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Old 3rd June 2016, 16:50   #61
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

Sorry for

Quote:
Originally Posted by quickdraw View Post
Actually they measure tire pressure via inertia. Only some cars have actual pressure monitors and temperature monitors.
As per inputs I got from guys from BMW in India (last year), not even 7 series came with individual tyre pressure sensors and direct pressure monitoring system in India (RDKS) among their model range at that time. Not sure about new generation of cars launched after that though.


Quote:
Originally Posted by the_skyliner View Post
Forget fully deflate, even if there is a loss of 3-4 psi in one of the tyres, iDrive will give you warning message - irrespective of your average speed.
ABS based indirect pressure monitoring aka FTM (Flat tyre monitoring) is not that efficient that it would detect 3-4 psi pressure loss especially in city speed limits, that too with RFTs that does not deform much and do not flatten even when fully deflated. I have experience with that on my 320d. One of the RFTs fully deflated due to a minor sidewall cut and got warning only the next day while driving to BMW after noticing pressure loss in one of the tyres (RFT doesn't look like a flat tyre even when fully deflated). I guess less deformation and slow speeds combined makes it difficult for abs module to detect it. I have been reading up regarding that when I experienced it and many owners accross the globe have reported same. That is why I retrofitted RDKS when I upsized and went for lower profile tyres. Now, I get constant pressure/temp reading of each tyre and warning works for minor losses in pressure irrespective of RFTs or slow speeds.

FTM is more effective on higher speeds, not that it will never work in city speeds. But higher wheel RPM (higher speeds ie) makes it easier for abs module to detect it. Its done by comparing difference between wheel RPMs as the circumference of a fully inflated tyre will be more than that of a tyre with lesser pressure, hence making the smaller one rotate faster. At lower speeds, it is not easily detected, from my experience as well as many who have reported same. May be the sensitivity of that alarm is not set too low to prevent frequent pressure warnings due to thermal variations. FTM is usefull but not as efficient as direct TPM or RDKS.
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Old 3rd June 2016, 17:32   #62
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

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Originally Posted by ajaypjayaraj View Post
ABS based indirect pressure monitoring aka FTM (Flat tyre monitoring) is not that efficient that it would detect 3-4 psi pressure loss especially in city speed limits, that too with RFTs that does not deform much and do not flatten even when fully deflated.
My experience has been different. Rear left tyre had a minor puncture and lost 4 psi and the iDrive detected it. All the other tyres had 32 psi and this one had 28 when checked.

BMW service center could not find the puncture but when took it to a local tyre (trusted one in Pune) shop, they found and repaired it.
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Old 3rd June 2016, 17:37   #63
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

Quote:
Originally Posted by the_skyliner View Post
My experience has been different. Rear left tyre had a minor puncture and lost 4 psi and the iDrive detected it. All the other tyres had 32 psi and this one had 28 when checked.

BMW service center could not find the puncture but when took it to a local tyre (trusted one in Pune) shop, they found and repaired it.
It does work. But from my experience I started investigating and there is a common opinion worldwide, from others experiences too, that you cannot count on it always as compared to a direct TPMS. That's all.
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Old 4th June 2016, 10:19   #64
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

Has anyone seen the new BMW X1 newspaper ad? The list of features include "twin power turbo diesel engine", "panorama glass roof" and ........ "spare wheel" Regular people would be wondering why BMW is listing "spare wheel" as a major feature!!

If they just give a wheel well in the boot, everyone will be happy. It is just that simple.
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Old 5th June 2016, 18:37   #65
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

What ever be the reason in terms of space saving, less weight etc that has prompted the BMW to have no spare tires is not justifiable, especially in India. As they themselves, have reintroduced the donuts in X1. I had a horrendous ride experience with the RFTs on my X1. The RFTs not only had a bad ride, the car also handled erroneously with tram-lining at certain instances. I changed over to CSC5 that are way better. I am looking for the donuts now.

The rear well under the boot where the batteries are placed could be better designed. I fully support the BMWs idea of the battery placement there for the purpose of safety. However a little better ergonomics could have made space for another full sized tire.

BMW should realize that a lot of people in India are moving away from BMW because of this tire issue. They may even consider subsidizing the donuts rather than exorbitantly prizing it, so as to support the owners to whom they have sold the cars with RFTs but with no donuts.
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Old 5th June 2016, 18:40   #66
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

Mildly OT. My son imported a TPM system for some ₹12k (from I think Amazon.com) and installed it in his City. He is quite happy with it. The small (detachable) dashtop unit shows the individual pressures and also the alarm thresholds for all four.
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Old 6th June 2016, 14:15   #67
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

Quote:
Originally Posted by RSUDARSANAN View Post
Think about it. They actually don't want you to dirty your hands at all, leave alone the boot .

Now that it's been brought up, I must confess, in 100k+ kms of ownership:
- I've never dirtied my hands, honest-to-goodness.
- The flatbed came to my rescue on three different occasions .
I am assuming the flatbed came to your rescue within city limits, because waiting for a flatbad in the middle of no-where at 3am is not a pleasant experience at-all.

