View topic: Please help me with wheel calculations...

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Hi guys,

Im getting new wheels for the car. It's an audi s3 20vt engine transplant, so the front driveshaft / hubs etc I know what I'm doing with.

Fronts: (first picture below)
4x100 PCD
57.1mm bore
current wheel size 8Jx15H2
current wheel offset ET15
Need about 160mm inner radius of wheel to clear brake caliper

Rears: (second picture below)
4x100 PCD
not sure on bore…I think 57.1mm, would this be right for the rears on standard mk1?
current wheel size 9Jx15H2
current wheel offset ET20
came with 5mm spacers - does this mean my offset for my new wheels I'm looking for is ET25 or ET15?…
Loads of room to clear rear brake calipers

I was thinking of some Rota Grid Drifts, but need to look at dimensions etc. Thanks for the help!!

Last edit: 06 June 2016, 11:07 AM by squirrelofdoom

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yes the rears are 57.1 as well as the fronts.

ET20 with a 5mm spacer would make them ET15.

The higher the offset the closer to the car they are, its safer to go with a higher offset as you can always space them out if needed. if offset is too low you cant correct that without machining the wheels, which can be expensive if its even possible depending on the wheel design etc

Hello my name is John and I'm a dub addict.

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Thanks John! Right, I'll be contacting places to get some engineering drawings of the wheels (if they'll let me have them). Only thing I really need to worry about is clearance for the front big brake setup

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General rule of thumb is that 9" rears need ET15 to clear the rear trailing arm. The 9" wide Borbet is actually TUV approved at ET15 for use on a golf