Glazed Rotors

[JetMech]

So, while I was at Autoclub, my brakes started to fade as the day went on and light vibration developed. Then I noticed my rotors were glazed. Now with a car, you take them down to Paco's Taco's & Tires, and get the rotors turned. Is it possible to turn a bike rotor? Should I get new pads or just stick with the stockers? There are only 3800 miles on the factory brakes and rotors.

[JetMech]

Oh forgot to mention, I looked into just getting new rotors and galfers are like $230 each!!!

[EtchaSketch]

220 grit Sand paper on a sanding block, red 3m pad, or a 3m roloc pad on and angle grinder will work to remove the glazing. Just be careful not to not go too deep and make the rotors uneven.

Have you checke the thickness to make sure they are still within spec?

[JetMech]

(04-26-2013 05:13 PM)EtchaSketch Wrote:  220 grit Sand paper on a sanding block, red 3m pad, or a 3m roloc pad on and angle grinder will work to remove the glazing. Just be careful not to not go too deep and make the rotors uneven.

Have you checke the thickness to make sure they are still within spec?

So i do t have to spend $600 on new pads rotors. That's a good thing.

Have not checked the thickness. Given they only have 3800 miles I'm sure they are but I will still check.

[EtchaSketch]

Here is an article on how to remove the glaze. It recommends an even higher grit sand paper though

http://www.ehow.com/how_4421355_clean-gl...tml#page=9

[The Doctor]

Would this be a side effect of not riding?

[Rev. That Guy]

a quick way that I learned how to do this and it is effective, although you can only get the outsides this way, is to get some 220 grit on a DA (orbital sander). Spin the tire as fast as you can while VERY GENTLY holding the DA to the rotor. This will take down that top layer VERY QUICK.

Also dont forget to scotch brite your pads too. Do this by hand and only take a few minutes.

you can usually scotch brite the rotors by hand to remove the glaze, just depends on how impatient you are. Most of the glaze on the rotors is actually brake pad amterial that has burned/built up on the rotor and is relatively easy to remove. Use brake clean as you go along as well to break up the deposits and remove any sanded away material.

- Justin

[Rev. That Guy]

After that, you can also check that you haven't created any hi or low spots by taping a sharpie marker to your fork leg so that it just barely touches the rotor and spin the wheel. If the line stays the same all the way around, you are golden. If it gets fatter or thinner, you have hi or low spots respectively and can spend a little more time on those area if you wish although if its very minor I wouldn't worry about it. floating rotors and calipers will, for the most part, negate that.

- Justin

[JetMech]

(04-26-2013 11:35 PM)The Doctor Wrote:  Would this be a side effect of not riding?

No. It's a side affect of a lot of braking and producing extremely high temperatures without enough cooling in between. With a lower temperature brake pad, for example. A stock pad is made to work at 300f (arbitrary figure). When the pad overheats, it leaves some material on the rotors, hence the glaze. Racers use a pad that operate at a much higher temperature to prevent overheating. Now, those pads do not work well on the street because they need heat to get to proper operating temps to produce the designed coefficient of friction for maximum braking. Typical street riding will not allow the pads to get up to proper temp. So street pads are designed to work at a much lower temperature and require very little to no heat to generate maximum braking.

[JetMech]

(04-27-2013 07:10 AM)That Guy Wrote:  After that, you can also check that you haven't created any hi or low spots by taping a sharpie marker to your fork leg so that it just barely touches the rotor and spin the wheel. If the line stays the same all the way around, you are golden. If it gets fatter or thinner, you have hi or low spots respectively and can spend a little more time on those area if you wish although if its very minor I wouldn't worry about it. floating rotors and calipers will, for the most part, negate that.

- Justin

Never tried the sharpie. I always use a dial. I guess it's a poor mans dial. Thanks for the tips. I know how to do a lot if this stuff on a car, but since I'm coming across a lot of firsts on my bike, I'm just wanting to make sure I'm doing things right.