Brake Judder
junglist_matty
Posts: 1,731
I have a Genesis Vapour (2009 model) off the shelf, no modifications.
I was lucky when encountering my first experience of brake judder... I was cycling to work when a stupid lorry driver drove straight out of a side road about 20m in front of me whilst I was doing about 20-25mph; instinctively I hit the brakes hard when I got the shock of my life with the front wheel bouncing all over the shop and was completely out of control. Fate must have been at hand because I somehow managed to stay upright on the bike and just about bring it back under control and slow enough to just get round the back of the lorry as it exited the side road.
Now my point here is that how in gods name is brake judder even an issue for an off the shelf bike? Surely they go through rigorous testing and to have such a dangerous element is beyond me. You wouldn't expect to buy a car and when you apply the front brake hard at +50mph the front wheels to disengage from the steering rack and wobble any which way they fancied would you!? So why on earth should this be the case for a bike!?
I'm astonished at this, simply cannot believe it. Especially considering that these types of bikes are at most times ridden on roads and at fair speeds on the roads.
I stopped using the bike instantly, looked into the issue and purchased myself a Tektro mini V front brake which eliminated the brake judder. Why I should have to do that to fix an off the shelf product is beyond me; had I fallen off the bike and injured myself thanks to brake judder, Genesis would have a letter of a compensation request (or threatening court action) in the post without a second thought.
My point is, I was never once warned of this brake judder when I bought the bike, there is no reference to it in the bike paperwork and only found out when I least expected it.
How can I start some sort of petition to ensure brake judder is never ever present on any off the shelf bike; I've noticed their latest version of the Vapour bike now has a statement on their page
"The Vapour 2011 uses Tektro wide-leg style cantilever brakes for added clearance and power, plus a front fork-mount brake hanger for judder-free braking."
WOW... Well done, you fixed a problem that should never have even been a problem on any of your bikes!
I was lucky when encountering my first experience of brake judder... I was cycling to work when a stupid lorry driver drove straight out of a side road about 20m in front of me whilst I was doing about 20-25mph; instinctively I hit the brakes hard when I got the shock of my life with the front wheel bouncing all over the shop and was completely out of control. Fate must have been at hand because I somehow managed to stay upright on the bike and just about bring it back under control and slow enough to just get round the back of the lorry as it exited the side road.
Now my point here is that how in gods name is brake judder even an issue for an off the shelf bike? Surely they go through rigorous testing and to have such a dangerous element is beyond me. You wouldn't expect to buy a car and when you apply the front brake hard at +50mph the front wheels to disengage from the steering rack and wobble any which way they fancied would you!? So why on earth should this be the case for a bike!?
I'm astonished at this, simply cannot believe it. Especially considering that these types of bikes are at most times ridden on roads and at fair speeds on the roads.
I stopped using the bike instantly, looked into the issue and purchased myself a Tektro mini V front brake which eliminated the brake judder. Why I should have to do that to fix an off the shelf product is beyond me; had I fallen off the bike and injured myself thanks to brake judder, Genesis would have a letter of a compensation request (or threatening court action) in the post without a second thought.
My point is, I was never once warned of this brake judder when I bought the bike, there is no reference to it in the bike paperwork and only found out when I least expected it.
How can I start some sort of petition to ensure brake judder is never ever present on any off the shelf bike; I've noticed their latest version of the Vapour bike now has a statement on their page
"The Vapour 2011 uses Tektro wide-leg style cantilever brakes for added clearance and power, plus a front fork-mount brake hanger for judder-free braking."
WOW... Well done, you fixed a problem that should never have even been a problem on any of your bikes!
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Comments
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Hmm yeah, mine was pretty much the same. Particularly with just-damp rims.
Modded mine along the lines of the 2010/11 model and it's been fine ever since.0 -
Welcome to the world of cross bikes and mini cantis.0
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That's why I didn't buy one. Test rode one and as soon as I looked at the brakes they juddered. The problem is with carbon forks and canti brakes. Bought a Kona Jake instead as it has steel forks. I believe the judder is caused by the forks fkexing under braking causing an increase in tension of the brake cable giving a self servoing effect. Unfortunately the amount of flex varies, causing the brake pressure to vary. Hence the juddering.0
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Can also be caused by canti brake blocks that are too thick, too soft and mounted with insufficient toe-in angle. Under heavy braking, the block gets "dragged under" by the moving rim.
Note that v-brake blocks are thinner, which avoids this issue.0 -
snailracer wrote:Can also be caused by canti brake blocks that are too thick, too soft and mounted with insufficient toe-in angle. Under heavy braking, the block gets "dragged under" by the moving rim.
Note that v-brake blocks are thinner, which avoids this issue.
Well the 2009 Vapour was supplier with Shimano cantis which used v-brake blocks, so it wasn't this.
I think Veronese is closer to the mark.0 -
Judder with canti's can be down to a number of root cause, any or all of which can cause or add to it, but yes its flexing that is the main issue, flex in the fork blades, in the steerer, in the headtube/frame, in the headset and in the cable stop.
The crown mounted cable stops (as opposed to above top of headset stops) eliminate a huge chunk of the flex.
SimonCurrently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
I find that I need regular aggressive toeing on my Tricross to keep this under control.0
