AWD and tire/maintenance costs

[Sukhoi]

Am I correct that AWD cars must have all 4 tires replaced at once because mismatch between front and rear diameters (if only replacing a pair) will result in excessive drivetrain wear? I may be in the market for a car soon and to me it does not seem that the extra costs in maintenance and tires for an AWD vehicle are worth it if I only drive in snow a few times a year. Or are most new AWD vehicles 2WD unless the 2 wheels are slipping, and consequently the costs are a lot lower than I am imagining? I presume if it runs 2WD 99.5% of the time then a diameter mismatch is ok.

On a slightly different subject, are there any passenger cars available with true 4WD? Or even push-button activated AWD? It seems like everything is full-time AWD now, but I want a car like the old Camrys that had push-button 4WD.

 

[T2urtle]

its not really just for snow, its for any weather, AWD can be great in the rain as well....

old camry's did not have 4wd. unless there was an all-trac version of the camry in the late 80's model. from 3rd gen on up ( 92+) all were FWD. I know celica's came with the all-trac system but it think that was full time.


certain cars are 2wd that can become 4wd under slippage, other wise it just goes into 2wd, my g35x is one of those cars. all subaru's are full time. i think most trucks have the 4WD button.

 

[halik]

The tires should be close, but they don't have to match exactly. I think mazda AWD system kicks on whenever needed, otherwise it's FWD.

 

[Nyati13]

Originally posted by: halik
The tires should be close, but they don't have to match exactly. I think mazda AWD system kicks on whenever needed, otherwise it's FWD.

The way the part time systems kick on is by measuring differences in wheelspeed. So varying wheel diameters can cause the AWD system to be constantly "on" and cause drivetrain damage even on the mostly 2WD style AWDs.
I can't give any specifics for other cars, but Subarus are certainly 4 tires at a time. There is some max diameter differential in the manual, I'd have to go look it up....

 

[Sukhoi]

Originally posted by: Nyati13

Originally posted by: halik
The tires should be close, but they don't have to match exactly. I think mazda AWD system kicks on whenever needed, otherwise it's FWD.

The way the part time systems kick on is by measuring differences in wheelspeed. So varying wheel diameters can cause the AWD system to be constantly "on" and cause drivetrain damage even on the mostly 2WD style AWDs.
I can't give any specifics for other cars, but Subarus are certainly 4 tires at a time. There is some max diameter differential in the manual, I'd have to go look it up....

Ah, that makes sense. I'm definitely not getting an AWD then. It's not so bad for regular wear, but it would really suck to pop a tire on something and have to replace all 4 instead of just 2.

 

[fbrdphreak]

Um, I'm pretty sure that the size differential due to tire wear would be fine. Put the same make/model tire(s) on there and don't worry about it.

Besides with AWD you shouldn't have to worry about replacing in pairs due to wear, as long as your alignment is good.

 

[LTC8K6]

I don't think if you have 20K on a set, and have to replace one, that you'd need all four.

Maybe two at the most.

Unless the set is worn down a lot in 20K, and then you need 4 anyway...

 

[Gand1]

I have a quattro TT and the fronts wear at a different rate than the rears, so I guess I'm saying you can definitely replace two tires at a time. I generally have them rotated front to back a few times a year so that the wear stays about the same though. When it's time to replace my tires, I end up having to do all four anyhow.

 

[daw123]

I have a 2005 Impreza WRX and I was told by my local Subaru dealer that you are allowed up to 4mm tread difference between the front and rear pairs. This dealer has always been very reliable in the past, so I have no reason to doubt what they are saying.

Any way, I replaced all 4 tires about 2 months ago - the front tires were worn, but the rear tires were not. Unfortunately, I had a nail in the side wall of one of the rear tires, which couldn't be repaired, so I had to replace the rears as well. It cost me about $675

 

[T2urtle]

$675... pricey... i think 2005 WRX came with 16's stock maybe 17's

tire rack has most 17's going for $100-125 a peice. 16's for less. say $500 for tires, 50$ for mount and balance.. is what it should be costing. of course a dealership charged their mark ups, +25% on tires and labor at $100 ish.


replacing tires isn't a SERIOUS deal. its part of owning a car, you dont replace it anymore often and a standard car. just need to rotate a little more often.

