V90 Indirect Tyre Pressure System

[Stewart1359]

I am looking for information about the V90 Indirect Tyre Pressure System please. I am thinking about changing my wheels and tyres. I have been told by the dealer that if I stay to the same wheel and tyre size I can change them about as much as I want without any problems. They said if I went to a larger wheel and tyre that I would need to get a software update every time I swap sets of wheels. I was thinking of going from 245x45x18 to 255x40x19. Has anyone done this and had to get a software update or can this be done without the software update as there is not much noticeable size in the rolling radius. Thanks

[Gazdok]

Indirect suggests that it uses the ABS wheel sensors to measure wheel speed and compares the axles. With a flat or underinflated tyre one wheel spins faster and you get an alert.
Much cheaper than pressure sensors on each wheel.

[EssexExile]

I would've thought you'd be OK if you calibrate the system after changing tyres but I'm no expert. Perhaps someone who actually knows will come along!

[Lexman8]

Twice per year I change between summer tyres (235x55x19) and winter tyres (235x60x18). The difference in circumference is 0.3% and I've never had any problems. After each change I simply recalibrate the iTPMS via Sensus.

Your proposed change would be a difference of 1.3% which in itself probably wouldn't be an issue after recalibration however the change in tyre width might be a problem. I vaguely remember reading that the tyre width is taken into account by various systems, including steering, so this may be why the dealer is saying a software update is required.

If you can keep to the same width tyre I don't think there'd be a problem but you'd have to check that whatever size you move to is one approved by Volvo otherwise there'd be insurance implications.

[Stewart1359]

I was hoping that if I went to 19” all I would have to do was reset the tyre pressure system.

[Stewart1359]

I could stick to 245x40x19 and I think it would be ok .

[nu11eaf]

The software update your dealer mentioned is to recalibrate your speedo to suit the different size wheels/tyres not the tyre pressure monitoring system, you calibrate the TPMS yourself via Sensus as you would if you adjusted the pressures.
Many owners do not bother getting the speedo recalibrate if changing from summer to winter wheels/tyres as they will only have to do it again when changing back to summer wheels/tyres as it will not be a large speed discrepancy, but it may be preferable to have it done if you are changing permanently to a different size.

[simonjedrake]

Originally Posted by Lexman8

Twice per year I change between summer tyres (235x55x19) and winter tyres (235x60x18). The difference in circumference is 0.3% and I've never had any problems. After each change I simply recalibrate the iTPMS via Sensus.

Your proposed change would be a difference of 1.3% which in itself probably wouldn't be an issue after recalibration however the change in tyre width might be a problem. I vaguely remember reading that the tyre width is taken into account by various systems, including steering, so this may be why the dealer is saying a software update is required.

If you can keep to the same width tyre I don't think there'd be a problem but you'd have to check that whatever size you move to is one approved by Volvo otherwise there'd be insurance implications.

I do exactly the same as a you and due to the very nominal circumference difference, I do not bother with the software change - seems a waste of money & time for such a minor 0.3% - there are more important things in life!

[ergonomist]

Don't forget that the rolling circumference changes as the tyre wears. By my very rough calcs, the difference between a new tyre (with 8mm of tread) and a fully worn one with 2mm is about 1.5% circumference - and none of us gets the speedo recalibrated for that.