Oh my god, I'm going round in circles with wheels and tyres sizes! So if it's a 20" wheel the tyre will be a 265/40/20 for my t32 ( when I'll actually get it god knows! ) .. This will through the speedo out by 4%... Is there a way to get the speedo adjusted so that it reads the correct speed? many thanks.. Also if I go 19" then I have to a 275/40/19.... Whats the deal with mpg with tyres of this width? many thanks Simon
can you adjust the speedo for the tyre size?
- Thread starter Kingsimon2000
- Start date
With the 265/40 on a 20 it won’t throw the speedo out. From the factory the speedo is set to over read. Fitting the 265/40 actually makes it read closer to the correct speed.
Similar story with the 275/40 19 but not to quite the same extent.
Also seen that there is a 255/45/19 tyre available.. what would the difference in ride quality / mpg be between the 275 and the 255? many thanks
HI all. I've just bought my dream van which has been converted in to a Camperking campervan. It is a T6.1 SWB with the 110PS engine in Highline Spec....and I love it.
However, it has been fitted with some (very smart) 20" alloys (aftermarket) and whilst they look great and the ride is fine, the speedo is well out! When showing at 50mph in the van the actual is around 53mph. At a shown 70mph it is closer to 75mph actual. I'm no expert at all and would appreciate some advice on what I can do to put this right.
The 20" wheels are wearing 275/40 ZR20 tyres. I notice that the only 20" alloys that VW do for the Transporter require a 275/35 R20...... would this make a difference?
I've been quoted over £2k by VW to put their wheels (and tyres) on my van and they tell me that this will solve the speedo problem. Needless to say, I'd prefer not to do this! Is there anything else that I can do to make the speedo read accurately? Would changing the tyres make it right? Can the speedo be recalibrated? The VW dealer suggested not......
Any advice would be really appreciated. Thank you
However, it has been fitted with some (very smart) 20" alloys (aftermarket) and whilst they look great and the ride is fine, the speedo is well out! When showing at 50mph in the van the actual is around 53mph. At a shown 70mph it is closer to 75mph actual. I'm no expert at all and would appreciate some advice on what I can do to put this right.
The 20" wheels are wearing 275/40 ZR20 tyres. I notice that the only 20" alloys that VW do for the Transporter require a 275/35 R20...... would this make a difference?
I've been quoted over £2k by VW to put their wheels (and tyres) on my van and they tell me that this will solve the speedo problem. Needless to say, I'd prefer not to do this! Is there anything else that I can do to make the speedo read accurately? Would changing the tyres make it right? Can the speedo be recalibrated? The VW dealer suggested not......
Any advice would be really appreciated. Thank you
Yes, changing the tyres should make the speedo read better. 275/40R20 are bigger than VW sizes.HI all. I've just bought my dream van which has been converted in to a Camperking campervan. It is a T6.1 SWB with the 110PS engine in Highline Spec....and I love it.
However, it has been fitted with some (very smart) 20" alloys (aftermarket) and whilst they look great and the ride is fine, the speedo is well out! When showing at 50mph in the van the actual is around 53mph. At a shown 70mph it is closer to 75mph actual. I'm no expert at all and would appreciate some advice on what I can do to put this right.
The 20" wheels are wearing 275/40 ZR20 tyres. I notice that the only 20" alloys that VW do for the Transporter require a 275/35 R20...... would this make a difference?
I've been quoted over £2k by VW to put their wheels (and tyres) on my van and they tell me that this will solve the speedo problem. Needless to say, I'd prefer not to do this! Is there anything else that I can do to make the speedo read accurately? Would changing the tyres make it right? Can the speedo be recalibrated? The VW dealer suggested not......
Any advice would be really appreciated. Thank you
You can compare tyre sizes and effect on speedo on willtheyfit.com
Speedo can also be recalibrated by someone with VCDS lead and software.
Just noticed its your first post. Welcome and dont forget to post an intro with some pics
Thanks for this Skyliner33. I'm confused by what the 'wheel width' and 'offset' figures would be on willtheyfit.com . How do I know this?Yes, changing the tyres should make the speedo read better. 275/40R20 are bigger than VW sizes.
You can compare tyre sizes and effect on speedo on willtheyfit.com
Speedo can also be recalibrated by someone with VCDS lead and software.
Just noticed its your first post. Welcome and dont forget to post an intro with some pics
I will put some pics up
No worries, wheel width will be a J number stamped on the wheel. eg 8.5J. (width in inches.)Thanks for this Skyliner33. I'm confused by what the 'wheel width' and 'offset' figures would be on willtheyfit.com . How do I know this?
