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2010 2011 BMW 5 Series Forum F10 F10 Technical Topics Wheels / Tires / Suspension / Brakes No tire pressure warning even at 15psi
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      11-09-2011, 01:46 PM   #1
androdev
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No tire pressure warning even at 15psi

My F10 doesn't alert me even when one of the tire's pressure goes down to 15 psi.

My car (in India) has the ABS based simple flat tire monitor. Runs on 225/50 R17 RFTs set at 30 psi. One of the tires is having a slow leak and the TPMS did not alert at 15psi. I filled up all tires to 30 psi, reset the TMPS through iDrive. After few days the pressure is down to 20psi but still no TPMS alert.

Dealer says this is not uncommon due to a stiff side wall of the RFTs and he says for some cars TPMS is alerting only when the tire is flat - but he is willing to diagnose the problem if I bring the car over to the workshop. In my previous VW cars, pressure loss warning was pretty reliable and was quite useful.

Is there anything I can do to get the right diagnosis? It is a new car with 5000 km on odo, ABS works great

Thanks.
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      11-09-2011, 01:51 PM   #2
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Quote:
Originally Posted by androdev View Post
My F10 doesn't alert me even when one of the tire's pressure goes down to 15 psi.

My car (in India) has the ABS based simple flat tire monitor. Runs on 225/50 R17 RFTs set at 30 psi. One of the tires is having a slow leak and the TPMS did not alert at 15psi. I filled up all tires to 30 psi, reset the TMPS through iDrive. After few days the pressure is down to 20psi but still no TPMS alert.

Dealer says this is not uncommon due to a stiff side wall of the RFTs and he says for some cars TPMS is alerting only when the tire is flat - but he is willing to diagnose the problem if I bring the car over to the workshop. In my previous VW cars, pressure loss warning was pretty reliable and was quite useful.

Is there anything I can do to get the right diagnosis? It is a new car with 5000 km on odo, ABS works great

Thanks.
You do not have TPMS in India - you have Flat Tire Monitor (FTM)

Your dealer is correct that FTM may not indicate a problem with RFTs - one reason that the direct TPMS was mandated in the US.
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      11-09-2011, 09:07 PM   #3
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Originally Posted by ceb View Post
You do not have TPMS in India - you have Flat Tire Monitor (FTM)

Your dealer is correct that FTM may not indicate a problem with RFTs - one reason that the direct TPMS was mandated in the US.
Thanks ceb. You are right, my car only has FTM. I have used TPMS in a generic way - for instance VW calls it TPMS (at least in India) even though it is ABS based indirect pressure loss detection.

Are you sure that FTM won't detect a drop from 30psi to 15psi - even when driven at 100 kmph? Hmmm.. that is a bummer for a bimmer, considering the cost of RFTs!
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      11-09-2011, 10:06 PM   #4
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Originally Posted by androdev View Post
Thanks ceb. You are right, my car only has FTM. I have used TPMS in a generic way - for instance VW calls it TPMS (at least in India) even though it is ABS based indirect pressure loss detection.

Are you sure that FTM won't detect a drop from 30psi to 15psi - even when driven at 100 kmph? Hmmm.. that is a bummer for a bimmer, considering the cost of RFTs!
It "should" detect it but the RFTs make it more difficult. FTM works by detecting differences in the outside rolling diameter of the tire from one tire to another.

Since RFT sidewalls keep the rolling diameter of an underinflated tire similar to the other tires, then the FTM has a hard time detecting the pressure loss.

That said, it should detect the fairly high pressure loss you described but the system may not have been set up properly initially.
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      11-10-2011, 03:13 AM   #5
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On the E60 the FTM only picks up a flat tire for RFT (meaning RFT with 0 psi) because as ceb said the RFT sidewall is stiff and it will create a problem for the FTM to pick up the slight difference of tire pressure as presented in a slow leaked situation.

I know because the comp prompt me about a flat on my RFT then I take it into the shop and they say no air inside the tire. Couldn't say is a design flaw as RFT tires are design to "Run flat" and you are not suppose to plug your tire on a RFT.

