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Old 05-30-2012, 09:17 AM   #16
Bullet Ride
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uhmm, can you please explain how this happens??
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^ It seems like there are no technical explanations other than how the behaviour has been observed by many users. I tend to agree that the tires wear unevenly; why, I don't know, but it's with the RFTs for some reason.
Picture a having a wooden wheel. There's essentially no compliance in the material because it's solid. If you dial in some negative camber to this wheel it's going to be riding only on the inner edge, so naturally that's the part of the wheel that's going to wear down first. The effect is similar with run flats. Since the side walls need to be so stiff for the tire to be able to run when flat there's much less compliance in the side wall than on a conventional tire and this causes the load to be focused on the inner edge. Combine that with the little bit of toe in that all cars have from the factory and your tires are riding and scrubbing on just the inner part of the tire.
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Old 05-30-2012, 10:23 AM   #17
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As someone that went from RE050A's to V12 K110's I can conclude that

RFT's are harsh, ride is firm.. hitting a pothole felt like a car crash (seriously), there was also quite a lot of tramlining

I hated the V12's at first cus of how mushy they were but have since have gotten used to it and realized that even though the ride is softer and it felt as if it was less "sporty" than the RFT's... they actually had WAYYYYYY more grip.

The RFT's would just jump over the bumps and kick the Stability Mngmt on every 5. Felt faster... but wasn't.
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Old 05-30-2012, 10:53 AM   #18
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I have RFTs on my 135i and have not been overly impressed. They do seem hard and I don't feel the performance is there. You also can't let any air out of them say if you want to try a 1/4 mile run because the sidwall is so stiff it makes so difference.

They are also super expensive.....I guess one advantage is saving the weight of a spare
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Old 05-30-2012, 01:26 PM   #19
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Picture a having a wooden wheel. There's essentially no compliance in the material because it's solid. If you dial in some negative camber to this wheel it's going to be riding only on the inner edge, so naturally that's the part of the wheel that's going to wear down first. The effect is similar with run flats. Since the side walls need to be so stiff for the tire to be able to run when flat there's much less compliance in the side wall than on a conventional tire and this causes the load to be focused on the inner edge. Combine that with the little bit of toe in that all cars have from the factory and your tires are riding and scrubbing on just the inner part of the tire.
Hmm interesting, but based on that analysis, I can't tell why my front right tire has worn from inside and left from outside, while the middle groves are in dandy shape.
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Old 05-30-2012, 02:25 PM   #20
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Hmm interesting, but based on that analysis, I can't tell why my front right tire has worn from inside and left from outside, while the middle groves are in dandy shape.
Wear only on the outside is going to be caused by a bad alignment, or a worn out suspension component that is causing an improper alignment. With negative camber tires will wear from the inside. Over inflated tires will wear in the centre and under inflated tires will wear on the outside and inside but not the middle. Pretty much all new cars will come with a little bit of negative camber up front and a little bit more in the rear. However the amount is usually not enough to cause uneven wear on conventional tires.
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Old 05-30-2012, 04:16 PM   #21
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Yup and I did get it checked by BMW and they said the alignment is good and the tires were also rebalanced, but still the uneven tread wear occurred resulting in two front tires loss.
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Old 05-30-2012, 04:24 PM   #22
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BMW's definition of "GOOD" basically means within specs. So, if the specs designate negative camber or toe in, then "GOOD" means you will have uneven tire wear.
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Old 05-30-2012, 11:35 PM   #23
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Now that I can definitely agree with. Their "ripping off customers" tactics are gross.
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