anyone running staggered steup 17x8 17x10?

[MainFrame]

I would assume with different width wheels you would want different width tires? Then what do you do about rotating the tires? They're supposed to be swapped front/back every 3000-7500 miles.


I suppose you could just buy all new tires every 7000 miles, but that seems awfully wasteful, especially considering that a good set of tires can cost upwards of $1200..

[SD_GR]

I would assume with different width wheels you would want different width tires? Then what do you do about rotating the tires? They're supposed to be swapped front/back every 3000-7500 miles.

You'd not swap.

Depending on compound selection they can last quite a while. For example I have a staggered car and go 20.000+ miles. However I am not interested in Φ differences there. For the Subaru I'd be wondering how I'll know when the difference front/rear in Φ is too much. I'd have to figure out a way to measure it.

[MainFrame]

With any sort of track time the fronts are going to wear down much quicker than the rears. I forget the tread depth limitations that Subaru recommends, but I do know on my previous WRX, 20k highway miles without rotating was enough to ruin my center diff.

[SD_GR]

With any sort of track time the fronts are going to wear down much quicker than the rears. I forget the tread depth limitations that Subaru recommends, but I do know on my previous WRX, 20k highway miles without rotating was enough to ruin my center diff.

Argh, sorry to hear.

Would the fronts wear down quicker than the rears if the fronts are wider though I wonder? I'm proposing wider up front.

Here as promised is a pic of a rally car with a staggered setup. In this example the design isn't stupid (the motor isn't where Subaru put theirs...) so they could make the rears wider rather than the fronts.

[MainFrame]

I guess in theory with wider fronts you could find a happy medium where the tread wear could even out. It would need to be a balance of driving style, width, and alignment.. in the real world I doubt you could ever get it to work out.


I don't think any setup used in professional motorsports is really relevant here. If you consider the fact that they replace tires under 100 miles of use, and the diffs are probably replaced every 1000 miles or less. Sure, you could do it on a daily driver, but it's not at all practical.

[SD_GR]

I don't think any setup used in professional motorsports is really relevant here. If you consider the fact that they replace tires under 100 miles of use, and the diffs are probably replaced every 1000 miles or less. Sure, you could do it on a daily driver, but it's not at all practical.

Oh sure; those tires were probably replaced every 50 km or less.

Still, there are AWD cars with staggered setups on the road. They're not rallye style cars though, so I didn't mention them given the OP's user name. Germans and Italians are doing staggered AWD on the street. However in both cases the engine placement is correct, or at the very least better than Subaru's, so they're doing the rears wider.

[Mikie13]

Symmectrical AWD...different widths mean different amounts of traction on each axle which would fry the center diff much quicker due to it being a daily driver...at least that's my take on the subject. Or am I off base here?

[SD_GR]

Symmectrical AWD...different widths mean different amounts of traction on each axle which would fry the center diff much quicker due to it being a daily driver...at least that's my take on the subject. Or am I off base here?

If there is grip there is no difference as far as I can work out, provided Φ is the same all around regardless of width.

It's when grip varies that there will be differences. How much this matters I don't know, but one can assay wear metals in the gear oils front and rear (front to include center) and one can check temperatures with probes.

I'd love to see someone do this.

EDIT: I'm lazy. By "Φ" I mean ⌀ but I don't have the keystroke handy.

[SD_GR]

Aha! Here's a 4WD Ferrari (the 408, one of my all-time favs for two reasons: it was 4WD and it's rare). It's an excerpt from Road & Track and it lists front/rear stagger in tire width plus front/rear dissimilar wheel offsets. (The issue also featured another interesting car -- DSM. This was AWD, turbo, 2L, and catastrophically bad. I should know, I bought one. When I hear "DSM" or "4G64" I get hives... It ran identical 205/55s all around unlike the Ferrari).

Now Ferrari have done many outright silly things but for the 408 they at least put the motor in the correct spot in the car (are you awake, Subaru?) so they could go wider in the rear, but that's another story).

[STiDriven]

You'd just need to match the tire heights. The only difficulty I see is finding the same size brand/tire.

For example - guessing on sizes you'd run for an 8" and 10" rim - if you ran 245/40/17 on the 8" you'd need a 280/35/17 on the 10" to match tire circumference.

Tire Size Calculator - Discount Tire Direct

But.... with the pushy Impreza - you'd want the wider up front which would sure look goofy.

[MainFrame]

You'd just need to match the tire heights. The only difficulty I see is finding the same size brand/tire.

But the tire height needs to be matched throughout the life of the tire, not just when they're new. Front and rear tires wear at different rates, that's why we have to rotate them at least every 7500 miles..