Replace back tires -> Never need to rotate tires?

[eethan]

After driving 26k miles without rotating my stock MXV4 tires, my back and front tires had 1/8" and 5.5/8" tread depth remaining, respectively.

So it appears that the back tires on the M3 wear out twice as quickly as the front tires. In that case, can you simply replace the back tires (with the same model type of course)?

After replacing just the back tires, the front tires will still be at 5.5/8" depth and the back tires will be at a full 8/8" depth. Then keep driving without rotating tires. Now, both the front and rear tires should reach 2/8" around the same time. At this this point, simply replace all 4 tires.

What do you all think about this approach? (Excuse me - I'm not a mechanical engineer by training )

 

[MODEL+]

I don't see the issue with this strategy. Do you have a SR+ or LR/Performance?

Danny

 

[ianc]

Interesting data point, but kinda useless unless we know whether the car is a dual motor or not...

 

[dmurphy]

This is a sane course of action but has nothing to do with which wore out first, or RWD or dual-motor, or even because it’s a Tesla.

When replacing a pair of tires, always always always put the new pair on the rear. Always.

This is because the more-worn tires are more susceptible to hydroplaning. Hydroplaning in the front, and not the rear, will cause an understeer condition. The car will track straight ahead.
The reverse - hydroplaning in the rear and not the front - causes oversteer, and hence, a spin out is likely.
Understeer when hydroplaning is much much easier to control. Just track straight ahead and slow down. Oversteer is worlds more difficult.

 

[eethan]

I have a LR.

If there's no issue with doing this, then isn't this practice superior? - No need to spend time rotating tires + Seems to maximize the life of all 4 tires.

 

[GtiMart]

In mechanical AWD systems it's important that all wheels be the same diameter otherwise you put strain on the center differential. Although you don't have that issue on an AWD EV, I believe the traction control and stability systems, and probably the ABS too, rely on measuring differences in rotation speed of the various wheels. If the diameters are too different, I would expect these systems to have a hard time doing their job.

In terms of putting the best in front vs rear, I've always heard the contrary: but the best in front so you can steer. Recently I've changed that to: put the best at the end where they use up fastest, to even out the wear
I wonder how much the argument still holds now that cars have stability control programs. Everyone that tried spinning out a Tesla on the snow have realized that it's virtually impossible.

 

[todd2fst4u]

Tesla recommends installing new tires on the rear.

 

[freeAgent]

After driving 26k miles without rotating my stock MXV4 tires, my back and front tires had 1/8" and 5.5/8" tread depth remaining, respectively.

So it appears that the back tires on the M3 wear out twice as quickly as the front tires. In that case, can you simply replace the back tires (with the same model type of course)?

After replacing just the back tires, the front tires will still be at 5.5/8" depth and the back tires will be at a full 8/8" depth. Then keep driving without rotating tires. Now, both the front and rear tires should reach 2/8" around the same time. At this this point, simply replace all 4 tires.

What do you all think about this approach? (Excuse me - I'm not a mechanical engineer by training )

This seems reasonable to me if the rears wear out at a rate that's a whole number multiple of the front tires (1x, 2x, 3x, etc. vs. 1.1x, 1.2x, 1.3x, etc.). Getting locked into the same brand for half of your tire purchases may not be ideal, but it's not the end of the world. I personally plan to rotate my tires according to the manual for now since I figure it's a good opportunity to check for other possible problems with the alignment/suspension, or wheels in general.

 

[eethan]

How much of a difference would it make if I replaced the back tires with Michelin Cross Climate or Pilot A/S 4 instead of the stock MXV4 that would remain on the front tires? (The CC is interesting because it provides snow traction)

 

[eethan]

Thanks all for the helpful info!

I saw my neighbor changing his tire today so I asked him whether it would be fine to have a different model of All-season tires on my back tires. He thought that should be fine.

So for my LR M3, my plan is to keep the stock Michelin MXV4 tires in the front - each with 5.5/8" tread depth remaining. Then install fresh Michelin Crossclimate 2 tires in the back - which would have 8/8" tread depth. The idea is that both front and rear tires should then reach 2/8" tread depth around the same time (w/o rotating tires).

Please please LMK if I'm making a mistake.

 

[Vaillant]

Thanks all for the helpful info!

I saw my neighbor changing his tire today so I asked him whether it would be fine to have a different model of All-season tires on my back tires. He thought that should be fine.

So for my LR M3, my plan is to keep the stock Michelin MXV4 tires in the front - each with 5.5/8" tread depth remaining. Then install fresh Michelin Crossclimate 2 tires in the back - which would have 8/8" tread depth. The idea is that both front and rear tires should then reach 2/8" tread depth around the same time (w/o rotating tires).

Please please LMK if I'm making a mistake.

When we bought our used Model X, the fronts and backs were different brands. Now the rears are worn out, so we are changing them for another type again. I don’t see any harm in it, as long as they are the appropriate size and similar performance.

