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Well seeing how AG didnt make the size and offset i needed... VMR had discontinued their wheels that i wanted.... wasnt going to pay for forgestars etc... I'll take some weight lol was just happy at this point to find a good looking wheel with the look i wanted.
 

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Well seeing how AG didnt make the size and offset i needed... VMR had discontinued their wheels that i wanted.... wasnt going to pay for forgestars etc... I'll take some weight lol was just happy at this point to find a good looking wheel with the look i wanted.
I totally understand. I've spent many hours so far looking at wheels and different sites. Finding the perfect wheel to fit your needs is harder than finding a golf course in Antarctica.
 

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What size tires are you using and are you lowered at all? I'm going to go with that very same wheel setup. I too want to know what your brake setup is. I'm doing 4 pot Brembos all the way around this summer so they'll need to clear.
Not lowered but looking at Koni/eibach setup this spring. Stock brakes. Sorry. I love the wheels though and highly recommend.
 
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Not lowered but looking at Koni/eibach setup this spring. Stock brakes. Sorry. I love the wheels though and highly recommend.
Forgot to mention tires. I'm running 245 40 up front and 275 35 in the rear.
 
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Ok, I need some guidance. Since the tires on my stock 19's are not holding air anymore, I had planned to switch my wheels over to a set of KMC wheels I bought many years ago but never got around to installing them. I thought I'd better test fit the rims first before getting the tires mounted on them. The fronts were 20X8.5 35ET the rears were 20X10 35ET so I was only really concerned with the fitment of the rears. Turns out 35ET is way to low of an offset for a 10" wheel. The outer lip of the wheel is flush with the outside edge of the rear fender. So some rolling a pulling would definitely have to come into play for that to work. I was fine with the idea back when I got the KMC wheels but now I would prefer to avoid having to roll the fenders and risk the paint cracking and giving rust a chance to start. So now I'm looking at buying a new set of wheels where I tell the seller what size and offset I want.

So here is the only part of this post that is relevant as far as my question goes.

What offsets do I need in order to avoid rolling the rear fenders with 20 inch rims?
Front 20X9 38ET (This seem to fall under the "it will fit" section so I'm not too concerned) Tires 245 35
Rear 20X10 45ET? - 55ET? Tires 275 30 (I know it's only a difference of 10mm but I don't want to put myself in a situation where you spent thousands of dollars just to realize you miscalculated.)

I do plan to lower the car but I am still on the fence as to which way I'm going to go about it. Coilovers or air suspension. I'm only considering air suspension just for the ability to lift the car up over bumps or steep inclines and leveling off the rear when full of passengers. But knowing when the air is all let out that you need to make sure the wheels tuck in 100% is what has me concerned. Where as coilovers are set to whatever height you last left if at. The rear of the car might sag low enough when full of passengers to be concerning of clearance issues but you can't do anything about it until you get back home. Sorry, rambling on about my pros and cons concerns. If anyone who has lowered their G8 with a 20X10 inch wide rear wheel and has managed to avoid rolling the fenders, any advice would be appreciated.

Moderators if this post is in the wrong area, I apologize.
 

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My 2 bits
I run a 285 on a 67 offset 9.5
My inners are extremly close , touching plastic full droop on a hoist but never touch driving.
The geometry of our cars , the wheel moves out as it goes up.
To get the same backspacing in a 10 , you would want a 60.
So , in my mind, for best rear fender clearance, 55-60 with a 10.
Is 60 was too close, you could space out .
 

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One thing I forgot to add was buying Brembo's for front and back. Not sure if a high offset would affect clearance on those or if that's more of a wheel spoke design issue.

Thanks for the reply. I didn't consider the wheels moving outward the further it squats down.

The more I sit and think about it, if I'm going with a 10 inch rear and lower the car, I may have no choice but to have the fenders rolled.
 

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Wheel design and spoke , yes that would be the Brembo answer, more than offset.
I have SS rear brembos but my 9.5s are widened stockers.

Can't answer the fender roll , as I am at stock height but the tires definitely would fit up inside. , least with my 9.5
 

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I think you are right, 10 would get pretty cozy.
Mine with the 9.5 , 67 offset , about .8 neg camber, measuring straight line, bottom sidewall, through top sidewall is 1/2 " clear of stock lip.
 

