.]]>Contrary Opinions - re: Tip#083: Anti-Lock Braking Systems (ABS)James R. Davishttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=1223&REPLY_ID=87695Contrary Opinions Sat, 20 Sep 2008 08:25:59 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1223 I have changed that safety article so that it now reads:

quote:
I think ABS makes sense for a cage, and maybe more sense for an 18-wheeler, but is of marginal value on a motorcycle EXCEPT IN THE EVENT THAT YOU ARE PRONE TO PANIC AND OVERUSE YOUR BRAKES (in which case ABS can easily save your life!).

Hope that addresses your concern and I appreciate your feed-back on the matter. The safety tips are generally not time sensitive. As ABS has become more available and better behaved, this tip became in need of some adjustment.]]>Contrary Opinions - Braking QuestionsAndrew Dresselhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=8666&REPLY_ID=86547Contrary Opinions Wed, 03 Sep 2008 15:22:58 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=8666

quote:
Originally posted by Grumpy

Other factors:
1) If each tire is capable of providing traction for deceleration, doesn't it make sense that when both tires are on the ground, more traction is available? If one tire is capable of 1 g of acceleration front to back, two tires would be capable of 2 g's of acceleration (all else being equal--I know they're not, but bare with me).

2) When the front brake is applied, a mechanical force or torque wants to throw the center of gravity of the motorcycle forward and around the contact patch. When the rear brake is applied, the mechanical force or torque wants to throw the center of gravity of the motorcycle downward (at a tangent to radius drawn between the contact patch and the center of gravity) between the two tires. Both these torques are separate and distinct from weight transfer, which will do what it wants to do, as long as there is deceleration and a cg above the contact patches, regardless of whether deceleration force originates from the front, back, or both wheels. So we'll try to ignore weight transfer as irrelevant to this discussion to simplify and illustrate some factors, which may prove to be minor.

What we see in the above illustration, if true, is that while using the front brake removes weight and traction from the rear wheel, using the rear brake sets more weight between the wheels, thereby creating traction for the front wheel.

I read through all the replies and didn't see these points addressed, but I didn't check the links, so forgive me if this is already handled elsewhere.

1. In general, two tires would provide twice the braking force only if they didn't have to split the total vehicle weight between them. The simplest model of friction does not include surface area by the same principle. Of course, the interaction of relatively soft rubber on hard rough pavement complicates things, but not nearly enough to make two tires twice as good as one. I'd love to learn exactly how much, if anyone knows.

2. The torque due to the force couple of tire friction and center of mass deceleration is not located at any particular point on the body because the two forces are perfectly equal in magnitude and parallel in direction. The torque generated by the front wheel is indistinguishable from the torque generated by the rear wheel, except that they have different built-in limits. Neither is "better" than the other, both increase braking effectiveness from the front wheel and reduce braking effectiveness of the rear wheel equally, until the rear wheel comes off the ground.]]>Contrary Opinions - Braking strategiesNightcoderhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=8644&REPLY_ID=85977Contrary Opinions Wed, 27 Aug 2008 07:49:41 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=8644

quote:
Originally posted by Misty Trane

Nightcoder, David Hough simply says if you habitually lock up your rear in that circumstance, then use only your front.

That would do the trick, I beleive. I think you're all right, and that it indeed depends on the motorcycle. The Nighthawk I crashed with only me on it was very light in the rear (as is my current bike), and I locked up the rear very easily when braking. The high riding position also increases weight transfer. But I shouldn't take that observation and try to make it everybody elses creed.

As for my accident - I panicked, and the brain wasn't involved in any way until after my face hit the asphalt (besides from taking me into the situation to begin with). It was reflexes that made me use the rear brake repeatedly, which - in combination with that particular bike and rider - didn't do me any good.

But again, I fold. Rider's observation and judgement skills based on full education on known facts wins every time.

Thanks for setting me straight! [:I]

And... be careful out there!
/Peter]]>Contrary Opinions - Bad Adviceradan2http://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=7135&REPLY_ID=83460Contrary Opinions Thu, 31 Jul 2008 21:54:56 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=7135 I agree, confronting someone is usually a bad idea. I would wait for the loudmouth to go away and quietly tell the newbie that the advice he had been given contradicts my experience and what I had read, then recommend either a BRC, the Hough book, or this website.

