FAQ: Offsets, Sizes for Rims and Tires on the GT! Xenonk Version! - Vol 2

I'm currently running 215/55-17 winter tires on a 17x7 +50 wheel on stock suspension.

 

I've run the same tires on a 17x8 +40 wheel on stock suspension.

 

I'm going to see if I can run 225/50-18 on a 18x7 +55 wheel sometime this summer.

 

The 225/50-18 is very close in diameter to something like a 215/60-17, if you can deal with Yokohama Geolandars.

Edited May 12, 2020 by JF1GG29

Why would you want to off-road a Spec-B? They are just not made for that. You'll bottom out on rutted roads. Just sayin', although it's your car.

Thanks for the responses. It's not that kind of road. I can't afford a truck right now. I take my Subaru every where. I like to camp. It's just a gravel roads. If feel better with some better tires. Most or the time I'll turn around if the road is not safe. I really want to get the outback that looks like the legacy. Maybe one day.

Here is a website you can use to calculate all the variables. Good luck.

https://tiresize.com/wheel-offset-calculator/

 

From what I remember about the Spec B, the stock alloys are 18". You can go with 17" minimum. Anything smaller will not clear the brakes (I'm sure you know that). I don't know how tall a tire you can go with, but just know that the taller the tire, even though you may not rub initially, will limit your suspension travel before rubbing. The website listed above is a great tool for figuring those things out. Also, consider the weight of the A/T tires you're want to use. That, plus the added weight of the steel wheels pictured above, could add a lot of unhinged weight, which will change the suspension characteristics and slow your acceleration. I'm sure you know all this, but I just wanted to put this out there just in case you didn't. Good luck.

Btw I nearly shoehorned (worn!) 235/55R17 on a 17x8 +45 wheel into my stock specB today. If they were 225s, I think they would've run without rubbing fronts or rears. Edited May 17, 2020 by JF1GG29

Looking to install Enkei NT03RR 18x8.5 +42 on my ‘07 spec B. Has brembo’s from ‘04 STI. Not certain rim will clear calipers. Anyone have experience with this setup? Trying to avoid spacers, if possible.

 

 

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you should be ok. most wheels clear 04 brembos at +45 on a 8.5" wide wheel. enkei PF01s clear brembos at a +48 offest in that wheel size so i think you will have pretty good clearance margins given the NT03RR wheel design

If all goes right, I'm picking up a set of 17" x 7.5" +47mm Prodrive GC-010e's this weekend. I say if all goes right because although multiple sources say they clear Brembo's I'm not 100%.

Looking at Keefe's sticky, very few of the tires he recommends have the aspect ratios available for the Michelin CrossClimate 2's (link). Would the 225/50R17's fit alright?

 

 

Edit: Using JohnnyT's provided link, if I sized down to 215/50 I would only be .1" closer to the inner well compared to where I'm at now. Just trying to figure this out loud her, these tires will be for road trips so I'm prioritizing tire noise, economy, and all weather readiness - I will have another set dedicated for the track. I think the higher aspect ratios are due to the beefy, almost off-road looking tread the tires have. I just purchased two sets for our SUVs, which these have been very good for.

Edited October 23, 2020 by Enlight

I'd do a test mount before committing if you can. Clearance might too tight on brakes.

 

7.5 is 12mm wider than stock. The 8mm reduction in clearance from the offset will put the face closer to brakes by a couple of mm. Maybe a clearance issue maybe not

Edited October 23, 2020 by boxkita

Yes, I'll be doing a test fit. The powdercoating on my brakes might actually put it over the edge. If 3mm spacers can take care of the issue I will pull the trigger, any more and I'll probably say no.

 

Edit: Additional assurance these will fit, they are listed for big calipers on the Prodrive Japan site.

 

2021 Edit: They fit with no spacers needed. The forging of the wheels allows a larger barrel. Plenty of brake clearance.

Edited December 11, 2021 by Enlight

Can anyone give first hand experience in running a 9.5” rim with 255s

 

What tires are you running, how much you rub. Etc

First we need more info. Sidewall height and wheel offset, and even then the tire brand/model can make or break you.

 

My question to this is “why?” Unless you’ve already got the hardware and the tires I would avoid that setup. It’s going to be a pita to fit.

 

I run 245/40 z2ss on 18x8.5 +44 and it took a lot of work to get it right. If I knew then what I know now.....

