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Do new car tires go on the front or the back when you only need two?
September 15, 2009 8:03 PM   Subscribe

Front-wheel drive car. Back tires worn and will be replaced. Front tires okay for now. Where should the new tires go?

My dad just asked me to get the back tires replaced on his 1995 Hyundai Elantra. It's front-wheel drive, no ABS or traction control.

The back tires are worn evenly, but there's not much tread left. The front tires are worn evenly and still have plenty of meat. I don't know if he regularly rotates the tires, and can't ask him as he's away and hard to reach. I want to get this done before he gets back.

So, I'll ask the shop to replace the bad tires -- I have that much figured out. What I don't know is whether to ask them to put the wheels with the new, meatier tires on the front and move the current fronts back, or just to replace the tires on the back and be done with it. He lives in southeastern NY state, which means he gets ice and snow in the winter, if that makes a difference.

What do you all think?
posted by Opposite George to Travel & Transportation (25 answers total) 1 user marked this as a favorite
 
New tyres to go to the front for traction and braking.

This question has been asked before
posted by Brockles at 8:10 PM on September 15, 2009


If the wear is even I think the best tire performance will be had by moving the fronts to the rear and putting the new tires on the front. FWD wears the fronts more, so if you're buying 2 new tires put 'em up there.
posted by Liver at 8:10 PM on September 15, 2009


The best tires go on the wheels that the engine is powering. When in doubt, you can always ask your mechanic.
posted by jessamyn at 8:10 PM on September 15, 2009


Yeah, I'm with everyone else. FWD cars make this an easy question: the new tyres go on the front.
posted by pompomtom at 8:14 PM on September 15, 2009


Some tire places will hassle you about doing this, athough it's relatively safe. Your dad can avoid this by rotating his tires.
posted by iknowizbirfmark at 8:28 PM on September 15, 2009


New tires go on the drive wheels. In an AWD car, they go on the front.

So I'm told by my mechanic, anyway.
posted by InsanePenguin at 8:34 PM on September 15, 2009


Front, front, front.
posted by Cool Papa Bell at 8:35 PM on September 15, 2009


On the front. Also, have them cross the existing fronts to the other side of the car (right left) on the way to the rear axle.
posted by notsnot at 8:44 PM on September 15, 2009


This question has been asked before,

Huh. I looked. Guess my search-fu isn't as strong as yours.
posted by Opposite George at 8:46 PM on September 15, 2009


Also, have them cross the existing fronts to the other side of the car (right left) on the way to the rear axle.

If they have a directional tread pattern, they'd have to be popped off the wheel and re-mounted to do that kind of rotation correctly (costing some extra cash). Most likely they'll just move FR to RR and FL to RL.
posted by knave at 9:01 PM on September 15, 2009


The better tires go on the back in all cars. Every time, all the time.

The reason is that the most important thing is maintaining control of the car. It is easier to control a car when its front wheels lose traction in a skid than when the back ones do. Think about the dynamics of a vehicle- it wants to keep going in the direction it is going. If you are in a situation where one end of the car or another is going to break free, there are only two things that are going to happen.

1- The front tires lose traction. You instantly feel the loss of control and adjust your driving. Usually all you have to do is let off the gas or the brake and the tires will re-grab and restore control. If you have to panic stop, the rear tires will drag the car to a stop. If you are in a situation where being unable to steer will cause you to hit something, there was nothing that was going to prevent it. Except having bought a full set of tires.

Or 2- The rear wheels lose traction. By the time you feel the rear of the car being out of control, you are pretty much already committed to the spin-out. Jamming on the brakes at this point will just stop the front of the car more quickly than the back, and you go sliding rear-first into a bad situation faster.

Thought experiment: Take a hammer. Try to balance it on your finger from the handle end and from the head end. It will be easier to balance when the head is up and your finger is on the handle. The lighter end of the object has less inertia and can change directions more easily. When you have control of the lighter end of and object, you have more control over the object.


While it is true that putting the better tires on the front will result in better traction, that is secondary to safety. No point in being able to get out of that snowdrift if you are going to fishtail into the river on the next turn.

Hydroplaning: if the front tires are weaker than the rear, you will start to feel the slip and adjust. If the back tires are weaker and start to hydroplane (which is likelier since the rear is lighter) you may not feel it. One small steering change and the rear of the car cannot follow the front and you go spinning into the ditch.

Also, since the front of the vehicle is heavier, a weaker tire in the front will be helped out by the added weight, moreso in a panic stop since even more weight will be transfered to the front of the vehicle.

