Staggered tires on AWD car?

[Jeremy02XType]

Is it dangerous to run staggered sizes on an AWD vehicle so long as you keep the overall diameter within say an inch or a half

[CapriRacer]

You'll have to talk to the vehicle manufacturer, but this doesn't even sound like a good idea. That's as much as a 5% variation and many ABS systems aren't tolerant of more then 3% difference from OE when all 4 tires are the same diameter. I'll bet your drivetrain wouldn't last a day with that kind of setup.

[Jeremy02XType]

Well this would be for a Jaguar X-Type which has a rearward biased awd system. The BMW 330Xi has an optional wheel package which uses 225/40R18 front P255/35R18 rear. This would make the rear tire .06 in shorter overall diameter. The ABS I dont even care about as I would probably have the system disabled

[CapriRacer]

OK, I'm confused!

Are the tires 1 1/2" different in diameter or are they 0.6" different in diameter?

My point about ABS was that the ABS systems expects the tires to be about the same, and an AWD system is less tolerant than that!

Just an FYI - All X types - even the high performance versions - came from the factory with the same size all the way around.

[Jeremy02XType]

I know all X-Types came with the same size tires but my point was there are AWD cars out there with staggered tires. BMW Xi, Porsche 911 C4, Lamborghin Diablo had an AWD version...all had staggered tires

ill probably end up running 225 all around so i can maintain rotation ability

just wanted to know if i could do this if i decided to down the road

[Rufe]

If this is what you are asking?

Can I use wider tires on the rear, if I keep the diameters within (the proper factory tolerances)?

Then Yes, you can.

You need to understand how your AWD system compensates or transfers power to know if this is a smart idea or not.

My opinion, unless you have a specific reason otherwise, keep all 4 tires the same width and diameter.

Brian

[Jeremy02XType]

the reason i would be doing it is with the 40/60 awd split it is a bit tail happy and i prefer a more neutral/understeer tendency, especially in a car that my wife will be driving

a 225/45/17 tire comes out to 24.97 in total diameter a 245/40/17 comes out to 24.72 that's just over 2/10 inch. would that difference cause problems?

[Rufe]

The Jaguar AWD seems to be more effective in bad weather and off road, as opposed to giving you better traction on dry pavement. So, for street driving, (non-winter weather) it does make sense to compensate for the rear power bias on the car.
If you plan to drive in the snow, you might keep two sets of tires.

If the front tires wear faster than the rears, (depends on your right foot) it would slowly reduce the difference. And vice versa. The difference is right at 1/4 inch new. Do you know what Jaguar recommends?

[Jeremy02XType]

I think im just gonna keep same size all around and run some good sticky summer tires and have seperate snows for the winter

[1010Tires]

Good idea to keep them the same, as my girlfriend worked for Jaguar for years, they do not recommend staggering at all. Like Jaguar needs another reason for one of their cars to be in the shop....ha ha

Originally Posted by Jeremy02XType

I think im just gonna keep same size all around and run some good sticky summer tires and have seperate snows for the winter

[nardeezy]

I found this thread on google. Very interesting I am in the same dilemma. However, my vehicle is a 2006 Lexus GS300 AWD, 30/70 dry 50/50 when it detects slippage. I love the staggered look I had the same discussion going on in our forum (http://clublexus.com/forums/showthre...=awd+staggered). What about overall wheel/tire weight? If you go staggered the rears will weigh more thant the front will this effect anything?

[Rufe]

The simple answer is yes, weight and size affect handling, mileage, CD, and a few other aspects.

The issue is all about compromise. To what degree will it affect the car, and the hardest question to answer, how much is the effect (%).

If you add several pounds to the wheel, it is going to respond slower to the road. If you never go over 75 mph, you will probably not notice it. You may see a slight drop in mileage though.

Jeremy has a valid reason for a wider rear tire, he needs to try to keep the diameters even though. Note: normal wear on the tires goes through about 10/32nds of an inch, (~1/3rd inch, or .3125 for the Math majors) Food for thought.

There are some systems that use a differential that works to keep all four tires rotating at the same speed. If there is a difference in diameter, these systems will ALWAYS be active, and can overheat and wear out prematurely. This is not true of all systems, though. Also of interest to the debaters, and the worry warts, turning a corner means your tires are NOT going the same speed!!! When you go around a corner, you are putting WAY more stress on those systems than different diameters. The important issue is how long the duration of the stress. That is why you need to study your system and determine how it compensates. (added: Asking these questions on the forum is a good start, but keep in mind, each system is different)