AWD spare - distance and speed vs damage?

As mentioned in another thread, I have a GX460, which is full-time AWD. For directional tires, which can't easily be part of a five-tire rotation, what do people do for spares, and how far and fast can you go without damaging the transfer case or other components? Around town would be one thing, but on cross-country trips of close to a thousand miles in a day, the inability to finish the trip makes a directional spare unappealing.

Yes, I have read the manual. It is not helpful - it says "Do not mix tires of different makes, models or tread patterns. Also, do not mix tires of remarkably different treadwear." It also indicates a non-crossing rotation, with the spare included on the passenger side (and the dealer has never done so to my knowledge). Even following that, the spare (and the passenger side tires in general) will perforce have lower treadwear than the driver's side tires. What's "remarkably" different, and can a long road trip be finished? What if it's a driver's side flat and the spare is pointing the wrong way?

The original question remains - what do people do for spares in this situation? Is it simply not worth running directional tires on AWD?
Spare tire is temporary, so it’s usually limited to 55 mph and 100 miles

But Toyota/Lexus tends to be good about matching the temporary spare diameter to the actual tire diameter
 
Spare tire is temporary, so it’s usually limited to 55 mph and 100 miles

But Toyota/Lexus tends to be good about matching the temporary spare diameter to the actual tire diameter

But when it's the same size, why those limitations? I had the same question with my old '07 GTI - it came with a narrower but same diameter real tire on a steel wheel, with the standard yellow warning sticker. No reason it should be subject to those limitations.

Being able to use the spare in a five-tire rotation makes it also senseless to say that the one currently under the floor is arbitrarily limited. Though from the perspective of the risk from a second flat it makes some sense to get it fixed ASAP.
 
When I worked for a Lexus dealership The differences allowed between tires with AWD 4wd was 4/32nds maximum between the two sides, or between any two tires.
 
But when it's the same size, why those limitations? I had the same question with my old '07 GTI - it came with a narrower but same diameter real tire on a steel wheel, with the standard yellow warning sticker. No reason it should be subject to those limitations.

Being able to use the spare in a five-tire rotation makes it also senseless to say that the one currently under the floor is arbitrarily limited. Though from the perspective of the risk from a second flat it makes some sense to get it fixed ASAP.
When it's the same size, but.. if you have a worn tire, then you do have some rolling diameter difference between the spare that is seldomly used vs the other 3 tires. Since the GX has a Torsen center differential, variations up to 1/4" (or 8/32") doesn't really bother the mechanical differential. Manufacturers will assume the worst case scenario to avoid liability issues.
 
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'18 VW Atlas and '18 VW Golf Sportwagen both w/ gen 5 Haldex awd = donut
'03 VW Passat w/Torsen ("Quattro") awd = donut
'08 Lexus RX350 awd (don't the know the specifics) = full size spare

Unless you don't have open diffs I can't see where you will damage anything with limited use as-intended with a compact spare...they wouldn't include if it did.
 
I'd get a matching 5th rim, get the same brand of tire but omnidirectional. That way you maintain full capability until you reach a tire repair shop.

Then there's the question of even wear...🤔 ...which is why I prefer non-unidirectional tires.
 
But when it's the same size, why those limitations? I had the same question with my old '07 GTI - it came with a narrower but same diameter real tire on a steel wheel, with the standard yellow warning sticker. No reason it should be subject to those limitations.

Being able to use the spare in a five-tire rotation makes it also senseless to say that the one currently under the floor is arbitrarily limited. Though from the perspective of the risk from a second flat it makes some sense to get it fixed ASAP.

There's a traction difference, the faster you drive the more risk of losing control. The further you drive, the more risk of driving faster AND more chances to lose control
 
I'd get a matching 5th rim, get the same brand of tire but omnidirectional. That way you maintain full capability until you reach a tire repair shop.

Then there's the question of even wear...🤔 ...which is why I prefer non-unidirectional tires.

I think the spare is already a matching rim, but I'll check.

There's a traction difference, the faster you drive the more risk of losing control. The further you drive, the more risk of driving faster AND more chances to lose control

True, but with a fully-matching, part-of-rotation spare, why is that different from the same speed and distance without a flat?
 
Directional tread shouldn’t matter much. The driveline won’t notice any difference because the rolling diameter is still the same. You just won’t have as much wet traction.

My RAV4 AWD busted a tire while on a trip. I ran the spare about 40 miles to find a tire shop. My tires were Toyos with low tread, they only had one new Goodyear my size. So 3 old and 1 new. I ran that another 400 miles until I could get home and order 3 more matching tires. Car still drives fine 6 months later. The GX full time 4wd system is much more rugged then a RAV4 AWD system.

Anything less than 1000 miles on mis matched tires should be completely fine. If Toyota didn’t say that in the owners manual I bet people would be running 4 different tire sizes for 100k miles.
 
You have to be very careful with that.

We sold and maintained/repaired Hyundais and Mitsubishis. The mitsubishis handled mismatched tyres indefinitely but the hyundais got damage in the blink of an eye. Not saying it's a quality issue, it's a programming thing, the Mitsubishis allow a little bit of slip, enough to overcome the diameter difference between a worn and new tyre., Hyundais don't and will attempt to run (usually) as new rear tyres as fast as the worn fronts. Something needs to give and most often it's the transfer case, sometimes the clutch pack, but also the pick up on the front diff casing can strip it's teeth.
 
