Switching to larger wheels

[Captain Bimmer]

How does switching to larger wheels affect the odometer reading? Larger circumference for same number of rotations equals larger distance travelled. Sorry if this is a stupid question.

[Chris735i]

If you switch to larger wheels then you will have to use a lower profile tire so the circumference stays close to the original. It is recommended to stay with 2% of the original circumference. There are tire calculators online on some tire websites unfortunately I cannot post links to the U.S. ones.

[black_box]

Chris735i is right, as you move to a larger wheel, you use a tire with a shorter sidewall so that the overall diameter is close to the same as the original. Being off by a little bit won't be too bad.

If the new tire/wheel combo is slightly larger, the speedometer will read slower than your actual speed, i.e. speedo says 80mph, but you're actually doing 82mph.

[elh0102]

Chris735i is right, as you move to a larger wheel, you use a tire with a shorter sidewall so that the overall diameter is close to the same as the original. Being off by a little bit won't be too bad.

If the new tire/wheel combo is slightly larger, the speedometer will read slower than your actual speed, i.e. speedo says 80mph, but you're actually doing 82mph.

But if his is typical of most BMW speedometers, it's probably 10% fast anyway, so you could run tractor wheels and not worry about getting it slow.