found one bad thing about subarus
 

maybe you guys can advise.

we just have a rapid tire failure on the new subie. almost 4k miles on the car. everyone keeps telling me that it is recommended to change all 4 wheels to keep them the same diameter. they say there isnt that much tolerance. i guess the 4wheel drive can bind up. what do you think? the tire is not wasted, but i did have to drive on the rim a bit to get off the freeway. i cannot even find where it leaked from. but i suspect that i did some sidewall damage, driving flat.

We've had permanent AWD vehicles for quite a few years and have heard the same story, although I do not know how much truth there is vs. desire to sell more tires!

I could imagine there is some truth in this, esp. if the differential or traction control mechanisms are computer controlled. However, how much tire circumference difference could there really be with only 4K on the tire? We're probably talking 2-3mm.

I've thought about this (having an AWD VW)

There's the tire diameter, and then there is the effective tire radius.
That is; you can measure any tire diameter, but what really matters is the distance of the center, to the road. (think tire air pressure -- hint hint);)

I drove over a 4 inch nail at 10,000 miles and found that tire places wouldn't change it because they were out of effective range. - I was at about 50% tread depth and the subaru tech guide he showed me showed that it was too far gone.

It sucks but I guess that's the price you pay for AWD... which is always nice to run around winding roads too fast.

BTW I recently put Kumho "711" tires on my 2002 WRX and they are much better than the "factory" Bridgestones etc. They are also really cheap.


Rallymax.

I wouldn't worry about putting a new tire in with 3 that have only 4K miles with normal wear. We have a Jeep with full time 4 wheel drive and the wear from front to rear can vary by a few 32nds at any given time.

Like Island said, even a low tire would have the same effect.

Good thinking getting off the fwy to a safer place, even if it means wasting a tire.

ok, here is what i did. i bought a new similar tire, same yokohama brand, just a diff model. and then i made that the spare, and had the spare tire put to full time duty use. so now i have all four matching tires. if i destroy something, i may not raise too much suspicion at the warranty counter at subaru. i dont forsee a prob anyways.

Vash,

Good thinking...

The advice I have received from those who know is that its important to keep all 4 within the same range if possible... however its more important to make sure that they are very similar side to side..

So I replaced one front.. used the unsused spare as a match and put the older front as the spare.... keeps everything ship shape...that way any wind-up is front to back only, not side to side as well....

Unless you drive the car like a bandit.. and lets face it a subbie needs some abuse on the road (not mush if DEing) to be abused..then wind up should not be a real issue.

winding roads!? :eek:

You drive AWD on winding roads!?

Don't you know, that when turning, the outside tires have to turn more rev's than the inside? --that can't be good.

Nothing but straight roads for my AWD.

:cool: (tongue firmly in cheek)

I see that you made the common assumtion that all four tires are below the point of loosing grip while on said "winding roads". :D

God I miss doing the state (pro) rally championship back in Australia :( If only I had the time and money to pick it up here again in San Jose.

Rallymax
(guess how I got my nickname :) )

:) I was just making fun of the concern over a few millimeters difference in tread height.

AWD's have to allow for differences. Simply loading the outside tire (in a corner) will decrease the tires effective radius . .. and that's beyond the issue of the outside tire having to travel a further distance (being on the outside radius of the turn).

So, what's a millimeter or two in tread height?

Island is correct, for a change.;)

There has to be accomodation for one axle to turn slightly faster than the other. I asked a trusted VW mechanic one day about temporary use of an odd-sized tire on the front (drive) axle. He said this will hurt nothing. That's because the front drive is a "transxle" system where both axles are being driven all the time, as opposed to a "limited slip" axle where one wheel drives the car, usually.

All-wheel-drive systems, I believe, need to use a similar axle drive system.

Again, you're not going to see this very often, but I am in complete agreement with Island on this one. Minor differences in wheel diameter cannot be problematic for Subarus. Heck, Subaru has been making all-wheel-drive cars since before canned beer.

Re: found one bad thing about subarus
 

Sounds like bollocks to me. (had 4 AWD subies over the years)

Classic Adelaide coming up, Rallymax....

I wish I could make it to the Classic!
>Classic Adelaide coming up, Rallymax....

Oh well, at least I have Sear's Point, Laguna etc around here. I was fortunate enough to crew on a GT-A team for the San Jose GP a couple of months ago. The track was very poor compared to the F1 Adelaide or Melbourne street circuits.

... I saw that ozzie Chris Atkinson won 3rd place in WRC Japan. First time in ages that I've seem an ozzie up in WRC - yippeee!

I am friends with Cody Croker (driver) and Greg Foleta (co-driver) from my universitu days so I was bummed that they didn't get the factory Subaru ride for Japan. Cody seems to be doing well as the factory driver for Subaru in the Oz Rally Champ'. I should ask Greg why he's not co-driving anymore.

anyhow....

Rallymax.

Wait a few years and you'll see Subaru isn't the benchmark of quality that people think it is. Our Forester had an overheating problem that was related to a crack in the engine block. This was a very common problem that was finally acknowledged by Subaru with a recall campaign. The recall consisted of a dealer visit for a cooling system service that involved pouring a bottle of official Subaru leak stopper in the radiator! It was a bottle of goop with copper particles in it! What a joke. The problem never went away and the car was sold at a dealer auction. The same dealer bought the car for resale.

A good friend of mine had an Outback wagon that was maintained at the dealer. The transmission failed right after the warranty expired at 50 or 60k miles. Fortunately, this was his second new Subaru purchase and the transmission was replaced for the price of the labor.

Hmmm... that's not good!
I got one of the very first WRX's in the USA, and from my experience in Australia knew that the turbo was a little weak. As a consequence I got the extended warranty on the turbo.
Just this afternoon I clicked over 57,000miles and have had no problems with the engine.

BUT! About two months ago I was driving very agressively from Willits to Fort Bragg CA.

http://maps.google.com/maps?q=from%3A+willits,ca+to%3A+fort+bragg,+ca&hl= en

It's quite a wild ride in the redwoods. Jumping from 2nd to 3rd in very short shifts I was shocked when the gate jumped out in the transmission. I couldn't get 1,2 or 3,4 to engage... fortunately I was able to jam it into 5th which freed the gates and I got all gear back.

So I guess my message is that the transmission might be a little weak too. - In it's defence I was throwing it between 2nd and 3rd very fast and am not surprised that a gate popped back while I slid into the other. I was lucky that I didn't end up engaging 2nd and 3rd at the same time.... mmmm CRUNCH! 5,000 miles later it seems fine though.

Rallymax.