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 Help! My Brakes Don't Hold My Bike.
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albert_tatlock
Male Junior Member
95 Posts


San Patong, Chiang Mai
Thailand

Honda

CBR250R ABS

Posted - 04/07/2016 :  5:39 AM                       Like
I am not a heavy guy, about 60KG, my bike weighs in at a little less than 200KG.

The problem I have found on some of the less well paved roads we have out here in Northern Thailand is that they can be very steep on approaching junctions, with adverse cambers, grit, potholes and such.

I hit a T- Junction the other day that must have been on a one in 5 gradient, the top of the junction for about 5 metres was entirely made up of loose gravel about 2 inches deep.

Normally I cover my rear brake on approach, drop into first gear ready to pull away, stop with my front brake and then hold with my rear - like a handbrake on a car.

Sadly, none of this worked, the brakes held OK but the bike just started to slide backwards in the gravel, if there had been a car behind me I would have slid into it, not sure what the correct procedure for this situation would be?

Any suggestions, it was a bit unnerving to say the least.

Cheers!

rkfire
Advanced Member
1695 Posts


Stratford, CT
USA

Suzuki

Bandit

Posted - 04/07/2016 :  10:22 AM   Join poster on Facebook as Friend  
I assume you were on the cbr250? Your profile photo shows a dual purpose bike.

If you have both types of bikes, a ride onto that type of roads would be better done on the dual purpose bike. Steep hills, deep gravel, and traffic is not a great place for a sport bike. The tires, ground clearance, low handlebars, steep fork rake, small diameter front wheel of the cbr is just not suited for that.

On the other hand, on a dual purpose bike with road legal, but knobby tires would be fun.

It just seems to me, that a steep grade before a junction, would have little gravel remaining on it, since traffic and gravity would tend to slide the gravel down the hill. But if you did have 2 inches of gravel, and were on a dual purpose bike with knobby tires, holding the rear brake should "dam" up some of the gravel within a small distance. Is it possible that maintenance crews had just spread gravel there? If that was the case, awareness of the situation might make you think twice about that route. Or possibly wait for traffic to clear the hill of gravel.

On the other hand, well worn (sharp edges removed) gravel in a thin layer on a hard surface whether pavement or hard ground, can act more like a ball bearing than traction.
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gymnast
Moderator
4267 Posts
[Mentor]


Meridian, Idaho
USA

Harley-Davidson

Sportster Sport

Posted - 04/07/2016 :  10:55 AM
1 in 5 gradient? Choose another route.
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scottrnelson
Advanced Member
6890 Posts
[Mentor]


Pleasanton, CA
USA

KTM

990 Adv, XR650L

Posted - 04/07/2016 :  12:13 PM
On loose surfaces, once it gets steep enough, your brakes aren't going to hold the bike in a stopped position regardless of how good your brakes and tires are. This is something that I learned the hard way many years ago.

My rule now, off road, is that once forward progress has ceased and the bike rolls back six inches or more, you may as well lay it down until you can get control of things. Otherwise, you'll just pick up speed backwards before it throws you off, and the damage will be worse. And it's better lay it down on the left side than on the right, because sliding back a bit more won't roll the throttle wide open and you can still get to the rear brake. [All useless information for those of you who never leave the paved roads - sorry.]

The only solution that I know of on steep hills is to either get to where it is more flat before stopping, or turn the bike sideways across the hill. Nothing else has worked for me.


On a side note, I was just riding some steep, narrow, rough trails yesterday. I had to specifically look for places to stop, because it would have been very difficult to get going again on some sections.
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scottrnelson
Advanced Member
6890 Posts
[Mentor]


Pleasanton, CA
USA

KTM

990 Adv, XR650L

Posted - 04/08/2016 :  7:42 AM
For the curious, this is the sort of road where you'll roll backwards down it if you stop. I was riding with a friend who was on a KLR650 and he got bucked off on this section. We had to pick the bike back up from an awkward position and head back down. My XR650L is in the background, parked against a tree stump so that it won't roll down the hill further. Parking it in gear wasn't enough to hold it in place on its sidestand here. This is a 25% to 40% grade.

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bachman1961
Male Advanced Member
2266 Posts
[Mentor]


colorado springs, co
USA

Honda

CB750 NightHawk

Posted - 04/15/2016 :  12:27 AM
I think I'm picturing the situation and I wonder if there may be times when it's advisable to try putting some power at the rear wheel as if riding the clutch but doing so to see if the rear tire will dig down some and actually get purchase.

It might not always work yet be worth a try. Spitting that loose stuff out might see the tire finding it's way to a more stable surface. At that point, the brake may hold.
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rkfire
Advanced Member
1695 Posts


Stratford, CT
USA

Suzuki

Bandit

Posted - 04/15/2016 :  7:15 AM   Join poster on Facebook as Friend  
The originator of this thread never came back to comment or clarify.

I suspect, the one in five grade may be a bit of an exaggeration. I still can't see gravel spread on a grade like that staying there.

No doubt they must have some steep mountainous roads, but they are presumably used by all kinds of vehicles.

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