ProgMetalHead

You guys are looking at it the wrong way! If your speedometer is reading higher than your actual speed, that works AGAINST you when speaking to a cop! If it's reading higher than your speed, why would you be breaking the speed limit even more-so?

It seems to me that my speedometer is reading higher than my speed as well. I'll be driving 130-140km/h on the highway, and it barely feels like 110km/h... especially when people are passing me regularily! With that second thought aside, don't tell me that this is just how amazing Audi's are... okay, please tell me that I've driven GMs all my life, so I'm expecting a very smooth and sturdy ride from Audi.

MattRaczka

That is exactly what is happening with myA4, 235/40/18 wheels.
If the speed is higher gps show me more diffrent speed compare to odometer.

K04-S4

On most Audi's, VAG-COM can adjust speedo in small increments to compensate for non-OEM diameter tires.

melissaamberko

FYI here is something that you may not know about German cars and may be the answer to your speedometer problems:

German law states that a speedo never must show less than real speed.
And it's limited the running ahead to max. +10% +4 km/h.

examples:
real speed 100 km/h - speedo may display max. 100 + 10 + 4 = 114 km/h
real speed 200 km/h - speedo may display max. 200 + 20 + 4 = 224 km/h
real speed 290 km/h - speedo may display max. 290 + 29 + 4 = 323 km/h

The main reason for this allowed great variances is because of different tires
(different rolling circumference), examples:
265/40/18 tire has a 203,4cm rolling circumference
265/35/19 tire has a 203,1cm rolling circumference
295/25/20 tire has a 199,3cm rolling circumference
so this all affects speedo. And 3mm less tread will affect about 1% to speedo.

In reality (by own experience) the german speedos displays about 5% + 4 km/h more than real speed, so

real speed 100 km/h - speedo display 100 + 5 + 4 = 109 km/h
real speed 200 km/h - speedo display 200 + 10 + 4 = 214 km/h
real speed 290 km/h - speedo display 290 + 15 + 4 = 309 km/h

Thanks to the guys from BMW.

K04-S4

Simply for point of interest, our B5 and C5 Speedo's read bang on with stock diameter tires at 100KM/hr.

ProgMetalHead

Well, what size tires would a 2004 A4 Quattro 3.0L normally come with? This way, I can compare! Thanks!

arimendiii

I thought that speed is measured inside transmission, and not on tires?!

ProgMetalHead

I don't know, but it is kind of upsetting me. I don't want it to show a higher speed than I'm driving because then I'm missing out on extra km/h I'd normally be doing! Driving 130 feels really slow to me!

K04-S4

You are correct. That is why changing the tire rolling diameter will cause the speedo to read inacurrately. The speedo is calibrated based on OEM tire size. VAG-COM can adjust speedo in small increments on most models to compensate for different tire diameters. Someone else should try it as it really does work

k1e1v1i1n

great post i never knew this