Due to some poorly thought out tire rotation, two of my stock advans are considerably more warn that the other two. As in DONE. The others are maybe 50%. I'm tempted to replace only the two warn ones (with the same tire), putting the newest two on the front. There are disadvantages of doing this, I know, but are any of them big enough deals to actually care? Yes, the heat cycles and wear will be off, but that just means I will need to continue to replace my tires two at a time. No biggie. Yes, the circumference/diameter of two of the tires will be ever so slightly smaller than the circumference/diameter of the other two, which in theory could mess some of our all-wheel-drive trickery up. But I do not believe the difference would be big enough to actually do so (although please someone enlighten me if I am wrong).

So am I missing something? Is there any problem with replacing only two tires? Thanks in advance.

 

i know for a fact it will ruin ur tranny after a while. cause your all wheel drive will always be trying to adjust for wear on one tire plus your diff will blow after a while too

 

sorry, , your wrong, the tires wear differently to start with , thats why you need to rotate them, if this was true everyday driving your car will destroy it. every time you turn one wheel is moving more than the other . what you are thinking about is changing tires and you change size significantly this will put undo stress on the system. the small tread depth change could even come from running 1 tire low on air compared to another .

 

When tires are replaced in pairs in situations like these, the new tires should always be installed on the rear axle and the worn tires moved to the front. The reason is because new tires on the rear axle help the driver more easily maintain control on wet roads because new, deeper treaded tires are more capable of resisting hydroplaning.

Its necessary that four-wheel drive and all-wheel drive vehicles use tires that are very closely matched on the same axel. This is because different diameter tires roll a different number of times each mile as a result of the variations in their circumferences. Tire diameter variations can be caused by accidentally using different sized tires, tires with different tread designs, tires made by different manufacturers, different inflation pressures or even tires worn to different tread depths.

As an example of different tire diameters resulting from tires worn to different tread depths, we'll compare two 225/45R17-sized tires, a new tire with its original tread depth of 10/32-inch and a second tire worn to 8/32-inch of remaining tread depth. The new 225/45R17-sized tire has a calculated diameter of 24.97", a circumference of 78.44" and will roll 835 times each mile. The same tire worn to 8/32-inch of remaining tread depth is calculated to be 1/8" shorter with a diameter of 24.84", have a circumference of 78.04" and will roll 839 times per mile. While the difference of 1/8" in overall diameter doesn't seem excessive, the resulting 4 revolutions per mile difference can place a continuous strain on the tires and vehicle's driveline. Obviously, the greater the difference in the tires' circumferences, the greater the resulting strain. This is why its best to install the newest pair of tires on the same axel.

Tire Rack Tech Center

 

Thanks for the advice everybody. Neal, questions for you:

Apart from hydroplaning, is there any other reason to put the new ones in back?


Just to clarify: the strain to which you refer is when putting two differently sized/worn tires on the SAME AXEL, correct?

 

Resistance to hydroplaning is really the main reason for putting them on the rear. My example above referred to installing two different tires on the SAME AXEL. For example, if you had a tire that was 80% worn matched with a tire that's new on the same axel, the left side will turn at a different rate as the right. This can cause some bad wear. If you have two new tires there's no problem installing them on the same axel because they will be turning at the same rate.

hope I didn't confuse things ...

 

Not at all...thanks!

 

what neal failed to say , was this idea of putting them in the rear if for people who cannot handle a car with oversteer, if you are a skilled driver you will want your tires on the front where you have the most advantage for braking and turning. the idea for putting new tires on the rear was gained from data showing that a car with poor rear tire traction had more tail swing and if you cannot drive a car then you lost control. but with all highperformance driving , we know some slide is perfered and may even set you up for better corner exits. the facts stand, when stopping or turning the better tires place on that axel performed better. now saftey issue with a standard driver who may Panic if the car does something else than understeer the rear is a better location. just to give you the true facts and reasons some people say place them on the rear as compared to the front. i drive in all weather and believe me i prefer my rear wheels hydroplaning than my driving wheels.

