[JonnyMystery]

Hello all!

Long time lurker and now poster!

Got some new alloys on my 335d xDrive M Sport, moving from 18" RFTs to 19" Non-RFTs (Michelin Pilot Sport 4s all round). The sizes are:

225 / 40 / 19 (front)
255 / 35 / 19 (back)

My question is - what pressures should I have for these? The TPMS is going nuts and refusing to reset my pressure sensors, always (eventually) returning "Unable to detect any loss of tyre pressure". Sometimes it gets to 49% but never gets further. The were fitted by the local garage so unsure what pressure they are at just now but just kinda figured that the TPMS would take care of it silently.

Cheers,

[Desertnate]

I don't think the problem is the actual pressure levels in the tires causing your TPMS to not work right. It sounds like the sensors are not sending information to the car, or it's not in a form it can decipher.

Do you have a pressure gauge you can use to check manually? I wouldn't depend on TPMS alone.

The run flats on my 435i in the same size are supposed to be 36F/38R per the door sticker. This might be a good starting point until you can figure out the TPMS and someone else provides better advice.

[chowser51]

What year is your car? The frequency changeover on tpms was around 2014/2015. You need to make sure you got the right ones.

Which you probably did since it goes to 49%.

I had the same issue with new tpms sensors from tire rack. It would stop at 49%. But all sensors were online. I ended up having a local place replace all the sensors and sent the originals back to tire rack. One was bad. They refunded me for the sensors but refused to pay for the labor involved in removing and replacing even though they said they would pay up to $25@ for replacing. Kinda soured me on tire rack.

[JonnyMystery]

Well this is embarrassing and I wouldn't post if I didn't think it would help some other noob.

In my haste to get the tyres onto my new rims... eh.... I didn't move over the TP sensors. Wish I were kidding....

But it does make you wonder how (on a number of occasions) the onboard computer managed to get half way through the process. Anyway, local garage is going to fit some today. Hopefully that'll be the end of it.

[cfm56d7b]

Originally Posted by JonnyMystery

Well this is embarrassing and I wouldn't post if I didn't think it would help some other noob.

In my haste to get the tyres onto my new rims... eh.... I didn't move over the TP sensors. Wish I were kidding....

But it does make you wonder how (on a number of occasions) the onboard computer managed to get half way through the process. Anyway, local garage is going to fit some today. Hopefully that'll be the end of it.

I am glad the mystery has been resolved. It happens ...

[Gen13 F36]