First we need more info. Sidewall height and wheel offset, and even then the tire brand/model can make or break you.

 

My question to this is “why?” Unless you’ve already got the hardware and the tires I would avoid that setup. It’s going to be a pita to fit.

 

I run 245/40 z2ss on 18x8.5 +44 and it took a lot of work to get it right. If I knew then what I know now.....

 

Hard to find wheels that I want in x8.5 width with that high offset

For reference I had to roll and pull all four fenders, kta124 rear arms, max positive camber on factory front camber bolts to move the tire away from the spring perch of RCE T1 coil overs. Then use camber plates to get negative camber on the front end. That’s a lot of BS when I could’ve just got different tires.

 

Dunlop z2ss 245/40/18 run wide and are a bit tall.

Edited November 24, 2020 by Code

Hard to find wheels that I want in x8.5 width with that high offset

 

not really. search tirerack.com under 2004 WRX STI, and you will easily find 30 or more wheels that are 18x8.5 that have an offset of +45 or higher that have the 5x100 bolt pattern needed for your car.

 

https://www.tirerack.com/wheels/results.jsp?autoMake=Subaru&autoModel=Impreza+WRX+STI&autoYear=2004&autoModClar=&package=false

Edited November 24, 2020 by whitetiger

What would happen with an 18x8 +35, running probably a 225/40/18 on an

05 Gt Wagon..stock height/everything..rub? Poke a little?

I say probably on the size cuz wheels have no tires right now.

Thanks

I've been running 225/45/18 on 07 Spec B wheels on both my old 09 2.5i (stock suspension) and my 06 LGT (coilovers but basically stock height) and haven't had any issues, so I think size-wise you should be fine.

I found a set of wheels https://www.forgestar.com/wheels/rotary-formed-monoblock-series/f14/ that are 18x8.5 +48 offset. The fitment expert told me that these would fit my Legacy GT with 235x40/18s with not problems. He also recommended a +45 offset instead of +48. Of course, I would be going with the SEMI CONCAVE wheel. From what I read on this forum, this should work also with no rubbing. If anyone can confirm this it would be greatly appreciated. Edited March 6, 2021 by JohnnyT

First we need more info. Sidewall height and wheel offset, and even then the tire brand/model can make or break you.

 

My question to this is “why?” Unless you’ve already got the hardware and the tires I would avoid that setup. It’s going to be a pita to fit.

 

I run 245/40 z2ss on 18x8.5 +44 and it took a lot of work to get it right. If I knew then what I know now.....

 

For reference I had to roll and pull all four fenders, kta124 rear arms, max positive camber on factory front camber bolts to move the tire away from the spring perch of RCE T1 coil overs. Then use camber plates to get negative camber on the front end. That’s a lot of BS when I could’ve just got different tires.

 

Dunlop z2ss 245/40/18 run wide and are a bit tall.

 

I found a set of wheels https://www.forgestar.com/wheels/rotary-formed-monoblock-series/f14/ that are 18x8.5 +48 offset. The fitment expert told me that these would fit my Legacy GT with 235x40/18s with not problems. He also recommended a +45 offset instead of +48. Of course, I would be going with the SEMI CONCAVE wheel. From what I read on this forum, this should work also with no rubbing. If anyone can confirm this it would be greatly appreciated.

 

that question was just answered 3 posts up.

also 235 are designed for 9" wheels something to do with their odd numbers.

The semi concave wheel will likely be hitting your brakes too. Unless they show a lgt with them mounted, I'd say sales pitch. s2baru had forgestars on his 5th gen, so might have direct knowledge on fitment issues.

I ran a rota wheel that was sized 18x8.5 with a +48 offset and it was a fantastic fit. Ran 235/40/18 and was lowered without any issues whatsoever.

 

I'd love to find a 17x8.5 +48 wheel that is light and not absurdly expensive.

that question was just answered 3 posts up.

also 235 are designed for 9" wheels something to do with their odd numbers.

The semi concave wheel will likely be hitting your brakes too. Unless they show a lgt with them mounted, I'd say sales pitch. s2baru had forgestars on his 5th gen, so might have direct knowledge on fitment issues.

