I suggest you all review these videos which show the impact of the different tire types during winter driving conditions. FWD, RWD and AWD cars are all shown.
Before you call bullshit, go watch the front wheel drive video at Aestivalis’ link. It shows a car with two winter tires on the front wheels in the snow (which is the same as two new tires on the front) Then come back and tell how it is front no question.
I just went through this scenario. I only needed front tires (38,000 mi on all tires; FWD; not adequately rotated), and when I researched it the consensus seemed to be that I’d get the best (forward) traction putting new tires on the front. But of course doing so would increase the chance of spinning out under wet or slippery conditions for the reasons noted above, since there would be a differential traction with the rear and it would spin out.
Tire installers seemed to suggest putting the grippiest (new) tires on the rear; there was at least some suggestion by some posters on my tire board that installers would obviously come down on the side of liability, even if the possibility was remote and even if my personal goal might be traction.
And then someone made this point: the same dealer who insisted putting a new pair on the rear for a FWD would recommend rotating the tires at 5,000 miles, and that rotation sequence puts those grippier tires right back on the front!
Good point.
The first message seems to be that if you don’t keep all your tires approximately equally grippy, you are doomed to replace all four if you want to be as safe as possible.
The second message is that sometimes not even the tire dealer thinks it through. OTOH maybe some dealers would refuse to rotate the tires if there is a substantial difference.
Me? I bought four tires. Ended up throwing away two good ones (I changed tire brands while I was at it.)
Rick?
Pretty sure my 95 Impreza has this potential problem, where I could wreck the differential by running tires with very small differences in tire size and wear. So I just made sure to buy four of the same tires and rotate them fairly often. I agree with Rick; check your manual to be sure and if it’s an issue, get another tire. Four tires is a heck of a lot cheaper than a new differential or other parts of the drivetrain.
I agree with you that for greatest safety you should have very similar tires on all four corners. I too have tossed one or two good tires in favor of all four being the same.
FTR when I sold tires back in the early 1970s, the tire council recommended new on the rear, and that is what I suggested, no lawyers involved.
But almost ALL cars were rear-wheel drive back then!
Engine weight isn’t an issue for tire wear in FWD because the engine is there for RWD too. I’m not sure the engine weight being over the tires affects tire wear appreciably in any case.
And not only are they your power wheels, but the front brakes do more of the stopping because a car pitches forward during a stop.
I think the argument about the rear wheels sliding out if the tires are less grippy is independent of front v rear-wheel drive, isn’t it? The change to FWD should not be considered to have reversed the recommendation should it?
Actually, it’s probably even more important to put them on the back with an RWD car, since it’s so much easier fo induce oversteer [than in an FWD car].
That said, oversteer can be controlled with the throttle much more easily in a RWD car, but only a tiny fraction of drivers can actually do it, so it probably doesn’t matter.
In terms of safety (the rear end breaking loose), no. But with FWD the front tires will wear faster, so in terms of treadwear, evening out treadwear, and rotation, it is reversed. Hence the dilemma.
That was what I was going to chime in with. FWD cars are (AFAIK) designed to understeer, when you’re whipping out the rear you’ve likely pushed it far enough that a slight difference in grip isn’t going to do much to help.
I have to say, that’s where you’re mistaken. If you take a look at the FWD video in my prior link, you’ll see that for two FWD vehicles traveling at the same speed, one with winter tires, and one all-season tires, the one with all-season tires breaks the back end loose fairly easily when going around a curve, while the winter-equipped car negotiates the course handily.
When they put winter tires on the front wheels only, it was even worse. Even when trying to brake on a straight path, the back tires broke free since the rear end couldn’t slow down as fast as the front. At least when all four tires were all season, it stayed straight instead of spinning out.
Even though they are pushing the cars pretty hard in these scenarios, you can tell that there is an obvious difference in performance when you put the grippiest tires in front. If these videos aren’t convincing, can you let us know why? I know they don’t show winter tires on the rear wheels, but you can tell that they won’t break loose like when they are in front.
All cars are designed to understeer. Not just FWD ones.
The problem here is not how the car is designed to handle, by having worn tires on the rear, you are changing the car’s handling characteristics. This is true regardless of engine position, or drive arrangement.
Picture this.
FWD car, brand new tires 12/32" of tread depth. On the rear are the old tires with 3/32" of tread depth. It is raining. You go into a corner at what seems to be a reasonable speed. The front tires are capable of channeling away the water and maintain grip. The rear tires however do not have enough tread depth, and start to hydroplane. At this point the back end of the car comes around to see what the front end is doing. You understeering FWD is now an oversteering car. Hit the brakes and you will probably spin the car all the way around.
Okay, so it’s unanimous - best tires on back with a FWD?
You think I read through an entire thread before posting, how little you know me sir/madam :dubious:
I was surprised at the braking test, but then I wasn’t really thinking of driving on ice/snow.