Hi,
I have a Volvo XC90 2019 early with Air suspension.
I got it with OEM summer tyres 275/45 R20.
For winter tyres I've researched and found 235/60 R18 would be the best choice, because of bad roads in my country and the possibility of snow chains mounting when I am going to the Alps.
So bought a Borbet C2C rims (EAN: 4051665042856) along with Continental WinterContact TS 850 P tyres 235/60 R18 tyres.
Apparently the Continental tyres are the officially supported Volvo wintertyres (party no. 31650787):
https://accessories.volvocars.com/en-de/XC90(16-)/Accessories/Document/VCC-515693/2019
Assembling and brake clearance was not a problem, but the speedometer writes wrong values.
With the summer tyres and the default factory software package (guess/hope it was the 20" SW pack) it was always +3 km/h at all speeds above 30 km/h (until 180 km/h tested).
With the winter tyre combination before and after the 18 inch Volvo software package adjustment (applied 3 times: 18" SW, Polestar, 18" SW, 1 month later 18" SW) it is the following:
Dashboard km/h GPS km/h
10 9
30 27
55 51
60 56
106 100
110 104
155 147-148
178 170
I've informed Volvo service after I came from there for a test ride of the 18" SW package and the Polestar upgrade (applied one after the other during the same service appointment), that there is this difference.
Then went back a few days later to the service to reapply the 18", we guessed maybe Polestar overwrote some settings. But after the 2nd SW application the km/h difference was the same.
1 month later in another EU country I've told to the local service and they made me sure they fix the problem, effectively they've reapplied the same Volvo software package number (32270045), and ofc still no difference in the km/h misalignment. :facepalm:
I've read in several forums that the tyre circumference had to be adjusted by the service/garage, because the default Volvo software doesn't cover this (then why do I pay for
).
I remember I found at the first time I've searched after this problem a forum entry, which mentioned this exactly, but I don't find it anymore, maybe it was a swedish/dutch/some other foreign country forum and I just google translated it, so I can't re-find it anymore.
The reason why I want it to be corrected are:
- turning off the safety features at the speeds they meant to, and not earlier,
- better fuel consumption measuring,
- saving engine/transmission from later problems because of earlier shifting in the automatic gear shifting programs,
- preciser Air suspension lowering (it depends on km/h),
- don't write more km into the odometer, than the real, which makes harder to sell the car years later,
- make it easier to me to set the desired real speed with the tempomat, than remember at which speed what speed is the real speed, have less looking at the GPS km/h number on my phone.
Anyone met this problem and/or know the real solution for it?