 

Thanks for your response. As for the 235s, I was going by the wheel and tire fitment sticky in post 1. 225mm = 7", 7.5", and 8"; 235mm = 8", 8.5", and 9". If you think 225x40/18 would be a better fit I can get those. What I hear you saying though is it wouldn't be a good fit without some work.

225/40/18 on 18x8 +48mm rim is about perfection. Using a good summer tire makes for a really grippy ride, too.

 

You can run a wider tire, but its more work. Also, there's rubbing, loading limits and increased wear. If you are running a wider tire because traction, you need a stickier tire not more tire. If for looks, well, all the work & dollars to make it look good should be worth it.

 

In the front, a 275/30/18 on 9.5x18 +35mm will fit and even turn, assuming you have small radius springs on your coilovers. On a wagon, the same tire is 2 inches beyond the body and rubs on everything. I believe the sedan has slightly more room, but never verified it.

 

Pretty much everyone running more than 8 inch rims and 225's, has modified their suspension and/or body in some way. Also their alignment has been tweaked. For the ones who claim it was a bolt-on, either bot a modified car or it rubs something fierce and they don't care.

 

If you were local, Id offer to let you sample my collection to see what actually fits/hits/fails for yourself. When I started upgrading tires, my tire guru let me spend quality time with the tire warehouse and a wheel simulator to find a good fit. I ignored the data and bought the 275's combo. What a waste of money.

 

It's your car and your money. If you can find a local who has a combination like you want, ask to see the car. Its covid so a ride along is probably out. But you can shine a flashlight or camera underneath and run your fingers on the inside of the fender lip. Ask them how fast they can go over speed bumps (or do they make passengers get out). How does it do in corners...any scraping or rubbing?

 

This advice sponsored by Driven Products, llc & Michelin, who sponsored me one summer a decade ago.

225/40/18 on 18x8 +48mm rim is about perfection. Using a good summer tire makes for a really grippy ride, too.

 

You can run a wider tire, but its more work. Also, there's rubbing, loading limits and increased wear. If you are running a wider tire because traction, you need a stickier tire not more tire. If for looks, well, all the work & dollars to make it look good should be worth it.

 

In the front, a 275/30/18 on 9.5x18 +35mm will fit and even turn, assuming you have small radius springs on your coilovers. On a wagon, the same tire is 2 inches beyond the body and rubs on everything. I believe the sedan has slightly more room, but never verified it.

 

Pretty much everyone running more than 8 inch rims and 225's, has modified their suspension and/or body in some way. Also their alignment has been tweaked. For the ones who claim it was a bolt-on, either bot a modified car or it rubs something fierce and they don't care.

 

If you were local, Id offer to let you sample my collection to see what actually fits/hits/fails for yourself. When I started upgrading tires, my tire guru let me spend quality time with the tire warehouse and a wheel simulator to find a good fit. I ignored the data and bought the 275's combo. What a waste of money.

 

It's your car and your money. If you can find a local who has a combination like you want, ask to see the car. Its covid so a ride along is probably out. But you can shine a flashlight or camera underneath and run your fingers on the inside of the fender lip. Ask them how fast they can go over speed bumps (or do they make passengers get out). How does it do in corners...any scraping or rubbing?

 

This advice sponsored by Driven Products, llc & Michelin, who sponsored me one summer a decade ago.

 

Boxkita, Thanks for all the time you have spent replying to my posts. It is greatly appreciated. Honestly, I just want to get nicer looking wheels than the stockers I have. It seems all the wheels I like don't fit my car. The wheel is either too wide or has too aggressive of an offset or both. The Forcestar wheels I posted seems to be perfect because of the +48 offset and I love the style, but alas, too wide and I don't want to do fender work. The car is pristine and I want to keep it that way. I guess I'll keep looking. BTW, I'm lowered on H&R springs over Koni yellows with a two finger gap from tire to fender all around.

Thanks again.

8" x 17,18, or 19 all fit. Pretty much any tire/wheel will work. Over 8" generally requires work.

Different tire manufacturers have varying standards for tread & section width. Tread width is contact patch, ie traction. Section width is what hits body parts and suspension bits. Tirerack has charts showing both as well as the rim width (which affects section width). Small delta of section to tread width generally makes a stiffer tire, ie better handling.

Fwiw, here's my current 17x8 +48 with a 235/45/17. I'm way lower than stock, completely stock fenders and I've never really seen any rubbing front or back with this setup. Been great.