I have heard blowhards give obviously wrong advice from time to time. So far, they have done it in a crowd, and their own mates have jumped on them.

The worst advice I have ever heard given is similar to what you have heard: in case of a sudden stop, hit the back brakes hard and never touch the front brakes. This was at the end of a charity ride at a Harley dealership, and the general manager, obviously appalled, immediately jumped in to set the matter straight.]]>Contrary Opinions - Regarding tip 053 on the riding tips pagegymnasthttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=8222&REPLY_ID=82987Contrary Opinions Mon, 28 Jul 2008 22:13:53 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=8222 Mutabilus. It very well may be that in some cases, suicide by bike is a definite possibility but I am of an opinion that the larger problem is far less complicated and not nearly as controversial as some aspects of PTSD. The more common scenario that I think relates to the problem is more along the lines of "I did that over there and there were real dangers so now I can do this here at home (get a really fast motorcycle that suits my daring do image) because I have confronted danger successfully and it is now behind me".

An adrenaline buzz is useful when one is in a situation that they have been well trained for. It can be deadly in situations one is unprepared for.

]]>Contrary Opinions - Stoppie?? information onlyMrDude_1http://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=7586&REPLY_ID=82506Contrary Opinions Thu, 24 Jul 2008 09:46:08 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=7586 A STUNT style stoppie is NOT anywhere close to effective braking.
Actually it’s a perfect example of what not to do.

I wont go into 'how to' level details, but in a rolling stoppie they basically 'spike' the stopping pressure. This initial spike raises the rear. After that they BEARLY use the brake. It’s just to balance.

On a PROPER stop, you avoid this at all calls. You SMOOTHLY apply the brake. Because of this, you can continue using more brake, longer.
On some bikes (ie: sportbikes, supermotards, and anything else with a high center of gravity), doing a proper stop may lift the rear wheel, but this is NOT desirable or intentional.
There’s a point of diminishing returns... on a sportbike such as my ducati, or the aforementioned MotoGP bikes, the rear tire reguarly lifts about a half inch off the ground under maximum braking.
If we continue braking harder (trust me, we still have a lot of lever left) the rear will rise up more... at that point, we must RELEASE some pressure, and brake less... so we effectively lose braking ability. If you wish to pursue and find this limit on your sportbike, trackdays are wonderful ways to learn the skill of maximum braking. The street is not. Streets have crowns in the roads along with sand, and the fact that you have to go fast to even see this effect. The crown will make your bike step out.

Tecpatl4:
The reason using one wheel is more effective then two is simply because the limiting factor is not traction. It is not braking capacity; the limiting factor on a modern sportbike is the center of gravity. The CG is so high that the bike will lift. You can accidentally help it by being too aggressive on the initial bike and that will jerk you up, or you can avoid it by being smooth and stopping properly.

If you watch people riding sportbikes properly (racers or experienced riders) you'll note that under braking they pop up and back. One of the reasons for popping back is to move more weight backward and limit the amount the bike tries to lift. The lower you can keep that bike, the harder you can stop.

Please keep in mind this does not apply to cruisers, touring bikes, some standards, etc... It does apply to supermoto bikes and some standards though...
If your rear tire is on the ground, by all means use it to stop.

Just remember while we're all on 2 wheels on the same road, some of us are in totally different worlds. At 70mph on the interstate, some bikes will feel twitchy, some riders are cupping wind. While other bikes may be at 4% throttle and the rider COULD (but shouldn’t) take one hand off and feel like he’s on a walk through the park.

What applies and works for some bikes will not work for all. Learn how things work, think about them for yourself, and then apply that knowledge... and if you have a bike capable of stopping (or anything else) at levels beyond what is appropriate for the street, please take it to a track or other appropriate place.
]]>Contrary Opinions - Laying it downdfpd273http://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=1279&REPLY_ID=81708Contrary Opinions Thu, 17 Jul 2008 00:42:25 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1279 The idea of sliding under a semi trailer, assuming the circumstances were perfect, may sound like a good idea to some but I would rather be upright if at all possible.

Not only do I not know how to lay a bike down intentionally, there is a lot of stuff under trailers. Sometimes there are spare tire holders or railings for added strength. Also whats the likelihood that the area you are aiming for would still be open when you got to it, as the semi would continue moving forward. It seems less painful to hit the side of the trailer (slower because you stayed on the brake) than to risk hitting a bar or getting stuck under a tire.

