All wheel drive tires.

I know a person who has a year old Subaru. Recently a pothole damaged one of the cars tires. The tire shop says she needs to replace all 4 tires because it’s all wheel drive.
What say you?

 

That's what I've always heard. They have to be within a certain percentage diameter wise otherwise Bad Things happen to the drivetrain.

 

I was wondering about that.
I had an all wheel drive car many years ago but never had to actually replace a tire.

 

More than likely. Should probably upgrade the tires anyways. My girlfriend’s Subaru is 3 years old, has 45,000 miles and the tires are almost to the wear marks. In the last year she’s had 3 tire repairs. One of them is leaking through dry rot cracks on the tread now... we ordered her some all terrains to solve that problem that should be in on Monday! I’ve not been impressed with the stock highway tires.

 

depends

brand new vs worn tyres different sizes can cause wear in the center drive

all brand new tyres dont wear exactly the same front to rear or side to side

so there is tolerance to lifes reality

AWD does not mean ‘ all wheels ar driving ‘ ALL THE TIME ...........

i would match up 2 best on 1 axle

2 new on the other

she only needs 1 new tyre ( use spare )+ new..............odd tyre becomes spare

 

Did this person's Subaru come with an Owner's Manual?
I would bet that info is readily available.

 

The Subaru AWD system is more picky about tires than most other AWD systems. It's part of the reason their system is so good.

Subaru allows up to 1/4 inch difference in CIRCUMFERENCE (not diameter).

Running a tire with a difference more than that will wear out the clutches prematurely, which will cost a lot more than a set of tires to replace.

The Tire Rack will shave a new tire to match the tread depth of the existing tires on the car (provided the other tires on the car are new enough to worry about keeping)

Need To Replace One Tire On Your Subaru?

With the car being only 1 year old, the tires are probably still pretty good.

 

That is excellent info!

 

with a Scooby, it's awd all the time

 

Conversely, you can find a shop that can shave down a new tire to an acceptable circumference as to avoid replacing all 4.

This is a bit of a lost art, but might save some cash with some phone calls.

 

its not locked

if it were locked

wouldnt differentiate on either axle

 

Shops always say this, but on a tacoma that is part time 4x4 I would argue that 30%-40% variation is fine, no ideal but fine.

 

that's 4wd, not awd, there's change based on slip/grip. depending on what year and what model, it'll be a minimum of 25% power all the time, usually 50/50

 

The Subarus have a center differential as well as differentials in each axle, basically 3 limited slip differentials (some are viscous and some use clutches, depends on the model and year)

Think of it like this:

If you have a new tire on the left rear and a worn tire on the right rear, the new tire will travel farther per revolution than the worn tire.

The differential sees this as the new tire slipping since it is rotating more, so the clutches try to lock up to control what it perceives as a spinning tire.

This is what wears them out quickly when there is a different diameter tire thrown in the mix.

The AWD system is constantly trying to control the "spinning" it sees at the new tire.

 

cant say U r wrong

all i was sayin is the has to be some slack in the system

it may have been tested .......maybe someone knows for sure

yet i dont believe ALL the tyres on a Subaru without any issues

wear the SAME !!

so im thinkin there has to be some amount of ACCEPTABLE slack/wiggle room
( however U want to Label it )

its also accptable if im wrong

 

There is but it's tight (1/4 inch circumference difference)

I used to have a Subaru and my son has one now.

Regular tire rotations are a must to keep the wear even.

They are really great cars if you know about their quirks.

I've had other AWD vehicles and actually have one now, but none are as confidence inspiring in bad weather as the Subaru AWD.

 

I ran into this situation when we ruined a tire on SWMBO's RAV4. The shop insisted we replace all four tires. We did; the tires were fairly worn anyway. Since then I have researched the problem and decided that Subaru's AWD system requires it. The RAV4 doesn't.

 

Thats because the Subies Drive system giving power to all the wheels -all of the time! The percentage varies with the traction conditions. Rav-4's do not do this -with the exception of some of the newest ones that have a different Optional drive system. (not sure but the system is called the "off-road option") On our 15 Outback you can see the drive system with a graphic on the dash. On dry straight hwy. the % is 60% Front and 40% Rear.
Most of the smaller SUV's -Crv's, RAV's, Rogue's and others actually turn off the AWD system on dry straight paved surfaces above a speed above 35 mph (or so) I think some of the mfr.s are changing some of their drivetrains to add extra capabilities
Any "experts" here feel free to correct me on any of this.
All I know for sure, is our 15 Subie will in some ways out "traction" our 17 4WD Tacoma -especially on paved surfaces!

 

Wow another reason why awd sucks

 

eh, maybe the ONLY reason. I loved my WRX, gas mileage wasn't great, but still better than the V6 Taco. Having to use premium kinda split the difference though. Nimble, quick, and good (nothing is great) in icy weather.