Vibration during high speed breaking

[trex000]

My B7 S4 vibrates big time on high speed breaking (80mph +). I checked my rotors and they seem to be fine. The break pads have at least 70% meat on them. Plus, lower speed breakings and stopping (80mph or below) are fine and firm. What could be wrong here?

Sorry to ask stupid questions here, but I do want to get a feel of what’s going on before heading to the dealers.

[jonmiles]

Sounds like your rotors are warped

[D.C. Designs]

^ what he said get them resurfaced :)

[Rodknock]

they sound like they are warped..

[joeycuccaro]

yeah sounds like the rotors

[Todd/AWE]

Also check wheel balance. A bent front wheel can cause vibration during braking.

[RAudi Driver]

My B7 S4 vibrates big time on high speed breaking (80mph +). I checked my rotors and they seem to be fine. The break pads have at least 70% meat on them. Plus, lower speed breakings and stopping (80mph or below) are fine and firm. What could be wrong here?

Sorry to ask stupid questions here, but I do want to get a feel of what’s going on before heading to the dealers.

I don't think that it's your front wheel or else you would feel it at speed without applying the brakes also. But checking wheel balance is probably a good move also as it won't cost you anything, unless they are out of balance. If they are, get them road force balanced. That Hunter 9700 kicks some serious A**.

How did you check your front rotors? Did you just look at them? I can put almost everything on the line and say that the other replies are correct in that your rotors are warped. Pull those things off and run them down to your local auto shop to have the turned. Then get yourself a nice set of pads and slap it back together. You should be fine after that.

Make sure that you torque your log bolts as this is a major cause of warping rotors.

[Todd/AWE]

I don't think that it's your front wheel or else you would feel it at speed without applying the brakes also.

An imbalance that only shows up for a few hundred rpms at speed can be much more obvious when braking.

In other words, the tire imbalance may not be very apparent to him when at speed, which is why he is overlooking it or not even really feeling it.

If his rotors were warped, it shouldn't take a high speed stop to reveal that.

[ZachPDX]

how weird, i just noticed this exact same thing when coming down from 100 super fast today. Its not a ton of vibration but I only feel it when im braking above 70ish, anything below that and its not there. I figured it was just the car doing some sort of ABS to keep the rear end straight.

[PenguiN]

new or resurfaced rotors needed!

[RAudi Driver]

An imbalance that only shows up for a few hundred rpms at speed can be much more obvious when braking.

In other words, the tire imbalance may not be very apparent to him when at speed, which is why he is overlooking it or not even really feeling it.

If his rotors were warped, it shouldn't take a high speed stop to reveal that.

True, but he may also be overlooking the vibration at the lower speeds as it may not be as noticable. Whatever the case is, it doesn't cost anything to have a shop toss your tires on a balancer to see if they are balanced. Shops do this for free. Turning the rotors are also cheap, so I would do both of I were the OP.

[asurugger]

your abs might be playing a role in that

[Maverick]

how are your rear rotors looking? is the outer edge thicker than the inner surface of the rotor? if it is, you need to change it

[RAudi Driver]

Before you get your brakes done, check out my sig.