Mixed tires? Dangerous..?

[tonywall]

I have a 2007 e93 Sport Package with 18" wheels.
RFTs on the front, conventional rear.
A garage has suggested this could be dangerous, but if I keep on top of the tire pressure readings, I think I should be fine......??
I have had no issues with the handling.

[mryakan]

Not advised at all. Regardless of pressure, the handling characteristics are vastly different and could prove dangerous in certain situations. Someone in the tire section reported that this mix felt very unstable.


I was linked into this thread, because I just posted about the mixing because my car is now scary to drive. DO NOT MIX them. The rear traces around if you turn slight right then lefta nd feels like its on a pendelum. The traction control light went on today on a highway turn I normally take at 80... I was at about 75 and I tested it with a slight extra turn inward. It should not have done that. The only way I can describe it is when you have destroyed rear subframe bushings and you get that rear steer on turn in. Not good. I beleive it is entirely from having stock run flats up front, with non-run flats out back. I was in an emergency situation on vacation over the early part of the week with a tire situation and had to take what I could get to get home. Now Im home Im buying the same tire for up front.


So, we had a flat on vacation in the 335i and had to put a stock size set of regualar (non-runflats) on the rear, while still having the stock run flats on the front. I noticed that now the car feels unstable and i swear almost feels like a re-steer. When going around a highway corner today at about 70, if a turn into it a bit more the traction (http://forums.bimmerforums.com/forum/showthread.php?t=1851934#) light flashed! So, I know its not just me. I more notice the instability at higher speeds (70-90), and its not bad around corners at lower speeds, but still not the same. Is this because of the difference in tire (http://forums.bimmerforums.com/forum/showthread.php?t=1851934#)-types from front to rear? I know the run flats are stiffer, and weigh much more, maybe a rotational mass difference Im feeling? Im going to put the same tires in back on front, but Im curious to know what you all think if this will help balance it out more?

[White94RX]

I think most would recommend that keeping runflats on all four is probably the best option.

[Critter7r]

I think it'll probably feel fine in normal driving, but in an emergency manuver is when the differences in handling characteristics will leave you hanging.

[bmweptx]

I know this is an old thread but I had to provide some input for anyone stumbling across this and thinking about mixing regular tired with runflats. DONT DO IT!!!!

I have a tire go bad in the back so I replaced the rear two tired with regular tired, the front were still runflats. When leaving the tires shop I completely lost control around a curve. I thought the tires was falling off. I played with it to figure it out, took it to four alignment shops, we changed the rear tires again thinking it was a bad tires, check suspension too. It turned out to be the run flats on from and regular on the rear!

With this mix, the car was so unstable and it had such a weird feeling in the steering, getting off the freeway at 65 I almost wrecked, got pulled over by the cops because of the danger they saw with the swerving which was uncontrollable. Easy way to kill yourself. Got up to 65 or 70 and held the steering wheel straight. Any sudden move or a curve, I would have lost control. Did research and figured out the issue. Put two regular tires on the front and it was like a new car.

Trust me, I don't always do things by the book, especially matching tread pattern, not a big deal. This though, holy crap it was a nightmare on wheels!!! Basically a death trap!