Brake rotor questions

stephenjpauls

stephenjpauls

New Member
All,

I just bought a used track bike, and while I was playing with it I noticed that the right front rotor is slightly warped (1/16 to 1/8 in).

First Question: Do I need to replace that before I get on the track? I don't think it would be found in Tech... the only way to notice it is to lift the front off the ground and spin the wheel and notice that there is a bit more drag in one spot of the rotation. Despite that I don't want to ride anything that could put myself or others in danger. I plan to replace it soon when my finances are a bit better, but would like to wait a few months (2 – 3 track days) before I do.

Second Question: It seems odd that you could, but is there anyway to fix a warped rotor? I just saw someone on e-bay selling one saying it could be fixed so I figured I should ask... If you can, how?

Last Question: If I do need to replace it now, anyone selling a front right rotor for a 2001 GSX-R 600 Cheep? Also is there a good, but not too expensive upgrade in rotors? I planned to upgrade the brakes over the winter and would like to know the best “bang for the buck” upgrade for my bike.

Thanks so much,
Steve
2001 GSX-R 600 #66 'B' Group Mid-West (Track)
2002 Triumph Daytona 955i (Street)
 
Steve

Steve

New Member
It's my understanding that if the rotor is even slightly warped you will feel a vibration from the brakes and it could affect braking performance. The sevice limit for my honda is .012", so it would be very difficult to get it that straight with a 2x4. I say either replace it or send it somewhere to be straightened.

Steve
 
JRSMAIL

JRSMAIL

New Member
I have had good success getting the rotor very straight using the 2x4 as a lever.

Work slow, and keep checking till straight.
 
Quantum_Ape

Quantum_Ape

New Member
Never bent a rotor back myself. My understanding of fixing rotors has always been to re-surface them, thus taking out any small imperfections in the rotor. If it's bent so much that you cant resurface it and keep it at a safe thickness (within servicing spec) then i always replaced the rotor. My theory is breaking performance is a big part of being on the track. I want my rotors to be in top shape and have no vibration or pulsing.

Also note, if your rotor is warped from heat buildup from breaking which is the main cause of warping, then you will have varying hardness/density in the rotor. This means that if you do fix it, there is a good chance it will warp again in the near future.

Just my 2 cents.
 
stephenjpauls

stephenjpauls

New Member
All,

I wanted to thank you for your help... It worked perfectly, and only took 15 min to do. I'm going to mention the steps I took (will probably only work if the rotor is bent in and not out).

1.Put the bike on a front stand
2.Loosen the two bolts holding in the caliper.
3.Rotate the tire... watch as the bolts move in and out to find the area of the rotor that is the most off
4.Tighten the caliper bolts so they just touch the fork when the rotor is most off
5.Mark the rotor in the worst place. (I tied a bit of safety wire on the inside of the rotor)
6.Play with the wheel for a few min and make sure that your mark is right in the middle of the high spot.
7.Take a short 2X4 (mine was about 1.5 ft) and use it as a lever between the rotor and wheel.
8.Push gently
9.Rotate the wheel, see if you fixed it at all (are the bolts still tight or are they a bit looser?) If they aren't looser at all, you need to push harder. I had to pry 4 times before I put enough pressure to even move it.
10.Now that you know how much pressure to use, apply that much, rotate the wheel, tighten the caliper bolts so they just touch the front forks.
11.Continue until caliper does not move at all on the loose bolts.
12.Tighten the caliper bolts down to the proper torque.
13.Spin wheel, should no longer have spots that slow the tire from rotating.

Note, when I pried, I did so at the high spot and used half the pressure on the spot just before and just after that.
 
BLARNEY

BLARNEY

Member
Glad to hear it worked.

I have a new set of EBC Wave rotors that will fit your bike FS in the parts forum if you are interested.

Tom
 
JRSMAIL

JRSMAIL

New Member
stephenjpauls;3988 wrote: All,

I wanted to thank you for your help... It worked perfectly, and only took 15 min to do. I'm going to mention the steps I took (will probably only work if the rotor is bent in and not out).

1.Put the bike on a front stand
2.Loosen the two bolts holding in the caliper.
3.Rotate the tire... watch as the bolts move in and out to find the area of the rotor that is the most off
4.Tighten the caliper bolts so they just touch the fork when the rotor is most off
5.Mark the rotor in the worst place. (I tied a bit of safety wire on the inside of the rotor)
6.Play with the wheel for a few min and make sure that your mark is right in the middle of the high spot.
7.Take a short 2X4 (mine was about 1.5 ft) and use it as a lever between the rotor and wheel.
8.Push gently
9.Rotate the wheel, see if you fixed it at all (are the bolts still tight or are they a bit looser?) If they aren't looser at all, you need to push harder. I had to pry 4 times before I put enough pressure to even move it.
10.Now that you know how much pressure to use, apply that much, rotate the wheel, tighten the caliper bolts so they just touch the front forks.
11.Continue until caliper does not move at all on the loose bolts.
12.Tighten the caliper bolts down to the proper torque.
13.Spin wheel, should no longer have spots that slow the tire from rotating.

Note, when I pried, I did so at the high spot and used half the pressure on the spot just before and just after that.
Click to expand...
Glad it worked for you. :adore:

It is mainly the carriers (alu) that get bent from hitting a wheel chuck or something, not so much the braking surface.

Add a note to the above is to put the steering head against the steering stop and then leverage the rotorcarrier.

Also note I don't loosen the calipers at all, (radial mount brakes) just turn the wheel on the bike stand. I use a dial indicator if I'm at home to use.
 
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