[NFS]

Originally Posted by OliH

Are the TPMS sensors only on the coupe - I didnt have them on mine - I thought the TPS was callibrated via the rolling radius of the tia formt he ABS sensor

There are 2 different systems. One which is built into the valves and an older one which picks up sudden changes in rotational speed.

If you have metal valve stems you need to re-use those valves when you change tyres.

I think the coupes all have the metal valve type, but could be wrong.

[red-max]

Originally Posted by needforspeed

There are 2 different systems. One which is built into the valves and an older one which picks up sudden changes in rotational speed.
If you have metal valve stems you need to re-use those valves when you change tyres.
I think the coupes all have the metal valve type, but could be wrong.

I'm pretty sure I've just got regular valves on my Coupe - I thought UK cars just used ABS sensors, and only American BMWs had actual pressure sensors...

[E92Fan]

Originally Posted by OliH

Are the TPMS sensors only on the coupe - I didnt have them on mine - I thought the TPS was callibrated via the rolling radius of the tia formt he ABS sensor

Correct - the TPMS are/were only used on the E92 and E93. The E90/E91 both used the ABS sensors to detect a problem. I believe that all 08 model cars now use the TPMS sensors

[E92Fan]

Originally Posted by red-max

I'm pretty sure I've just got regular valves on my Coupe - I thought UK cars just used ABS sensors, and only American BMWs had actual pressure sensors...

No, you'll have TPMS sensors on the end of the metal valve stems

[E92Fan]

Originally Posted by DaveC

Whats ET37 offset? ET39?

The offset, or ET measurement in millimetres, determines the position of the mounting point of the wheel in relation to the centreline of the wheel (see diagram below)



Looking at the picture above, note that the left hand side is the brake side, and the right hand side is the outer edge of the wheel.

In the left image, you can clearly see that the mounting point is positively offset to the right of the centreline of the wheel - so for instance an ET37 wheel will have the mounting point 37mm to the right of the centreline.

The middle image shows no offset at all, so the mounting point is in the same position as the centreline of the wheel.

The right image shows negative offset.

The higher the positive offset value, the more the wheels sits IN towards the hubs. The lower the offset value the closer to the wheelarch. In both cases, the width of the wheel is constant, the only thing that changes is the mounting position relative to the centreline of the wheel.

[330cdsport]

Originally Posted by E92Fan

The offset, or ET measurement in millimetres, determines the position of the mounting point of the wheel in relation to the centreline of the wheel (see diagram below)

Attachment 121637

Looking at the picture above, note that the left hand side is the brake side, and the right hand side is the outer edge of the wheel.

In the left image, you can clearly see that the mounting point is positively offset to the right of the centreline of the wheel - so for instance an ET37 wheel will have the mounting point 37mm to the right of the centreline.

The middle image shows no offset at all, so the mounting point is in the same position as the centreline of the wheel.

The right image shows negative offset.

The higher the positive offset value, the more the wheels sits IN towards the hubs. The lower the offset value the closer to the wheelarch. In both cases, the width of the wheel is constant, the only thing that changes is the mounting position relative to the centreline of the wheel.

Great description. Thanks for that.

Also - going back to the Tyre pressure sensors..... My valve stems are rubber and not metal, does that mean my coupe uses the older 'wheel diameter' method to detect pressure.
I also found that when i recently got a slow puncture, the warning light did not come on until the pressure went below 20psi (from about 38psi). This seemed a very slow reaction to me.

[E92Fan]

Originally Posted by 330cdsport

Great description. Thanks for that.

Also - going back to the Tyre pressure sensors..... My valve stems are rubber and not metal, does that mean my coupe uses the older 'wheel diameter' method to detect pressure.
I also found that when i recently got a slow puncture, the warning light did not come on until the pressure went below 20psi (from about 38psi). This seemed a very slow reaction to me.

Hmmm, I'm 99% sure you should still have the TPMS sensors.
The tyre monitoring system works at its best at sudden pressure loss - slow leakage over a period of time can fool the sensor into thinking everything's ok, until the pressure difference is quite large (ie when it got to 20psi). The TPMS sensor is not designed to give readings if the pressure is 2 or 3 psi under, as a pressure change like this can be attributed to temperature of tyre or driving conditions...

