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Discussion Starter · #1 ·
2012 X5 E70 M50d with RFTs & a space saver spare.

I got a TPMS alert 200 meters from a service station & found a nail in the center of the R rear tyre tread. Only lost 5psi....... topped up the pressure & drove the short distance home without further loss. Independent tyre repair shop was able to fix it next day. When I raised the topic, I was told I couldn't replace the RFTs with non RFTs as I had "RFT wheels". My understanding was that RFTs need a second rim in the wheel & can't be fitted to a conventional rim but that a non RFT can be fitted to a RFT wheel. Can anyone confirm this?
 

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It might depend on the exact rim but I have gone both ways (putting rft on rims not "made for them" (and driving as much as an hour @60 on zero pressure) and putting non RFT on rims from factory mounted RFT.

The very first RFT used Special rims I don't think modern RFT need them. I think your guy just have not gotten an update in a couple decades.
 

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Discussion Starter · #3 ·
Thanks for the info.....that's reassuring & I'll have a good look at non RFTs at the next tyre change. With my SUV coming up for 10 years old, it must have those special RFT rims which are not now needed but clearly, they don't prevent me mounting non RFTs.
 

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No, you can absolutely put NON runflat tires on those rims.

Which RFTs are you running? RFT isnt one tire, it is a feature of MANY differnt tires. Also what size?
 

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Thanks for the info.....that's reassuring & I'll have a good look at non RFTs at the next tyre change. With my SUV coming up for 10 years old, it must have those special RFT rims which are not now needed but clearly, they don't prevent me mounting non RFTs.
Welp, there is another 'explanation'...the tyre guy may be full of crap. E70 rims are NOT 'special run flat rims'

Maybe some car once had special runflat rims, but I wouldnt necessarily assume the shop is honest or knowledgeable.
 

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Discussion Starter · #6 · (Edited)
Bridgestone Duelers H/P sport - staggered Front 275/40 X 20, Rear 315/35 X 20.

Even though it's an M, the ride is better than what I had with my previous X5 E53 4.8iS running the same size in non RFTs but the E53 is a shorter wheelbase & the iS probably had a sporty suspension.
 

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Discussion Starter · #7 ·
I've not seen inside my wheels. There was a recent post on Bimmerfest, I think of a 6 series, with a photo of a shredded RFT & you could see 2 additional rims on the wheel.
 

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The F15 is miles ahead of the E53/E70 for ride quality - run-flats, or not.

Having said that, I prefer my E70's handling even with its bouncy-jouncy Tigger nature. lol.

Sky Cartoon Happy People in nature Mammal
 

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I would have to know more about the exact rim.

The rim should have marking for the type of flange and it could be possible that it's not compatible but I have not seen this personally.

I have non ROF tires mounted on E70 wheels and have used ROF tires on e53 wheels.

I had them mounted at a reputable place and their only comment was "thanks for switching to non ROF, run flat are a pain in the ass to mount".

Explain please the confidence in your claim it's not possible. (I'm learning here; if it's not possible that is a fine answer with whatever backs that up with facts so I can add that to my database).
 

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I've not seen inside my wheels. There was a recent post on Bimmerfest, I think of a 6 series, with a photo of a shredded RFT & you could see 2 additional rims on the wheel.
I think you are referring to the bead flange and some wheels do have an extra bump. Many ROF do not need that and some rims have that that aren't meant for ROF tires. We call that "coincidence".

Coincidentally, some ROF surely require a special rim.

I can guarantee my e53 rims are not special and worked just fine with my ROF tires, holding at zero pressure driving long enough until the steel belt wore though 360° around the tire.

I'm speaking from experience of mounting ROF tires on e53 rims that certainly were not expecting them and putting non RFT on E70 wheels expecting RFT (though they may be aftermarket wheels designed for either).
 

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Discussion Starter · #11 ·
The wheels are a pattern only fitted to the M50d & I'm unable to see any marking on them for the type of flange. Incidentally, I haven't claimed it's not possible to fit non RFT to E70 wheels - I only quoted the tyre repairer's comment & I've posted this question on Bimmerfest to get the real information.
 

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You should never take anything that comes out of a car sales or service person's mouth as truth without confirming it elsewhere, e. g. the Interwebs.

You don't need special wheels for run-flat tires... normally.

Michelin PAX tires were a different kind of run-flat. They have an inner rigid tire, special wheels, and you need a special tire machine to install and remove the tires from the wheels. PAX never really caught on. They ended up on Bugattis and some Honda mini-vans. Like Betamax, they were probably better, but never really took off.

