About a month ago, my bike started to shake while I was braking at high speeds. It would also brake in and out with light pressure at slow speed. I got new pads just for the heck of it, but the problem was still there, so I figured a had a bent rotor. Well I get my replacement rotors today and I still have the exact same problem. What else could it be? I don't feel like spending $100 to rebuild my calipers and MC without knowing that it will fix it.... Thanks.

 

Could be your suspension is way out of whack. If you haven't had it set up specifically for you by a pro, I'd highly recommend it. Should cost ~$40. Also try squeezing the tank hard with your knees when you brake.

 

Do you feel it more with the handlebars or with the bike itself?

 

RolandK, ona side note...... Where can you get your bike's suspension custom tuned by a pro? Like at a dealer or someplace similar? I've been wondering recently so any input would be appreciated!

 

i noticed the other day when I was at a dead stop that when I press the brake down real hard, it will vibrate just a bit more than if i do not have the front brake on at all. have you tried hitting the brakes while you are stopped to see if it vibrates then? Obviously that won't tell you exactly what it is, but it will tell you what it isn't which sometimes is more valuable when troubleshooting...

 

If you have arace track in your area, ask around on a race day or track day. Or any bike shop that specializes in race bikes.

 

Did you replace the rotors with brand new ones, or used ones?? If youhave a dial indicator you canput it on each rotor and see if they're out of spec.... spec is 0.20 mm (0.008 in). New rotors torqued to spec?? One loose or missing bolt WILL warp the rotor (don't ask how I know, lol [:@]) And which pads did you get?? I've found that the stock pads and EBC HH pads always warped my rotors. Been using the Galfers for awhile now and never a warped rotor. That's just my experience though...

Also check the wheel bearings, make sure there is no play and they're spinning smoothly

 

Thanks for all the replies guys. I had my suspension setup by a guy who works for Ohlins a while ago, so its been rock solid for a while. The rotors are used, and the seller claimed they were straight so Im hoping that they really are. Don't have a dial indicator, but maybe ill run them to a shop and see if they can check the specs. I just snugged down the bolts, ill go out and torque them correctly right now. I put Galfer pads on the bike, the regular, non-sintered ones. If it was a wheel bearing, wouldn't i be able to feel it while just riding?

 

^^^ Yea a wheel bearing you should feel other times as well, but just figured I'd throw it in there as that too can cause weird braking issues.

But if you bought them used, I can almost bet one or both of them are bent. Don't take the sellers word for the truth.... it doesn't take much at all to bend the rotors (or carriers, rather), and if they didn't check them with a dial indicator then they really don't know either. Even just dropping them on the floor or a good whack in shipping could have bent them as well... it really doesn't take much at all. If you have an extra axle, ora piece of pipe the same diameter as the axle, a vice, and a large pipe or prybar, and a dial indicator,you can straighten the rotors yourself as long as they're not toooooo far bent

See if you can find a dial indicator though... I'll bet that's the problem. I've got one here I'd be happy to let you use, but you'rea lil far away, lol

 

cupped tire? old brake fluid? did you bleed your brakes?
easy way to see if your suspension is causing issues is by changing the preload and damping and seeing if the vibration varies with it.