Developed rear brake shudder?

[MacLean]

Hi all, my bike is only a few months old, other day I had the rear wheel off and since putting everything back together the rear brakes now has a horrible shudder when under mid to heavy braking.

Sounds like a bus and I sense the brakes vibrating, also not as effective at slowing me down because of the shudder.

Now appart from unhooking and rehooking the rear brake quick release thing I havent touched a thing with the brake so dont understand how I've caused it?

The bike is a 2010 specilized tricross btw. Uses a center pull cantilever brake on the rear.

Thanks!

 

[twentysix by twentyfive]

Puzzler when you haven't done anything to the brakes I know.

But - any oil/grease got on the rims when you had the wheel out?

Or - have the pivots loosened somehow?

Or - did the brake blocks get moved taking wheel in and out? Are they set correctly still?

Or - is there any grot/slivers of stuff got stuck in the brake pads?

 

[PpPete]

Things I'd look at first ... are the pads "toed-in" ? A toe-out pad could judder, because the "nose" of the pad hits the rim first.

Another possibility - did you service the hub when you had the wheel out?
Loose bearing hub insufficiently tightened could be another cause.

 

[MacLean]

Okay thank you, given me some stuff to look for when i get home!

Never done any adjusting of brakes etc but going by your post, I should first check for oil dirt etc on the rim and blocks...

If no dirt or oil then fiddle with brakes till they work... lol

 

[MacLean]

Things I'd look at first ... are the pads "toed-in" ? A toe-out pad could judder, because the "nose" of the pad hits the rim first.

Another possibility - did you service the hub when you had the wheel out?
Loose bearing hub insufficiently tightened could be another cause.

Okay im really not up to speed with the names of everything, but I quick released out the brakes and wheel cleaned then lubed the cogs then put wheel back. Pretty confident I done up the quick release more than tight enough, followed by hooking up brakes again...

Not sure what the bearing hub is but if it is basically the quick release lever for the wheel then yes im pretty sure I done it tightly.

I will check for toe ing in, basically have the bit of pad closest to the front of the bike touching a bit before the rear yeh?

 

[Globalti]

Yes, it can be quite difficult to achieve with certain designs of brake because the pad moves out of position as you tighten the bolt holding it.

I do it by folding the flap off a cereal packet in two then wedging it under the rear of the pad, holding the pads tightly against the rim and gently tightening the holding bolt while trying to prevent the pad from moving out of position. You can then finish tightening the bolt while countering any movement of the pad with your fingers. If you've done it right, braking will pull the pads into a parallel position against the rim and they won't squeal.

....or sell the bike and get one with disc brakes!