 

[android04]

After driving 26k miles without rotating my stock MXV4 tires, my back and front tires had 1/8" and 5.5/8" tread depth remaining, respectively.

So it appears that the back tires on the M3 wear out twice as quickly as the front tires. In that case, can you simply replace the back tires (with the same model type of course)?

After replacing just the back tires, the front tires will still be at 5.5/8" depth and the back tires will be at a full 8/8" depth. Then keep driving without rotating tires. Now, both the front and rear tires should reach 2/8" around the same time. At this this point, simply replace all 4 tires.

What do you all think about this approach? (Excuse me - I'm not a mechanical engineer by training )

Just wanted to add a slight correction to your tread measurements. They are in /32nds of an inch unless you are using metric. 1/32” is almost bald and less than legal tread depth and you are more likely to hydroplane. I know you are in California, so you don't deal with snow, but 5.5/32" tread depth would probably be good for one more winter season on winter tires.

As far as mixing tire brands, it should be fine as long as they are comparable types. I would not mix low rolling resistance all season tires (the Primacy MXM4) and ultra high performance all seasons (Pilot Sport A/S 3+).

 

[eethan]

Thanks for the advice! Couldn't find the rolling resistance spec but looks like my stock MXM4 and CrossClimate2 are both classed as "Grand touring All-season" so I figure they have similar characteristics.

Will be interesting to pair the CC2 in the back, with their snow traction, and the MXM4 in the front, with their quieter acoustic foam.

 

[PhysicsGuy]

I agree. When you are not getting oil changes or needing any other service, it doesn't seem worth it to rotate tires. I plan to replace the rear two tires soon and just stick with MXM4 every time I get two tires.

 

[PhysicsGuy]

I agree. When you are not getting oil changes or needing any other service, it doesn't seem worth it to rotate tires. I plan to replace the rear two tires soon and just stick with MXM4 every time I get two tires.

Or maybe I am mistaken. Maybe maintaining uniform tire radius, as mentioned above, is more important than I realize.

 

[Vaillant]

Or maybe I am mistaken. Maybe maintaining uniform tire radius, as mentioned above, is more important than I realize.

Left to right uniform radius is likely a lot more important because of the differential, than front to back, which are not mechanically connected.

Our X has a staggered set up so I imagine the diameters don’t match exactly, and that’s as it comes from the factory.

 

[scarpiamod3]

When I changed out the tires on my SR+ the back were below the wear bars the front had about double, I hate those tires so I changed them all anyways but ya if you don't rotate them the back go more than twice as fast as the front, I only got 30k kilometers out of the back.

Note - I never bothered to rotate them because I was always going to throw them out, they just needed to make it through winter.

Changing the backs only on the rwd is perfectly fine.

 

[Gasaraki]

After driving 26k miles without rotating my stock MXV4 tires, my back and front tires had 1/8" and 5.5/8" tread depth remaining, respectively.

So it appears that the back tires on the M3 wear out twice as quickly as the front tires. In that case, can you simply replace the back tires (with the same model type of course)?

After replacing just the back tires, the front tires will still be at 5.5/8" depth and the back tires will be at a full 8/8" depth. Then keep driving without rotating tires. Now, both the front and rear tires should reach 2/8" around the same time. At this this point, simply replace all 4 tires.

What do you all think about this approach? (Excuse me - I'm not a mechanical engineer by training )

It sounds legit.

 

[Gasaraki]

In mechanical AWD systems it's important that all wheels be the same diameter otherwise you put strain on the center differential. Although you don't have that issue on an AWD EV, I believe the traction control and stability systems, and probably the ABS too, rely on measuring differences in rotation speed of the various wheels. If the diameters are too different, I would expect these systems to have a hard time doing their job.

In terms of putting the best in front vs rear, I've always heard the contrary: but the best in front so you can steer. Recently I've changed that to: put the best at the end where they use up fastest, to even out the wear
I wonder how much the argument still holds now that cars have stability control programs. Everyone that tried spinning out a Tesla on the snow have realized that it's virtually impossible.

For RWD cars and rear wheel bias cars like the Tesla, the two tires with the most thread should always go on the back. For FWD cars, where the front wheels have to do the moving and braking, the better tires should go on the front.

 

[gearchruncher]

For FWD cars, where the front wheels have to do the moving and braking, the better tires should go on the front.

I had a guy go into the barrier on the highway in front of me in a heavy rainstorm once, and he said he had just done this, with this same logic.

Like mentioned earlier in the thread, tread is about water resistance, not dry performance (race cars run slicks), and handling a car hydroplaning in the front is way easier than in the rear. The same is true if you really think you have more grip from your "better" tires. Last thing you want is the back stepping out.

Admittedly, in a modern car like a Tesla with incredible stability control, this becomes a lot less important.