[Genieman]

Anyone go from 245-40 R19 to 245-40 R20 (and 285-35 R20 rear) ?

Was looking at my car today and noticed that even tho the stock wheel gap is too much, on a stock car, there is the same amount of gap above the wheel and on the sides as well. On dropped cars the gap above is gone, but the gap on the sides is still there. If on a stock suspension car, if you increase the wheel diameter from 19 to 20 but don't decrease the aspect ratio and therefore increase the overall diameter of the wheel by an inch you will reduce the gap by 1/2 inches all around including the sides... wonder if that would rub in the front with the wheel turned all the way...

Anyone try this?

[bake]

This will throw off your speedo and the taller tires will make your wheels look smaller and overall will make your car less sporty. You will gain some extra cushion for rough roads though.

[Genieman]

yea, i did the math. Speedo is off by 5% at that point, so 60 on the speedo would be 63 in actuality. But I've also heard (in the past) that a lot of BMWs were about 5% slower in actuality than the speedo showed when tested against GPS on stock wheels...

as far as making the wheels look small, maybe the solution is then to get 21s and do 35 and 30 front and rear aspect ratios instead of 30 and 25...

[.BMW.]

245/40-20 is 3.7% taller than 245/40-19.

The speedo in my F31 show 3% higher speed than actual (checked with GPS).

I think the speedo will be spot-on.