Run Flat Tires

"Jim" wrote

Many people are doing that - they claim significantly better ride, and somewhat improved performance due to the lower un-sprung weight. However, you have to buy either a flat repair kit or a spare (most are buying a temp spare). Carrying a spare takes significant room, as there is no well to use so it takes up trunk space.

You *MUST* keep the TPMS senders, unless you want the car dinging at you all the time.

My son's run-flats (on a 2007 335i) lasted around 25K miles, perhaps a bit more. He currently has brand new Michelin PS/2 run-flats and says they're much better than the Bridgestone's. The current run-flats (I have a 2010 335d with Bridgestone RE050s) seem like they're quieter and better riding than earlier ones. I'll probably just stay with the run-flats. YMMV.

FloydR

Mite?

No, it will not have an effect on performance. Well, the added weight of an spare could change thing a bit, but I doubt you would notice.

We recently obtained an ex-demo, 5000 mile 320D SE fitted with Bridgestone RFTs. The ride was so hard that within a week they were replaced by Continental Sport Contact 3s and a compressor/sealant kit.

Tramlining was eliminated, the bangs and crashes generated by the RFTs were replaced by muffled thuds and the vehicle can now be relied on to go where it's pointed without constant corrections. All in all, it was a successful solution.

If our experience is typical, and looking at a number of forums it may well be, don't wait for the RFTs to wear down - replace them straight away.

It would be interesting to hear what you think after you've driven the new car.

Every tire failure I have had was of the sort that run-flats or a flat repair kit wouldn't have helped with anyway. So you pays your money and you takes your chance.

I think you'll be amazed at how much better decent tires feel than the run-flats.

Incidentally, on a totally different tire issue, I have the e.22 rims on my E28, and they take 195/70R-14 which appears to be becoming a bit hard to find now. This time around, Tire Rack gave me only ten different tires in that size, not counting snow tires, and not much in the way of higher performance tires. Michelin HydroEdges are gone in that size too. What are other people doing? I got the Sumitomo HTR200 and they seem decent but I haven't had the chance to try them in rain yet.

--scott

It only takes one.

I had a Jeep with a brand spanking new spare tire hanging on the rack for more than 5 years. Several years ago, I upgraded the tires on my E36 from

15s to 17s, including the spare. The spare tire has never seen the light of day. So, I can safely say that I have gone for at least a decade without exercising my jack and lug wrench. That's not entirely true, one of those 15s that I upgraded to 17s blew out a few weeks before the upgrade was done. It is the event that prompted the upgrade.

I honestly cannot recall ever changing a flat tire on the side of hte road, save that one instance.

And, I said earlier that changing away from the runflats would not impact performance. That's not entirely correct either, performance should improve a little.

I'm not certain what the space is in the bottom of the trunk of your E90, but if it's anything like its cousins of earlier times, the E36 and E46, there is a well below the floor that is specifically intended to hold the spare tire and the jack. I'm not certain that I would characterize the weight of a spare tire as, "alot." What does a tire and rim weigh, 25, 30 poiunds? Hardly a burden for the likes of a twin-turbo with what might be considered one of the best suspension systems available.

If you want to move away from runflats, then buy yourself another rim and five tires.

My first E36 took 225/55x15s because it came with the Sports Package. That tire size has pretty much gone away, leaving the only source being Michelin. The last set of 4 that I bought was just a tad over $1000, out the door. $250 each for a tire was more than I cared to spend.

I bought a set of M3 rims on eBay that carry a 225/45x17, and these tires run about $100. I bought 5 rims and 5 tires, wore out the first four tires and bought replacements, and all 9 tires + 5 rims was less than the cost of

8 of the 15-inch tires. Now that I have recovered the cost of the upgraded rims through the cheaper tires, any new tires that I buy represent significant savings compared to keeping the original tires and wheels. Get it?

You can make the move from yoru 195/70x14s to a 225/45x17, and your overall diameter will be only one-quarter inch larger. I see no reason why this would not fit your car. Another tire option is the 225/50x16. Again, a functionally identical tire size. So, your challenge is to find either a 16 or 17 inch rim that fits your car -- backspacing and hole placement being the main considerations, and you can go to a 7.5JJ width, which is a common size. I don't know what sort of fender space you have, but yoiucould perhaps go to an 8.5JJ width and get even wider tires, but you would be required to trim some of the sidewall height if you wanted to do that. For example, you could go to a 255/35x17 if you got the wider rims, but I think your cost basis would actually go up on a combination like that, and you would be spending more for tires instead of less.

The 225/50x16 and the 225/45x17 are sizes that you can get at Costco for about $110. America's Tire (Discoount Tire) has a wide selection of these sizes also.

"Jeff Strickland" wrote

E90s do not have a tire well. There is a small tray area that you can place small things in, like a briefcase. The diesel cars do not have even that, as the urea tank is there.

FloydR

So, ALL E90s come with runflats?

"Jeff Strickland" wrote

In the US, that statement is true. And they all come with low-pressure warning systems - 2007 and later use the in-tire monitors.

FloydR

Agree, but in some markets, there is an alternative floor plan that allows a spare in the E90/92:

One person posted early this year that he found the part number for the E90 alternative boot / trunk floor to store a space saver / emergency wheel, it is 51472146914. There are also part numbers for the spare tire, jack and other related stuff. Search realoem.com for more!

He actually ordered the item from BMW UK, BMW Germany declined it. I think the alternative boot/trunk floor may be available in China or Saudi Arabia or South Africa. Definitely not available in the US.

On the other hand, if you're in the US and want this alternate option, perhaps one of the BMW independent shops who order directly from BMW Germany might be able to source it. Contact someone like RD Garage, Maxmillian Imports, Pelican Parts or even Dinan to name a few. Good Luck!

While you're at it, replace those filthy dirty brake pads. 8)

It might be the Bridgesone run flats though. I've seen a lot of negative reviews of those so have steered well clear. The Michelin run flats (I have) don't appear to exhibit the problems you've had and generally get the best reviews of the run flats. They are a little more expensive than the Bridgestones though..and a LOT more expensive than your Contis.