E 70 Run Flat Tires

[emcman]

I did not want to hijack another thread but run flats have already come up. I wonder what brand they will be. I was on the Corvette Forum for some time and the Goodyears can run more distance on the inner tire than they state. Over 100 miles at reasonable speeds. They also have pretty good warrenty service. That said a good tire pressure system is key. Iif you do end up buying one they are expensive. I also wonder about those of us that want to run seperate winter tires. Is there a run flat winter tire? dunno:

[pseto]

The current e90s have Bridgestone RFTs, and I thought I remember reading somewhere that winter RFTs are now available. Just don't know who makes them.

[simmikie]

i have read that they are noisy and harsh. though they have been around for a bit, i feel the tech needs more oven time before i will consider them...but i still have 8 track tapes.


Mike

[Juanted]

I drive an e90 with RFTs. They are NOT as loud as people make them out to be... I have no issues with them at all.

[LeMansX5]

My guess is the Bridgestone Dueler as shown in this pic.

[xx3]

Originally Posted by Kaefer

I drive an e90 with RFTs. They are NOT as loud as people make them out to be... I have no issues with them at all.

Exactly. Early BMW's suffered a harsh ride with runflats because:

1) Tires were very very hard.
2) The BMW cars that wore them didn't have suspensions designed especially for them.

The E90 is the first run-flat BMW that's handling isn't overly harsh and very acceptable. Runflat tires are now softer, and the E90 suspension was designed from day 1 to accommodate run-flats...

[rooster328]

is that the sport package rims in the pic?

[JCL]

These runflats are referred to a 4th generation by BMW. That means that the harshness, which has been an issue on early run-flats, is likely diminished even further than on the E90.

Bridgestone is the OE supplier for the 5, 6, 7, Z4, and E90, so it is probably a Bridgestone, and the shot of the pre-production model supports that.

Bridgestone isn't listing these tires on their website yet, which doesn't bode well. No-one needs one yet, but they are obviously a new product. With the Z4, no tire distributor had them in stock for some time after the vehicle was released, and the only place to get a replacement tire was from BMW, at BMW prices.

These tires don't have a support ring as is mentioned above. They rely on a stiff sidewall to support the vehicle. That is one reason for the special rim with the retaining lip on the inside. It doesn't require special mounting/demounting equipment, but it makes it more difficult to mount the tire due to the combination of very stiff low profile sidewall, and modified rim.

On the Z4, it is possible to mount regular (non-RFT) on the same design of rim, so I presume that will be possible with the E70 but it remains to be seen. Fitting non-RFTs is a common upgrade on the Z4 boards, but then with the very low profile and sport suspension that vehicle can be a little harsh anyways, and the tires don't help much. The X has the advantage of that 'road-hugging weight', to quote an old non-BMW advertisement. Without any real data, we are going to have to wait and see how early adopters like it. I just think that there is a potential risk for people not being able to buy a replacement; remember that after a flat, the tire usually needs to be replaced (at least if you have driven on it). The internal cracking that shows up is the sign that it can't be patched, even if the hole is in a safe part of the tread.

[motordavid]

My unXpert 25Cts on RFs...

Picks:
-they allow Buffy and even any of us troglodytes to
"drive/get to" somewhere, for tire repair. (Assuming
you aren't 100+ miles from "repair".
-they negate the need for a jack; important in sports
cars, where space is a premium; maybe not so important
in a 5,000+ lb SUV.
-they are trendy and a necessary me-too, at least in
the minds of the car marketeers.
-they tend to ride well and are not overly "noisy", when
new or, less than half consumed.

Pans:
-Not every TarJoint can/will work on them, currently.
-Even less of those joints know what they are doing
in an R&R dismount/mount operation, espc. due to
in-wheel sensors.
-Many of your TarJoints will not have any replacement RFs,
espc. in the steam roller wheel size that tend to be fitted on
sports cars, BMWs, et al.
-That 50-100 mile "cushion" can become pretty confining
in many driving situs and many locales. Even when/if you
can get "there", points 1,2&3 come into serious play.
-No more changing a flat and just "going on"; the clock
is ticking to get that sumbitch replaced.
-In my exp., albeit with older gen RFs, they do tend
to get noisy and "hard" around post-3/4s+ of tire tread life
use.
-BringMoneyWith you for a new tar or, a new set.

But, whatchagonnado...it's progress.
BR,mD

[simmikie]

Originally Posted by Kaefer

I drive an e90 with RFTs. They are NOT as loud as people make them out to be... I have no issues with them at all.

then one could agree it is a matter of personal taste and tolerance. btw i have no real issue with them either, merely sharing what i have read about them. on cars without spares, then they are the obvious choice.


Mike