Racing Brake is in the game.

[UNBROKEN]

How much space is needed for this upgrade on front running 21" OEM wheels? I've read 12mm. On racing brakes website they only mention a single 3mm spacer for a 19" wheel. Can I stack four of the 3mm spacers they reference? Link below.

https://www.amazon.com/Hubcentric-W...t=&hvlocphy=9031610&hvtargid=pla-904358741711

No you can’t stack that much spacer. 1/4” is the thickest you can do with a slip on spacer. Everyone else has gone to a 1“ or 1.25” Bora bolt on spacer.

 

[Warren-RB]

How much space is needed for this upgrade on front running 21" OEM wheels? I've read 12mm. On racing brakes website they only mention a single 3mm spacer for a 19" wheel. Can I stack four of the 3mm spacers they reference? Link below.

https://www.amazon.com/Hubcentric-W...t=&hvlocphy=9031610&hvtargid=pla-904358741711

Since your have upgraded your wheels from stock 19", so an easy way to evaluate how thick of a wheel spacer you need is to check your existing brake caliper to wheel clearance - If you have more than 3mm* at the tightest spot, you don't even need a spacer.

*Due to the fixed piston caliper has a wider body than OE's floating caliper - 3mm=~3 credit cards

And if you ever need a wheel spacer, make sure you pick one that's hub centric and "One solid piece" instead of multiple pieces as "UNBROKEN" pointed out for the integrity consideration.