[kend]

Originally Posted by E92Fan

Hmmm, I'm 99% sure you should still have the TPMS sensors.
The tyre monitoring system works at its best at sudden pressure loss - slow leakage over a period of time can fool the sensor into thinking everything's ok, until the pressure difference is quite large (ie when it got to 20psi). The TPMS sensor is not designed to give readings if the pressure is 2 or 3 psi under, as a pressure change like this can be attributed to temperature of tyre or driving conditions...

On my 06 coupe the TPMS system is based on the rotation method with rubber valve stems. matbe the 335 have the pressure system.
Ken

[red355]

Originally Posted by E92Fan

No, you'll have TPMS sensors on the end of the metal valve stems

My replacement wheels have standard valves fitted by the (fairly) low tech (but excellent) under the arches tyre fitting guys . The tyre pressure warning system still works .. one of the rears has a got a slow puncture (only when its cold) and looses about 5 or 6 PSi/week. It needs hat level to trigger the system. thats consistent with what have found with the system in the MINI

Not sure if it makes a difference but my E92 is one of the earliest ...build date is 09/06

Originally Posted by kend

On my 06 coupe the TPMS system is based on the rotation method with rubber valve stems. matbe the 335 have the pressure system.
Ken

Thats answered that question

[ChrisMWard]

A 6 psi drop triggered the warning when we picked up a screw in the E90.

Regards

Chris

[dxb335d]

So will my pressure sensors still work on my non runflats?

i will still be alerted whenthe pressure drops?

ALso what sort of mobility kit do i need?

I am going into the city to buy one this afternoon, any recommendations and can i get one from halfrauds.

[330cdsport]

I bought a rapid tyre inflator from Halfords for about £25 i think and then a 12oz bottle of slime from ebay. The compressor sits snuggly in the little section above the tool tray.

[dxb335d]

I already have a compressor. Seems redundant now as i have bought this stuff which pumps up the delfated tyre and has a layer of latex to hold pressure and get you home! 6 quid a bottle.

[SoYank]

My understanding of the two types of FTM is:
1) The earlier type, like on the 2006 E90, uses the rotation of the tyres to detect a deflated tyre.
2) The TPMS uses a sensor inside the wheel at the end of the valve stem to detect the pressure and transmits this to the computer inside the car which then does its algorithmic magic to tell you that that swerving and "whop, whop, whop" you're encountering and hearing is due to a flat tyre. This is an example taken from TireRack.com website.

[alpini]

you all seem to know at what pressure loss the car alerted you that something was up - does the car display this reading? i got a puncture this evening - warning light came up - than pulled into garage to pump with air to see what was up and the tyre was hissing away!

hope i don't need to replace whole tyre since i'm thinking of changing wheels altogether very soon!!

btw, if i'm buying brand new 19" rims with non-runflats what's this about TPMSensors? do i need them?

[Yahoo]

I changed my run flats today. M 08 e92 does not have TPMS. There are no metal valves and when asked, BMW said that they have returned back using the ABS sensors. My tyre place changed my tyres using regular valves and all seems fine.

As for the tyre, I used Vredesien Ultrac Sessantas. They are getting such good write ups all over the place, I couldn't resist. Oh, and the price is right as well (£110 for 225/35/19 and £123 for 265/30/19 from Pneus Online). The tyres seem excellent. Quiet, sticky, smooth, nice feel through the steering wheel - I really can't fault them. I have not pushed them hard yet, but I suspect that they are more capable than I am. I was tempted to get some F1 Assymetricals, but the £200 difference was impossible to ignore.

I have driven the car twice on the new tyres and I can honestly say that the drive is night and day. The best way I can describe it is that the 'harshness' has gone. Whereas before I would brace myself when going over some undulations or cats eyes, the car simply rides them much better now.

It is still a relatively hard setup, don't get me wrong, but the whole exerience is so much more fluid now. I can definately see why the 'sportier' 3 series don't use RFTs (M3. Alpina etc), they are just not up to the job.

