funky_monk_flying

can someone please put my mind at rest

just fitted sti03/04 wheels to my wrx ,looking good

just noticed the tyre size is different! 225/45/17 as opposed to 215/45/17

i realise this is the width of the tyre but i noticed the wheels/tyres sit closer to the rear suspension mounts ond obviously closer to the body on the front

will this affect any handling or anything ?

need to be sure before i go booting it around

edited to ask "what tyre pressures do i now use?"

any help mucho apprecio





ps.for sale 1 set wrx std 17" wheels with gyear f1 (almost new,i was hoping to use the tyres but i guess now they wont fit!)

ZIPPY

Your car will be fine, i ran my old MY01 on 225/45/18's with no problems at all.

Zippy

BrynO

The STi wheels are a slightly diff offset and 1/2 inch wider (7.5"), like Zippy says fine on the WRX, they stick out about 1cm more in the arches which looks much better than the standard 7" wheel.
Your old tyres will fit on the STi rims no problem at all, a 7.5" rim can take either the 215 or a 225.
Not sure on the pressures, maybe an STi owner can confirm what it says in the handbook?

mmmiddy

As above, they will work fine, but your speedo will be slightly out, best bet is to change to 215's.

Are these ex WR1 wheels with RE070's?

funky_monk_flying

speedo will be out?

the new wheels are wider not bigger in diameter

am i missing something here?

ZIPPY

Mate your speedo wont be out at all, you are correct as making the tyres wider wont increase the rolling radius, they probably think you mean 18's

Zippy

NotoriousREV

Actually, your speedo WILL be out a MASSIVE 1.4%

Remember, the 45 in your tyre size is a percentage of the width so 225/45x17's are slightly bigger in diameter than 215/45x17's but it's not a significant figure in this case.

ZIPPY

Dave, you sad little man, fancy you knowing the percentage figure.

Zippy

NotoriousREV

Nah, I just know the website that knows the percentage figure

http://www.miata.net/garage/tirecalc.html

Very handy if you're planning a tyre size change.

powerman

225 refers to the width...45 the tyre depth ...17 is the wheel diameter..so the answer is the speedo will not be out,if you go for an 18inch wheel you will have to reduce the 45 figure to 40 and this will keep the speedo accurate.....ie 225/40/18..powerman

ufcboxer

how much 4 wheels n tyres mate, and would u px on just wheels or sell me the tyres as ive already got the wheels?

mmmiddy

If you go for an 18, you'd actually be better going for a 215/40/18 tyre to reduce the percentage difference.

We're only talking small percentages either way, but you could end up with your car showing more miles than you've actually done.

This is all assuming that your speedo is correct in the first place!

funky_monk_flying

can anyone actually answer my questions?

mmmiddy

Your old tyres will fit fine

Your new wheels are 1/2 inch wider but ideally you should still be running 215/45/17's

Try 34 on the front and 32 on the rear

225/45/17's will be ok but as I said your speedo will be slightly out - 1.4%
You will be going slightly faster than the speedo says.

You're right the tyres are wider, but the 45 is not an exact measurement, it's a percentage of the width. 45% of 225 rather than 45% of 215, hence the difference in the sidewall.

Hope this helps

AJbaseBloke

I've got 215s on a 7.5" wheel. Been doing it for more years than I'd care to admit

In the past, when sidewalls were floppy, it was a trick used to help keep them square under cornering forces without pumping them up so high that the tread went bow shaped. Still works today, of course, although tyres are heaps better at keeping the tread flat on the road.

By having alarger diameter tyre, your gearing will get a bit taller, but the extra rubber width will probably add enough grip and rolling resistance to negate any extra mileage you could expect. Slightly wider tread should equate to a bit more grip/traction (although there are never ending arguments about that), and the slightly taller sidewalls should give a slightly better ride (more room to give). All in all, they should be an improvement (if the tyres are good/the same model as you had in 215/45).

As for pressures, not too much change from whatever you've been running to date IMHO. I run 34f/30r mostly, others prefer more (or less), and the make/model of tyre will make a difference too.

HTH

jpor

iTrader: (1)

Hi. I currently run my 17" set on a 03 STi as the following:

f31 r32 these are on bridgestone Potenza tyres. Had tried 34 allround but found the grip not too good, and get bad tram lining on the fronts. Hope that helps?

funky_monk_flying

CHEEEEEEEERS ALLL