DRLski

Ok, so I have a pair of Easton EA70X rims that have tubular Challenge Fango tires glued on them. When I took the rear wheel off the bike last year I had no braking issues to speak of, road them almost the entire season. I just put the rear wheel back on for a race tomorrow, replacing my clinchers, and noticed the brakes grabbing in certain spots. I clean the surface of the rim, brake pads have not changed but have plenty of life in them. After rubbing my finger over the rim, one side of the rim had a few ever so slightly raised spots, I hardly noticed them. Unsure if this would cause the issue or why my braking was not effected last year when I took the wheels off. They look pretty true when I spin them although have not checked them on a truing stand yet.

Any advice? Pretty bummed that I'll have to race with my clinchers tomorrow, guess I should have checked them sooner but figured they'd be fine since I put them away good.

DRLski

Also, FWIW, I've checked the brake pad alignment and toe in with no change

Andrew R Stewart 

Rim blips/dents will most certainly effect the brakes' crabbiness. The brakes act as a measuring caliper of sorts with a tactile feedback as the read out. As the dent passes by the pads it, being slightly wider the the rest of the rim that the pads have been brushing against, hangs up between the pads. Then as the dent goes past the pads the feel is as was before. So there's a rhythmic pulsing. One dent will be one pulse per wheel revolution. More dents will be more pulses per revolution.

A build up of stuff on the rim's braking track can do the same. Like sew up glue. Andy.

DRLski

So this all makes sense to me, what doesn't make sense is why before putting these in storage they were fine and now several months after when putting them back on my bike I'm getting this feedback. Why would I feel the feedback now and not before?

fietsbob

double ferruled,m double wall rims when the spokes are tensioned, tend to do that ,
My Mod 3 Mavic clinchers have that slight high spot at each spoke hole ..

Obsess or ride them . its a choice [i obviously cannot personally see the amount .
it may just be a hundredth of a MM .


You might like those deep section carbon things better


I've been fine with my wheels as I spoke of , for 0ver 25 years (they have a 6 speed freewheel on them **

maybe use them when the course is really muddy and braking is not the same feel, as when the course is Dry.

Andrew R Stewart 

Maybe you weren't as tuned into the feel back then? Maybe the wheels that you have used since are in better shape? Maybe your feel/standards raised? Andy.

FBinNY 

Step one, spin the wheel with your fingers as calipers to confirm that there, in fact, blips. Then it's a question of figuring out how and when they got there. If the blips are at the outer edge than they are probably the result of road hazards. Tubulars are nice in that they can absorb an impact big enough to blip a thin walled rim, that's good news when it happens because you don't have to walk home, but you still have a blip. OTOH, if the blip isn't of the type caused by road hazards, then you need to figure out how they got there.

Now, it's entirely possible that you don't actually have meaningful blips, so it's simply an issue of sticky/slippery zones on the rim. That happens all the time, and like many things on a bike can happen slowly and be subtle enough that you accept and factor it without noticing. Then you switch wheels, and all is good, but when you switch back all the flaws stick out like sore thumbs.

BTW- blips in the brake tracks of tubular rims are easily squeezed back with pliers, and some supporting material for control.