Philadelphia Mountain Biking Association - Forums

I am new to disc brakes and i have bent my rear rotor somehow.  Not bad, but enough that you can see a wobble when you spin the tire and the brake squeaks now when I apply force.  How do I fix it or do I have to replace it?

This is my idea to avoid $$$ - Try an adjustable wrech or a chainring tool. Both have a narrow enough grove to grasp the rotor. Be careful, take your time and use a rag to cover the tool you're using. You don't want to scratch the rotor. Determine where it is bent. Apply a small amount of torque evenly spaced against the rotor and you should be good - good luck

$15 is well spent for a new one! (buy two while you are at it! www.Greenfish.com

I was reading a mag once where they had a tool that was used to straighten them. It was expensive though. I forget who makes it but if you do a search you'll probably find it.

We have a rotor bending tool at Bucks County Bicycle Company. Stop by and we can help you out.

Thanks for the advice.  I just bought a new one.  It wasn't that expensive.  I will hold on to the old one and see if i can bend it back in to shape.

I have a Park's rotor adjustment tool if you ever need to stop by. I live near the "Bowl" and can put it in my CamelBack. The tool isn't that expensive, but you can get a new rotor for $20

PS. Since I went to 4'' rotors in the rear of my rigs, I have not needed to tru them at all. Not only lighter, but less area to get wacked by something.

Less likely to stop you too if you're on the clydesdale range of rider weight.

There are rotor specific tools out there - park and morningstar come to mind.  A well equipped shop will also have a rotor truing gauge - a spring loaded micrometer that indicates the level of deviation.  Nice to have - we love ours, but not critical for the diy guys.

As Riggs mentioned, a monkey wrench is adequate - don't need to pad the jaws though.  You must not have any grease, lube, nasty crap come into contact with the rotors - either from your greasy mitts or your tool.  Find where the rotor comes closest to making contact with the pad, judiciously apply pressure in other direction with wrench, rotor tool, etc, repeat as necessary.  Unless you put a funky "s" bend or sharp crease/chunk in the rotor, it doesn't need replacing. 

Regarding new rotors - new doesn't necessarily mean true - always double check it. 


Karl