you COULD, but you shouldn't...speedometer will be off.

unless you could use a wider tire, then a smaller aspect ratio to maintain the same overall circumference

 

you COULD, ...speedometer will be off.

Just keep that in mind, so you could recalibrate your speedo.

 

I ran 224/45s on stock 17x7 wheels. It was pretty nice, actually. Speedo will be off.

Stan

 

Im going to do general g max ultra performance all seasons 225/45/17 on stock rims. How do you recalibrate the speedo?

 

I think the dealer can hook up to the port and change the tire size in the computer. Might charge you a little bit.

It should handle tighter with lower profiles.

 

I'm running 235/45/17 on my 08. The speedo is off by about 5%, not a big deal. If you want to see pictures with stock suspension then look in the OEM wheel fitment thread for my post. The lower STi suspension will definitely help the look if using that size.

I would bet you can run 235 without a problem if you are on stock rims because I am on 17x8 with et53 and have to use a 5mm spacer, stock and without a spacer you should have more clearance than me, on paper at least.

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Or if you had a GPS that shows your speed, you can use that.

 

i did for a more aggressive look and wider footprint.

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Although Stan thought they were pretty nice and Superacerc reckons they will handle better, personally, I think Foresters running around with smaller profile tyres on stock rims look a little silly as there is a big gap under the arch. As far as handling goes, a stiffer side wall will make the cornering feel tighter under pressure but the there is a trade off. The lower the profile and stiffer the sidewall, the more noise will be transmitted into the car along with increased effect from road defects/seams etc. There is a reason why the older Rolls Royces and othe luxury cars were running around on 70+ profile tyres, comfort and noise reduction.

The smaller rolling diameter of a lower profile on the stock rim, unless you expand the width out to 235/245 (if that's even possible, relative to rubbing) will also highlight and exagerate undulations and potholes as well as increase noise from the larger footprint. On top of this you have the gearing issue. If most of your travelling is urban, then I guess it doesn't matter but if you do sustained highway driving (60mph+) on a regular basis then the reduced gearing of the lower diameter wheels (225/45/17) will become irritating and tiring because the engine will be working at a slightly higher speed than before for the same given speed. The difference between 110 and 120km/h (that's only a 6mph reduction) in my Foz on the motorway has quite an impact on longer journeys, engine/exhaust/tyre volume wise and while some of the guys over here are geared for a maximum of 100mph in 5th on their Imprezas (diff setups) and go "whoopee look how instant the throttle response is in 4th and 5th" :icon_rolleyes:, if that sudden surge is needed, surely you can drop a gear? Some of them who travel distance will admit though that noise becomes a real issue after about thirty miles, as well as fuel consumption, I should imagine.

If none of these things seem relevant to you, go for it but as a word of warning: This really good AWD setup we have is unforgiving of anything but good tyres and while many boots would be fine on pretty well any 2WD car, your Foz may not like them, and that's a costly experiment. It might also be an idea to check out what's actually available in your region. Over here, not so much for my OEM profile (I'm on 16"s) and I had to order the Avon ZV5s I now have and am happy with. Over there, you have a much bigger market so I expect most things are available. Perhaps an online tyre/rim size calculator and a look in the tyre section of the site might help?

 

i think just the different brands (still factory size) can have a difference in "sound."

i've had the same brand tyres my last two changes. first time was the factory size. second time was the wider, smaller profile (+updated model). none of which any new sounds were introduced. better than the whiny tyre that was on there when i purchased the car, used.

the gap isn't too bad.


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^^I agree, the gap usually doesn't look too bad if the car is nice and low. We've used 215/45/17 and 225/45/17 on our 98. You can plug the specs into a tire calculator and it'll tell you by how much your speedo will be off.

 

i always like how small slynki looks in these two pics.

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Yea im not worried about gap since im on 2012 sti suspension and am dropped about 3'' and have zero gap on my 55's. Im def going with 45's i calculated it and it will only be off about 4mph at most on the speedo which is doable. The new question now is should i stay with 225 or go all ou t and go for 235? I would love to go 235 on the stock rims but want to make sure im not going to rub. How would i go about checking this? It will be about a 1/4 inch on both sides of the rim so i wouldnt think it would be an issue.

 

Are your stock wheels 7" or 7.5" wide? I ran 225/45s on 17x7 wheels, and honestly, it wasn't ideal. 225/45 would be perfect on a 7.5" wheel -- the sidewall will be dead square, which is what you want for good handling IMO.

225/45s on 7.5" wheel:

Same tires on 7" wheel:

Those same tires appeared to handle better on the BBSs vs the stock wheels. Could have been the weight of the wheels, but I think it was due to the angle of the sidewall.

Those Goodyear Eagle F1 tires were great btw.

As far as looks go, I've come to realize that I much prefer the look of "square" low profile tire setup with wheel gap to the fat high profile tire setup with no wheel gap. As far as ride comfort goes, of course the stiffer sidewall will ride harsher.

Stan

 

Are your stock wheels 7" or 7.5" wide? I ran 225/45s on 17x7 wheels, and honestly, it wasn't ideal. 225/45 would be perfect on a 7.5" wheel -- the sidewall will be dead square, which is what you want for good handling IMO.
of "square" low profile tire setup with wheel gap to the fat high profile tire setup with no wheel gap. As far as ride comfort goes, of course the stiffer sidewall will ride harsher.

Yes mine are 7's i cant afford new rims at the moment and to be honest i actually like the stock rims i think i will stay with 225 to be safe but will still go ahead with the 45's.

 

Time to get some lightweight rims and see if it improves your time any!