As far as the initial question of the guardrail. Who knows. I don't know how you would ever prepare for a situation like that, but I would like to think that trying to steer out of danger or panic stopping would be far more beneficial to my health than dumping the bike and hitting the rail.]]>Contrary Opinions - The Third Gyroscopepimariderhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=7980&REPLY_ID=79952Contrary Opinions Mon, 30 Jun 2008 16:33:21 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=7980 As a result of one of James’ comments, last year, I went to my practice area and tried slow speed riding on my Honda Aero using high engine revolutions for additional stability. I was amazed at the extra stability the engine provided even at almost 0 mph compared to the stability at slow speed with the engine just above idle. Now that I have a Honda ST1300 with the engine crankshaft parallel to the longitudinal axis of the bike frame, increasing the engine RPM has no apparent positive effect on stability at low speeds. By the way, Honda has engineered a counter rotation in the power-plant design, so there are no rolling forces as one adds or reduces engine RPM on the ST1300.

PimaRider]]>Contrary Opinions - Low speed turningTburdhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=7973&REPLY_ID=79945Contrary Opinions Mon, 30 Jun 2008 15:45:41 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=7973 This would have been a good time to do a little experiment but my bike is in the shop, again.

A good explanation of this along with a few nice illustrations can be found on pages 41 and 43 of "Proficient Motorcycling" by David Hough. It involves the rake angle and trail of the front end which I'm sure you are very familiar with.

The trail dimension is the distance the contact patch is behind the steering axis. When the front is turned so that the wheel points to the left for example, the contact patch moves to the other side of the steering axis which is to the right side of the frame. When looking at the top view on page 43 this makes sense, at least to me, except that Hough is showing a right turn in his discussion.

Actually if the bike is stationary the front patch doesn't really move, the frame makes a lateral shift. But it's the relative position that's important in this discussion concerning the cg relative to the contact (support) points.]]>Contrary Opinions - MSF article errorsWarlock622http://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=7950&REPLY_ID=79830Contrary Opinions Sun, 29 Jun 2008 09:35:11 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=7950 Night Train, I do appreciate the kind words and am glad I helped in some small way, but please don't change your riding habits because of my little experiment. Those habits seem to have kept you safe thus far.
IMHO, although your wife shouldn't "slam" into you even in an emergency stop, there's always the possibility that she won't hear you say, "OH S**T!" just ahead of that stop and will do so. It would definitely be a distraction and have an adverse effect on you. However, since you seem to be prepared for that eventuality, (through experience and safe riding practices), I don't see it as a major concern for you.
Your statement did get me to thinking though. So, I took my daughter with me last night to the parking lot (old Walmart lot, so there's PLENTY of room) and did a few "panic stops."
Did the first with no warning to her and sure enough, she slid up against my back pretty hard. As I was expecting this I was prepared for it and had no problem compensating for the distraction. She fussed at me for doing that to her, but got over it after I explained why and we went on to do some more stops, etc. She loves riding with me and trusts me not to do anything stupid.
Anyway, we did 6 more stops and even with the addition of her 140 lbs, had no problems stopping within the distance measured in my earlier experiment, (all my chalk marks were still there). So, IMO this just reinforces James' earlier statement that;

quote:
It is a FACT that weight is not a factor in determining stopping distance on a motorcycle provided it is within normal load carrying capability of the bike.

And it put all this "theory" etc., in perspective for me as well.
However, even with all this extra info (and the fun I had while doing this), I'll still "ride my own ride" and continue to do what has kept me safe these 40+ years of riding.
Ride safe!!]]>Contrary Opinions - Rubber HardnessVulcanV2Khttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=7728&REPLY_ID=78509Contrary Opinions Tue, 10 Jun 2008 19:46:51 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=7728 The rest of his message was deleted because of this part: JRD

quote:
Your argument is really weak and based on numbers that have an odor that hints where they were pulled from.

