Run Flats/non-Run Flat mix

[Dumbas 0]

Having wasted 2 days of my life attempting to learn about tyres ( with very limited success) I seek opinions/views on the mixing of run flats "RFTs" and non-run flats.

Firstly, i accept that this solution is not ideal and certainly not in line with BMWs commitment to "run flat technology". However I have a 2010 5 Touring and need to replace a tyre and no suitable RFTs are available in NZ. I have decided to switch away from RFTs (I am lucky the car has a space saver). Two of the fitted RFTs are in good condition and probably have at least 10000km left in them. Secondly, the consensus of opinion is that a mixed configuration is warrantable so long as each axle has matching tyres. So some questions;

1. Does the mixing of RFTs and non-RFTs markedly affect the handling of the car? The car has some electronic trickery that assists handling and I am sure some immensely intelligent German chap has done some calculations on the suspension based on the fitment of RFTs. That said, the car very rarely does more than 130kph.. Oops... I mean 100kph. Whereas the clever German chappie would have based his sums in 200+kph.

2. If I do mix them, would you put the new non-RFTs on the front or the back?

If any of you have any experience of this, I would be appreciative of your advice.

[kiwi535 538]

Having wasted 2 days of my life attempting to learn about tyres ( with very limited success) I seek opinions/views on the mixing of run flats "RFTs" and non-run flats.

Firstly, i accept that this solution is not ideal and certainly not in line with BMWs commitment to "run flat technology". However I have a 2010 5 Touring and need to replace a tyre and no suitable RFTs are available in NZ. I have decided to switch away from RFTs (I am lucky the car has a space saver). Two of the fitted RFTs are in good condition and probably have at least 10000km left in them. Secondly, the consensus of opinion is that a mixed configuration is warrantable so long as each axle has matching tyres. So some questions;

1. Does the mixing of RFTs and non-RFTs markedly affect the handling of the car? The car has some electronic trickery that assists handling and I am sure some immensely intelligent German chap has done some calculations on the suspension based on the fitment of RFTs. That said, the car very rarely does more than 130kph.. Oops... I mean 100kph. Whereas the clever German chappie would have based his sums in 200+kph.

2. If I do mix them, would you put the new non-RFTs on the front or the back?

If any of you have any experience of this, I would be appreciative of your advice.

i got some pirrellis neither contis or bridgestones were avaiable...i realise they are more than likely different sizes

Edited January 19, 2012 by kiwi535

[Dumbas 0]

Hi kiwi535,

The size is 245/35R19.

[zenetti 0]

Having wasted 2 days of my life attempting to learn about tyres ( with very limited success) I seek opinions/views on the mixing of run flats "RFTs" and non-run flats.

Two of the fitted RFTs are in good condition and probably have at least 10000km left in them. Secondly, the consensus of opinion is that a mixed configuration is warrantable so long as each axle has matching tyres. So some questions;

2. If I do mix them, would you put the new non-RFTs on the front or the back?

If any of you have any experience of this, I would be appreciative of your advice.

hi Rod

Firstly, welcome along to the forums.

Unfortunately a mixed configuration will NOT be warrantable. You will either have to go for one or the other. In the WOF rules it states that tyres must be of the same construction type. RFT and "normal" tyres are constructed differently. In addition your can should have the same tread pattern type on all 4 corners, eg asymmetric, directional etc. Again you are not allowed to mix and match.

As you have a space saver I can't see any problems in going to a non-rft. Bear in mind though that the rims are designed to use a RFT and are usually substantially heavier than a normal rim as they have an extra bead seating in them. ( it is not the technical term, but probably the easiest way to describe it - lol)

On a positive note you will find that 'normal' tyres are a whole lot cheaper, and generally quieter. In fact you could probably get a new set of rims and tyres for the cost of 4 RFT's!

Feel free to give me a call on the number below if you want to discuss any further

cheers

Johno

Edited January 19, 2012 by zenetti

[Dumbas 0]

For anyone with a similar scenario, I put 2 Pirelli Rossos non RFTs on the front and swapped the 2 Dunlop RFTs to the rear axle.

After much debate and head-scratching it was decided the car was warrantable. The source for this was 2 Service Centres authorized to warrant vehicles, including Jerry Clayton BMW.

I have driven the car a bit over the weekend and the car drives no differently. We haven't done a long trip yet to establish if the tyre temps rise enough to possibly increase the circumference of the non-RFTs and trigger the Tyre Failure warning.