Tire Wheel Land vehicle Vehicle Automotive tire


A lot of BMW's offer non-run-flats as options. We ordered them on Frau Putzer's G01 X3. I switched my F10 535i from run-flats to non-run-flats with no problems.
 

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The wheels are a pattern only fitted to the M50d & I'm unable to see any marking on them for the type of flange. Incidentally, I haven't claimed it's not possible to fit non RFT to E70 wheels - I only quoted the tyre repairer's comment & I've posted this question on Bimmerfest to get the real information.
There should be a stamp usually on the inside of a spoke that shows what type of bead flange eg J or JJ etc and the "ET" or offset. Same place it will usually show the country of origin and perhaps the BMW logo if factory wheels.


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I stumbled across an automotive blogger (Colin Austin) & SA who writes,

"...However, it should be known that BMWs are designed with softer suspension spring rates to compensate for the stiff sidewall of factory runflat tires, changing to non runflats can result in sometimes undesirable floaty ride, not the connected-to-the-road feel that BMW engineers strive for."

I wonder if there is truth in that statement?
 

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Recently changed from RFT to non on wife's 50i e70.

Noticed a slightly softer ride, no significant change in the turn in or understeer but with e70 the road feedback already muted a lot compared to the e53.

I'll prob know much better in about a year.

I'm about to acquire an e70 with RFT mounted and plenty of tread so I will run out those tires. I may switch to my winter tires next fall that are non RFT and I'll definitely share my findings.

If I could find a similar deal on my favorite brand/model in RFT I would stick with them but I found them almost half off in non RFT model so that's why I bought them.

2 month later my car totaled but a deer. Kept the new tires when I turned over the car.
 

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Not sure about my E70, but recent BMW wheels have an H2 designation which I understand means they are suitable for RFT's. It is cast or stamped into the rim and says something like 8jx18H2 ET36........ H2 defines the shape of the hump that the tire bead passes over to get seated.
 

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I stumbled across an automotive blogger (Colin Austin) & SA who writes,

"...However, it should be known that BMWs are designed with softer suspension spring rates to compensate for the stiff sidewall of factory runflat tires, changing to non runflats can result in sometimes undesirable floaty ride, not the connected-to-the-road feel that BMW engineers strive for."

I wonder if there is truth in that statement?
Yes

irrespective of RFT or non-RF, you should take care to ensure the sidewall stiffness is matched to the car, suspension and weight.

people read that runflats are horrible…the switch to a non RFT with high marks on tirerack (based on owners of 3 series or other small, light cars)…buy 4 tires for 600 installed(I’m sure THAT is a quality tire!)….and then wonder why their X5 seems to wallow.


op has ONE specific car with ONE specific rim…..yet people are posting confusing nonsense about double rims, special rims…. kind of silly.
 

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If your X5 is wallowing with non-run-flats, you can put more air in them. BMW's recommended pressures for <100 MPH are not ideal for even tire wear. They're for ride quality and for maintaining adhesion to the road when going over discontinuities (expansion joints, etc.) The recommended pressures for >100 MPH are closer to what's needed for even tire wear and no wallowing. Non-run-flats at the >100 MPH pressures will likely ride better than the run-flats at the <100 MPH pressures.
 

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If your X5 is wallowing with non-run-flats, you can put more air in them. BMW's recommended pressures for <100 MPH are not ideal for even tire wear. They're for ride quality and for maintaining adhesion to the road when going over discontinuities (expansion joints, etc.) The recommended pressures for >100 MPH are closer to what's needed for even tire wear and no wallowing. Non-run-flats at the >100 MPH pressures will likely ride better than the run-flats at the <100 MPH pressures.
RIght. But what if you take tread measurements, accurate to 0.0000001", and these show perfectly even wear- yet they wallow.

More pressure?

Or maybe sidewall stiffness cannot be independently controlled by fill pressure as you indicate...
 

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What is the wheel style number that the OP is referring to that only came on the 2012 X5 E70 M50d ? If we knew the BMW wheel style number...we could verify if it is a special wheel that only takes runflat tires. If it is a wheel like all the other wheels that were offered on the e70...then that's one that we could put to rest. :)

If you don't know the BMW wheel style...just go to one of the online part database sited, type in the last 7 digits of your VIN...then click on the WHEEL DIAGRAMs and scroll down until you find your wheel style:

Here's a link to one of the online part database sites in case the OP isn't familiar with any: Wheels BMW E70N SAV 54681
 
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