Tire sizing question

arrutled · 02-13-2009, 08:26 AM

if you had 19x8.5 et46 front and 19x9.5 et50 what are the biggest tires you think you could fit on there?

arrutled · 02-14-2009, 10:04 AM

seriously? nobody knows?

pkcormier · 02-14-2009, 11:33 AM

I'm not sure an et 46 8.5 wheel will fit on front without spacers. The wheel lip will be almost 11mm closer to the strut, and I think 10mm is about as close as you want to get. If the wheel did fit, you could get a 235 on front. A 235 tire fits better on the stock 7.5 wheel with the 49 offset. If you added a spacer to ensure you clear the strut, you will need to roll the fender or add negative camber.

As for the rear, you can safely run a 255 without issues. A 265 will clear the suspension with plenty of room to spare may rub the fender under load. I think 10-12 mm is about the limit on the fender side and an et 50 wheel with a 265 tire is about 12 mm closer to the fender. Of course all of these measurements are variable based on the backset of the wheels, the type of tires you're running and the tire sidewall height. Not to mention build tolerances between cars.

I would not use the front wheels without at least a 5mm spacer. And then you could fit a 225 tire without rubbing. A 235 would fit if you roll the fender. See above for the rear.

I have a tire fitment excel spreadsheet I created for just this kind of exercise. I've tried to post it before but it won't work and the site administrator won't return my message with steps on how to do it. If you want, pm me and I'll send it to you.

Philip

mechanicalmagic · 02-14-2009, 11:48 AM

OK, I'll try and give you an answer of sorts.
From the early posts on the "OFFICIAL Wheel/Tire fitment..."

Berk says 18" with 255/40 18" rub. In a 19" wheel, you would need 255/30 x 19" (same rolling diameter, width) and would also rub. However, Berk can get 255/35 18" to go, that would be a 255/25 19". Keep in mind Berk has some mods.

mikeo tried 245/35 18" and they were too tight. So in a 19" wheel for the same rolling diameter, you would need a 245/25 tire, and that again would not work.

TT1351 shows a 225/35 19" on a 19" 8.5" rim. From the picture, I'm not going to guess if it rubs

A little time on that thread might be a wise use of your time.

AND, I have no idea about your offsets.

02-13-2009, 08:26 AM	#1
arrutled Colonel 104 Rep 2,474 Posts Drives: Olsa Join Date: Jun 2008 Location: Western Mass iTrader: (0)	Tire sizing question - HELP if you had 19x8.5 et46 front and 19x9.5 et50 what are the biggest tires you think you could fit on there? __________________ AW 135i w/ blackette, performance short shift kit, BMW alarm, Performance rotors, APEX ARC-8 wheels, Direzza Star Spec 235/275, Dinan stage 3 suspension, M3 wishbones/tension rods/front sway/rear subframe bushings and thats all folks! Last edited by arrutled; 02-13-2009 at 09:49 AM..
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02-14-2009, 10:04 AM	#2
arrutled Colonel 104 Rep 2,474 Posts Drives: Olsa Join Date: Jun 2008 Location: Western Mass iTrader: (0)	seriously? nobody knows? __________________ AW 135i w/ blackette, performance short shift kit, BMW alarm, Performance rotors, APEX ARC-8 wheels, Direzza Star Spec 235/275, Dinan stage 3 suspension, M3 wishbones/tension rods/front sway/rear subframe bushings and thats all folks!
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02-14-2009, 11:33 AM	#3
pkcormier Private First Class 15 Rep 189 Posts Drives: 135i Join Date: Jul 2008 Location: Dallas, TX iTrader: (0)	I'm not sure an et 46 8.5 wheel will fit on front without spacers. The wheel lip will be almost 11mm closer to the strut, and I think 10mm is about as close as you want to get. If the wheel did fit, you could get a 235 on front. A 235 tire fits better on the stock 7.5 wheel with the 49 offset. If you added a spacer to ensure you clear the strut, you will need to roll the fender or add negative camber. As for the rear, you can safely run a 255 without issues. A 265 will clear the suspension with plenty of room to spare may rub the fender under load. I think 10-12 mm is about the limit on the fender side and an et 50 wheel with a 265 tire is about 12 mm closer to the fender. Of course all of these measurements are variable based on the backset of the wheels, the type of tires you're running and the tire sidewall height. Not to mention build tolerances between cars. I would not use the front wheels without at least a 5mm spacer. And then you could fit a 225 tire without rubbing. A 235 would fit if you roll the fender. See above for the rear. I have a tire fitment excel spreadsheet I created for just this kind of exercise. I've tried to post it before but it won't work and the site administrator won't return my message with steps on how to do it. If you want, pm me and I'll send it to you. Philip
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02-14-2009, 11:48 AM	#4
mechanicalmagic Private 12 Rep 99 Posts Drives: 135i Cashmere Silver Join Date: Dec 2008 Location: Pleasanton, CA iTrader: (6)	OK, I'll try and give you an answer of sorts. From the early posts on the "OFFICIAL Wheel/Tire fitment..." Berk says 18" with 255/40 18" rub. In a 19" wheel, you would need 255/30 x 19" (same rolling diameter, width) and would also rub. However, Berk can get 255/35 18" to go, that would be a 255/25 19". Keep in mind Berk has some mods. mikeo tried 245/35 18" and they were too tight. So in a 19" wheel for the same rolling diameter, you would need a 245/25 tire, and that again would not work. TT1351 shows a 225/35 19" on a 19" 8.5" rim. From the picture, I'm not going to guess if it rubs A little time on that thread might be a wise use of your time. AND, I have no idea about your offsets. __________________ 2009, tuned 135i, gone, but not forgotten. Fear of dying exceeded thrill of speed. (and coordination.) Last edited by mechanicalmagic; 02-14-2009 at 12:14 PM.. Reason: More info.
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