This is likely a stupid question but through some basic searching I can't find the answer (admittedly I didn't read every word of every post and link).

So I understand when you change the wheel size there will be a change in diameter in the overall size. It will be close but it won't exactly the same. Now my question is, is there a way I can adjust something in the car that will make the speedo/odo readings accurate to the new size?

I can live with a 2% or whatever difference, but if I can get it right, it'd be preferable. The reason why I think it's possible is when you buy the xB you're given the option of the stock 16" steelies and the 19" TRDs. I believe the tire sizes are 205-55-16 and 235-35-19 respectively giving it a 2.4% difference. So one of two things is going on. Either the dealership can correct the difference in the cpu (or whatever) or the dealership just ignores it and you're driving slower than you really think.

Any info about it would be great. Thanks.

 

With the stock tires, the speedo is a little off to begin with. When it says 60mph, you're actually going about 58. When you go up a little bit in overall tire diameter (about 1/2") the speedo is almost perfect.

The dealerships just ignore it, because with the TRD wheels and 235/35 tires, it's more accurate than with the stock steelies.