Front rotors....again
#1
Front rotors....again
I spent most of the morning doing a search about front rotor/brake issues. Lots of info, but I still need to ask a question.
I noticed recently the Hawk exhibiting the classic "front end pulsation must be warped rotor(s)" symptoms. If you jump on the front brakes at higher speeds you can feel the front end shake, and if you look down the fork tubes I can see the front wheel doing a front to back motion. At lower speeds you can feel a release/pressure/release/pressure sensation. All things point to the rotors.
Here's the interesting part. The bike has about 26,000 on it. I wanted to overhaul the front end anyway, so I ordered all the stuff I needed. New fork guide and slider bushings, fork seals and dust covers, fork oil, tapered steering head bearings, new brake pads, etc.
Before I tore it down I built a steel plate that bolts where the caliper bolts. Remove the calipers and installed the plate. Put the dial indicators on and checked runout both sides. Left rotor has .002", right rotor .005" runout. Manual calls for a max runout of .012". I'm under.
Rebuilt the front end, removed the Metzler M-1s, put on a set of
M-3s, and rechecked the runout numbers. Same numbers as before. Still very much the same at high speed. Maybe a little less or non-existent low speed pulse. I put about 100 miles on so far.
Runout has been checked at the furthest inside and outside points of the rotor since the middle is hard to check without the holes in the rotor wanting to interfere. The left rotor is a slow movement several times per one wheel rotation from .000 to .002. The right rotor is one swing per wheel rotation from .000 to .005 and back to .000.
I'm considering building a brake pad blockoff plate so I can run the bike with one caliper off the rotor and the plate inbetween the pads. This would allow me to ride it and brake with one caliper active at a time. This way I could isolate which rotor is causing the problem, if either. It's just interesting I'm under the max runout but experiencing what I believe is a rotor problem.
The question:
Anyone had this from a rotor that was under the max runout limit?
I've been eyeballing the rotors on the F3. It's a 96. They look close to the same as the Hawk, but I don't know if they would work as a temporary swap to see if they would cure anything.
I noticed recently the Hawk exhibiting the classic "front end pulsation must be warped rotor(s)" symptoms. If you jump on the front brakes at higher speeds you can feel the front end shake, and if you look down the fork tubes I can see the front wheel doing a front to back motion. At lower speeds you can feel a release/pressure/release/pressure sensation. All things point to the rotors.
Here's the interesting part. The bike has about 26,000 on it. I wanted to overhaul the front end anyway, so I ordered all the stuff I needed. New fork guide and slider bushings, fork seals and dust covers, fork oil, tapered steering head bearings, new brake pads, etc.
Before I tore it down I built a steel plate that bolts where the caliper bolts. Remove the calipers and installed the plate. Put the dial indicators on and checked runout both sides. Left rotor has .002", right rotor .005" runout. Manual calls for a max runout of .012". I'm under.
Rebuilt the front end, removed the Metzler M-1s, put on a set of
M-3s, and rechecked the runout numbers. Same numbers as before. Still very much the same at high speed. Maybe a little less or non-existent low speed pulse. I put about 100 miles on so far.
Runout has been checked at the furthest inside and outside points of the rotor since the middle is hard to check without the holes in the rotor wanting to interfere. The left rotor is a slow movement several times per one wheel rotation from .000 to .002. The right rotor is one swing per wheel rotation from .000 to .005 and back to .000.
I'm considering building a brake pad blockoff plate so I can run the bike with one caliper off the rotor and the plate inbetween the pads. This would allow me to ride it and brake with one caliper active at a time. This way I could isolate which rotor is causing the problem, if either. It's just interesting I'm under the max runout but experiencing what I believe is a rotor problem.
The question:
Anyone had this from a rotor that was under the max runout limit?
I've been eyeballing the rotors on the F3. It's a 96. They look close to the same as the Hawk, but I don't know if they would work as a temporary swap to see if they would cure anything.
#6
There's a good chance you have uneven distribution of pad material on the rotors. This will cause one or more areas to have more friction than the rest. The best way to get rid of this is sandblasting, but they can also be wet-sanded using a 120 grit and a strong detergent such as Dawn with water.
#8
I did the rotate/spray with brake cleaner and no difference. I'm going to swap to my F3 rotors, which I don't have any probelms with, and see what happens.
#9
And? And?
Is there an end to this story or what?
I'm experiencing the same warped feeling, especially at low speed when coming to a stop. So F3 rotors bolt to 'Hawk wheels? Cause I'm about to just get some new wheels while I'm at it for the track.
Is there an end to this story or what?
I'm experiencing the same warped feeling, especially at low speed when coming to a stop. So F3 rotors bolt to 'Hawk wheels? Cause I'm about to just get some new wheels while I'm at it for the track.
#10
My guess is that you weren't measuring them in the right spot. It's really difficult to get accurate measurements on the bike, even though your setup seems nice. Mine was doing the same thing before my front end swap - one rotor had .015 runout. I think even at .012 you would notice that something isn't right.
#11
My guess is that you weren't measuring them in the right spot. It's really difficult to get accurate measurements on the bike, even though your setup seems nice. Mine was doing the same thing before my front end swap - one rotor had .015 runout. I think even at .012 you would notice that something isn't right.
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