wheel flex?
 

my wheel seems to flex and rub the brake when pushing a big gear, for example when doing like 40 km/hr which is like 25 mi/hr and when i downshift so going from a cadence of say 90ish to 80 it seems like its rubbing all the time and not smooth and very annoying. is this because the rim is weak? i'm like 185 pounds and ride mavic kyrsium rims. thanks for the help

no help here? come on counting on u smart bike forum people.

I was wondering too. Granted I have crappier rims than that, and my current solution is to just open up the brakes a little more, but I was wondering if giving every spoke 1/4turn would tighten everything up. I haven't done it yet - I'm worried a stress test afterward would knock the whole thing out of true, putting a real project on my hands.

Yeah sometimes the brake surface of the rim might rub onto the brakes itself because the brakes might be too close to one side of the brake surface.

You might have to center the whole brake caliper itself if that's the case. Does it only rub when you tilt the bike in one direction?

If you hear/feel some rub in both directions, try to loosen the tension of the calipers again, check if they're centered, and then try it out again.

I'mnto sure but don't those irms use a special spoke wrench?

I was once riding up a mtn climb with some dude that was telling me that I should invest in a better wheelset. My Deep V/Ultegras aren't good enough I guess. Just as he was rec'ing the wheels, the front hub nearly fell apart. He was able to screw it back together with his hands for the remainder of the ride I've read that this has been a problem with some Ksyrium wheels. Maybe verify the hub isn't loose in any way.

What disturbs me about it is you apply less torque to the wheel itself as you go faster and shift to higher gears. If the wheel was actually flexing under force you'd notice it hammering up steep climbs in low gears.

Are you sure it isn't the chain rubbing against the front derailleur cage instead?

I guess I should have asked (not mentioned) front or rear?

its the rear. and no its not rubbing on the front derailleur cage i checked that before i figured it must be the back brake. basically if i'm going decently quick and cadence is less than 85 it makes a gross rub. and it does it when i sprint too. i think. but i can't really tell when i'm sprinting cause my heart is too loud. aha.

Is it possible to rotate the caliper to give more clearance?

FYI, when my rear starting doing this it was because it wasn't true. Might want to get your wheels trued.