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how can i straighten out my rotor

2K views 16 replies 8 participants last post by  nauc 
#1 ·
its off just enough to rub a little on my brake pads each time it goes around. you can hardly hear it, but when i brake, it pulsates and feels rough. the rotor looks and feels fine tho

i already tried the zip tie (as a guide), adjustable wrench (to bend it back) trick, which helped a little, but i think thats about as close as i can get it

im trying not to spend any $, but if i must, i must

any other tricks, thoughts, etc. i dont have many tools lying around, not even a vise, but a buddy has some stuff

thanks

ps, the brakes are 6" Juicy 3s
 
#2 ·
Hang in a stand and use a white rag or old t-shirt as a backdrop on the floor. Look at the brake down onto the rag and you'll be able to more accurately see where the rotor needs most work. Park does make a tool for this but as mentioned you can use a crescent wrench to make your adjustments.

Sometimes the issue could be fixed by adjusting the caliper as it may have moved after a crash.
 
#9 ·
the whole Adjustable wrench thing works only about 50% of the time as the issue with the rotor is usually closer to the hub plate not out at the pads contact face. Quite often I've seen guys rotors that are "dished" or have "s" bends in the arms as they use the Adj wrench and it wont reach in far enough. They get it lined up but the area becomes weakened and it just warps again in no time. The Park tool works great! worth the 8 bucks. a straight metal ruler helps to find the exact spot the rotor is warped.
 
#14 ·
I'm not sure if you are serious or not so I'll bite . . . bike rotors can't be turned. They are only 2mm thick to start with!

I've finally come to perfect (in my opinion) truing a rotor. It takes TONS of patience and a really good ear. I do use a piece of white paper but only so I can tell which pad the rotor is rubbing against. I do not use the paper to sight where the rotor is bent. I figure out where based on listening as it passes through the caliper.

I also use gloves and my fingers. A rotor bend creates 3 points of misalignment. 1) the starting point. 2) the midpoint of the arc, and 3) the stopping point. When I have found an out-of-true spot, I put my middle finger on the midpoint of the arc and my 1st and 3rd fingers on the end points. Thumb as close to the center of the rotors as possible and pull (or push) SLIGHTLY. It takes VERY little force to bend the rotor.

Rinse and repeat until true. If you are doing it correctly, you will notice the arc of your bend getting smaller each time until its gone. It usually takes me anywhere from 2 to 10 minutes to true a rotor this way.

Note: I NEVER use tools/wrenches of any kind as they can damage the brake track and apply to much force.
 
#15 ·
so i got it more straight, its not rubbing, but you can hear that its not perfectly straight when you start to squeeze the lever. it goes *****, *****, *****, as the wheel goes around.

i may play with it some more just to see how good i can get it.

thanks for all the replays
 
#16 ·
Rarely ever will you get a rotor perfectly true. Before you go messing with it again, try giving it a REAL good run down a looooong hill if you can. In other words, try to get it good and hot and see if that helps. Sometimes it does (for example with my Hope 2-piece rotors, getting em good and hot can straighten out slight variations.)
 
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