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Thank you for the pics!

Looking at where things line up at 9.5" and seeing that it's tucked in as far as it can go without coming in contact, makes me think that adding a .5" twards the outside edge might not be possible without rolling. Or I would have to figure out a way to prevent the suspension from getting low enough to make contact. Which I would imagine on coilovers would mean a stiff as hell ride.
 

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Ok, after looking back a few pages on here, looks like the general rule of thumb is 9.5" is about as wide as you can go without rolling the fenders.

The basis for me thinking 10" would work is based off of the Ace Alloy Wheels that Maverickman sells on his website.
Front 20X9 +38 offset
Rear 20X10 +45 Offset
The offsets being labeled a conservative fit made me think that maybe they cleared anything of concern. Plus the pictures showing the wheels on the cars are lowered
 

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The math says, with the same tire a 10x45 will stick out 1 1/8 inches further than my combination of 9.5 x 67

We all seem to have different definitions of "fitting"
Mine is, you should be able remove the springs and put the car on the subbers without the tire running into stuff.

Try plugging in some numbers into that calculator
stock is 8 x 48

Good lick
 

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I have said this in many posts. A +60 offset puts the center of the wheel directly in the center of the rear wheel well. You can fit a 295 tire on a 10" wide wheel with that offset without a roll and without hitting the brake bracket on the inside. To go bigger you have to roll the fenders and back off on the offset (ex 305 and +54) or modify the brake line location. Hope that helps everyone.
 

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Hey guys I’m interested in buying some rims that are 19x9 with a et40 will these fit my g8 running 245/40/19 up front and 265/40/19 in the rear I currently have pedders xa coilovers
 

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Do 275/35/19. You may need to roll fenders a bit, but I think you'll be all set.
 

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i heard the g8 forums was the place to be for proper numbers, this is the ****. bloody nice work lads.
 

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2009 G8 GT
Stock 19x8 48 offset stock wheels with 255/40-19 tires. These have been used as winter set.

Axis XGT wheels added
Front 19x8.5 45 offset, 8 mm spacer (they fit with no spacer), 255/40-19 tires. No fitment issues.
Rear 19x9.5 45 offset, 285/35-19 tires. Rubbed on the inner fender lip; rolled the fenders and no rub.

Upgraded brakes to 04-07 CTS-V 4 piston brakes. Aftermarket wheels front and rear would rub the calipers. Front may fit using too much spacer. Rear may fit with too much spacer but would definitely rub the fenders.

Stock rear wheels fit with about 1mm clearance. Front wheels needed longer studs and 10mm spacer to fit.

So, I'm now looking for aftermarket wheels, 19x8.5 and 19x9.5 with offset and backspacing that will work.
 

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Just an update on a question that has been asked here a few times. I have finally found a second set of 18 x 9.5 +45 Axis XFactor wheels. They were a clearance wheel on TireRack about 6-7 years ago. A lot of my local G8 guys were scooping them up because they were fairly light weight (about 23 lbs), were a kind of Advan knock-off, cleared Brembos and were going for a little over $100 a wheel. When I bought them, no one could confirm if a square set-up would work on the car so i went with a staggered set up like everyone else. Pretty soon after, the wheels were sold out and discontinued. After 6 years, an unused pair of 18 x 9.5's fell into my lap. I had previously test fitted my rears on the front and knew that they fit with a 285/35/18 Firestone Firehawk tire. However, that was with the stock struts/ H&R springs in the front. I have been through a couple different sets of struts and am now on PPV's. Went to fit the new wheels and the tire rubbed the PPV strut. I ordered a generic set of 5 x 120, 5 mm wheel spacers off Amazon. The wheels and tires now clear with plenty of room.
So, 18 x 9.5 + 45 wheels will not fit on the front if running PPV struts without a 5 mm spacer. Rears do require a roll. I am also using a 275/40/18 tire on all 4 corners.





Here are some older pictures of the wheels on my car in different colors (they are currently silver) I do not have pics yet of the square 18 x 9.5 +45 setup with 5 mm spacers on all 4 corners
 
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