I will put some pics up
The offset is an et number. You might have to take the wheel off but for comparison of diameter it doesnt really matter. It tells you how far out the wheels will "poke".
So you could put 40 in (for example for both wheel as it wont really matter as you are comparing just tyres.)(
Are you using a gps speed app? Or just calculating?HI all. I've just bought my dream van which has been converted in to a Camperking campervan. It is a T6.1 SWB with the 110PS engine in Highline Spec....and I love it.
However, it has been fitted with some (very smart) 20" alloys (aftermarket) and whilst they look great and the ride is fine, the speedo is well out! When showing at 50mph in the van the actual is around 53mph. At a shown 70mph it is closer to 75mph actual. I'm no expert at all and would appreciate some advice on what I can do to put this right.
The 20" wheels are wearing 275/40 ZR20 tyres. I notice that the only 20" alloys that VW do for the Transporter require a 275/35 R20...... would this make a difference?
I've been quoted over £2k by VW to put their wheels (and tyres) on my van and they tell me that this will solve the speedo problem. Needless to say, I'd prefer not to do this! Is there anything else that I can do to make the speedo read accurately? Would changing the tyres make it right? Can the speedo be recalibrated? The VW dealer suggested not......
Any advice would be really appreciated. Thank you
At an indicated 70 with std wheels and tyres, you won’t be doing 70.
I’ve got 245/45/20 and they have exactly the same rolling diameter as yours. I’m doing 71 at an indicated 70. GPS apps checked.
You could change your fronts for some 245/40/20 as you are probably on 8.5j rims (check first), and it’ll probably be a little under indicated. You’ll be impressed how much better the steering and handling feels.
Thanks huw169, I've GPS app checked the van at 30mph, 50mph and 70mph and it is around 5-7% out, putting me at risk of triggering a speed camera!!! I've tried the same app in my cars and they all show under what the actual is!
I had no idea this was going to be so complicated! Ha!
Would a tyre place (Kwik Fit etc.) be able to advise me?
I had no idea this was going to be so complicated! Ha!
Would a tyre place (Kwik Fit etc.) be able to advise me?
Ok, so your software will have different compensations in for diameter. This has been discussed on here but is not something I have dabbled with.
Not sure how able you are, but best thing you can do is take the wheel off and see what space they are as skyliner33 says.
If you want to stay legal, then the load index is key. For T32 you need 103 minimum.
Not sure I would advocate asking kwik fit anything, but your choice.
You will get better advice of this forum than quick fit.
As far as I can see, you have 2 options.
1. Drive with the app showing speed being aware the van speedo is under indicating.
2. Change your tyres for ones of a better size. The best size will depend on the width of the wheel (eg 8.5J) and the diameter (yours are 20"). With these 2 numbers you can pick the best tyre size. It will also be helpful if you can tell us the 'flavour' of the van. Is it a T28, T30 or T32?
245/40 would recover 3.4%
275/35 would recover 4%
Neither getting you where you want to be.
Did you buy direct from a dealer? If so, talk to them. They may have a VCDS wiz, or someone on here may be able to help. I’m sure @mmi has looked into this.
www.t6forum.com
275/35 would recover 4%
Neither getting you where you want to be.
Did you buy direct from a dealer? If so, talk to them. They may have a VCDS wiz, or someone on here may be able to help. I’m sure @mmi has looked into this.
[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...
Thanks again…..it is a T28 I think!
Thanks…….not very able at all I’m afraid!
Thank you. I’ll do that tomorrow when it’s light.
Many thanks for the responses on my first post from yiy and Skyliner…….a very impressive forum already!
Unfortunately the link is T6 only.[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...
At the moment tyre size change for T6.1 speedo is "one-way ticket" - irreversible
VW Transporter T6.1 2021 Wheel size coding changes issue
Hiya folks! A customer of mine changed his wheels to 20" and wanted his speedo coded to suit the new wheel size. No issue as this is an available change via the "K-Number" coding in 17 Instrument Cluster and done this many times in older Transporters and Amaroks. Well, turns out there is an...
Welcome bud...believe me, there isn't a question or issue or situation you can think of that isn't covered on this forum. I used to worry about things and find out it's all been covered before. You'll soon sort the solution to your speedo problem and you can sort it in a way best suited to you...you'll already have the options above.
Similar threads
