Letting the Van know you’ve changed wheel size

[thomasamoht]

I know lots of people just swap the wheels on California/ transporters but can VW change the settings on the cpu to adjust for speed differential. I’m only going 17-18” so I know it’s minimal but I was wondering because I used to work at Ford and we’d do it there.

 

[Mr T]

I know lots of people just swap the wheels on California/ transporters but can VW change the settings on the cpu to adjust for speed differential. I’m only going 17-18” so I know it’s minimal but I was wondering because I used to work at Ford and we’d do it there.

If you stick to the correct factory specified tyre size then there isn’t a difference between 17” and 18” worth calibrating for.

 

[ArunAlec]

I know lots of people just swap the wheels on California/ transporters but can VW change the settings on the cpu to adjust for speed differential. I’m only going 17-18” so I know it’s minimal but I was wondering because I used to work at Ford and we’d do it there.

Doesn’t the overall diameter remain the same ?

 

[WelshGas]

Doesn’t the overall diameter remain the same ?

If the correct sized tyres are fitted then there is no change in diameter/circumference.

 

[thomasamoht]

Cool thanks

 

[Ting Tong]

Your 17” will have 215/60r17 or 235/55 r17 tyres and as long as you fit either 235/50 r18 or 255/45 r18 there won’t be any significant difference in diameter or speed reading. The 235/50 r18 are cheaper and are more widely available in different makes.

 

[Chris_BLG_Ocean]

https://www.willtheyfit.com

Useful tool on a web site to see differences in speed readings etc


Sent from my iPhone using Tapatalk

 

[Cooper68]

What if someone was to put wheels on with much bigger tyres? I saw a nice set of swamper wheels/tyres on eBay with 255/55/18 tyres. Can the Speedo be reconfigured to allow for a larger circumference?

 

[ArunAlec]

If the correct sized tyres are fitted then there is no change in diameter/circumference.

Agreed!

 

[WelshGas]

I know lots of people just swap the wheels on California/ transporters but can VW change the settings on the cpu to adjust for speed differential. I’m only going 17-18” so I know it’s minimal but I was wondering because I used to work at Ford and we’d do it there.

What if someone was to put wheels on with much bigger tyres? I saw a nice set of swamper wheels/tyres on eBay with 255/55/18 tyres. Can the Speedo be reconfigured to allow for a larger circumference?

Yes it is possible.

See here:

[Guide] [T6_modified] T6 Speedo Adjustment with VCDS

Module 17 – Instruments carries also the coding to select a few scaling factors for speedometer. Byte 0, bits 0..3 have mysterious value “K-number”. It turned out changing this coding adjusts measuring values IDE00842 (K-number) and IDE00845 (Wheel circ. mm) of module 17 - Instruments, and...

www.t6forum.com

 

[Loz]

What if someone was to put wheels on with much bigger tyres? I saw a nice set of swamper wheels/tyres on eBay with 255/55/18 tyres. Can the Speedo be reconfigured to allow for a larger circumference?

if you go slightly larger then the speedo will read closer to true(gps) speed without need for adjustment, only if you go much bigger and the speedo were to under read, then yes a small adjustment can be made with VCDS tool.

 

[Cooper68]

if you go slightly larger then the speedo will read closer to true(gps) speed without need for adjustment, only if you go much bigger and the speedo were to under read, then yes a small adjustment can be made with VCDS tool.

Thanks Loz

so, if Woodstock wheels with 235/55 R17 were swapped for a swamper set with 255/55 R18, according to the willtheyfit website the Speedo will be out by -6.43%. Is that considered enough to have the VCDS adjusted?

 

[B J G]

Thanks Loz

so, if Woodstock wheels with 235/55 R17 were swapped for a swamper set with 255/55 R18, according to the willtheyfit website the Speedo will be out by -6.43%. Is that considered enough to have the VCDS adjusted?

Fitting oversized profile tyres will give arch clearance problems which be more acute on the front outer arch area on lock. Lowered suspension will of course make it more of an issue.

Higher Profiles that do work on 17" are 235/60/17 and on 18" 235/55/18 with virtually no speedo error.

255/45/18 & 235/50/18 will give a slightly reduced tyre circumference than the 235/55/17, marginal but will result in a loss of actual road speed/distance travelled.

 

[thomasamoht]

Cheers folks! Much clearer