Wheel Balance Shudder After Changing Rotors..

[jjman]

Hey people,

Iv found that after changing all 4 rotors and pads i now have that wheel balance shudder through the steering wheel at 100kmh+.

Prior to the new rotors i didnt have this problem and have brand new rims and tyres.

I have had a 4 wheel alignment done but that didnt make any difference.

Any suggestions what it might be? Iv checked and it doesnt look like iv knocked off a balance weight doing the rotor change.

Perhaps incorrectly balanced rotors? (RDA's)

cheers

Justin

[DVS JEZ]

rust where the disc meets the hub can cause this,

also some aftermarket wheels require hub centric rings as they dont match the hub of the car.

did you rotate the wheels?

have you got the wheels rebalanced / checked on a balancer

[UNR33L]

You might have to machine the rotors? to make sure they are completely level I know sometimes that can fix this sort of thing. Just a idea

[jjman]

cheers people,

ill start with the rust on the hubs. its a possibility. Ill make sure all the balance weights are there and sitting right too.

yeah iv got the hub centric rings (spigots).

wheels and tyres are brand now so dont need rotating. And were on the car for 2000km before doing the rotors and there was zero shudder then.

rotors shouldnt need machining as they are brand new yeah?

n the supplier said that they are balanced before being sold...

Hopefully is the rust/dirt on the hubs as i sooo dont want to have to go down the route of claiming faulty rotors and proving it and then wating with the car on blocks for however long it takes to get replacements...

thats why you buy brand new to avoid this shit yeah? :s

[Equinox]

Clean all the rust off the face of the wheel hub. Every last but of it. Also get a straight edge and check for any high spots. File these off.

Get yourself a dial indiactor and stand and measure the runout on the hub alone and the rotor and hub as one. If brand new rotors aren't under 0.002mm of runout then I wouldn't be satisfied.

[jjman]

OK will see if i can check that too.

A further point to mention is that the brakes work fine. No shudder under braking like if a disc was warped. Which would also mean that it is unlikely to be somethin on the hub surface as this would also misalign the rotors rotation and forcing a shudder under braking too?

Or would a slight bit of rust/dirt be enough to cause balance shudder at high speeds but not enough to cause a shudder under braking?

[DVS JEZ]

i have seen rust causing wheel shudder and brake shudder.

but i see your point on no brake shudder,

i think you should just get the wheels onto a balncer for $35 it will tell you whether your problem is that or the brakes.

takes the guess work out of it.

and while the wheels are getting balnced pull the brakes off and clean the rust.

WIN WIN

[jjman]

I like the way you think Jez.

I think that is the best place to start.

quote name='DVS32R' date='29 Jul 2010, 04:02 PM' post='5373149']

i have seen rust causing wheel shudder and brake shudder.

but i see your point on no brake shudder,

i think you should just get the wheels onto a balncer for $35 it will tell you whether your problem is that or the brakes.

takes the guess work out of it.

and while the wheels are getting balnced pull the brakes off and clean the rust.

WIN WIN

[DVS JEZ]

let us know how it goes