DavidNJ

Wig, I looked at some road tests. At least Car and Driver seems to love the Audis. I can't claim the same love for the A6. I don't agree and other magazines haven't been as laudatory.

They do have the 3L turbo as quicker than the the 535/640 and E350 although all have similar peak power. A glance at the power curve indicates the Audi is a bit more powerful (maybe 10hp, no much) and has a similar power curve to the BMW. The normally aspirated E350 does have less power under the curve. However, in street use with direct injection and variable valve timing few would notice.

I found a video for E-classy that might help him get up to speed with suspensions:

mikemargolis

Mine are Bridgestone Turanza, 245/45 P17. I bought the car Feb 2012 with 20K miles on it; when they CPO'd the car, they replaced the tires, so for me they were brand new at 20,000 miles.

I now have 44K miles on it, but ran snows for about 10 or 12K miles this past winter, so these tires have about 12K or 14K on them, and they look great.

E Classy

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instantfob

Another key thing about Runflats.

People then to forget to proerly inflated them because it looks good all the time and then blame it for crappy ride quality. Please note that US version of BMW doesn't provide exact psi reading unless you have your car modified by a software coder. The normal TPMS warning only goes on when the pressure is out of spec by 20%.

Most new cars come with big wheels and low profile so air will leak like 1 or 2 psi per month. So a lot of careless drivers will be complaining about the ride 6 months down the road.

DavidNJ

Undoubtedly true. However, the runflats are virtually always old technology. That may improve if more manufacturers go to them; it appears the new Infiniti Q50 is on runflats.

However, for now, they are virtually all old technology. The newest designs are the Bridgestone and Michelin Ultra High Performance All-Season tires, W-rated. Both one generation older than the current non-runflat alternative. Neither as good as their summer tire equivalent.

Some reviews. The first compares the runflat and non-runflat version of the same tire. The second compares that tires with some competitors. Interestingly, by the time the first test was done, the successor to the non-runflat was on the market when the test was done. Michelin just introduced its successor non-runflat.

Is the Third Generation Bridgestone Potenza RE960AS Pole Position RFT 3G Run-Flat the Charm?

Testing Performance All-Season Run-Flat Tires

The only runflat snow at Tire Rack in E250CDI sizes (245/45-17) is the Pirelli Winter Sottozero, a 2009 tire.

Porsche and the BMW M models use regular tires with inflation kits.

Good news, I've hot a question on another forum and no one has reported the failure problems on the tires with the 245/45 sidewall. The 19" wheels with 245/40 tires have extensive failures reported. One person getting a new car of that brand said he had 6 failures on 19" rims, but it was ok because he had wheel and tire insurance. It should be interesting for Infinit since the Q50 apparently is on runflats and has 19" wheels (I believe with 245/40 sidewall tires) standard on the popular sport models.

BTW, E-not-to-classy, I should introduce you to my 'wall of springs'. 2.5" Hypercoils, 12" and 14" tall. When the rules limit rear percentage to 48, total weight at 3000#, and a $150 shock rule, you need to do a bit of testing to get things right.

mleskovar

Replaced my wife's BMW run flats with conventional tires when they were due. My experience: RFTs cost much more, wear quicker, have a harsher ride (marginally), and are often unrepairable for even the simplest of punctures (ask me how I know) and many car dealers won't patch them at all (that tells you something). A big part of the problem with RFTs is the driver continues to use them beyond what a normal flat tire would allow and the side walls, made to handle the extra abuse, fail. So a simple slow leak turns into a new tire. I can't knock the extra safety afforded by RFTs but in today's environment I don't think it's worth the price.