So would I recommend that people change . . . . . definately. I can not think of a single reason why I would to opt for RFTs again. Expensive, harsh ride, unable to repair, very limited UK stock etc. I know that the technology is improving, but I just don't think it is anywhere near good enough. I wasn't particularly disappointed with the ride when on RFTs, but having changed, I can't explain just how much better the e9X runs on non RFTs - as I said, night and day.

I am not disappointed that I didn't go for the F1s either. These are undeniably the best tyre out there, but I am pretty confident that the Ultrac Sessanta's offer 95% of the 'quality' of the F1s, for 65% of the price. I am not sure whether I would ever push my car to the point of actually ever using the 5% that I am missing by opting for the Sessantas - particularly on UK roads.

This is the first performance mod that I have done, all others have been aesthetic so far, and I am really pleased that I have made this decision. I can't wait for the SSTT now so that I can move the performance on to the next level.

I have to say that overall, the e9X 335i/d is an excellent package from stock - but with an extra £1k thrown at one - they are truely exceptional in all departments .

[Ant397]

Originally Posted by DaveC

Whats ET37 offset? ET39?

Its means if you take a theoretical line straight through the centre of the width of the wheel, this would be 0mm ET offset. So with ET37, the rear of the hub mounting face is 37mm biased to the outside of the wheel. So the same width wheel with an offset of 10mm would have a much deeper dish effect to it when seen from the outside as the hub mounting face would move futher in towards the car.

You can then also get -ET negative ET so this gives a really wide sticking out wheel, with a massive 'dish' effect.

[Ant397]

Ok, now found page 2... Read above for a far better explanation!

[BC4J]

Originally Posted by Yahoo

...So would I recommend that people change . . . . . definately. I can not think of a single reason why I would to opt for RFTs again. Expensive, harsh ride, unable to repair, very limited UK stock etc... .

This is the single reason you seek - http://www.e90post.com/forums/showthread.php?t=127609.

[335DJim]

Originally Posted by Yahoo

I changed my run flats today. M 08 e92 does not have TPMS. There are no metal valves and when asked, BMW said that they have returned back using the ABS sensors. My tyre place changed my tyres using regular valves and all seems fine.

As for the tyre, I used Vredesien Ultrac Sessantas. They are getting such good write ups all over the place, I couldn't resist. Oh, and the price is right as well (£110 for 225/35/19 and £123 for 265/30/19 from Pneus Online). The tyres seem excellent. Quiet, sticky, smooth, nice feel through the steering wheel - I really can't fault them. I have not pushed them hard yet, but I suspect that they are more capable than I am. I was tempted to get some F1 Assymetricals, but the £200 difference was impossible to ignore.

I have driven the car twice on the new tyres and I can honestly say that the drive is night and day. The best way I can describe it is that the 'harshness' has gone. Whereas before I would brace myself when going over some undulations or cats eyes, the car simply rides them much better now.

It is still a relatively hard setup, don't get me wrong, but the whole exerience is so much more fluid now. I can definately see why the 'sportier' 3 series don't use RFTs (M3. Alpina etc), they are just not up to the job.

So would I recommend that people change . . . . . definately. I can not think of a single reason why I would to opt for RFTs again. Expensive, harsh ride, unable to repair, very limited UK stock etc. I know that the technology is improving, but I just don't think it is anywhere near good enough. I wasn't particularly disappointed with the ride when on RFTs, but having changed, I can't explain just how much better the e9X runs on non RFTs - as I said, night and day.

I am not disappointed that I didn't go for the F1s either. These are undeniably the best tyre out there, but I am pretty confident that the Ultrac Sessanta's offer 95% of the 'quality' of the F1s, for 65% of the price. I am not sure whether I would ever push my car to the point of actually ever using the 5% that I am missing by opting for the Sessantas - particularly on UK roads.

This is the first performance mod that I have done, all others have been aesthetic so far, and I am really pleased that I have made this decision. I can't wait for the SSTT now so that I can move the performance on to the next level.

I have to say that overall, the e9X 335i/d is an excellent package from stock - but with an extra £1k thrown at one - they are truely exceptional in all departments .

Great write up - thanks!.. ordered my Goodyear Asym F1's last week from PNEUS - should be here sometime this week - these RFT are just awful over bumps when cornering - I would say near on dangerous, the car skips across the rode because there is NO give in the side walls!