Hey guys so here are my wheel dimensions:
20 X 10 Rear (24mm offset)
20 X 8.5 Front (24mm offset)

I want to know the maximum size spacers I can install without any rubbing. I want the wheels to stick out as much as possible. Let me know! Thanks.

Raffi

 

I have 19x10 +25 for my rears (only 1 mm different than yours) with 275 width tires and I have been wondering the same thing. Out of the commonly available spacer sizes I think 5mm will still allow you to clear without fender rolling. 7 or 10 mm might be pushing it, but if you roll the fenders it should work. You might even consider 12mm or 15mm if you are rolling your fenders.

Other factors that affect this are the width of your tires, as well as the amount of camber you are running. The more negative camber you have, the more clearance you can get between the top of the tire and the fender - but you should probably base it off of your car being aligned within OEM specs so that you aren't totally wearing out the inner edge of your tires.

The best method will be to go out to your car with a tape measure and see how much distance you have between the top corner of your tire and the edge of the fender well. The distance you measure should be roughly the allowable thickness of your spacer.

 

Thanks. For 19's I believe you could add 10 mm spacers if you have 25 mm offset right now, because most 19 inch Volks are about 14-17mm offset in the rear with my understanding. But for 20's I think 5mm will be the maximum, but I don't have too many references on this forum since most people go with 19's on their Z. You have plenty of references because most people on this forum have 19 inch Volk wheels. You should look at some threads and you could get a good idea of how big you could go.

 

But don't confuse diameters and offsets - they are in two different planes. Theoretically, if your 20" tires are sized correctly, they should be the same outer diameter as your OEM tires (within a few percent). That is why the sidewall height decreases, to maintain the same outer diameter while fitting a larger wheel diameter on the inside. So on that logic we can assume that my 19" tires are the same outer diameter as your 20" tires, and then it's a question of width and offset.

Example: The Outer Diameter of my 275/35/19 rear tires is 26.58".

If your rear tires were size 275/30/20, the Outer Diameter would be 26.50".


So I guess my point is that whether you are running 275/35/19 or 275/30/20, the outermost, envelope dimensions of the tire are basically the same, so therefore you should be able to base your spacer sizing off of someone with 19" wheels whose tire sizing and wheel width are similar to yours, which is why I chimed in with my wheels since they are also 10" wide and my offset in the rear is close to yours.

I might be totally wrong on this issue though - hopefully someone else can chime in with some insight?

 

Not sure. I would check with the pros at performwheels.

 

! Had The Same Set Up As You....20x10 & 20x8.5....i Had 15mm Spacers In The Rear And 10mm In The Front(rear Fender Lip Was Rolled)

 

A 5mm spacer f/r would be fine.