Wheel judder

pesky_jones

Recently replaced my front wheel, the previous wheel had play in the hub - If you grabbed the wheel you could have like 4-5mm of movement, and was just old and fancied a new one.

Anyway there was always a judder when coming to halt with the old wheel, but I thought with this new wheel the juddering would go as there is no play. When I first fitted the wheel the juddering did go, but is slowly coming back. It's quite a significant judder, you can physically see the fork lowers vibrating back and forth. There is no apparent play in hub, or headset or forks.



I have heard the size of holes in the rotor can have an affect, but surely not to this extent...

Thewaylander

Is there any play in the fork or headset? also check your disk/brakes are tightened up correctly. I had this spend ages looking then realised the bloody disc bolts had come loose felt like a plonker.

pesky_jones

I don't think there is any play in the headset or fork. If there were play in the headset/fork, it would be apparent by raising the front end of the bike off the ground, and "wiggling" the fork around, wouldn't it? The fork turns smoothly in the headset and there is no vertical play.

The bolts in the rotor aren't loose either.

No Sweat

IF the judder really went away after fitting the new wheel, then it suggests that something installed at that time has since come loose.

As the waylander says, check the disc bolts, brake caliper bolts, and the bolt-through wheel clamp (or whatever it is) too, and also the new wheel bearings - you never know! I'd also look to see if there is contamination on the disc or the pads... try a good specialist degreaser spray like the Hope one.

Good luck! I once spent a frustrating 10 miles trying to work out why my rear wheel/rear mech SOUNDED like it was rattling loose, only to eventually find it was one of the bottle-cage bolts rattling......

cooldad

Couldn't you squeeze a bigger tyre in there?
Could be fork bushings worn.

iasgair

I don't know if it would make a difference but is that brake disc on the right way round?

Chunkers1980

Yes it is. Bars push into the caliper.

pesky_jones

No Sweat wrote:

IF the judder really went away after fitting the new wheel, then it suggests that something installed at that time has since come loose

My thoughts aswell.

Im pretty sure (will double check) that all the associated bolts are tight. This makes me think it’s the fork bushings. TF time?

cooldad wrote:

Couldn't you squeeze a bigger tyre in there?

Almost definitely, but I don't feel the need

pesky_jones

Forgot to say thanks. Thanks.

No Sweat

Pesky Jones wrote:

If there were play in the headset/fork, it would be apparent by raising the front end of the bike off the ground, and "wiggling" the fork around, wouldn't it? The fork turns smoothly in the headset and there is no vertical play.

Forks provide a lot of leverage to the headset. I have found sometimes that although there is no 'apparent' play when you wiggle the forks around, if you put the bike upright on the ground, apply the front brake and 'rock' the bike forward and back you can sometimes feel a movement in the headset. Try putting you spare hand's fingers across the lower headset bearing whilst rocking the bike (there is usually bushing play - some is normal - in the forks which will mask the headset play). If there is headset play, tighten a quarter turn (after loosening the stem bolts) until it stops......

The Rookie

Juddering is much more common with 'saw tooth' rotors.....

pesky_jones

No sweat - I have done this and it appears that it does indeed have a small amount of play, and I mean small. Almost undetectable. Do you mean tighten it from star nut? I will do this. Thanks for your help – some of the most accurate, coherent and helpful information I’ve had off this forum.

The beginner - are my rotors "saw tooth" then?

The Rookie

Yes.... each 'peak' has a near vertical element as it's leading edege, this will give a pulse to the braking forces as it pushes it's way between the pads.

Loosen the stem bolts, tighten the top cap bolt (that screws into the star nut) then retighten the stem bolts.

You have to loosen the stem bolts first or the stem won't move to increase the preload on the bearing.

No Sweat

I hope it helps!

bluechair84

I can't view the picture at work but I've previously had, and resolved this problem. I wonder if you have the same issue as me; I run wavey rotors which do not wear the tops of the pads as fast as the middles. The thicker top 'pulses' into the wavey rotor creating a terrible juddering sensation when the middle and bottom of the pads are well worn. I don't know if this also happens with saw tooth rotors, but you could take your pads out and make sure they aren't worn into a wedge shape - thicker at the top.

pesky_jones

bluechair84 wrote:

I can't view the picture at work but I've previously had, and resolved this problem. I wonder if you have the same issue as me; I run wavey rotors which do not wear the tops of the pads as fast as the middles. The thicker top 'pulses' into the wavey rotor creating a terrible juddering sensation when the middle and bottom of the pads are well worn. I don't know if this also happens with saw tooth rotors, but you could take your pads out and make sure they aren't worn into a wedge shape - thicker at the top.

I followed No Sweats advice (tightening star nut) and it worked - removing the small amount of play, but there was still a small, small judder. I settled for this reduced judder as I put it down to the "saw tooth" and large holes in the rotor.

Reading your advice however, it sounds likely that I may be able now to completely remove the judder as I believe my pads are probally in a condition similar to the condition you described as I havn't changed the pads in the front brake for about 6 months - havn't needed to.

Thanks a lot!

YeehaaMcgee

New bearings would have been cheaper than a new wheel, and that's not a new wheel. I don't think they've made those rims in, oooh, about 10 years? something like that.
Headset and fork bushes may cause judder, and that kind of brake disc will just make things worse. Stick to normal discs.

pesky_jones

Pfft