If your daily routine includes certain types of surfaces, the inherent sidewall hyper-stiffness essential on RFTs, we can see how it might get to you. On cracked roads, potholes, and pavement edges, our car can deliver an occaisional hard hit. And when we're honking through a corner at a good clip, rippled asphalt or even an ill-placed small bump makes the 330i feel skittish, making grip feel lower than it might otherwise and making it hard to put the power down with confidence when shooting away from the apex. In our car, it's there. But still, it isn't a deal (or back) breaker.
Others felt more strongly, and went so far as to ditch their RE050A 18" RFTs for "normal" tires. One such person, a regular poster here, offered up his car for a little back-to-back. Karl's 330i is identical to ours, except for the Kumho ECSTA ASX all-season non-RFT tires, and its white.
As a control, Karl and I took turns driving our long-term test car first. On the roads he selected, I could feel the symptoms. No more than I had on other surfaces back home, but it was there. There were a couple of rough, and unfamiliar, cloverleaf ramps that I didn't feel comfortable charging through because of it. For his part, Karl admitted that when his car had the original RE050As, it felt worse than this one, especially in the rear. "Does our car feel bad enough to have still made the switch?" I asked. "Yeah." was his response.
Next up was Karl's Kumho-shod 330i. Right away we could sense that it was quieter over the coarse asphalt sections. The skittish feeling was reduced, and so it was easier to feed the power on earlier coming out of rough corners. It seems that the extra envelopment possible with softer sidewalls kept the rubber more firmly planted, increasing confidence, and probably mechanical grip. Reduced unsprung mass should theoretically be helping keep the rubber on the road too. But in this case, the improved enveloping characteristics seem dominant. We don't know limit behavior. We weren't at ten tenths, and the Kumhos are all-seasons, after all.
With regard to the steering, all I can say is that it DID change. Karl liked it better, I didn't. He appreciated the lighter feel around center, making it feel more responsive, while I felt the reduced immediate effort build-up gave me less information. Steering is a matter of taste in this region, so I guess we're both right.
Yes, there is a difference, and Karl's Kumhos, on this brief city loop anyway, seem to work well in the sub-limit driving we did. I don't know if I'd be saying this if he had chosen some other brand and model of tire, as every manufacturer brings different compounds, treads, and constructions to the aftermarket table. And BMW's suspension was theoretically calibrated to the Bridgestones, not these Kumhos. It might work out, or not. It can be a crap shoot. But then again, people are always buying aftermarket tires and wheels, so this issue isn't really new.
Still, the hard sidewall character of RFTs is real. It harms ride, and it harms the ability to keep the tires planted when the pavement isn't smooth - which can affect handling if you are in a corner at the time. BMW's decision to use them extensively is hard to understand, but with continued use and development of both tire and suspension, they should improve over time. Our 335i coupe test car felt better than our long-term 330i sedan.
As for the logic of using RFTs, I'm not convinced. I grew up in the wide-open west, the land of "next service 90 miles" signs, so I'd much rather have a spare and a lug wrench. Keep your RFTs and give me the freedom to stop into any tire store I want when replacement time comes around. Others think the benefit of RFTs is worth it.
But at the same time, taking RFTs off a car that isn't engineered to carry a spare is a problem. Instead of a spare, Karl showed me the Continental kit, an air compressor and tire sealant combo that usually comes with the non-RFT M3. It works just fine of Karl's 2006 330i, but with a 2007 3-series, such as the 335i Coupe I recently tested, this wouldn't be advisable, as the new tire pressure monitors and fix-a-flat don't mix. Well, they do, but you have to endure a constant dashboard warning light until you buy and dismount the tire to install a new sensor after you squirt that goo in a tire/wheel so equipped.
vvk says:
01:02 PM, 11/28/06
You have cracked roads in California?!!! I think you need to take a vacation in Michigan. You know, to calibrate your frame of reference :)
On a more serious note, exclusive use of run flats was what made me cancel my plans to buy a new BMW. Instead, I bought a slightly used E46 with full size spare tire, thank you very much.
actualsize says:
09:54 PM, 11/28/06
You Wolverines think you're so much better than everyone else! ;-)
http://www.motorhomemagazine.com/output.cfm?ID=1168993&Newswire=1
The MI didn't even make the top ten! Phbbbppt!!
Wait a minute! I think I just lost.
And Arizona has the highest per capita boat registrations!
Wait a minute - that one's a myth.
http://phoenix.about.com/od/lakes/l/blboats.htm
And Reno Nevada lays West of Los Angeles.
desmolicious says:
03:21 PM, 11/29/06
But we all know that right now Wolverines are praying to Bruins...
cbanct says:
04:26 PM, 11/30/06
Thank you for the input Dan.
Some owners of RFTs have noticed uneven wear of the tires and loud road noise after 10,000 miles. Any thoughts on that ?
cbanct
cdnpinhead says:
07:58 AM, 12/ 1/06
This is useful stuff.
