Wheel size

[ThatLadOnTheSpanners]

Hey guys!
 

I’m changing the wheels on my A4 from 17 inch to 18 inch wheels. Do I need to change anything via vagcom? 
 

many thanks 

Nath

[Magnet]

Hello Nathan,

18 inch were probably an option, and I guess you know you will need to fit lower profile tyres than your current profiles on the 17 inch, to ensure the ‘rolling’ outside diameter remains the same. It would be worth checking in your handbook or tyre pressure sticker on the car, what the correct tyre size should be. I cannot see why any computer adjustments would then be necessary. 
Kind regards,

Gareth. 

[ThatLadOnTheSpanners]

5 minutes ago, Magnet said:

Hello Nathan,

18 inch were probably an option, and I guess you know you will need to fit lower profile tyres than your current profiles on the 17 inch, to ensure the ‘rolling’ outside diameter remains the same. It would be worth checking in your handbook or tyre pressure sticker on the car, what the correct tyre size should be. I cannot see why any computer adjustments would then be necessary. 
Kind regards,

Gareth. 

Thanks Gareth.

 

I’ve gone for a lower sidewall size so in theory they should be the same rolling radius. 
 

Many thanks

Nath 

[Magnet]

Thanks Nathan,

I think I would be actually double checking/ working it out, since variations in rolling diameter will affect at least speedometer readings and possibly far more. 
Kind regards,

Gareth.