I've noticed that on some performance cars that they use different size tires from the front to the rear.

Example:
Like say if on a WRX with 17" rims that some one used 215/45-17 on the front and 225/45-17 on the rear.

I've not heard of anyone doing this on a Subaru and just wondered why do some performance cars do it and what would it do on a WRX?

Is there any reason to consider this?

The reason I'm asking is that I have 215's currently and the two front ones are shot (my fault from not enough psi, and overheating). The rears are fine. I'm getting 4 new 225's but I was thinking I could save the (2) 215's that are good and use them up front at some later date, or rear I guess depending on the answers to the above. Then I could have two full size spares but they would just be different from the 225 of course.

Am I all messed up or would this set up work at any time?

Thanks,

Lowball

 

the reason to put wider tires on the rear of a car is to get more grip with a read wheel drive car. i would just go with 225 on all 4.

 

it works on 2wd cars cause more contact means more traction to put power to the ground and the less contact the less friction to slow it down, hence the wider on drive tires and narrower on the non drive tires. with subarus having awd you do NOT want to put different tire sizes on the front and rear, this will cause the differentials to work harder (primarily the center diff) cause you have different levels of traction between the front and rear and the diffs are the ones working harder to have everything at the same rate. plus the weight difference would put more stress on the differentials

summary, put the same size tires all around (for your diffs sake)

 

That's good info. Just what I needed. Makes sence. I plan on getting 4 new tires for sure. I just wasn't sure about the 2 extra 215's that I will be in possition of, if I should hang on to them or just try and sell them. Sounds like the latter.

Thanks again for the info 4XREX and wrx_ish.

Lowball

 

well if they are on extra wheels then i would keep at least one of them as a spare tire. its better to use a 215 tire as a spare then the donut. again as reasons i listed before. if you dont' have wheels for them though then just go ahead and sell them.

 

Good points above. There's no benefit to staggering on a WRX unless you're having a problem with too much oversteer (HIGHLY unlikely). The cornering abilities on our cars are limited by the traction in front.

 

This is what I have read in an artice about the Bozz Lancer Evo. It said that the different tire sizes in the front and back can be good on certain cars. On this particular car, the rear tires were a little narrower. The reason was that it helped the rear of the car rotate a little better.

 

That was in an SCC issue about time attack (I think that is what it's called) racing - it's kinda like drag racing on a track - 1 go 'round, fastest man wins. At any rate, the tires were the same size, but the rear wheels were .5in smaller. I do know that there are some S4 guys with staggered tires, & BMW & Porsche stagger some of their AWD cars from the factory, but I suspect they designed the center diff to compensate for this.

 

That is 100% correct. The tires were the same size, but the rear wheels were a little narrower. I think the term used was that the different sizes promote "more progressive breakaway characteristics."

 

I would be very interested to find out additional info on this. Also, I'm suprised no one has touched on this before. I guess since we all have AWD it seems only logical to use all the same tires. And if it's true that our diffs. are not made to handle staggering.

I went a head and purchased the 225's but now I'll have to get my rear fenders rolled (only bad thing about the wag). I think the BFG g-force T/A KD's are a bit on the wider side

I ended up having to give back the 215's so I won't have to sell them after all.

LB