In sum, so far so good. However, as to whether or not I would buy another late model BMW, that will be the subject of another thread when I have collected my thoughts. In the meantime, if you have a BMW with RFTs, you must buy a tyre pressure gauge and religiously check your pressures every month (fortnightly, if you read your handbook!!!). You also have to check the rear tyres for wear on the inside edge. Although not recommended by BMW, it is probably wise to swap your tyres around 6 monthly to limit the wear to the rear inside edge. Failure to religiously carry out these measures will not only result in higher fuel burn and tyre wear, but will almost certainly result in tyre failure, long before the tyres get close to the wear indicators!! Alternatively, you could just buy an Audi and save yourself the grief!!

Edited January 22, 2012 by Dumbas

[Allanw 1072]

Alternatively, you could just buy an Audi and save yourself the grief!!

True. Or a Camry.

[Rodg1350 0]

I have tried for days to get 2 x 255x35x18 runflats for my wifes 2007 323...there are none in New Zealand ..new or second hand that I could find. I have no room for spacesaver so my wifes car will be off the road for about 2 months while awaiting new stock...then..I will be asked to pay the $700 each...Dont buy a BMW with runflats..

[zenetti 0]

I have tried for days to get 2 x 255x35x18 runflats for my wifes 2007 323...there are none in New Zealand ..new or second hand that I could find. I have no room for spacesaver so my wifes car will be off the road for about 2 months while awaiting new stock...then..I will be asked to pay the $700 each...Dont buy a BMW with runflats..

PM Sent

[matt45 1]

i dont mean to hi jack but...

What are the options for a BMW (1 series) that simply has no space for a spare even if you wanted to buy one.

so far all i can see is:

A. shell out for run-flats all around

B. run normal tyres and keep a can of that gummy compressed sealant crap in the boot with a pump and hope that would get you to a tyre shop.

options?

[*Glenn* 855]

i dont mean to hi jack but...

What are the options for a BMW (1 series) that simply has no space for a spare even if you wanted to buy one.

so far all i can see is:

A. shell out for run-flats all around

B. run normal tyres and keep a can of that gummy compressed sealant crap in the boot with a pump and hope that would get you to a tyre shop.

options?

Shares or part ownership in a towing Company

[kiwi535 538]

i dont mean to hi jack but...

What are the options for a BMW (1 series) that simply has no space for a spare even if you wanted to buy one.

so far all i can see is:

A. shell out for run-flats all around

B. run normal tyres and keep a can of that gummy compressed sealant crap in the boot with a pump and hope that would get you to a tyre shop.

options?

can you option them WITHOUT run flats???in my case i had to pay 400 each for a pair of pirelli 205/55 16 i think.They seem to more compliant than the bridgstone turanzas that they replaced.I have a pair of contis and the pirellis.I will SERIOUSLY consider non runflats and a pando.Isnt that what the e39 M5 has as standard?

In sum, so far so good. However, as to whether or not I would buy another late model BMW, that will be the subject of another thread when I have collected my thoughts. In the meantime, if you have a BMW with RFTs, you must buy a tyre pressure gauge and religiously check your pressures every month (fortnightly, if you read your handbook!!!). You also have to check the rear tyres for wear on the inside edge. Although not recommended by BMW, it is probably wise to swap your tyres around 6 monthly to limit the wear to the rear inside edge. Failure to religiously carry out these measures will not only result in higher fuel burn and tyre wear, but will almost certainly result in tyre failure, long before the tyres get close to the wear indicators!! Alternatively, you could just buy an Audi and save yourself the grief!!

my experience with runflats hasnt been as testing as yours.I find the pressures hardly vary at all.Whenever i top up the pressures i re initialise the system.I have never had the warning .Good point about keeping an eye on the inside edge of the rears tho,i learnt that the hard way on my old e34.I used to swap the fronts to the back about halfway through(the fronts used to wear the OUTSIDE

[matt45 1]

can you option them WITHOUT run flats???in my case i had to pay 400 each for a pair of pirelli 205/55 16 i think.They seem to more compliant than the bridgstone turanzas that they replaced.I have a pair of contis and the pirellis.I will SERIOUSLY consider non runflats and a pando.Isnt that what the e39 M5 has as standard?

didn't understand a word of that

[kiwi535 538]

didn't understand a word of that

1)I wonder i f you can order a new 1 series WITHOUT run flats

2)I had to get two new tyres just before xmas.The car already had bridgstones Turanza and Continentals but neither of these were available.I got some pirelli P7 run flats but they were 400 each but they do seem to be slightly softer riding than the Bridgestones

3) I will consider getting non run flats next time and trust a tyre pando and or tyre repair kit and a compressor

4) forget about the M5 comment its not important

[matt45 1]

1)I wonder i f you can order a new 1 series WITHOUT run flats

2)I had to get two new tyres just before xmas.The car already had bridgstones Turanza and Continentals but neither of these were available.I got some pirelli P7 run flats but they were 400 each but they do seem to be slightly softer riding than the Bridgestones

3) I will consider getting non run flats next time and trust a tyre pando and or tyre repair kit and a compressor

4) forget about the M5 comment its not important

re:

1. i was under the impression that there was physically no room for a spare due to the diff placement? meaning BMW would i imagine be very reluctant to sell a car without an emergency solution ( i could be wrong)

2.

