Is running 309mm discs up front & 288mm in the rear cause a brake balance problem...

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Oct 22, 2006 | 04:22 PM

Regenmeister

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Is running 309mm discs up front & 288mm in the rear cause a brake balance problem...

Guys on other sites say no, others say yes...
Some suggest getting a Tilton valve if I track the car(I don't ever track the CQ). The seller of the upgraded rear brake setup says no, He says that Audis own proportioning valve will make sure no in-balance problem happens.
Ops?

Oct 22, 2006 | 04:35 PM

Merkin

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I'm test fitting a 4 lug 256mm rear brake system soon, that should be fun. 288 is too big

Oct 22, 2006 | 04:40 PM

Regenmeister

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Why? Don't think the proportioning valve will do it's job? I got Porsches...

up front & OEM rear UrS6 calipers in back.

Oct 22, 2006 | 04:48 PM

Merkin

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it'll work but probably takes a bit of tweaking the bias

Oct 22, 2006 | 04:52 PM

Regenmeister

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Can't tweak the OEM standard proportioning valve on a CQ.

Oct 23, 2006 | 02:58 AM

NoNonsense

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so put in a proportioning valve =)

Oct 23, 2006 | 05:34 AM

520

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Your ABS may act up. Its designed to work with OEM sizes/proportion....

But your bias also matters on the size of the pistons in your calipers...there are formulas out there if you want to bother calculating. You can just get a Tilton and set it up where you like it, ie. turn off your ABS and go testing...its tough to say simply from the size of the rotors. You can also adjust bias with different pad compound.