As mentioned in another thread, I have a GX460, which is full-time AWD. For directional tires, which can't easily be part of a five-tire rotation, what do people do for spares, and how far and fast can you go without damaging the transfer case or other components? Around town would be one thing, but on cross-country trips of close to a thousand miles in a day, the inability to finish the trip makes a directional spare unappealing.

Yes, I have read the manual. It is not helpful - it says "Do not mix tires of different makes, models or tread patterns. Also, do not mix tires of remarkably different treadwear." It also indicates a non-crossing rotation, with the spare included on the passenger side (and the dealer has never done so to my knowledge). Even following that, the spare (and the passenger side tires in general) will perforce have lower treadwear than the driver's side tires. What's "remarkably" different, and can a long road trip be finished? What if it's a driver's side flat and the spare is pointing the wrong way?

The original question remains - what do people do for spares in this situation? Is it simply not worth running directional tires on AWD?

Don't take this the wrong way, but your GX460 (and the previous gen GX470) are basically 4runners (in fancy clothes). Many of the mechanical parts are interchangeable between the two.

First, good on reading your owner's manual...people who do that seem to be rare.

Second, I would post your question and concerns on forums that deal with 4runners/GX470/460. The popular t4r.org has a section just for the Lexus GX470/460. There would be people there more familiar with your vehicle specifics.

Third, your vehicle (if it is similar to my '05 4runner) should be 'full time 4WD'...at least that's what people on the Toyota side call it since you have a transfer case that can be placed in 4Lo and locked. AWD vehicles like Subaru's don't have that option.

And if like my '05 4Runner, you would have an open differential in the front, back and center with electronic stability and traction control. This means that as long as you don't lock the center diff, the wheel between front and rear can turn at different speeds and wheel between left and right can turn at different speeds without any mechanical binding.

Ideally, you'll want to run tires with that are the same type (all season, all terrain, etc.), same tread depth and same model on all 4 corners...and you want to keep the tires at the same tread depth by proper tire rotations.

As for the spare...I wouldn't worry too much about it. In the owner's manual it states that treadwear (tread depth) shouldn't be too different. How different? Well, ask ten different people and get ten different answers. In my opinion, as long as the tread isn't worn out on the spare or the running tires, you shouldn't have any problems....at least mechanically. Now, the electronics may throw a code or two because if the rotational speed of one wheel is different (cause by a significantly higher/lower tread depth) from the others, it might 'confuse' the electronics.

But you might be able to compensate with adjusting air pressures or by simple turning the electronic 'nannies' off...if you have that option.
 
Don't take this the wrong way, but your GX460 (and the previous gen GX470) are basically 4runners (in fancy clothes). Many of the mechanical parts are interchangeable between the two.

First, good on reading your owner's manual...people who do that seem to be rare.

Second, I would post your question and concerns on forums that deal with 4runners/GX470/460. The popular t4r.org has a section just for the Lexus GX470/460. There would be people there more familiar with your vehicle specifics.

Third, your vehicle (if it is similar to my '05 4runner) should be 'full time 4WD'...at least that's what people on the Toyota side call it since you have a transfer case that can be placed in 4Lo and locked. AWD vehicles like Subaru's don't have that option.

And if like my '05 4Runner, you would have an open differential in the front, back and center with electronic stability and traction control. This means that as long as you don't lock the center diff, the wheel between front and rear can turn at different speeds and wheel between left and right can turn at different speeds without any mechanical binding.

Ideally, you'll want to run tires with that are the same type (all season, all terrain, etc.), same tread depth and same model on all 4 corners...and you want to keep the tires at the same tread depth by proper tire rotations.

As for the spare...I wouldn't worry too much about it. In the owner's manual it states that treadwear (tread depth) shouldn't be too different. How different? Well, ask ten different people and get ten different answers. In my opinion, as long as the tread isn't worn out on the spare or the running tires, you shouldn't have any problems....at least mechanically. Now, the electronics may throw a code or two because if the rotational speed of one wheel is different (cause by a significantly higher/lower tread depth) from the others, it might 'confuse' the electronics.

But you might be able to compensate with adjusting air pressures or by simple turning the electronic 'nannies' off...if you have that option.

Oh, I'm aware it's a 4Runner. Well, more like, the 4Runner is a cut-rate version of the Prado, and the GX is very much closer to it. Those two were the only considered option when I got it because they're able to accept my and my wife's bikes inside, vertically, with only the front wheel removed. The 4Runner would have been more sensible, but I was feeling bougie and the GX is wonderful.

Thank you for the detailed info! I assume your 4R is a Limited to have the similar full-time system. I would have sworn on the proverbial stack of Bibles that Lexus and Toyota called the GX and the 4RL "AWD", but indeed no, both the manual and the Lexus site say 4WD. So that sets my mind at ease more. Again, thank you!

From the Lexus site right now:

ONLY STANDARD 4WD IN ITS CLASS*​

What gives this rugged SUV better traction in both on-road and off-road* driving situations? Having power directed to all four wheels—all of the time. Off-road, the transfer case can run in locked or unlocked mode, as well as in high or low range.
 
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