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      02-28-2015, 03:06 PM   #1
pokeybritches
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Hello all. I've got a square setup of 245/40/18 winter tires, and a set of stock sport package non-M wheels (8" front, 8.5" rear). I can get a set of stock M wheels, and there's an EC-7 group buy going on. I'm trying to figure out the best way to mount up these winter tires.

Ideally I'd like a setup that works with a non-M, and I can add spacers to run it on an M.

Option 1 - mount onto my stock non-M wheels: 18x8ET47 and 18x8.5ET50. These would require huge spacers if I were to put them on an M, and one M has 75mm studs in the rear (limiting spacers to 12mm). I'm concerned about rubbing and bowing of the tire (245 is right around the max width for an 8" wheel).

Option 2 - purchase a used set of M wheels: 8" front, 9" rear. The offsets would be better, but again 8" is a very narrow wheel for 245 width tires.

Option 3 - get in on the EC-7 group buy with square 8.5" wheels. The offsets and performance will be ideal, the wheels are new, and I can select a color that hides brake dust. Obviously this is the most expensive option.

Thoughts?
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      03-03-2015, 04:09 PM   #2
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I'd say just go for the new wheels. If you mount on the 8's you'll sit there wondering about your tires and you won't have the peace of mind that this extra set is supposed to bring you.

Between the spacers and wear concerns, there are just too many factors that make it not worth it in my opinion. If you weren't going to buy the new set of wheels this time around, I bet you'll end up dropping the dough for it in the near future. Get 'em while they're cheap.


I ran 245/40/18 on the stock fronts before I switched to the ARC8s and found a decent amount of should wear, compensated with letting some of the pressure go but still found in spirited driving the wear would continue to tear up the shoulders of the tire. There's some wiggle room for it, but it wasn't ideal. Just my experience, these were on Conti's.
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      03-04-2015, 03:21 PM   #3
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Thanks or the advice. I ended up getting new wheels... but the wrong ones for this application lol. Fell victim to the most expensive spontaneous purchase of my life - new RS31's (summer only). I'll probably put the winter tires on my Apex wheels (possibly getting some narrower rear wheels).
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      03-04-2015, 09:05 PM   #4
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Quote:
Originally Posted by pokeybritches View Post
Hello all. I've got a square setup of 245/40/18 winter tires, and a set of stock sport package non-M wheels (8" front, 8.5" rear). I can get a set of stock M wheels, and there's an EC-7 group buy going on. I'm trying to figure out the best way to mount up these winter tires.

Ideally I'd like a setup that works with a non-M, and I can add spacers to run it on an M.

Option 1 - mount onto my stock non-M wheels: 18x8ET47 and 18x8.5ET50. These would require huge spacers if I were to put them on an M, and one M has 75mm studs in the rear (limiting spacers to 12mm). I'm concerned about rubbing and bowing of the tire (245 is right around the max width for an 8" wheel).

Option 2 - purchase a used set of M wheels: 8" front, 9" rear. The offsets would be better, but again 8" is a very narrow wheel for 245 width tires.

Option 3 - get in on the EC-7 group buy with square 8.5" wheels. The offsets and performance will be ideal, the wheels are new, and I can select a color that hides brake dust. Obviously this is the most expensive option.

Thoughts?
I'm running 255/35 x 18 front and 275/35 x 18 rear on non-M sport package wheels (8" front, 8.5" rear) with no real issues. I'm seeing some shoulder wear on the outside front, but I'd attribute that more to a lot of autocross on concrete than the slight pinch fit of the tires.....
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      03-06-2015, 12:13 PM   #5
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Wow, that's a pretty extreme setup. Good to hear it's working out, especially on a car that gets pushed every once in a while. I might spring for my buddy's stock M wheels.
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      03-19-2015, 11:26 PM   #6
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I don't know the fitment on the non-M, but I ran 245/40/18x9 +42 up front with no rubbing on stock alignment. Then I added camber washers for -2.7* camber up front and the inside shoulder of the tire was hitting the strut, so I added a 5mm spacer to effectively make it +38 and I have no rubbing at all with a couple mm to spare on the strut side. The car is autocross driven so it was OK under heavy compression.
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      03-20-2015, 02:27 AM   #7
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Putting a 245 steet tire on an 8" rim might fit, but it's far from optimal and you'll often have less contact patch than a 235. I've run both. And measured tire temps. Over stuffing the 8" is a detriment with most street tire setups. 8.5" or 9" is better. My rule is to use, at minimum, the measured rim size or preferably .5" wider than that front, measured size rear.
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