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      10-29-2020, 09:51 AM   #258
ZM2
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Drives: 2017 LBB M2
Join Date: Mar 2017
Location: Baltimore

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Quote:
Originally Posted by SEAT TIME RULES View Post
I don't have a choice unless I buy 4 more rims. I have the SM-10's now and the only size they have in 10.5 or 11" is the 19x11 ET44.

I did the math:

Front setup is the 18x10 ET33 with 12MM spacers and 265/35 A052's.

Tire Diameter=25.4" /Sec Width=10.6

Going to 275/35 NT-01 = 25.55 & SW 10.91" so almost identical diameter and .31" overall ....0.155" more inside and outside.

Rear setup now 18x10" E33 with 295/35's

Tire Diameter=26.2 with SW=11.8

Going to 19x11" ET44 with NT-01 305/30/19's

Diameter=26.26 (same) and SW=12.32 (0.48" more) or 0.24" inside and outside.

With the 44 vs 33ET's 33mm=1.30" 44mm=1.73" , So 0.43" more inboard.

So 0.07" further out with the rims and the tires would be 1/4" more.

I've got the camber shim kit and can take the tabs out and roll them also.

I don't want to add anymore Neg camber than needed in the rear. I'm at 2.0 right now...

Sounds really tight...
Yeah, did all the same math, along with measuring off my 19x10.5" ET45 305/30/19 setup before deciding to go with the 18x10.5 ET40 vs 18x11 ET44. Plus, I wanted the EC-7R, so that ruled out the 18x11 Apex options.

Either is going to be such a tight fit for a 305/35/18 on a lowered car running -2.0-2.1 rear camber that I didn't want to risk the 18x11. A 305 is a 305, but the 10.5" rim will pull in the sidewall a little, giving a couple more mm clearance and I think that couple mm will be necessary to not have to do fender work other than trimming the tabs.

Essentially I'm estimating that the 18x10.5" ET40 will provide 3-4mm more fender clearance than the 18x11" ET44 with a 305/35/18, which is a lot considering how tight we're talking about. If this had been a normal track year, I already would have tried the 18x10.5" and 305/35/18 so we'd all have an answer.

All this said, I hope the 18x11 ET44 works, as that would be a great fitment. I'll follow up with a link to some pics for visuals on my previous setup that I've been measuring from.
Appreciate 0