But really, if the older pair of tires is worn enough for any of this to be an issue, you really need to replace all four tires.
posted by gjc at 9:17 PM on September 15, 2009 [4 favorites]


Seconding gjc. Unlike RWD autos where it is considered somewhat acceptable to have better traction at the rear FWD cars should have equal traction all around if you can swing it (for example up here in the great white north no tire shop will install only two winter tires on a FWD car). Next best is highest traction at the rear as oversteer is a much bigger problem for your average driver than understeer. Understeer is easier to recover from and less dangerous if you don't. Which is why practically every modern car is set up to understeer at the limits. So if you can only afford two tires put them at the back.
posted by Mitheral at 9:38 PM on September 15, 2009


I agree with gjc. Replace all the tires and have your dad rotate them regularly. That'll be best for traction and breaking.
posted by Taurid at 9:41 PM on September 15, 2009


bizarre, I have never heard such a thing that "all cars, all types, always have better tires in back?" I could not imagine what lab this thought comes from, but real world advice from race track here (road track, rally, etc.)... put the new ones on the drive wheels, rotate them all often (8000 miles), cross rotate if non-directional tires.

If possible for best performance, even wear, load balance, predictable response on road, change out all four!

plenty of knowledge base on this from racing sites, from tire manufacturers, from mechanics... just my .02... don't feel like backing it up with links, as I think the overwhelming opinion here is already that this is the case also.
posted by Jiff_and_theChoosyMuthers at 10:02 PM on September 15, 2009


can't leave it alone...

snow conditions are very different from rain, from gravel, from pavement in traffic...

yes, with snow, assuming there is decent tread on the "bad" tires, maybe this would work to counter "how a bad driver reacts"... but understeer/ hydroplaning (in turns esp or while in traffic on highways) is not something to mess with. no extreme is great... there are always extreme cases where even saying "wearing a seatbelt will kill you" may be correct... but for most driving, most economical use of tread, best chance of clearing water through less worn sipes (tread) on drive tires... generally put better tires up front.

also, the vast majority of stopping power comes from front brakes! by far... rears don't even come close.
posted by Jiff_and_theChoosyMuthers at 10:09 PM on September 15, 2009


TireRack says on the rear. Always what I've been told and I've done plenty of track events also. Keep in mind we are talking about what to do for street driving with most drivers and safety should always be the main deciding factor.
posted by white_devil at 10:51 PM on September 15, 2009


Good video from Michelin about this subject.
posted by white_devil at 11:00 PM on September 15, 2009


Jiff_and_theChoosyMuthers writes "plenty of knowledge base on this from racing sites, from tire manufacturers, from mechanics... just my .02... don't feel like backing it up with links, as I think the overwhelming opinion here is already that this is the case also."

None of those opinions are from people who manufacturer tires. Tire manufacturers however are unanimously behind putting the grippiest tires to the rear. At least for those who I could find a preference. I couldn't find anything on the websites of Falken, Cooper, Nokian, or Coker and I couldn't think of any one else.

Goodyear: "When you select a pair of replacement tires in the same size and construction as those on the car, we recommend you put them on the rear axle."

BF Goodrich endorses "grippy tires to the rear" [same vid as Michelin]

Dunlop: "When you select a pair of replacement tires in the same size and construction as those on the car, we recommend you put them on the rear axle."

Bridgestone/Firestone via their TireSafety spin off site: "If winter tires are applied to the front axle of any vehicle, they must also be installed on the rear. Do not apply winter tires to only the front axle --- this applies to all passenger cars and light trucks, including front wheel drive, 4x4 and all-wheel drive vehicles." [PDF Internal page 17]

Toyo: "If winter/snow tires are applied to the front axle of any vehicle, winter snow tires must also be installed on the rear axle. DO NOT apply winter/snow tires only to the front axle. This applies to all passenger and light truck vehicles including front-wheel-drive, 4WD, and
AWD vehicles.
"
Also: "REPLACING TWO (2) TIRES - When a pair of replacement tires is selected in the same size and construction as those on the vehicle, the two newer tires must be installed on the rear axle." [PDF Internal page 60]

And finally from the Rubber Manufacturers Association: "REPLACING TWO (2) TIRES - When a pair of replacement tires is selected in the same size and construction as those on the vehicle, the two newer tires should be installed on the rear axle unless the new replacement tires are of a lower speed rating (see “Tire Mixing” at left and “Important Considerations” on p. 7). Generally, new tires with deeper tread will provide better grip and evacuate water more effectively, which is important as a driver approaches hydroplaning situations. Placing greater traction on the rear axle on wet surfaces is necessary to prevent a possible oversteer condition and loss of vehicle stability" [PDF Page 4]
posted by Mitheral at 12:34 AM on September 16, 2009


If your remaining tires still have plenty of tread, it's not going to make that big of a difference which axle you put them on. If the tread is low enough that you're concerned, you should look into replacing them anyway.
Debates about driving dynamics aside, I'd say put the new ones on the front just for the sake of extending the life of the other two. Rotate them to the back and let the brand new tires take some of the FWD abuse for a few thousand miles.
posted by Jon-o at 4:09 AM on September 16, 2009


Mitheral is the man around here when it comes to car questions. Brockles too.