JFYI

 

well i guess then the head mechanic for mitsibushi should be fired and the job handed to Neal@tirerack cause that is the info he gave me based on the research they have done and the head mechanic at suburau should be fired too then some inf as other mechanic

 

On any all-wheel drive you want tires that are close to each other in diameter. Yes, same axle is most important but you don't really want a continuous load even on a viscous center diff.

Regarding Neal's suggestion of putting more tread on the rear axle I have a slightly different view. As long as you are not braking in the water, I prefer to be able to steer but I would endorse this on a FWD or RWD vehicle only and everyone's got to take their own chances.

Anyway, rotate tires early on an AWD so they tay the same diameter and then shell out some bucks to get 4 equal size donuts.

 

yes Yellance the Mech at Mitsu and Subi should be fired. some people cannot think for themselfs nor have the technical ability to comprehend physical law. try sitting down with the Mech. and talking to him about why ? you will see there are standard tolerances for all these issues and just because one person can understand doesnt mean all can understand. their stance is all new tires to less the chance some changes the tires to a different size that could be significantly different and possible cause damage. lets use your brain for one sec. less say you put tires on your car and they 5 inches taller, big difference can you drive 1 mile before something breaks or 10 miles or 10,000 miles they cannot give you an exact answer. we now it will stress the system that ok if is limited. just like if you tires are .001% different how long can you drive on them , probably forever, this stress is within the change an can be tolerated for well over the life of the tire. so calm down and just try and gather all the info. this will help you understand why and where they are coming from. rotate your tires often, keep even tread wear if you can. and if possible change all tires at the same time. this will be the safest and easiest for most people so they dont end up damaging the vehicle due to ignorance. does it make since to you if you have 60% treadwear on the tires and you have road damage to one of your tires , you will replace all the tires at once.

 

It does go against what we have all been told over the years, but when you do the testing over and over and see others do it (Michelin and Bridgestone have both done the same test here and at their proving grounds) its makes a lot more sense. We have a good article on this subject at "Where To Install New Pairs of Tires".

 

how much will you pay for the 2 new tires? you might as well pick up a used set with low milage and replace all four (i am selling a set with 3000 miles for 500 shipped)

 

here is part of their quote, just like i said and have seen before

If the rear tires have more tread depth than the front tires, the front tires will begin to hydroplane and lose traction on wet roads before the rears. This will cause the vehicle to begin to understeer (the vehicle wants to continue driving straight ahead). Understeer is relatively easy to control because releasing the gas pedal will slow the vehicle and help the driver maintain control.

However, if the front tires have more tread depth than the rear tires, the rear tires will begin to hydroplane and lose traction on wet roads before the fronts. This will cause the vehicle to begin to oversteer in which the vehicle wants to spin. Oversteer is far more difficult to control, and in addition to the initial distress felt when the rear of the car starts sliding, quickly releasing the gas pedal in an attempt to slow down may actually make it more difficult for the driver to regain control, possibly causing a complete spinout.


but they didnt answer the question. if you want the maximum braking and turning you want them on the front . but you better know how to drive and handle oversteer.

they even have the nerve to say , suprise oversteer, how can this be a surprise if you reacting quickly you should know how to handle your car and this doesnt account for AWD which all wheels have power if you lift some the effect is not as dramatic , but it is correct in stating if you can compensate and control power you can drive right out of it. this is a demonstration for uneducated and erratic driving. if you slam your brakes on in a straight line with good tires in front your stopping distance will be shortened. try and prove me wrong. if you are turning in a controled situation see how much more g force can be maintained before spinning. if you quickly jerk your wheel and cannot drive. it will be easier to just let go of everything and drive straight ahead right into what your trying to avoid. will someone please teach people to drive. if you start to oversteer and counter steer the front wheels you can still manuver the cars front end and possible avoid whats in front of you. who cares if you spin a 180. you just missed what your about to hit. get the facts and know your car and driving ability. practice your spins, drifts and cars handling then you wont be in a position that you cant drive out of.

 

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