Speedo recalibration
 

I've just replaced my tyre with ones with a lightly smaller aspect ratio. Was 255/40/19 now 255/35/19. (Wanted Michelin Super Sport but could not get them in the 40 series. Never mind.) Now that the rolling radius is slightly smaller the speedo is obviously out. (Reads 70 but actually doing about 67). This will also affect the mileometer. Is it possible to re-calibrate the speedo using VCDS to take into consideration the new tyre size.

(I think) There is an option for winter tyres (+5%), but don't forget that if your speedo shows 70 the actual speed is below that.
Every car has a little room.
If possible at all this isn't easy.
Your variance is 3.7% so even if there is that option of 5% I personally wouldn't do anything unless you get the speedo warning if there is one on 8's
Your real fuel consumption will not change.

Get a good GPS app and go for a 70mph (on your speedo) run and see what GPS says, I wont be surprised if that will actually make your speedometer showing the correct speed now.

I may be completely wrong, but lets see what others think.

Just thought about it, send Ross-Tech a short email and see what they say.
If it's doable then you would need VCDS anyway

Support@Ross-Tech.com

Thanks for that. I'll email Ross Tech and see what they say.

+++ No problemo, email them as they are best people to ask in regards to VCDS functions ;)
Take care