Alright, I HAVE to ask...

[The HACK]

On the other "other" forum (Roadflee.org), someone claims that run flat tires can only be mounted on special "run flat" rims, and that all the new rim designs on the Z4 are special run flat rims that has a special "ridge" that prevents the runflat sidewalls from collapsing in.

That runs counter to everything I know about how tires are mounted and how run flats work. :dunno: I wonder if that poster was pulling another Ripsnort "I have an official memo/statement from BMWNA that some modern BMW colors do not have clearcoat" bullsh*t.

[Doug]

To the best of my knowledge you can mount run flats on any rim.
Heck, you can buy most of that at any tire store

[The HACK]

To the best of my knowledge you can mount run flats on any rim.
Heck, you can buy most of that at any tire store

I am 99% positive on that, but the poster who's "arguing" with me insist that BMW "run flat" rims are special.

Whatever. I figure it's some information "fabricated" to cover his arse. I'll find out when I mount those Toyo Proxes T1-S on the Z4 later.

[JST]

To the best of my knowledge you can mount run flats on any rim.
Heck, you can buy most of that at any tire store

I am 99% positive on that, but the poster who's "arguing" with me insist that BMW "run flat" rims are special.

Whatever. I figure it's some information "fabricated" to cover his arse. I'll find out when I mount those Toyo Proxes T1-S on the Z4 later.

There are run flat tires that do require special rims in order to retain the rim bead. The advantage of this system (e.g., Michelin PAX) is that you don't have to have the super stiff (and heavy) sidewall that other run flats use. On the other hand, you have to have a special wheel.

To the best of my knowledge (which is very limited) the Z4s and Cooper Ss do not need special rims, and any rim can be mounted in place of the run flats.

[ZBB]

To the best of my knowledge you can mount run flats on any rim.
Heck, you can buy most of that at any tire store

I am 99% positive on that, but the poster who's "arguing" with me insist that BMW "run flat" rims are special.

Whatever. I figure it's some information "fabricated" to cover his arse. I'll find out when I mount those Toyo Proxes T1-S on the Z4 later.

There are run flat tires that do require special rims in order to retain the rim bead. The advantage of this system (e.g., Michelin PAX) is that you don't have to have the super stiff (and heavy) sidewall that other run flats use. On the other hand, you have to have a special wheel.

To the best of my knowledge (which is very limited) the Z4s and Cooper Ss do not need special rims, and any rim can be mounted in place of the run flats.

This is true -- I vaguely remember when run-flats first appeared on the Corvette many years ago reading an article in R&T or C&D about the 2 different systems with pros and cons on each. I don't remember which system the Corvette had back then.

I'm also 95% certain that our Cooper S with runflats does not require special rims just for runflats -- I remember reading the manual about what to do when you got a flat and I think it explains that the stiff sidewall will allow it to be driven for up to 50 miles. I'd be surprised if the Z4 and other BMW runflats were any different...

By the way, with the Cooper S, the battery sits in the spare tire well -- so no place to even put a spare (and maintain luggage space/all seating)... The regular Coopers have the battery under the hood...

[The HACK]

Thanks y'all.

[operknockity]

Hmmmm. Wouldn't a quick e-mail/call to Tire Rack get you a better explaination?

[rost12]

There are run flat tires that do require special rims in order to retain the rim bead. The advantage of this system (e.g., Michelin PAX) is that you don't have to have the super stiff (and heavy) sidewall that other run flats use. On the other hand, you have to have a special wheel.

AFAIK, the new RR uses those PAXs, don't think any other cars do. BMW has been using run-flats for some time now on the Z8, no special rims required.

Some people are just "special", Hack :)