Hi All,

I've tried searching but struggled to find anything relevant, I'm looking to move from 19" wheels with 235/40 tyres to 17" wheels with 215/55 tyres on my Superb TDI190 L&K.

It looks like there is a tiny difference in overall circumference that will mean the speedo is slightly over reading. Is there any coding that should be done to account for this?

Your speedo is already over reading. The difference is just a ba;s hair. The new tyres might if you put a tape measure around the circumference be the same as worn tyres.

As above - Exactly right, a theoretical 6mm wheel/tyre diameter difference ~ a 3mm difference in your tread depth

I’m sure I’ve seen settings in vcds

Tbh I’d much rather the car speedo to over read in case any mobile speed cameras are out fishing

Ross-Tech Forums

Error trying to set tire circumference on 2018 VW GTI DSG.

Hello, I have been trying to adjust my tire circumference via 17-Instrumentation/Coding/Long Coding/ Byte 3/ but the setting will not take from "varient 3". I need "varient 4" for my larger tire size

Edited 8 January8 Jan by Danoid

As you can see in the chart below, changing from 235/40R19 to 215/55R17 will make the speedometer over-read more.

Outside diameter of tyres

235/40R19 670.6mm

215/55R17 668.3mm (0.3% smaller outside diameter compared to 235/40R19)

Edited 8 January8 Jan by Carlston

225/40R19 should read 235/40R19.

Edited 8 January8 Jan by Carlston