http://forums.bimmerforums.com/forum/archive/index.php?t-85127.htmlThe car rolled into Edge on a late Wednesday afternoon for her new shoes. I decided to keep the fronts on and squeeze a few more miles out of them. I was warned by both Gordon and Tony at Edge that it could cause some handling issues. Although, none of us really knew to what extent the handling would be affected.
I rolled out on my new rollers and went home quite happy albeit a short & slow drive.
The next day's drive to work in Walnut Creek was an eye opener. First off, at speed, the rear end would shimmy around quite a bit with very little steering input. It almost felt like the rear sway bar was disconnected. It also felt like the tires were squishy. It seemed like the rear end would 'fish around' a bit after a lane change (sorry for all the technical jargon).
Def, You are correct. We have done testing with two mismatched tires and the handling in an emergency situation was hard to control. We tested all season tires on the front with snow tires on the rear and in an emergency lane change a spin out was inevitible. Now that is an extreme difference and two performance tires would not be nearly as extreme but there will be differences. I would think as long as the handling is similar and you are matching the axle and the same kind of tire you should be fine.
Long story short, had one kind of tire in front and another in back. Handling was spooky - grooves in the pavement on the highway would make the car dart unexpectedly far worse than just tram-lining. Finally was able to find two matching tires for the rear, and the issue disappeared.
I can understand the floaty feeling if you've gone from worn RE050A tires to two new, full tread depth V12 EVO tires on the rear only. Mismatching tires like that can make a car feel unstable, especially at highway speeds. Adjusting air pressures won't help much.
Kind of a horror story I guess. I've always just gotten the original Continental 205/R17 93W tires. Well just recently I thought I'd give Big 10 Tires a chance since they seem to be great with a friend's car. I told them the tire I needed and they said they have them in stock. I took my car down there and gave it to them. Went to pick it up and they had put on some other brand with 205/ZR17 89W. I told them I can't use those and they told me that they would replace them but would have to order them. I said just put my old ones on but they'd already hauled them off. Well I've been running these stupid tires for 3 days now and am surprised I haven't had a wreck. When I turn sharply, the rear wheels don't track properly and it feels like the backend wants to keep going straight. And at high speed on the interestate the car just sort of meanders all over the road. I'll so happy to get the correct tires back on. I was quite surprised to see how MUCh difference mismatched treads can make.
http://www.currysauto.com/Articles/Tips_for_Buying_and_Maintaining_Your_Tires.pdfMismatched tires: This can cause poor vehicle handling and hydroplaning. A mechanic or seller of a car in such a state may be liable in this circumstance.
http://www.robertreeveslaw.com/dangerous-products/tire-defects.html#When replacing less than four tires, always replace them with the same model and brand. Mismatched tires can cause awkward handling or pulling to one side due to the fact that all tires are made with different compounds, tread design and internal construction. Optimally, all tires should be replaced at the same time.
Mismatched tires — Mismatched tires will adversely affect handling of a vehicle and could lead to accidents.
Or, the tires. Not sure how you get from tramlines pretty badly, to not having any of the weird issues described. It is very possible that you have the issues, to a less severe degree, due to a closer match in your mismatched tires.It does tramline pretty badly, but that's probably my alignment settings.
Mismatching tires like that can make a car feel unstable, especially at highway speeds
at high speed on the interestate the car just sort of meanders all over the road
grooves in the pavement on the highway would make the car dart unexpectedly
Some mismatches are better matches than others. To say that there is no problem, in the face of overwhelming evidence that there could be a problem, is pretty foolish, but yes, if you crash, that would be a cool story.I have PZero Nero's in the front (non-runflat) and Potenza RE050A's in the front... Had that for half this summer until a month ago... didn't crash or feel unstable at all... Next year do you think i will crash? I'm sure it'll be a cool story bro moment. OP I wouldn't sweat it too much if you drive like a respectable human.