 

[Kelvrick]

The only time it screws you is when you get a nail in the sidewall or such. With regular maintenance and rotation, you still gotta replace all 4. What I do is have a 5 tire rotation with a full-sized spare.

 

[daw123]

I forgot to mention that I live in the UK (or rip off Britain) and it wasn't the dealer that replaced the tires. I shopped around about 6-7 places and the cheapest I could get them for (17" Eagle F1s) was $675.

The dealer was going to charge me $840 for the standard tires - reliable dealer, but very expensive.

 

[Sukhoi]

Hmm, guess I'll have to think about this some more. Maybe tires aren't as big of a deal...

 

[sdifox]

Originally posted by: daw123
I forgot to mention that I live in the UK (or rip off Britain) and it wasn't the dealer that replaced the tires. I shopped around about 6-7 places and the cheapest I could get them for (17" Eagle F1s) was $675.

The dealer was going to charge me $840 for the standard tires - reliable dealer, but very expensive.

Just out of curiosity, is there a lot of internet shopping on car stuff over in the EU? Could you have scored a better deal online or is shipping just killer there?

 

[T2urtle]

Originally posted by: daw123
I forgot to mention that I live in the UK (or rip off Britain) and it wasn't the dealer that replaced the tires. I shopped around about 6-7 places and the cheapest I could get them for (17" Eagle F1s) was $675.

The dealer was going to charge me $840 for the standard tires - reliable dealer, but very expensive.

yea, that can make a serious diffrence and F1's as well, i know they aren't the cheapest tire in the world.



to the OP, the MAIN difference when it boils down is, less MPG because of weight of the system, you have to a transfer case/ gear box of some sort extra to change fluids on at 30k.

other then that its the roughly the same in terms of cost, well if things go wrong on it, it will cost more in some cases. you cant get towed by a normal tow truck, you need a flatbed.

i've heard people say the AWD models of BMW's are completely different from a RWD, the feel of the car isn't the same, i guess the " ulitmate driving machine" is meant to be RWD in some driver's eyes


I just got my G35x, i would of honestly went with RWD g35 but i like in chicago where snow happens often along with other crazy acts of nature, plus i love the feeling of being able to accelerate normally in the rain

 

[DivideBYZero]

AWD cars I have had:

Golf V6-4Motion :- Changed in pairs across the axle.
Subaru Impreza WRX: - Changed in pairs across the axle.

 

[daw123]

Originally posted by: sdifox

Originally posted by: daw123
I forgot to mention that I live in the UK (or rip off Britain) and it wasn't the dealer that replaced the tires. I shopped around about 6-7 places and the cheapest I could get them for (17" Eagle F1s) was $675.

The dealer was going to charge me $840 for the standard tires - reliable dealer, but very expensive.

Just out of curiosity, is there a lot of internet shopping on car stuff over in the EU? Could you have scored a better deal online or is shipping just killer there?

I'm not sure how good the internet shopping is for cars, but I'm guessing it would be no different to any other country.

I'm forced to use local garages becuse I can't afford for my car to be off the road for a long period of time - 95% of my driving is for business use.

 

[jdkick]

There's no need to be totally paranoid re: AWD and tire wear/tread depth. Just check them periodically and rotate as required. IMO as long as you rotate your tires at an appropriate frequency (depends on driving style and how much you drive) then the tread wear shouldn't differ that much between the front/rear.

I'm currently driving a FWD VW (2001 Jetta) but plan on looking at a 2009 Impreza 2.5i 5-door maybe next year. I've driven a '97 2.2L Impreza and a '98 Legacy 2.5GT in the past and tires were usually the furthest thing from my mind.