Tire tread differences

[jesus_man]

What, if any, are the issues with running a full size spare with a brand new tire while the other side has a tire that's probably got 30% tread on it? I can't see that being any different than running the stock spare. I assume the differential is open under normal driving conditions and that should account for any difference in tread depth right? And those of you who are lucky enough to have a rear locker probably need it because the surface is slippery and the tread depth is irrelevant to abnormal wear on the axle assembly when the locker is on. Correct me if I am wrong.

J.D.

 

[blackforestham]

I can't imagine a significant issue will arise. Just be sure to rotate in the spare and soon enough all tires will have the same tread depth. If you need replacement tires (30% depth) now's the time to pop for at least 2, preferably 4, then rotate in your new fullsize spare.

 

[Houm_WA]

There were questions about whether different size tires would drive the TC and DSC crazy, though.

...not sure if the scenario you describe creates a significant-enough difference in tire OD though to confirm or refute that theory.

 

[MilehighLR3]

I can't imagine a significant issue will arise. Just be sure to rotate in the spare and soon enough all tires will have the same tread depth. If you need replacement tires (30% depth) now's the time to pop for at least 2, preferably 4, then rotate in your new fullsize spare.

When I bought my '05, it had/has different tire tread depth (one looks new, the other three are obviously not), but I have to admit I've not had it long enough to gather any intell.

 

[jesus_man]

I'm just trying to avoid the next 300 mile trip home at 50mph that we just took.

J.D.

 

[bgsntth]

Not for Land Rovers, but for Subaru's they warned about having tires with significantly disparate tread-depths, as this will strain\wear the differentials. I can not remember the details, but it was a warning in the manual.

 

[Geotrash]

Let's look at the math. 6/32" tread difference equates to .59" additional tire circumference. On a 30" tire, the circumference is 94.2", so you're adding 0.63% to the circumference of the tire. Your tires rotate 672.6 times per mile. That means the worn tire will rotate an extra 4 times more than the new tire, every mile. Over 10,000 miles that's an extra 40,000 rotations for the friction material in the differential to absorb. Not huge, but not insignificant either.

If you're driving 60 MPH, that means the 4 extra rotations will happen every minute. That may be enough to generate heat over several miles and start to stress fluids. Dunno, but I suspect this is why Subaru cautions against it, and I bet the same would be true for our rigs.

Cheers,
Dave

 

[JackMac]

Let's look at the math. 6/32" tread difference equates to .59" additional tire circumference. On a 30" tire, the circumference is 94.2", so you're adding 0.63% to the circumference of the tire. Your tires rotate 672.6 times per mile. That means the worn tire will rotate an extra 4 times more than the new tire, every mile. Over 10,000 miles that's an extra 40,000 rotations for the friction material in the differential to absorb. Not huge, but not insignificant either.

If you're driving 60 MPH, that means the 4 extra rotations will happen every minute. That may be enough to generate heat over several miles and start to stress fluids. Dunno, but I suspect this is why Subaru cautions against it, and I bet the same would be true for our rigs.

Cheers,
Dave

TireRack's Tech info agrees with Dave's comments above: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=18

and concludes:

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.

 

[MilehighLR3]

I know that when you're shopping for new tires, the tire shop folks always tell you to replace all four . . . . but I've always chalked that up to the tire sales person trying to up sell . . . . . I'm a firm believer in matching tread thickness.

Though I do find it odd that the dealer (Land Rover Denver East) didn't find it necessary . . . .

 

[ryan-in-oregon]

Unless I am off base here the subies have limited slip differentials right??? If so the rover is equipped with three open differentials so it really isn't that big of a deal. Where it comes into play is the point in which traction control engages? Which is likely the same point in which the center/rear difflocks would engage. But with three open diffs there would be no extra friction on the tire. I wouldn't expect it to be a big deal but I can bolt up a stock diameter wheel with my bfg AT and see what happens (1.75" diameter difference)