The best solution is get rid of the RFT then the FTM will pick up a slow leak.
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      11-10-2011, 10:08 AM   #6
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Quote:
Originally Posted by AC_S5 View Post
On the E60 the FTM only picks up a flat tire for RFT (meaning RFT with 0 psi) because as ceb said the RFT sidewall is stiff and it will create a problem for the FTM to pick up the slight difference of tire pressure as presented in a slow leaked situation.

I know because the comp prompt me about a flat on my RFT then I take it into the shop and they say no air inside the tire. Couldn't say is a design flaw as RFT tires are design to "Run flat" and you are not suppose to plug your tire on a RFT.

The best solution is get rid of the RFT then the FTM will pick up a slow leak.
There is no reason not to plug a RFT like any other tire (tread only, not close to sidewall) assuming that you are absolutely, positively sure that the tire has not been driven on in a low pressure state.

The OP wil need to replace the tire as he has driven on it with extremely low pressure - however - an owner with TPMS gets an alert, tests the pressure and sees 25psi. The owner pumps it up to the proper pressure and drives to a tire shop where a nail is found and the tire patched.

Most BMW dealers won't patch a tire because they don't know how long the tire was used with low pressure (or how low the pressure actually got) but most tire places will.

It is perfectly safe to do assuming you know that the tire was never driven severely low.
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      11-10-2011, 08:38 PM   #7
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Quote:
Originally Posted by ceb View Post
There is no reason not to plug a RFT like any other tire (tread only, not close to sidewall) assuming that you are absolutely, positively sure that the tire has not been driven on in a low pressure state.

The OP wil need to replace the tire as he has driven on it with extremely low pressure - however - an owner with TPMS gets an alert, tests the pressure and sees 25psi. The owner pumps it up to the proper pressure and drives to a tire shop where a nail is found and the tire patched.

Most BMW dealers won't patch a tire because they don't know how long the tire was used with low pressure (or how low the pressure actually got) but most tire places will.

It is perfectly safe to do assuming you know that the tire was never driven severely low.
Of course I patched my RFT given how expensive these tires are and to do my little part in helping the environment by producing one less scrap tire any shop other then BMW will happily do it for you and in most case free of charge.

You are absolutely right in the sense that it is ok to patch a RFT given it have not been driven a long time with no air pressure but the problem is this is a personal judgement of the driver as you can't really see the state of the RFT, but I rarely drives in autobahn speed so no harm in patching it.

Most BMW dealer or service center will not patch the tire because of liability issues as they don't want someone suing them after they got into an accident, so they just recommend you to change it and if the tire fail, they can always sue the tire company

For those who don't have the luxury of a government mandated TPMS, just ditch the run flats if you don't need it, is so convenient for us to call a tow truck and they wouldn't charge you an arm and a leg for towing it to the nearest tire shop.
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      11-12-2011, 10:05 AM   #8
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It turned out to be a small nail (1mm dia) thats why the leakage was very slow. The tire barely has run 5K km, since I don't know for how long the car was riding on this leaking tire (this car sits at home more than 50% of the week), I decided to take a chance and got it repaired with a plug.

It was a mistake to trust the flat tire monitor to report any pressure loss. The same system works great in my non-RFT VW car. I plan to get an after-market TPMS fitted (Orange or Hella TPMS).

What was BMW thinking by giving this lame system on cars equipped with RFTs - it is simply useless and gives a false sense of security.
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      11-14-2011, 05:25 AM   #9
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Quote:
Originally Posted by androdev View Post
It turned out to be a small nail (1mm dia) thats why the leakage was very slow. The tire barely has run 5K km, since I don't know for how long the car was riding on this leaking tire (this car sits at home more than 50% of the week), I decided to take a chance and got it repaired with a plug.

It was a mistake to trust the flat tire monitor to report any pressure loss. The same system works great in my non-RFT VW car. I plan to get an after-market TPMS fitted (Orange or Hella TPMS).

What was BMW thinking by giving this lame system on cars equipped with RFTs - it is simply useless and gives a false sense of security.
As you have seen in the above post. The FTM can pick up a slow leak for non RFT because it can sense the change in diameter of the tires. For RFT, it is impossible to pick up the change unless there is a huge variance in tire pressure ie 30 psi vs 10-15 psi.

