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When i bought the car it had RS6 wheels fitted to it, am i right in thinking audi can change the seting so the car knows it has 19" wheels..
The speedo is out by about 7 mph at all speeds.. 20-90.

Just been in to Audi and they are saying they can't find anyhing on the plug in but are looking in to it ? with Audi Germany.

The car had 16 " or 17 " wheels when new and some later models had 18 " as option... surly there must be something...

what do the RS6 owners do on the swtich from 18 " to 19 " or 20" rims..


Anyone have knowledge? the car is a 2000 S6 avant.

Mark

Think you will need to change the profile of the tyre to bring it in line with the correct ration.

My 2001 S6 Avant has 17" wheels on it instead of the original 18"ers (as shown by the spare!) and the tyre sizes have gone from 40 profile to 35s to correct overall rolling circumference.

However, I know speedos can be changed for diffferent wheel sizes - may be wrth a general search, only thing you want to make sure is you don't have to dismantye half the car to get the speedo out!! Pretty sure it can be done in situ for most vehicles nowadays. The Web is your friend )

I don't know if anyone with experience of VAG-COM knows if the wheel size is something that can be changed, from the lack of response I'm guessing not....?
The standard wheels were either 255x40x17 or 255x35x18 which have a diameter of 636mm. To get the same diameter with 19" wheels you would need to go for 255x30x19 tyres. Have a look at http://www.alloywheels.com/Tyre_Calculator - as this will give an idea of how far out the speedo is reading currently. Alternatively impress the wife with your restrained driving by sticking just below the advertised limit and enjoy the brownie points

(adam b) i tried the web but to no avail, Audi have said it can't be done...?? how are the RS6 cars running on 255/35/19 then with accurate speedos???

(Quattro25) i have not give up yet, will check out the link...cheers

Here's another thought for you to consider - we are making an assumption that Audi calibrated the speedo to be 100% accurate when they left the factory....... this may not be the case.

I'd noticed a while ago that with the standard 17" rims my Garmin satnav was suggesting the speedo was reading faster than the GPS readout, by 3-4 mph. I also now have 19" RS6 rims and 35 profile tyres on the car now and have rechecked the speeds using the both Garmin and an iPhone GPS app. In both cases with the cruise control set at different speeds between 30 - 60 on a straight flat road, they indicate the speedo is now completely accurate.

Having looked at a few online GPS discussion threads, there seems to a common view that the manufacturers intentionally set the speedos slightly higher than the actual speed and VAG seem to no exception. So before you invest in a new set of rubber, it might be worth checking to see what GPS readings you get first.

yep i ahve checked 3 diferent GPS devices, all are showing 7 mph faster than the speedo..

All the gps devices i have compared speed with show a 2mph difference . That's all been done over the years with different cars and trucks with different satnavs,phones ect ect

time to change to 255/30/19 then to try and sort it..

changed the tyres, no bloody difference at all grrr.