3. yea thats what i was thinking, also just realized there is probably no jack either?

[kiwi535 538]

re:

1. i was under the impression that there was physically no room for a spare due to the diff placement? meaning BMW would i imagine be very reluctant to sell a car without an emergency solution ( i could be wrong)

2.

3. yea thats what i was thinking, also just realized there is probably no jack either?

i havnt seen a jack no.....i found a tow bar but no jack

[matt45 1]

i havnt seen a jack no.....i found a tow bar but no jack

tow bar parking sensor

[turbolizard 38]

3) I will consider getting non run flats next time and trust a tyre pando and or tyre repair kit and a compressor

4) forget about the M5 comment its not important

You are correct that the e39 M5 has 4 regular tires and a can of goo and a compressor. It is a constant nagging worry.

[my_e36 43]

i havnt seen a jack no.....i found a tow bar but no jack

Doesn't need a jack to use the tyre gum sealant does it?

This run-flat business, we all heard more bad things than good. I reckon it's a penny pinching scheme on a global scale, just imagine saving a jack, a tyre and a rim for every car made. Car manufacturers are saving tens of millions per year for omitting these! Then trying to justify to us consumers with marketing BS like safety, fuel economy, etc... then "conveniently" forgot to mention about their noise, ride quality and replacement cost.

Edited January 26, 2012 by SpikeyLemon

[M5V8 337]

You are correct that the e39 M5 has 4 regular tires and a can of goo and a compressor. It is a constant nagging worry.

X2 M5's. 60 odd + highway km's. Never had to use the M mobility unit. touch wood.

Modern tyre design these days is pretty good. You'd have to hit something serious or have previous damage to have a blowout from a low profile tyre.

[Dumbas 0]

Other options to Runflats?

You can go the can of goo, but I harbour serious doubts about its effectiveness and I am told it makes the tyre unrepairable. Some people change to non-RFTs and throw a spare in the boot when they do a longer journey. It's a fair compromise, but it's hardly commensurate with the BMW image of the joy of driving.

BMW's answer is that there is no need for any of this. They say just pull over, check the tyre is still structurally sound and then consult the manual. From the manual, pick a speed and then drive to a BMW Service Centre. It all sounds good until you realize that the service centre won't have a RFT tyre and the cost and hassle of getting one couriered to you (possibly from overseas), makes it all a nightmare.

Another problem I encountered. I was not prepared to drive on the failed RFT as the tread was peeling away and the tyre punctured because the sidewall was splitting away from the tread. I did no more than 5kms on the tyre, no way would I do 150 km. I think the tyre manufacturers factor their calculations on the basis of a simple puncture, not a structural failure like I had. As M5v8 said, what's the chances of a structural failure? I have been driving for decades and this is the only time a tyre has structurally failed.... and it occurred during the 23500 km of driving on RFTs... Bad luck or what?

Actually, I think maybe the tyre failed because it was a RFT, in that the inside of the tyre became worn/stressed. Whilst BMW point to my failure to monitor my tyre pressures every fortnight (remember the car doesn't monitor Tyre Pressure as such), I have been checking other 5 and 7s around town and the inside wear is common and I think maybe it's due to the rear suspension being angled, coupled with the RFTs non compressing tyre wall, causing the inside of the Tyre to stress/wear prematurely and ultimately failure. Whilst maintaining the Tyre pressure at the max recommended helps spread the weight/wear across the width of the tyre, I remain unconvinced it is a solution. The inside tyre wall is still bearing the weight of the car. A normal tyre will deal with this stress by flexing, whereas the RFT doesn't flex and the inside tyre wall bears the strain.

I think BMW would be wise to review the history of Betamax. It can be very expensive to back the wrong

technology.

As aside, I am told that Porsche with the Panamea and Maserati with Quattraporte are no longer designing space for a spare tyre. I understand they not using RFTs and essentially rely on the AA. This information on the Porsche and Maserati comes second hand, so I stand by to be shot down.

Edited January 27, 2012 by Dumbas