The speedometer on my S70 GLT read ~2% high when I was running 205/55-16. Now that I've moved to 215/45-17 it readss 2.9% high. This is still in an acceptable range, but is borderline annoying.

What have other folks experienced in terms of speedometer accuracy?

Is there any way to adjust this? With all of the computer controls in the model there must be a setting somewhere (like on Chevy trucks)

A larger tire next time such as 225/45-17 would obviously help, but size of a tire isn't going to fit my car well.

Thanks

I asked the local dealer about this. I thought maybe my car was calibrated for the wrong wheel option. They verified the ECU settings and told me reading fast is normal and Volvo knows about it. It's not a problem (for them at least) however I do find it rather annoying. No speeding tickets yet though..

how are u measuring the accuracy, i tried using the sat nav, came up with some strange readings (3mph high evenly...) then put it in another car and got the same result..ergo satnav out!

I'm using my GPS.

I ran another experiment. I locked the cruise control on 61mph. I then cleared the average speed in the trip computer and it came back with 59 and then 60 and held there.

So it seems that the speedo is calibrated to read higher. This difference added to the 1% expected from the tire size difference brings me to the ~3%.

-Ted

i too used gps..like i said came out consistantly 3mph higher...weird..try it in another car, or try a different speed (say 25mph...)

Been doing some reading on this. Apparently with 3% I'm doing really good compared to others. Other have reported 6%, even 8% on some of the newer models. It seems that Volvo has dialed in some error by default as a cushion. This shows up in the speedo reading, but not necessarily the odometer (next road trip I'll have to check that).

But anyway, the question remains how to program what you want.