That aside, were it me, and the tires up front were 80% or better, I'd put them on opposite sides on the back and put the new ones up front. (Typical rotation pattern.)

Front right goes back left, front left goes back right. (Then typically backs go to front w/o changing sides---but they'll be new, so you can ignore that part.)
posted by TomMelee at 4:49 AM on September 16, 2009


White Devil- awesome! That shows exactly what I was trying to verbalize. It's actually worse than I expected! Those cars were only going 45, and the "bad" tires were only at half tread...

mitheral- thank you for the links. It worries me that so many people might take bad advice and end up hurting someone.

Understeer is when the car doesn't turn as much as the driver turns the wheel. The front wheels are unable to counteract the forward momentum of the car, and it just "plows" forward. Oversteer is when the car reacts MORE than what the driver told it to. In other words, the rear of the car becomes "loose" and as that video shows, makes for a wild ride.

And again- yeah, the front does more of the braking work. That is because when you stop the weight of the car is transfered to the front. Which makes the rear that much lighter, especially in a front wheel drive vehicle. What's worse? Jamming on the brakes and losing a few percent in stopping distance, or risking losing control of the vehicle? In the first scenario, maybe you stop short a few times, or even rear end someone. But in that situation, you would have already slowed down to almost nothing, and the accident would be minor. In the second situation, if the rear breaks free, you risk a spinout or getting hit by another driver when your rear end suddenly enters their path. Maybe it is less likely, but the risk-reward is not enough.

Further study- watch some NASCAR, or drifting videos on youtube, or general crash videos on youtube. I think you will see the sorts of bad, or at least unpredictable, effects of the rear end losing traction.


Good luck out there.

*- I'm not just talking out of my ass here- I have had the displeasure of driving a vehicle with better tires on the front, done for exactly the reasons people have suggested. And nearly killed myself when the car did unexpected things. Not even so much that I couldn't react to what was going on (I couldn't, but that's my problem), but that other drivers can't react. It was comical in the snow, but downright scary that one time on dry pavement. I was doing 20, 25 mph on a side street. A bad driver misjudged a stop sign and tapped me in the rear fender. The tap was light enough that it bent the fender in about 4 inches- you could probably do worse with one whack from a largish sledgehammer. And caused my car to do a 180. I had absolutely no control of it. If there were kids around, I shudder to think what would have happened. In retrospect, if I'd have had the reaction time to do it, I could have gunned it and the front of the car probably would have pulled the rear back into line. If I had the reaction time and the engine power to do it.
posted by gjc at 5:45 AM on September 16, 2009


Placing greater traction on the rear axle on wet surfaces is necessary to prevent a possible oversteer condition and loss of vehicle stability

Depends on the car. Most of those on the road these days are heavily biased to understeer to begin with, the Hyundai probably being no exception. If the difference between the two pairs of tires is great enough that it would bias the car to oversteer more than the driver would like (or at all, if the driver doesn't think about such things) then for sure put the better ones at the rear. If not, they're better at the front.

The safer choice given no other information is probably to put the new tires on the rear, but depending on the car and tires this might be far from optimal both for driving dynamics and efficient use of rubber. Thus the usual controversy, since there's not really a right answer.
posted by sfenders at 6:32 AM on September 16, 2009


wha'er... lotsa info out there... guess I'm wrong here.
posted by Jiff_and_theChoosyMuthers at 7:07 AM on September 16, 2009


Lots of good answers. Though I marked apparently-contradictory answers as "best," it's because they all raised good points. Jon-o pointed out the potential bean-plating here if the other tires are still pretty good, and sfenders pointed out that there may not be A best answer.

Given my dad's age, I'm going to go with the new tires on the back, as I'm not sure how readily he'd recover from a oversteer-induced skid.

Thanks everybody!
posted by Opposite George at 7:14 AM on September 16, 2009


What gjc said. New tyres go at the back.
I bought a new tyre to replace a flat last week and there were posters all over the tyre shop saying that new tyres go on the back axle to best counter oversteer.
posted by arcticseal at 6:26 PM on September 16, 2009


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