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Discussion Starter #1
ok i have a sti and lowered 1.5/1. now im looking to get the 18x8 volk gt-n in gunmetal finish and this offset is killing me. what offset do i get to fit a 245 40 18 on it and the thing wont rub. some say 48mm offset. whilethe 18x7.5 is 44 mm offset. now on a 7.5 id get a 235 40 18.

im not going to coilovers so any help would be appreciated.

thanks guys

tony
 

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Can't say I can help with the 8" width but Prodrive recommends a +46mm offset on their 18x7.5" P1s to clear the Brembos.

Most times (when the caliper clearing the spokes isn't a problem), offset is only to get the wheels centered up over the hub properly. With our unique situation, you have a two fold problem.....getting the wheel in under the fenderwell properly AND keeping the spokes off the calipers. I'm assuming you are considering the spoke issue as well?
 

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Heads Up - linearzero

Unfortunately, that particular size is missing from our db :), so I will confirm it let you know sometime Monday, unless you find it before that.
 

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forget too wide, 245/40/18 is going to be WAY to tall for the STi, our stock 225/45/17s have and overall diameter of 25", I ran 245/40/17s that are the same OD as 225/45/17s, but going to 245/40/18s effectively adds an entire inch to the OD of the stock size :eek: is there a reason you want to add an inch to the stock OD?? are you aware of what this will do to your gearing and ride height??
 

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NorcalSTi - The proper offset for the GT-N wheels at 18x8 is +37mm and fits the STi. The list price is $540/wheel; you can PM me for the discounted price if you are interested.
 

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I'm running the 18x8 51mm offset, OZ Superleggeras on my '02 wrx. The STI must have a different offset from the brembo's if you are recomending an et37. Can anyone verify this difference? What is the stock 17x7.5 wheel offset?

I'm also running 235/40 Pirelli Pzero nero m+s on the OZ's and am having a slight rubbing with the Tein High-Tech springs on the rear inner fender edge molding. I went with the larger tire because I didn't want rubber bands on these crappy roads. Dealer already mentioned my inner wheels are slightly bent after 35000 miles.
 

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Each wheel's design is different, hence the offsets will be different as well. The STi's 7.5" wide BBS wheels have an offset of +53mm.

For example, 18x8.5" Volk Racing TE37/LE37 have an offset of +50mm for the STi, but CE28N's 17x8.5" have an offset of +30mm and you have to roll the fenders to fit them :( (This is direct from Macin Industries, NA distributor).
 

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Thanks for the info, but to be more specific, when you modify wheel width you must also compensate with offset to maintain the same position of the face edge of the wheel. Knowing the stock width and offset we can calculate what a wider rims offset should be. We can also select an offset that will push the wheel more flush with the wheelwell for a cleaner look or to preference. (I know this can be dangerous because of potential rubbing issues, but subaru and tire rack tend to be conservative with their wheel offsets).

The 18x8 et51 OZ superleggera which fits very well, but I would prefer it to be more flush with the wheelwell. If you look at the attached image you will see what I mean.
 

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Discussion Starter #9
ok this is gettin me mixed up

look at this link
http://www.clubwrx.net/forums/showthread.php?s=&threadid=48756

he has 18x7.5 with 37mm offset on his and 225 no problems so the 8 inch rim is the same.

i can get the 18x8s for 385 out here cash im just so lost on fitment


im going with 235 40 18 guys if i have 7.5 and 245 with 8 i want to fill up the fenderwells thats why
 

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From your link they are talking 18x7.5 et37. an 8" rim will stick out .25" with the same offset.

I think the 18x7.5 et37 will work and give you that flush look but i would be careful what tire you put on and may need to roll the lip.

If you want to 18x8 i would go 45mm offset and greater. That will make up for that extra .25" and keep the flush look. But also keep in mind that calipers need to clear the wheels so check this with the manufacturer.

So your best bet would be 18x8 et 45 with a 235/40 ... but you will definitely have to roll the rear lip if you have lowered it. Trust me I have 18x8 et51 with 235/40 and have some rubbing on the lip with a .75 lowereing in the rear. It's not bad though. Also I wanted a little taller sidewall, about .4" cause i don't like rubber bands.

That's why tire rack recommends a 225/40 because they know it wont rub and matches the tire diam. With a 245/40 you're asking for trouble and a 245/35 is a lower sidewall height than the stock. Calculate it at this site...

http://gs.tolan-hoechst.com/tirecalc.htm

I'll post pics of my wheels and tires so you can compare.
 

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Discussion Starter #11
Ok i think im going to get a 18x7.5 now 37mm offset if i get a 38 or 43 mm offset it will stick in more right
 

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Discussion Starter #14
ok but doesnt some rims have a different sett up

like i see some rims 18x8 48 mm offset fit where as others say no 18x8 in this other brand 48 is no good you need 44.

i have a feeling im going to go e mail a company and tell them look if it doesnt fit are you willing to take back the rims and tires and send another set that fits for no cost.

right now im htinking that 18x8 will be pushing it.

i just dont understand if the sti wheel is 52mm offset why cant i get a 18x7.5 in 52mm offset which is the same width in the volk wheel. heck they dont even make it the same. wouldnt the tire sit exactly the same in both volk with 52mm offset and sti stock wheel with 52mm offset?
 

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Discussion Starter #15
OK QUESTION OF THE DAY IF A RIM IS 18X7.5 AND 37MM OFFSET WHAT OFFSET IN 18X8 WOULD I NEED TO SIT EXACTLY THE SAME ON THE OUTSIDE LIP AS THE 18X7.5. 42, 43 44 45 MM OFFSET.