And that caused his departure from the board. What was deleted was, essentially, a statement that his tire contact patch is oval in shape and nowhere near 5 inches wide so that my commenting about a typical rear tire width was irrelevant. In fact, unlike car tires, when you add weight to a motorcycle tire its contact patch gets longer AND wider (because the tire is rounded side to side) so that as that weight approaches max capacity the contact patch approaches that width. In any event, personal shots are not the way to argue on this board. JRD]]>Contrary Opinions - 1st bike optionElwoodhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=7687&REPLY_ID=77501Contrary Opinions Fri, 30 May 2008 09:38:49 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=7687 WZ, I just bought as my first mc a 98 Shadow ACE. I was a bit intimidated by it at first, but having ridden it for three weeks now, I love it. The price seems right and it sounds like a good deal. I know that others on this site would advocate for a smaller first bike, however, I wanted a 5th gear for highway speeds. I, as others will also, encourage you to sign up immediately for a BRC. I am really looking forward to taking the course next weekend. The slow drills and excercises are not nearly as easy as I thought they might be.

Love my ACE!]]>Contrary Opinions - What is a California Stop?Tamarack58http://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=4633&REPLY_ID=77488Contrary Opinions Fri, 30 May 2008 08:33:28 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=4633

quote:
Originally posted by BikeWhisperer

Just my .02 for this thread. Does or can anyone come to a complete stop, on a two wheeled vehicle and not put a foot down? And with that question, does anyone roll through a stop sign dragging a foot?

Don't mean to revive old dead posts but since the last entry to this one was a couple of weeks ago I'll add my thoughts. Won't debate the CA stop since that's been talked about to completion but want to respond to the above question.

I almost always (when safe conditions permit) TRY to come to a complete stop before I put my feet down. For some reason it's very satisfying to me to be able to come to a complete stop and stay stopped for a second or so before I need to put my feet down.

I guess it's similar to being able to make a full lock turn without using your feet. Just makes me feel totally balanced and one with my machine.

I better add a clarification to the above. When I am able to do this I DO NOT consider it my "complete" stop at a stop sign. I still "stop look and listen" before proceeding.

]]>Contrary Opinions - RE: Tip#171 - Helmet laws, bogus conclusions.gymnasthttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=1695&REPLY_ID=70063Contrary Opinions Fri, 29 Feb 2008 12:46:26 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1695

quote:
Originally posted by Lockjaw

Food for thought. A friend of mine in college was getting driven home because he was drunk. He didn't want to walk back from the parking lot. The driver (who was already annoyed) did not want to stop. The guy dove out of the car which was only going 10-15. He hit his head on the curb. Almost died. Was in a coma for months. Also had a buddy who caught a flowerpot to the head (his eye came out). And one who got sucker punched with a beer stein in the back of the head. All of them were close to death, and none of them were ever the same again.

Heads are fragile!

Following up on your "Heads are fragile", most people have no idea of how fragile. Do a web or Google search of the term "Traumatic Brain Injury" or TBI and a person can become well informed of how little is required in the way of injury to produce trauma with life changing consequences. When a person tells me "helmets are dangerous" I know that I have met a person who avoids reality.

]]>Contrary Opinions - countersteering is only half of itdbalvarezhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=1725&REPLY_ID=68213Contrary Opinions Mon, 14 Jan 2008 22:20:51 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1725

quote:
Originally posted by James R. Davis

I will remind you that counter-steering works even if you replace the front wheel with a ski - no precession involved.

Mr. Davis, the first time that I read the term of countersteering, I didn´t beleive it. I tried it and it functions. But with your explanation I have no doubt at all, thank you.]]>Contrary Opinions - OK---so you think you know how to steer your bike now?jeffareidhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=5542&REPLY_ID=65360Contrary Opinions Sat, 27 Oct 2007 17:07:21 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=5542

quote:
Wow, that was cool. But I didn't see any steering going on during that run, rear or otherwise.

He's steering:

Rear view, driver (pilot) has to steer to compensate for yaw, most of which is probably due to slight imbalance in the jet engines thrust.
http://www.youtube.com/watch?v=fr0KdxhYgfY

Cockpit view:
http://www.youtube.com/watch?v=vHnNxMJLfvA

update - actual picture of rear wheel steer bicycle from this web site http://www.rowvelo.com :

]]>Contrary Opinions - Tank Bags Safer Than Saddle Bags?scottrnelsonhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=5553&REPLY_ID=61048Contrary Opinions Fri, 27 Jul 2007 10:17:23 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=5553 I consider tank bags to be more convenient than saddlebags. I like having my maps, camera, and extra pair of glasses in there. That's about all that I keep in the tank bag on normal one-day trips, though. There is no way I would put glass or anything sharp in there.

