just had a new tyre fitted on the weekend. I rode the bike yesterday to work and noticed a slight shudder when coming to a stop on the rear brake.  I use both front and rear.  it only comes in at maybe 20kph, and is slight but I can feel it throught the frame and the pedal.

I got home last night and bled the rear brakes just in case I got air in them when removing the caliper when doing the tyre.  I haven't had this before so I am sort of at a loss. 

 

No loss in brakes or stopping poweer just this slight vibration through the bike.  if I put the brakes on hard no vibration.

Could it be the tyre?  only done 36Km since fitted,  Brakes pads are fine.  One thing, I didn't remove the pads when I took the tyre off.  Just moved the caliper out of the way to get the wheel off.

I believe I have aligned the wheel as close to equal distance using a straight edge with marker. ( The wire with a strap tie on it to measure from pivot bolt to rear axle). 

 

Wheel spins freely when off the ground, brakes are not binding.   brakes seem to work fine no grinding or pulsating of the pedal so I doubt it is a a warped disc. 

 

Any ideas appreciated. 

Sounds like a warped disc ?? anyone you know have a dial indicator you can use ?
You should be able to feel it by spinning the wheel with light pressure on the brake.
Did you clean the disc to get rid of any oil/grease ?
The four spot Calipers can have sticking pistons as well.

I will have another look tonight. Got a Dial indicator at work.

Could be that that brake pads may not be seated in the metal clips. On the rear brake pads there is a metal clip on each brake pad which is located at the base of the pad, the squared off end.

Sometimes the pads are not pushed back into these clips correctly. May or may not be the problem but check it out. Also if this is the case eventually the pad can come out and lock the rear wheel.

Or a warped disk rotor

Well I took off the wheel again, removed the pads, checked everything out all seems ok, I have put it down to the tyre I have put on the bike. Checked the disc, bearings etc. I have run it for 2 days now and the shudder is getting less and less. The reasoning behind the tyre is that I didn't have it on Friday but changed the tyre and Monday when I rode it I got this slight shudder through the bike when coming to a stop at about 20kph, hard to explain. I thought it might be the pads chattering in the caliper, but you don't get it if braking harder than normal, ei: more back than front. I am off to Edenhope this weekend so that will settle the tyre down I hope, especially with 2 up. I thought about balancing as well, but I don't get anything else through the bike driving at normal speed and even at 140kph, smooth as. So I am at a bit of a loss.

On another note have you run the bike with the O2mods yet? I have ordered the bungs from the US and will be doing the same as you in a few weeks. Just got to practice my Tig Welding of Stainless Steel. I was taking to a bloke at work about the positioning of the sensors in the pipes and he had a look and couldn't believe they would sit them out so far from the stream. So mate you might be onto something there with this mod. When I get the bungs I will drop you a few questions regarding length etc that you ground them down to.

Hey AJ do you know wether or not they balanced the rear wheel when they put the tyre on, alot dont bother as it is not as critical as the front. Could be worth a shot if you dont find anything obvious

Grim that is one of the things I thought as well, Now when I was in the shop I was watching the young bloke start on my wheel. Right next to him just standing there and he was having some issues getting the bead of the rim onto the tyre machine to take the tyre off. No problems as he wasn't doing any damage to the wheel, just the bead slipping off the lever. Anyway the head comes up to me and asks me to please move over past the entrance to the shop. I though OK Fair enough OH&S etc, however as I was leaving I said to the young bloke "Don't Scratch it".... Poor bastard probably was having issues and feeling a bit under pressure with me standing over him watching his every move. In answer to your question I don't know actually, I had a look at the weights on the rear wheel and they are different I know that for sure. Had 3 before now only one. So you could assume that they balanced the wheel, but how well that is another point.

Also they use the weight method on a rod, not dynamically balanced like a car.

Cant argue with gravity Mate--the heaviest part of the wheel/tyre will gravitate to the bottom as the wheel slowly rotates itself, so the top is the lightest. If you mark the top and rotate it 90 degrees and start putting weights on that point till the wheel/tyre dosen't rotate she should be well balanced--cheers Grim

Hi all...AJ,Does the bike have ABS ????

Nah no abs 07 heritage. And the shudder has gone. Went to the Pub run for the weekend and all good, I put it down to the tyre.

try de glazing the disc clean with light  dry sand paper  F/R,  i do it to all my bike's