Quote:
Originally Posted by NKR View Post

BMW should realize that a lot of people in India are moving away from BMW because of this tire issue. They may even consider subsidising the donuts rather than exorbitantly prizing it, so as to support the owners to whom they have sold the cars with RFTs but with no donuts.
Absolutely agree, they should not be charging over 10k for a single space saver, considering how essential it is for this country. I'm majorly pissed off about it and have been exploring option of getting full size spare wheel with a cover and it will still cost lesser.
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Old 6th June 2016, 15:14   #68
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Cool Re: Pics: BMW's incredibly stupid spare tyre solution

Quote:
Originally Posted by quickdraw View Post
I am assuming the flatbed came to your rescue within city limits, because waiting for a flatbad in the middle of no-where at 3am is not a pleasant experience at-all.
Outside city limits:

1. Masinagudi - 3.00 pm (limped into town)
2. Gundulpet - 3.30 pm (limped into town)
3. Yelagiri - 2.30 am ! (limped back to the resort).

Time mentioned is when the flat bed reached.

Waiting is a given.
In the middle of no-where isn't an option. Just bad luck.
Else, avoid night drive, per individual call.

Last edited by RSUDARSANAN : 6th June 2016 at 15:19.
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Old 9th December 2016, 08:37   #69
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

I think this thread needs a title change. If BMW India is (or perhaps was) bad with run flat tyres and no wheel wells (until the latest 7, X1 and X5), Mercedes Benz is far worse. As some of you are aware, I am in the market for a new SUV. The GLC sold in India does not come with Extended Mobility tyres (Mercedes' run flat solution). But it has no wheel well and so the space saver takes up a massive amount of boot space - in fact I could barely fit 2 medium sized suitcases after removing the luggage compartment cover in it. Worse, there is a decent amount of storage space under the boot floor - which can't be accessed except by removing the run flat. The Audi Q7 solution is far better as are the run flats on the BMW that at least give you the option of leaving a space saver at home for those airport or Lonavala runs.
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Old 9th December 2016, 11:15   #70
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Default

Just sharing my experience with run flat.

Coming back to Delhi from Jaipur at night I had tyre burst with more than 120km to go.

The cause was bitumen hump, caused by overloaded trucks, in middle of highway. Driving at 120kmph the choice was either hit the engine sump or try to take the wheel above the hump. The tyre burst on hitting the hump.

Reduced speed to 60kmph and drove all the way back without problem.

Even I was surprised at robustness offered by run flats. Pictures taken next day morning outside the house.
Attached Thumbnails
Pics: BMW's incredibly stupid spare tyre solution-1481262254827.jpg  

Pics: BMW's incredibly stupid spare tyre solution-1481262270456.jpg  


Last edited by sudev : 9th December 2016 at 11:18.
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Old 9th December 2016, 12:27   #71
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

Quote:
Originally Posted by sudev View Post
Just sharing my experience with run flat.
Holy cow! That tire is literally ripped apart.

But are you sure sudev other components like rim etc are fine? Do get that checked please.
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Old 9th December 2016, 16:30   #72
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

Quote:
Originally Posted by sudev View Post
Just sharing my experience with run flat.

Coming back to Delhi from Jaipur at night I had tyre burst with more than 120km to go.

The cause was bitumen hump, caused by overloaded trucks, in middle of highway. Driving at 120kmph the choice was either hit the engine sump or try to take the wheel above the hump. The tyre burst on hitting the hump.

Reduced speed to 60kmph and drove all the way back without problem.

Even I was surprised at robustness offered by run flats. Pictures taken next day morning outside the house.
Oh, that looks really bad!
Sorry to see this but good that you didn't panic and let the tire take the hit rather than the sump. That would have been much more inconvenient and not to mention, expensive.

What tire size is that? And did you at all felt loss of control for even a milli second? I am curious to know this as I prefer RFTs over normal tubeless for the safety they offer and a change is due for my car.
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Old 9th December 2016, 19:54   #73
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

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Originally Posted by GTO View Post
I got a bone to pick with BMW India for 4 reasons:[*]Making runflats standard. Can't wait to move to pure tubeless rubber! Fixable in the after-market.
I totally agree with everything you have said except the point above. Even the RFTs can be repaired very easily the same way as a tubeless in any aftermarket small puncture repair set up. No special tools are needed. Or were you trying to say something else?
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Old 9th December 2016, 21:57   #74
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

Quote:
Reduced speed to 60kmph and drove all the way back without problem.
120 Km - You are lucky. I could not do more than 60 Km many Years ago. Maybe due to different profile or quality of tyres have improved.

I never go on outstation trips without a space saver since that incident. RFT's are good if you are withing 50 Km of any major city but anything beyond -No and neither will I recommend anyone to go without one.


http://www.team-bhp.com/forum/techni...ml#post2522505 (Run Flats could go Flat)
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Last edited by Turbanator : 9th December 2016 at 21:59.
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Old 11th December 2016, 18:43   #75
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Default Re: Pics: BMW's incredibly stupid spare tyre solution

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Originally Posted by Turbanator View Post
120 Km - You are lucky. I could not do more than 60 Km many Years ago. Maybe due to different profile or quality of tyres have improved.

http://www.team-bhp.com/forum/techni...ml#post2522505 (Run Flats could go Flat)
You are right mate! The rubber compound has improved a lot. It leads to a new problem though.

After taking a whack on a pothole, now the alloy wheel may get bent but the tyre remains intact. The insurance company now haggle and neither pay for the tyre nor the rim UNLESS both are damaged.

Otherwise for now, run flats have been giving me good service. If their is a leak, I get it fixed at the nearest puncture wallah and no need to stop by the roadside for changing wheels while risking car and self.
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