IF that other guy runs 18x7.5 37mm offset and no probs with 225 40 18 then me with 18x8 and ??? offset and 235 40 18 should fit on the outside of the lip and im not running coilovers so i should have a ton of room on the inside to the strut that i can use since im not using coilovers?
 

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Re: Soooo pissed off...

Okay bro,

Im running 18X8s with 42mm offset and 225/40s with no rubbing, ever. Im dropped to about .5" gap in the rear and 1" gap in the front, you mention not wanting to use coil-overs to avoid rubbing but since coil-overs are adjustable, they are exactly what you DO want to avoid rubbing, with conventional lowering springs your stuck with whatever height they lower your car to and you have to chose your wheels accordingly, with coil-overs you have alot more flexibility on what size/offset/tires you run and can set your ride-height perfectly around them :wink:

Also, and I know your not going to want to hear this, but 225/40s are going to work all around better on 8" wheels than 235/40s. First of all, the 235s are .5" taller than the 225s(width is not the only thing that makes you rub!) this not only sucks for gearing and rotational inertia, but the WRX is already WAY too high off the ground, even when lowered, anything that raises it more is counter productive IMHO. Also if you just want a 235 because its wider than a 225 forget it, with both of them on an 8" rim you will be getting the same contact patch out of either tire, the 235s wont even look wider! I had those 245/40/17s shoe-horned on 7.5" rotas, they fit alright and were at least the same diameter as the 225/45/17s but these 225/40s handle better and yes, LOOK WIDER than the 245s ever did, just look at the 225/40s in the pic od the OZ wheels above, yes those are 225s.

Anyhow, just had to pass along my own personal experience, I too wanted the 245s because I thought the would look nice and fatter back there than 225s, they didnt so I got rid of them. If you REALY want to get something wider under there I would try what I mentioned on the other forum and find some 18X8.5s and fit 255/35s on there, they're the right diameter and would just look sick, you would probably need coil-overs though to get the ride height set correctly to them :lol:
 

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heres my setup, I would post other close up pics but the filesize limit has been reached on this post :-?

BTW, these are JDM Stich 3-piece 18X8" 42mm offset, on top of that Im running 5mm H&R spacers/studs up front and stilll no probs with rubbing ,if anything its still closer in the rear.
 

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First of all your car looks very clean Invisiguard. i don't know how you kept from rubbing your rear fender with a 42 offset unless you did not get an alignment and removed your rubber fender edge guard. But I guess you have achieved it. So add that one to the database of wheel offsets we can use. I guess the range has gone from 51 to 42 on an 8" rim. As for my car the rubbing only occurred after I had an alignment because the rear wheel's camber gets higher after you lower the car.

By the way, that is my WRX with the OZ's and those are 235/40/18's. You are not correct about the width not being wider on the 235/40's versus the 225/40's. A 235 is only .3" taller but is .4" wider. Just right in my mind. Look at the pics! To each his own though.

My WRX's wheels are inset more close to factory and Invisiguard'a are more flush (looks awesome by the way you're lowering looks much better) I was trying to achieve a more flush look but came out conservative. Not many car manufacturers like to have their wheels flush with the wheelwell for some reason. So an offset decrease (from 53 to 45 or 42 in this case) is acceptable. Just keep in mind that the width of the rim affects the offset.

As for the tires, it may be better going with 225/40 to be safe on the 7.5 or 8" rim. Or you could chance it and go the next step up... 245/35's which is only slightly smaller in diameter than stock.

Learn as much as you can then take the plunge when you feel right man! I took a chance on my setup and am not dissappointed.
 

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This was a thread I COULD NOT RESIST.

UberSTI said:
By the way, that is my WRX with the OZ's and those are 235/40/18's. You are not correct about the width not being wider on the 235/40's versus the 225/40's. A 235 is only .3" taller but is .4" wider. Just right in my mind. Look at the pics! To each his own though.

not dissappointed.
heh, ya know I saw those exact same pics(what I thought) a whiles back and swore they said they were 225s, after I posted this I looked at those pics again and wasnt sure but I didnt feel like going back and editing my post, ha busted! oh well:lol:

when I was looking at 18s I couldnt find any 235s that were only .3 taller than any of the same tire in 225, all of them I saw were .4 and .5, I do admit that was a bit of a deal-breaker for me, I would rather run a bit smaller diameter than any amount taller but thats just me, and yes I realize 235s are technically wider than 225s(of course) but rim width directly affects tire width and I still assert that on an 8" wide rim your not getting any more contact patch from a 235 as a 225 since the design rim width for a 235/40 is 8.5" and the design rim width for a 225/40 is 8" btw, what tires are you running?

Where in the bay area are you? You ever at UCKK? Im sure we'll run into each other at some point and you can check out my setup, I really thought it would rub too which is no prob since we have a fender roller at our shop but so far it has not been a problem unless I have a full tank of gas and all my work equipment in the trunk(150+lbs) and hitting a sharp up hill turn very hard, if this sounds like a very specific situation it is, its the on-ramp from the 101 to highway 12, this was the only time and situation where it rubbed once, but considering the circumstances and the amount of weight in the back I dont consider this a "rubbing issue" I hit the back roads around here hard and frequently and if it ever rubbed I would not hesitate to roll them out. And yes I am running about 1.5- camber F/R, I guess if I set it back to spec it might cause problems, but I really like where its at for how I drive, treadwear be damned! :wink:
 

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NORCALSTI said:
im not running coilovers so i should have a ton of room on the inside to the strut that i can use since im not using coilovers?
Oaky just noticed what you posted here, this clears up a bit about your concerns with coil-overs. Where did you hear that our stock springs/struts allowed for bigger wheels/tires than using coil-overs??
 
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