Just curious if I should be doing anything after updating my wheels from 22" to 20". I was hoping the speedmeter would have improve but still same +4mph off. I also feel like the transmission is a bit sloppy esp at low speed ~1500 RPM. Not sure if they previous owner tuned the ecu to adjust for the wheel size? Any suggestions would be appreciated.

 

Did you adjust the tyre size to maintain the overall circumference?

C

 

No I didnt. The new tires are 245/40/20, I believe Bentley uses 40 for 19" and 35 for 20" rims from the factory. The old 22" rims had 22 sidewall. I dont see rub being an issue and I dont mind the extra side wall. Is this something I would use VCDS for or should I take this to someone who knows what they are doing?

 

I'd suggest, personally (not that I have much value) using a tyre size calculator to work out what the 'correct' size would be (i.e. circumference). If you want to adjust that then, you can correct the mph reading. But it's only going to be correct at one speed.....

FWIW 4mph is not something I'd worry about......

C

 

I was more worried that I had to recalibrate the ECU for the transmission to adjust for the new rim size.

 

I've never seen a car where that was a thing. But anyway, the *rim* is not the issue. The circumference of the wheel / tyre combo *might* be.....

C