02-23-2014, 02:57 PM | #1 |
Private
24
Rep 95
Posts |
Tyre initialisation feature
Baffled by this, checked the tyre pressure 2 weeks ago, ran the initialisation in idrive. Friday jut gone car felt funny, had a look and rear right looked flat, checked pressure with my gauge 10PSI. Took to kwik fit slow puncture but all tyres well below from last week.
All put back to correct pressure but isn’t this system designed to let you know about flat tyre of low psi per tyre. I take it that this system isn’t working on my car?. |
02-23-2014, 03:29 PM | #2 |
Brigadier General
266
Rep 3,290
Posts |
The problem is that runflat tyres have rather stiff sidewalls, so you need a very significant pressure drop to make enough impact on the dynamic tyre diameter. I am running non runflats on our F20, and it warns me when the tyres drop from 35 to 27 psi or so.
|
Appreciate
0
|
02-24-2014, 06:57 AM | #3 |
Second Lieutenant
14
Rep 223
Posts |
Was going to say the same as @ovekvam regards run flats -as I had the same issue because I thought the pressures didn't need checking because the car would warn me. So I have gotten back into the habit of checking once a month... and recently switched to non-run flat tyres too (for which I understand the system will work as expected).
__________________
Current: 2014 F21 M135i Estoril Blue
Previously: 2012 F21 116D M Sport Estoril Blue |
Appreciate
0
|
02-25-2014, 02:13 AM | #4 |
Lieutenant
53
Rep 485
Posts
Drives: 116i (F20) Auto
Join Date: Sep 2009
Location: Athens, Greece
|
The system works by calculating the difference in rotation speed of each wheel (so if you have a flat tyre the diameter of the wheel is smaller and thus it spins at higher rpms) and it does not actually read the tyre pressure. So, it needs a significant drop in tyre pressure for the diameter to be altered and the system to read it and register it. In my car I have found it needs to drop below 20psi to give me a warning.
I read that BMW is launchin a new and improved system from March 2014 (in all models bar the X6) onwards.
__________________
2011- : BMW 116i (F20)
2009-11: BMW Z4 2.5si (E85) 2007-09: Mini Cooper S (R56) 2005-07: BMW 325ti (E46) 2004-05: BMW 318i (E36) |
Appreciate
0
|
02-25-2014, 06:44 AM | #7 | |
First Lieutenant
11
Rep 353
Posts |
Quote:
If fitting yourself you can equip such a kit quite easily from somewhere like Halfords or you carry a spare in the boot. I like the convenience of runflats myself but would still rather the car had a wheel well capable of holding a full sized spare as I'm quite happy buying an extra alloy for punctures.
__________________
120d Sport gone and replaced with X1 18d XDrive MSport Auto.
No Xenons but plenty of creature comforts. |
|
Appreciate
0
|
02-25-2014, 06:45 AM | #8 | |
Second Lieutenant
14
Rep 223
Posts |
Quote:
*Edit: 14 years
__________________
Current: 2014 F21 M135i Estoril Blue
Previously: 2012 F21 116D M Sport Estoril Blue Last edited by matthewcornish; 02-25-2014 at 06:53 AM.. |
|
Appreciate
0
|
02-25-2014, 07:16 AM | #9 | |
Private
24
Rep 95
Posts |
Quote:
|
|
Appreciate
0
|
02-25-2014, 08:35 AM | #10 |
Brigadier General
266
Rep 3,290
Posts |
What pressure was it initialized at?
|
Appreciate
0
|
02-25-2014, 03:39 PM | #11 |
First Lieutenant
11
Rep 353
Posts |
Good point, some easy fit type places have been notably shocking in the past for either generating work or not actually carrying out work correctly.
Potentially pressure wasn't actually checked just a visual and if the TPM is then reset, it takes the 8psi as the reference and you are non the wiser alarm wise.
__________________
120d Sport gone and replaced with X1 18d XDrive MSport Auto.
No Xenons but plenty of creature comforts. |
Appreciate
0
|
02-25-2014, 04:43 PM | #12 | |
Lieutenant General
6659
Rep 15,858
Posts |
This is likely the issue.
I'm aware of users thinking they have initialized the system and have not even checked the tyre pressures first. There has to be the baseline reference, as has been stated. We need it to be of meaning, by being accurate. The other issue is the system is not initialized correctly, some users think they have done it correctly, but not OK'd the action. Note the pressure drop can be up to 30% before a warning is triggered. A tyre set at 35 psi should trigger before dropping past ~25 psi. BMW Wrote: Quote:
Last edited by HighlandPete; 02-25-2014 at 04:49 PM.. |
|
Appreciate
0
|
Post Reply |
Bookmarks |
|
|