Slightly different tire question (1 Viewer)
- Thread starter mhidpa
- Start date
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This should apply (AFAIK) to all AWD vehicles including the 100. Different vehicles have a different tolerance and Subarus are notoriously difficult in that regard. Since Cruiser tires are significantly taller than Subaru tires, 1/8" of wear difference between tires is a less significant percent of total tire height and thus less impactful on your diffs.
General sentiment is that it isn't catastrophic when used as a spare or for short distance, but over time running different size tires (ex: replacing one punctured tire when the remaining 3 or 4 have 30k miles on them) is never kind to your diffs. Each car will have a different tolerance for how large of a % difference in circumference they can reasonably handle, but I can't give you a percent or advice on the 100 in specific besides why risk it? If it is a spare or off road I wouldn't sweat it, if it is for permanent and daily use then run matching tires whenever possible.
General sentiment is that it isn't catastrophic when used as a spare or for short distance, but over time running different size tires (ex: replacing one punctured tire when the remaining 3 or 4 have 30k miles on them) is never kind to your diffs. Each car will have a different tolerance for how large of a % difference in circumference they can reasonably handle, but I can't give you a percent or advice on the 100 in specific besides why risk it? If it is a spare or off road I wouldn't sweat it, if it is for permanent and daily use then run matching tires whenever possible.
I’m curious why everyone calls 100s AWD
- Thread starter
- #4
Not sure if serious, or trolling. I don't really care what anyone calls it or the semantics around it having Hi and Lo range making it full time 4WD vs AWD. I just want to know if dissimilar tire circumference will cause damage.
Because they have a center differential. Same with 80s and 200s.
Trunk Monkey
Moderator
You might be able to get away with a minimal difference that occurs between manufacturers, say 33 vs 33.4, but you can't run totally different sizes, like 31 and 33.
Only thing to really think about is yeah you might throw an ABS light when the system senses a wheel is turning at a different compared to others.
So once the ABS light on
1-No ATRAC
2-No ABS
3-Don’t even think about locking that center diff.
YMMV,
Good luck…
I do wanna ask what you’re doing?
So once the ABS light on
1-No ATRAC
2-No ABS
3-Don’t even think about locking that center diff.
YMMV,
Good luck…
I do wanna ask what you’re doing?
This.
Same with Sport Touring setups. I custom built my wife’s 955 Porsche Cayenne, put lowering coilovers and ran staggered wheels 22x9 and 22x10. It’s important to know the total diameter size of the tire. In most cases esp on this community, the owners here don’t usually use staggered wheel setups, just box setup wherein all wheels have the same width. I also haven’t seen a manufacturer that produced wheels for the 100 and the 200 that has staggered width.
Teslas are awd and lack a center differential. Doesn’t awd imply power to 4 wheels but no transfer case? With transfer case=4wd? Or is it just used interchangeably for anything with power to 4 wheels?
need a little education due to my opinion: front/back...side/side tires always turn at different speeds due to cornering (at least on paveement w. center diff open). the diffs are designed to handle that. otherwise manufacturers would advise against turning.
tires of different diameter also turn at different speeds.
Please explain how the two affect the diffs differently.
tires of different diameter also turn at different speeds.
Please explain how the two affect the diffs differently.
You’re actually going straight most of the time. Most awd/4wd systems are part time or open, and become active via viscous coupler or other during slip. Mismatched tires beyond a certain spec can trigger the system to run all the time, including on the highway, overheating components causing premature failure. It can also affect abs, traction and stability systems, and tpms
- Thread starter
- #12
Yeah, I'm not talking about different tire sizes, I'm talking about replacing 2 tires instead of 4. Same tire size, but different circumference due to wear. Like I said some vehicles have pretty strict tolerances on that. Sounds like that's not an issue for the 100
- Thread starter
- #13
Well, Teslas have motors at the front and rear so they are a little unique vs something with an engine. AFAIK everything with one engine driving all 4 wheels will need to have some sort of transfer case. But having a differential (AWD) will allow different power distribution front to rear, a straight geared t case (4wd) drives both axles at the same speed, not great for road use. When you engage the CDL, then you are in true 4wd.
A standard Subaru won’t have a transfer case, just a center diff. No hi/low range, like a 4wd would have.
What is the tread difference you are looking at?
uHu
Bridgeburner
AWD is when all 4 wheels are powered all the time. On a vehicle with a single ICE, that normally means that you have 3 diffs, one in each axle and one in the transfer box between front and rear. If you have several engines, or motors, you might not need any diffs in order to take up the difference in speed (travelled distance) between the four wheels. In a dual motor electric car with AWD, you have one diff for the front and one for the rear. There have been made cars with four motors as well, one for (or inside) each wheel, and then you have AWD with no diffs.
My old Tercel 4wd, and my old 80-series 4wd (Africa Edition), also had a transfer box, but without a diff. The function is only to connect the front propeller shaft to the rear, so that the front and rear axles are forced to move at the same speed. That is a really good solution on soft surfaces: Driving winter roads with several inches of fresh snow is very stable (just like CDL-on for the 100), and that is something you don't get on an AWD without a CDL. No Atrac or ESC is as fast and immediate as a diff lock.
You’ll be fine, I’d do that if I had to bro.
Now shop around and find a clean cheap set of Tundra Gen-2 take offs.
You might get four almost brand new Michelin’s with tundra wheels for what you pay for two new tires depending on brand.
Many awd systems do not power all the wheels all the time. They use clutch packs and/or electronics to engage the other axle, and 97% of the time are 2wd for economy.
I always thought the transfer case with high/low is what made 4wd 4wd. Toyota calls it Full Time 4wd and it’s certainly a beefier and more premium system than any awd system I’ve seen. I’ve always seen it as awd<part time 4wd<full time 4wd in terms of price point and quality. There’s only a few similar systems and they are only available on top trims from oems while even a camry or Mazda3 can be had with awd.
makes sense (oil temp)
Now an overarching question: is the 100 a "full time 4 wheel drive" or is it an "all wheel drive" when the center diff is not engaged....inquiring minds need to know
Warning: I'm using this as ammo in a simmering discussion in my club.
I think it's all arguing semantics and playing with words for marketing purposes. IMO, it's an AWD until the center diff is locked. That doesn't make it any less if a 4wd than a traditional part time 4wd that is 2wd until the transfer case is locked.
On the 80/100/200 there is power to all 4 wheels, all the time, and most can transfer power by vc or electronics where needed. Part time systems only have power to 2. Many awd systems lock the center diff and many 4wds are completely open so having a differential lock can’t be a defining feature. I guess it’s really just semantics.
