Safe to replace just 2 tires on 4WD (V8)?
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NJshadow93
New member
I think a more important question would be, why are 2 tires more worn than the others? As long as they're being rotated regularly, they should wear pretty evenly.
Second question would be, how worn are the other two? If they're like-new, it shouldn't be a big deal. You want to try to avoid having mismatched sizes if you can, even though with the center differential open, it shouldn't affect much.
Rancid13
New member
If they weren't rotated regularly assuming full time 4WD (no burnouts etc from rear)the front 2 would wear faster due to turning
Edit: thats assuming the more worn ones on his rig are in the front.. If not, then forget that! Yeah that'd be a little strange
BlackWorksInc
New member
Toyota says they need to be within a few 32nds of each other otherwise it could cause issues. Tough you may be able to get away with 2 similar on the front axle and 2 similar on the rear axle.
I will mention that the Center Differential on all US model 4th Gens is a Torsen T3 "Torque Sensing" unit and according to Toyota while unlocked has the ability to mechanically adjust power ratio (at least that's what their literature says, I never bothered to verify this.)
JB.
New member
Depends on what exactly it is that you're asking.
If you're asking about otherwise identical tires (and hopefully you are) where the new pair simply has more tread depth then it's a matter of how much difference is acceptable.
Personally, I'd be okay with anything less than 4/32 difference.
I bought the truck used with 4 new (crappy) Americus(?) tires on it. 1 of my rear tires picked up a utility knife blade that cut into the shoulder of the tire - irreparable. I wasn't going to put another Americus on it (wouldn't even know where to find one of those), so I bought 2 new Michelin LTX M/S 2's (of the same size). New tires on the back, best 2 of the remaining 3 crap tires are on the front. I really don't want to spend the additional $550-$600 right now if it's not necessary. I'm hoping it can wait a few months.
Thanks for the responses, I appreciate it.
Thanks for the responses, I appreciate it.
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thatoneguy
New member
I'm surprised it would be a problem with a open center diff? I know its a serious thing on Subaru's with symmetrical awd. With the open diff i don't see an issue.
BlackWorksInc
New member
NJshadow93
New member
Isn't it basically open but distributes power accordingly due to imbalances?
BlackWorksInc
New member
Yes, but consider that an imbalance can occur due to the vehicle having different diameter tires, thus requiring more or less effort on those axles. Like I said Toyota say even a few 32nds difference could cause issues in the system.
V8Man
Member
Wouldn't the problem be if you were driving in snow or otherwise traction limiting surface. I have seen 4wd trucks were the rear was trying to pass the front because of tire differences.
Not saying this would happen with the 4R but like Blackworks said I think you could put some stress on things causing wear and $.
Not saying this would happen with the 4R but like Blackworks said I think you could put some stress on things causing wear and $.
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lilreds21
Member
you need to do all 4. think of it this way... imagine you wearing a tennis shoe on one foot and a flip flop on the other. you won't feel anything causing damage but over time it will cause bad damage. having the different 32nds will/can cause issues with your drivetrain! one down fall to full time AWD!
Stuck CAPS
New member
That's just untrue. Having different wear on 2 of 4 tires (if they're the 2 replaced are on the same axle) will probably not cause issues with the drive train since it's AWD. If OP drove around with center diff always locked, it'd be different, but that just doesn't happen.
gshadow325
New member
With all the debate, in the end, are you willing to find out the results ? The hard way with an expensive drive train repair ? All to save ~$500 vs $2500+
Your money your truck.
Your money your truck.
Problem is the are all connected by a torsen and an ecu that monitors wheel speed to decide where to shift power. When the the tires are more than a few 32nds different the ecu sees the difference and the torsen is always engaged. This can cause wear and failure.
But if it was mine I would replace all four or get 2 from Tirerack and get them shaved to the matching depth.
Quoted from TireRack:
Matching Tires on Four-Wheel Drive and All-Wheel Drive Vehicles
The ability of four-wheel drive and all-wheel drive vehicles to divide the engine's horsepower between its four tires is especially useful on loose or slippery surfaces such as sand and dirt, as well as on wet, icy or snow-covered roads. However it's important to remember that in order to transfer this extra power, the four-wheel drive and all-wheel drive vehicle's driveline mechanically connects the tires so they work in unison.
Four-wheel drive and all-wheel drive vehicles are equipped with additional differentials and/or viscous couplings that are designed to allow momentary differences in wheel speeds when the vehicle turns a corner or temporarily spins a tire. However, if the differentials or viscous couplings are forced to operate 100% of the time because of mismatched tires, they will experience excessive heat and unwarranted wear until they fail.
This necessitates that four-wheel drive and all-wheel drive vehicles use tires that are very closely matched. 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 makes maintaining the vehicle manufacturer's recommended tire inflation pressures and using "matched" tires on all wheel positions necessary procedures to reduce strain on the vehicle's driveline. Using "matched" tires means all four tires are the same brand, design and tread depth. Mixing tire brands, tread designs and tread depths may cause components in the vehicle's driveline to fail.
Mismatched tires or using improper inflation pressures for all-wheel drive and four-wheel drive vehicles can also result in immediate drivability problems. Some Control Trac equipped vehicles in 4Auto mode may exhibit a shutter on acceleration and/or a noise from the front driveline and transfer case while driving. Some all-wheel drive and four-wheel drive vehicles may exhibit axle windup or binding while driving. Some four-wheel drive vehicles (manual or electronic shift) with a two-wheel drive mode may refuse to shift "on the fly" into 4x4 Auto or 4x4 High at highway speeds.
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JB.
New member
No disagreement with the overall sentiment but, for the record, the operation of the Torsen is purely mechanical.
