I need to replace two snow tires on my truck (RWD with on the fly 4WD). Due to money I’d rather get two really good offroad tires that are rated pretty good at handling snow and ice and then when the snow tires need replaced have all 4 tires the same but according to the tire dealership, doing that would be horribly dangerous. Is it really that unsafe and if not, should my two good snow tires be on the front or back?
I wouldn’t call it horribly dangerous, but I’d be certain all four tires were the same diameter. I’d also be very caution while in 4WD mode.
I wouldn’t call it “horribly dangerous” but it puts a lot of unnecessary stress on your vehicle and will cause things to wear out faster. It’s also going to make your performance in 4WD mode a little wonky. I definitely would not do it unless you are guaranteed never to switch into 4WD mode. You are losing a lot of the benefit of 4WD by having the tires fight with each other.
For 4WD you want all four tires as identical as possible. If you have front wheel drive (2WD) then you want your best tires on the front since those tires are used for both steering and acceleration/deceleration. With rear wheel drive it gets to be a bit debatable but I have always put the bigger and more grippy snow tires on the rear and I’ve never had a problem.
If you have to have different quality of tires, the best ones should be on the back. If you start to lose traction, having the back tires grip means you can stay pointed more or less forward while the back tires work to stop you. If the back tires slip, when your fronts try to stop you, the back of the car will swing around wildly.
You might end up wearing out those off road tires quickly running on pavement at high speed. It depends on the tread design. Some of them are terrible on smooth surfaces after some wear even if they’re still decent off road or in heavy snow. I’d second what Cheesesteak said, put the good ones on the back. Fishtailing is a common problem with trucks in a skid.
Cheesesteak is correct. When changing only 2 tires the best tires go on the REAR and the worn tires go on the front. Explainations here:
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=52
Agreed. With 2WD, having front and rear tires of different diameters is no big deal. But you should restrict the use of 4WD to really mushy conditions, or (better) avoid it entirely.
IOW, this is probably not a wise choice for a vehicle capable of 4WD.
Right.
I have a friend who does vehicle accident investigations. His comment on this advice, based on much experience, is “Believe it.”
The number of potential safety problems is so great with mismatched tires, especially on a large vehicle with a high center of gravity and the compounding issues of 4WD and a setup that will be driven in poor road conditions, that I can’t see any justification for getting the last $50 worth of wear out of the other two tires.
That’s the big issue for me. If it were a passenger car that’s one thing but in my Jeep Liberty I really do not want to mess with stability issues.
Dallas Jones, your cite is referring to front wheel drive vehicles but the OP has rear/four wheel drive.
This is indeed what my intuition tells me but I’ve learned to defer to experts and when the experts disagree, go with the consensus. From what I’ve heard, there is a strong consensus among automotive engineers that the better tires should be on the rear on front wheel drive cars.
It is absolutely correct that the best tires go on the back, regardless of drivetrain configuration.
However, in this case, we’re going to have some trouble deciding what the “best” tires are. AT tires with aggressive treads are great in deep snow and off-road, but they’re not all that great in slick road conditions. The mostly-worn out snow tires are probably still technically the “best” tires for on-road winter driving conditions, but putting them on the back with AT’s on the front is going to result in some funky handling if you get into the really deep stuff.
Simply buying four AT tires would be much better, and then you don’t have to deal with this same situation down the road when those start wearing out in pairs.
Replace all four and see if you can get some trade-in credit for the two salvageable/resalable ones. Really, you’re trying to decide if the safety of you, your family and passengers and anyone sharing the road with you is worth $50 to maybe $100 in remaining life on the two better tires.
IMVHO: They’re not.
W/regard to the “same diameter” issue, the interest of doing so relates to the spare tire. One definitely does not want different tire diameters on the same axle.
Does not matter. In a braking situation if the best tires are on the front they will grip better than the worn tires on the rear. The front will grip and the rear end will come around and you will be facing the direction you came from. If you aren’t already in the ditch.
It seems counter-intuitive, but the best tires go on the rear in either case.
Not being able to move forward in snow can be dangerous but for the most part it’s immediate impact is inconvenience. Not being able to control the car’s direction when braking is always dangerous.