I mostly ride with my saddlebags on the bike and they weigh between 10 and 15 pounds total most of the time, with the first aid kit, tire repair kit, assorted rags and an extra pair of shoes that I normally keep in there.

When I take the saddlebags off I can tell a difference in the handling on twisty roads. The bike leans into turns quicker and is a bit more responsive.

I don't consider either one to be a safety issue. My tank bag can't affect steering, since the grips are at the level of the tank. Now those tank panniers would be a problem, though. I think those things are meant for narrow dirt bike tanks. I can't see using them on any bike I've ever owned or expect to own.]]>Contrary Opinions - How do you really steer your bike?BC KLR650http://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=5449&REPLY_ID=60291Contrary Opinions Tue, 17 Jul 2007 14:41:29 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=5449

quote:
Originally posted by nomad dan

quote:
Originally posted by James R. Davis

........
It is the righting force that you are maintaining pressure against ....

That makes sense to me.

Would you like a cookie? Some of us are still finding this confusing.]]>Contrary Opinions - Steering, ONCE AGAIN!Bodhislackvahttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=5578&REPLY_ID=59614Contrary Opinions Sat, 07 Jul 2007 00:42:02 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=5578

quote:
Originally posted by SteveM70…I've now began thinking that maybe "more would be better". I'll collect my thoughts and we can argue that one later.

P.S., Our local DMV motorcycle testing course is open to practice whenever tests are not being given. Although I have my endorsement I still swing by and go through the coarse whenever I find myself in the area…

Thanks. I look forward to disagreeing with you again in the future.

That DMV test course is a fine place for your wife to practice low-speed maneuvers. Low-speed skills are particularly important because they transfer directly to high-speed (anything over 20 mph) application. Beginners are able to quickly acquire low-speed techniques that can be very frustrating for us experienced riders to learn. Jerry Palladino's Ride Like a Pro IV video teaches low-speed riding techniques based on police motorcycle officer training and concentrates on doing difficult maneuvers with large bikes in small spaces. Beginners don't know it's particularly demanding but soon figure out it's fun. It might be something you and your wife could learn from together.]]>Contrary Opinions - Covering the front brakescottrnelsonhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=5480&REPLY_ID=58430Contrary Opinions Sat, 23 Jun 2007 08:14:41 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=5480 Now we have two threads on this subject. I started one in the General section on the same subject. Any of my answers will be there.

http://www.msgroup.org/forums/mtt/t...OPIC_ID=5479]]>Contrary Opinions - RE: Tip #225James R. Davishttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=5373&REPLY_ID=57381Contrary Opinions Thu, 07 Jun 2007 07:30:49 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=5373 Thanks. I changed the tip to include the word 'USUALLY'.]]>Contrary Opinions - Tip #1 - "low speed damage"scottrnelsonhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=4778&REPLY_ID=56212Contrary Opinions Wed, 16 May 2007 09:58:47 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=4778 It must have been too early in the morning when I gave my answer. Pushing forward is correct. Now I'm embarrassed. [:I]]]>Contrary Opinions - Re: 217: Your Motorcycle CANNOT Fall DownJames R. Davishttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=4916&REPLY_ID=53731Contrary Opinions Sat, 24 Mar 2007 19:04:54 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=4916 My intention was not to teach that you should not worry about low traction situations (that's a given), but that you need not worry about your bike falling over by itself because of an unfamiliar lean angle.

It is aimed at the newer rider who is specifically experiencing trouble (fear) in handling curves at highway speeds.]]>Contrary Opinions - Accelerating in a turn makes the bike lean more?IronAvatarhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=1740&REPLY_ID=50979Contrary Opinions Tue, 16 Jan 2007 09:46:05 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1740 I have to say, I don't think I've ever seen so many people disagree on one subject! Maybe this is because, compared to normal car dynamics; bike dynamics are bloody hard to get to grips with and understand, even when you're an experience rider.

While I don't actually ride a motorcycle, I do have the benefit of having a rigid body simulation all set up with a two wheeled vehicle that I can drive around at speed.

I first got my simluation up and running with a basic two wheeled vehicle without any method of balancing. What happened at this point is pretty predictable.

If I turned the front wheel slightly without any form of balancing, the lateral forces generated by the front (and ofcourse the rear tyre slightly after) cause a rotation around the local z-vector. This cause the top of the bike to fall-away to the outside of the turn.