I think the VW sensor will not pick up a slow leak on vehicle equipped with RFT unless it is fitted with a TPMS. So again is not a design flaw, the FTM does it job by letting you know when there's a flat tire. When you hear the warning, you are suppose to drive slowly (80km/h or below) to get the tire change. So I don't think you will be put in great danger by the system.

I would just ditch the RFT and go with non RFT and a mobility kit.
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      11-15-2011, 10:25 AM   #10
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Originally Posted by AC_S5 View Post
As you have seen in the above post. The FTM can pick up a slow leak for non RFT because it can sense the change in diameter of the tires. For RFT, it is impossible to pick up the change unless there is a huge variance in tire pressure ie 30 psi vs 10-15 psi.

I think the VW sensor will not pick up a slow leak on vehicle equipped with RFT unless it is fitted with a TPMS. So again is not a design flaw, the FTM does it job by letting you know when there's a flat tire. When you hear the warning, you are suppose to drive slowly (80km/h or below) to get the tire change. So I don't think you will be put in great danger by the system.

I would just ditch the RFT and go with non RFT and a mobility kit.
I understand your point of view. I should have explained a bit more. In India (where I bought this car), RFTs are mandatory. You can't buy any BMW here with regular tires. I can do an after-market swap and that voids my warranty (no kidding) as per the dealer. RFTs are expensive to replace. They have to be replaced if driven at low pressure for extended period. So the only way I can ensure I don't risk the premature replacement of RFTs due to low-pressure (not flat) ride is to manually check pressure regularly. I have the RFT insurance but my premium will go up if I claim replacement for minor issues.

Ideally BMW should have thought about it. They should have either given TPMS (direct one) when they made RFTs mandatory here - or given the option of having tubeless tires with FTM (flat tire monitor).

I agree the worst-case (flat tire) is addressed. But all my life I have only dealt with slow-leaking tires and never really a sudden flat tire.

Last edited by androdev; 11-15-2011 at 11:19 AM.
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      11-16-2011, 02:42 AM   #11
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Quote:
Originally Posted by androdev View Post
I understand your point of view. I should have explained a bit more. In India (where I bought this car), RFTs are mandatory. You can't buy any BMW here with regular tires. I can do an after-market swap and that voids my warranty (no kidding) as per the dealer. RFTs are expensive to replace. They have to be replaced if driven at low pressure for extended period. So the only way I can ensure I don't risk the premature replacement of RFTs due to low-pressure (not flat) ride is to manually check pressure regularly. I have the RFT insurance but my premium will go up if I claim replacement for minor issues.

Ideally BMW should have thought about it. They should have either given TPMS (direct one) when they made RFTs mandatory here - or given the option of having tubeless tires with FTM (flat tire monitor).

I agree the worst-case (flat tire) is addressed. But all my life I have only dealt with slow-leaking tires and never really a sudden flat tire.
Changing to non RF voids the warranty? That sucks!

But you can afford a BMW in India mean you shouldn't be worry about the cost of replaceing RFTs
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      12-02-2011, 12:52 PM   #12
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Quote:
Originally Posted by androdev View Post
It turned out to be a small nail (1mm dia) thats why the leakage was very slow. The tire barely has run 5K km, since I don't know for how long the car was riding on this leaking tire (this car sits at home more than 50% of the week), I decided to take a chance and got it repaired with a plug.

It was a mistake to trust the flat tire monitor to report any pressure loss. The same system works great in my non-RFT VW car. I plan to get an after-market TPMS fitted (Orange or Hella TPMS).

What was BMW thinking by giving this lame system on cars equipped with RFTs - it is simply useless and gives a false sense of security.

Why don't you buy some BMW TPMS sensors and get your dealer to activate the TPMS monitoring that your car should already be capable of.
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      12-26-2011, 09:53 PM   #13
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Originally Posted by Jim_in_Calgary View Post
Why don't you buy some BMW TPMS sensors and get your dealer to activate the TPMS monitoring that your car should already be capable of.
How to find if my car has the ability to work with BMW TPMS sensors - as in, I am not sure the car is pre-wired with receivers and control modules, etc?
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