Snow tires have transformed the car.
I cannot believe how much of a difference the new snow tires (which aren't exactly know for quiet ride themselves) have made the ride of my E so much more enjoyable. To all of my fellow E owners with RunFlats, don't wait to scrap the bridgestones. The Bridgestones are hiding half of the vehicle you purchased. Shame on MB for using these tires. I bought a simple "slime compressor" kit (similar to the MB TireFit kit) to support the non-runflats I have now. This is what MB does for Canadian Bluetecs that do not have the run flat tires. I am very satisfied with the results. Now, I hope the snow tires make a difference in the snow. I am pretty sure they will as they X-Ice Xi2's reate just below the Nokian Hakkapilita R's for overall performance.
Peace.

BTW I searched for the Elbrus IO6 wheels that you mention - very nice! Do they have the same 48mm offset as the OEM rims?
I cannot believe how much of a difference the new snow tires (which aren't exactly know for quiet ride themselves) have made the ride of my E so much more enjoyable. To all of my fellow E owners with RunFlats, don't wait to scrap the bridgestones. The Bridgestones are hiding half of the vehicle you purchased. Shame on MB for using these tires. I bought a simple "slime compressor" kit (similar to the MB TireFit kit) to support the non-runflats I have now. This is what MB does for Canadian Bluetecs that do not have the run flat tires. I am very satisfied with the results. Now, I hope the snow tires make a difference in the snow. I am pretty sure they will as they X-Ice Xi2's reate just below the Nokian Hakkapilita R's for overall performance.
Peace.
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First, what will you do in case of a flat; and
Second, did MB (like BMW) tweak the suspension of those cars designed to be sold with runflat tires for that application? If so, what handling (or warranty) issues might you run into with non-runflat tires.
I just thought of a third issue - for those that lease. BMW requires runflats on the car upon lease return. I suspect that MB does the same. If so, you may want to remove the runflats before they get to the "lease turn in minimum" and store them until you get ready to return the car.
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Good Luck.
Last edited by aeggroup; Nov 21, 2011 at 10:20 AM.
BMW has gone on record to say that the use of non run flat tires may cause warranty issues and some dealers even have signs posted to that effect. That said, many people replace the run flats with normal tires and have had no issues. It is very dealer and problem specific. BMW contends that the suspension has been tuned to take RFTs into consideration and replacing them may cause suspension issues not covered under warranty.
Once driven without air, a RFT is toast - regardless of the distance driven. While you certainly can repair a RFT the same way you repair a normal tires, most dealers will refuse to repair even a slow leak based on liability (like you said.) The issue is simple. The dealer cannot determine by a visual inspection if the sidewall on a RFT is damaged so they just refuse to repair it.
So when can you safely repair a RFT? RFTs can be repaired under the same guidelines as a normal tire (ie, hole in the tread portion only, not near the sidewall) if - and only if - you can be absolutely, positively sure that the tire has not been driven on with extremely low pressure.
If you get a low pressure warning on your TPMS, check the pressure and find it to be low (say 25psi.) You add air to the proper amount and then go to get your tire checked. The tire place checks your tire, finds the pressure at 25 again, removes the nail and plugs it properly then all is well.
If, OTOH, you got in your car one morning, saw the warning on your TPMS and drove to a tire shop where they checked the pressure and found it extremely low (say 15 or so) then that tire is toast and should not be repaired as there is a high probablity that the internal structure of that tire has been compromised.
Why RFTs at all? In many cases they will allow you to continue to drive so that you can reach a safe place. Think the flat tire scene in National Lampoon's Vacation or think about a flat on a fairly busy two lane twisty road in the rain. Those are times where you say "screw the $500 for a new tire, I just want to get out alive."

The MM act prohibits a manufacturer from denying warranty service for issues caused when a consumer has replaced an OE product with a substantially similar product from another manufacturer unless they can show that the replacement caused the issue.
The MM act does not prohibit a manufacturer from setting standards, requiring specific maintenance using parts that meet certain specs (fluid types for example) or requiring replacement parts meeting certain specs.
In this case, BMW has spec'd out the car to require RFTs. It is well documented that BMW requires RFTs on lease returns and that is perfectly legal.
Non RFTs do not meet the BMW specs so the MM act does not apply. RFTs are a separate category and non-RFTs will never meet the RFT specs.In a dispute, the manufactures need only show that the car was spec'd for RFTs, the consumer did not use RFT's and make some sort of plausible argument showing that the use of RFTs was mandated.
Is it likely that the use of non RFTs will cause issues? Of course not, but the possibilty exists. My goof-ball BMW dealer refused to do a wheel alignment I was paying for because my winter tires were on aftermarket wheels. He felt unpersuaded when I showed him that the tires were the identical size and the wheels were the same offset and weight of the OE wheels. Another dealer down the street did the alignment without issues and BMWNA had a little talk with my dealer but the bottom line is that it is dealer specific. Each dealer decides (most likely depending on how often they've been burned) how strictly they interpret the rules coming from BMWNA.
BMW (and I suspect other manufacturers as well) frequently requests parts replaced under warranty back from the dealer for inspection. If BMWNA determines that the failure was not one that should have been covered by warranty, then the dealer is charged back. Once burned, dealers seldom give other customers the benefit of the doubt and deny everything that might cause them problems.
Much of this discussion may be acamemic because MB may to have "tuned" the suspension for RFTs and might not care one whit.
Last edited by CEB; Nov 21, 2011 at 04:13 PM. Reason: Added last sentence
The MM act doesn't protect squat. Let's assume you have a dispute with the dealer, the manufacturer sides with the dealer but you believe that the MM act applies. What are your options?
The Feds aren't going to come swooping out of the sky to save you. Your only realistic option is to sue the dealer or manufacturer. Meanwhile, you car sits unrepaired at the dealer's or you've fronted the money to pay for the repair. Will the costs of a lawsuit outweigh the return? Will the manufacturer come armed with reams of statistics showing why your use of aftermarket tire valve stem caps caused your electrical system to explode? Will that befuddle the judge used to deal with squabbles between neighbors? Will you really prevail by holding out the MM act as a shield?
All good questions and they may get answered the next time somebody gets me fired up about the MM act.
Aftermarket wheels can cause legitimate warranty woes. A wheel with an unusual (for that application) offset can add stresses to the suspension that were unexpected - again, an extreme example but one that can lead(and has led) to suspension problems.
I had the X-ICE (first generation) on an older car - they are excellent tires and perform very well on ice and snow,. At the time, they were better than than the stock All-season tires in comfort and noise.




