Inertianinja

dudes,

I got my set of Soul S2.0 wheels the other day, and took them out for a few rides.
The front wheel shudders under braking - there is a spot where the brakes seem to get tighter, so as the wheels turn it creates pretty violent vibration.

there is no visible damage to the braking surface.
the wheel is true, and the brake is centered.
the hub is running very smoothly.
i have checked and re-checked brake pad alignment - but it happens just the same on 2 bikes.

if i hold the brake constant and slowly push the bike forward, there's a spot where the brakes seem to catch more than elsewhere on the wheel. it's faint, but i can see that the brakes are hitting that spot harder (more rubber on the track in that spot).

i'm able to isolate the spot where it happens - i ran my fingers over the braking surface but can't detect any deformation.


any ideas on what i can check for this?

side note, i contacted Sean @ Soul, but he's at a trade show until the 20th (frustrating) so zero contact.

banerjek

If your wheel is true and the surfaces seem OK, I'd be inclined to believe your problem is more likely a loose headset than your wheel.

Cdy291

I have not seen Soul wheels to say for sure but it sounds like where the rim is welded together is not very smooth. There should be a seam in the rim most likely opposite the valve stem.

Inertianinja

well, truth be told, on this bike the headset was loose and that was remedied.
shudder still happening on both bikes though.

mmmdonuts

Brake pad toe-in can improve things but not always. Give that a shot if you haven't already.

If you find a rough spot or bump on the braking surface a good quality flat (mill) file can level it out. I find that sandpaper doesn't leave a flat and even surface the way a good file does. If you do use a file take light passes with long strokes in the cutting direction.

Inertianinja

what can be done, then?

banerjek

This is what I'd focus on now. BTW, after you tightened the headset, is there still any play? If there is, that could still be causing problems.

San Rensho 

If wheels are new, take them back. If not, file the rim as stated above and also file/sand the pads. Also, clean rim surface and pads with a good water based solvent.

banerjek

Problems with the rim seam should manifest as a ticking/catching rather than a shudder. OP ordered wheels from Singapore so shipping is nontrivial.

This could easily cause a shudder. Clean this rubber off and adjust your toe in (how much are you using right now?). Also, know that a very small amount of variation is within spec for a new rim.

Inertianinja

Taking them back would be my first impulse; since they're new, but since the manufacturer is in singapore I'd like to see if I can figure this out myself.

By toe-in, you mean that I should angle them slightly so the front of the brake pad is closer to the rim than the rear?

FrankBattle 

I'm interested in this also. My issue is not with Soul wheels though. Useful thread.

Inertianinja

Googling, found this post: https://www.twowheelblogs.com/front-brake-shudder
Lots of good chatter on the subject

FrankBattle 

funny

runningDoc

so there are whole threads about this? like a whole community?

Inertianinja

Well it doesnt give a clear answer, but it does identify some potential causes.

The thing that puzzles me is that the braking surface appears smooth enough - even the weld point isn't clearly rough.

I'm going to investigate the possibility that with new brakes and new wheels, everything's just too grabby and it's causing skipping.

runningDoc

its like you're Leo, and have a confusing problem to solve... only there might be a "twist" in this tale... and the problem may lie in the headset....

banerjek

This is what points to a toe in problem.

Yes. It doesn't take much (maybe the width of a dime or thin piece of cardboard you can use as a spacer). This little tweak will make a big difference. Make sure both sides are even.

BTW, before sending the wheels back if you can't solve it yourself, definitely go to a shop since they'd be able to identify what's going on very quickly.

FrankBattle 

Toe-in. Will try this. Mine wasn't always this way .. twas after a bunch of riding (probably >1500 miles).

rm -rf

Wow, that seems too drastic to me. Even wet-and-dry 400 grit fine sandpaper can wear down a depression in aluminum rims if I'm not careful. Maybe some 400 grit with a wood backing block, then take only a few light strokes at a time and test it again.

-----

If there's rubber marks on the rim, that could cause it to grab there. Try cleaning with a scouring pad, and wiping the whole braking surface with rubbing alcohol. Use a file on the brake pads to level and clean them up.

meanwhile

Yes - this shuddering problem is a common one on cyclocross bikes. Most of the causes for a crosser can be eliminated - a loose headset is the only left.

Inertianinja

I used a penny to toe-in the pads, turned the wheel around, checked the headset, cleaned the brake tracks, and realigned everything.

mmmdonuts

A penny seems like a lot but if it improves things you are on the right track. I adjust the toe-in using cardboard from a cereal box. New rims with grooved machined surfaces tend to be grabby. My Fulcrum Racing 5s have some shudder but my old smooth rims don't with the same brakes.

sd790

This. Just corrected the same problem by adjusting my headset this evening.

Inertianinja

No play as of now. Going to test it out tomorrow morning

max power

my rear soul wheels do the same thing