So no surprises there right? What I did next to get the bike to balance is not really an issue here, needless to say I came with a method that does not move the combined center-of-mass (CoM) around.

I now had to think how braking and throttle apply to a bike while it's leaning over. In order to lean the bike, a rider normaly hangs (to varying degrees) which shifts the combined CoM of the bike + Rider.

It's perhaps important to remind ourselves of a fact about rigid body dynamics; all forces act through the center of the body's mass

Why is this important? Well normaly, the position of the force generated from the rear wheel is in line with the combined CoM of the bike + rider. But when the bike is leaning into a turn with the rider hanging-off, this is no longer the case! The position of the force is offset from the combined CoM and this produces a turning torque.

And why does the bike lean more when accelerating? Probably because the rider is trying to balance the change in centripetal forces generated by the bike wheels, and the increaed torque this produces that would normaly tip the bike over to the outside.

Check it out for yourself. In order to calulate the torque generated by a positioned force;

C = CoM
P = position of force,
F = force vector,
T = resulting torque
x = vector outer-product (not multiplication)

T = (P - CoM) x F

]]>Contrary Opinions - Point of throttle application in cornersklx678http://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=4202&REPLY_ID=50356Contrary Opinions Sat, 23 Dec 2006 10:35:58 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=4202

quote:
Originally posted by Taxi Jack

As Code explains, your suspension is designed to opperate best with a bit of throttle. I can only assume the same is true for a big tourer, but I suppose it may not be.
Your advice on lines suggests that you only touch the throttle once well past the apex (the real or practical apex - point of tightest cornering), which usually isn't a good idea.

In Weight Transfer (74) you advise using the throttle in corners yoursef.
"In general, however, you will want some (minor!!!) acceleration in a curve as this tends to increase the slip angle of the rear tire which increases traction, and because you want your rear-end suspension modestly loaded to enhance control."

There are a number of reasons for it, but that doesn't matter. My point is you haven't applied it to your advice on lines/cornering.

Another reason for the partial throttle is to unload the front suspension. There was a rider killed in a crash at Mid Ohio back in the 80s. My friend was at the Code school there that following week. Code asked if anyone knew why the accident occurred. His explanation was that the rider was on the brakes with the suspension compressed, so there was not adequate travel to deal with the bump early in the corner. The front wheel bounced since there was no suspension travel left, the bike washed out, the rider hit a barrier ( I think the bike hit him) and was killed. Code emphasized being off the hard braking when in the corner, to have suspension travel.]]>Contrary Opinions - Rear/front skiddingTaxi Jackhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=4201&REPLY_ID=46947Contrary Opinions Mon, 23 Oct 2006 20:23:50 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=4201 Alright, I've seen you make the point at least (in tip 100) that you were assuming (I assume) that you had the front brake on while you locked the rear.]]>Contrary Opinions - Tip number 195 is wrongWarHawkhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=2721&REPLY_ID=44957Contrary Opinions Fri, 15 Sep 2006 19:37:55 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=2721 I think the MSF guys really need to go into this further at the training..I really didnt understand it, and on those tiny 125cc I was able to manhandle the bike below me like a dirtbike

It wasnt till after I saw the video posted here where the guy pulled the handle and the bike leaned the opposite direction (which goes right along with the push the handlebar in the direction you want to go (well duh if you really pay close attention its almost like pulling the other side). I then tried it on my way home from work...just a teeny mild pull (opposite/counter of the dir I wanted to go) and the bike would lean, a teeny push towards and it would go, so perhaps differentiating the two and make sure the students understand it might be better
]]>Contrary Opinions - red light runners, left turners and blockingMydlyfkryzishttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=3243&REPLY_ID=39871Contrary Opinions Thu, 06 Jul 2006 20:34:05 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=3243 I am confused. What opinion are you contrary to?
I think this is better placed in the general forum.]]>Contrary Opinions - Anonymous Peer Review - is it good or bad?SuzieQhttp://www.msgroup.org/forums/mtt/topic.asp?whichpage=-1&TOPIC_ID=2380&REPLY_ID=32780Contrary Opinions Thu, 23 Feb 2006 21:04:00 -0500http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=2380 lol well I get a laugh out of them, actually..the comments are funny as heck. And definitely explains why they are too cowardly to sign their names on them!
This is what my recent negative review said:
"self righteous fuddy duds unite!"

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