Thanks.
drcamel says:
09:24 AM, 12/ 1/06
There is an alternative RFT to the Bridgestone. My dealer replaced the original Bridgestone RFT after I complained for the third time about the noise and cupping at 14,000 miles. They put on Continental ContiProContact SSR at no charge. I've had them for 11,000 miles and I can tell you that the Conti is MUCH better than the Bridgestone’s. I'm gad to see that you heard our complaints and did a side by side comparison. I think the idea of a RFT is a good, but there is some work to be done.
king11 says:
12:44 PM, 12/ 2/06
I took delivery of my '06' 330XI on Sept. 1, 06, I was apprehensive about the RFTs from the start. Not just the run flat aspect, but the low profile as well. However, I let the overall quality of the car and BMW's reputation overcome my better judgement.
I live in Massachusetts, and pot holes are a way of life here. About two weeks ago, I hit a pot hole doing about 35mph. The result is two bent rims. The tires are fine. Now I've owned this car for three months, driven it for about 5000 miles and I'm faced with a $650 bill if i decide to fix it. $250 for new wheels and $150 for a wheel alignment. I think that's ridiculous. I think this car with RFT's is just too fragile to be driven on country roads. Shame on BMW.
striker1_504 says:
07:28 PM, 12/23/06
I bought a 2006 325i last November, and in the course of the last year have put almost 28,000 miles on it, mostly on the NY State Thruway and Mass Pike. At about 15,000 I started to notice a bit of noise from the rear tires which increased gradually. Other than that, I wouldn't say there was anything I'd have thought to complain about, I like the feeling of connectedness I associate with the somewhat stiff suspension & road feel.
Anyway, I was advised to replace them soon (at 28k), and purchased winter tires on new wheels, figuring I'd put new tires on the old rims & swap them out every spring and fall.
What I got are 17" Michelin PA2 Alpin high performance winter tires mounted on BMW style 71 Double Spoke wheels, which I must say look pretty hot. The performance characteristics were so radically different, though, that it took me almost two weeks to adjust to the change.
The sidewalls are SO much more flexible than the RFT's, that cornering, or even taking a windy road at speed is a new experience. It's almost like riding a cushion of air by comparison. I have to say I'm enjoying it now, and will be carefully considering what kind of tires I'll buy for spring. I think my dealer service rep said they were switching over to Michelin themselves.
Thanks
ginzica says:
06:33 PM, 01/28/07
I bought my BMW in June 2005 (2006 330i BMW “RUN FLAT TIRES”). I have 30000 mile on it and I changed my tires twice.
After 2000 miles the tires have shown excessive wear. I went at the dealer and they told me that is normal and that is because they are new.(lie) At 6000 miles I went again at the dealer because the tires were in bed shape. The answer was that “maybe not enough pressure in the tires” (lie again). At 18000 miles I could not drive my car anymore because of the noise that was coming from the tires. They change my tires at no cost. Now I have 29000 miles on it and the noise is even worst than before. I went at the dealer again and they told me that they have to replace the tires again. I think this is unacceptable, to change the tires after every 11000 miles, and the worst thing was that they asked me to pay for two of the four tires ($700). I called BMW of North America and nobody wants to listen to me. I thing somebody should be responsible for these Run Flat Tires. I thing is unacceptable from now on to change the tires every 11000 just because they are RUN FLAT and is a BMW. This is the first and the last BMW for me.
I would like to make somebody responsible for all this problems that so many people have with these Run Flat Tires.
inagada says:
07:51 PM, 01/21/08
While an old topic to this board, its been relatively new for me. I have a 2006 300xi, with about 26,000 miles. About 3 months ago I cracked a rim on a pothole in NY. Thats right, cracked it, all the way through the entire rim so that part of it was still attached to the wheel, and the other part was only attached to the car by the rubber of the tire. I replaced that wheel.
Now on the left hand side (front) the inside "track" of that wheel is worn down and is bald. There is also a very noticeable rattle. The outside track is worn down as well. The midddle not as much.
I cringe at every bump I hit thinking I am going to crack another rim.
I will never buy another bmw based on my experience. The steering column was faulty and car would not start at one point also.
dan1000 says:
01:32 AM, 01/25/08
my 335ci had only 3000 miles when the light came on. I immediatley reduced the speed to 50 miles and I directly went to the dealer. guess what? I have been told that the tire is damaged and therefore the warranty does not cover it. the cost was $600. at first I was upset as I did not expect to pay that much after only 3000 miles.
this time I am so mad! what can I do though. the car has 12000 miles and the tires did not touch anywhere and the two tires on the passenger side are again damaged. what a luck! this time I am not going to the dealer as I know tiretrack , for example, has the same tires for half the price.
I am , therefore, agree with all of you.change these RFT tires. I do not know why BMW sells these tires with their cars. I guess they want to make their "free maintenance" money by selling the tires!