70white402 Posted January 24 Share Posted January 24 What tire size can I use in the rear with a 15/8.5 “ with 3 7/8” backspace? Thanks. Jeff Quote Link to comment Share on other sites More sharing options...
Montemedic Posted January 24 Share Posted January 24 Jeff, Your not clear as to what you’re trying to do with your tire size. There are many sizes that can fit a 15 inch rim. Is your Monte stock or modified? Are you going for a certain look, maybe taller or wider tire in the rear? Quote Link to comment Share on other sites More sharing options...
502ci Posted January 24 Share Posted January 24 If you have measured your wheels properly and those are correct measurements then you have a wheel that will be sticking outward further than normal. All depends on how tall a tire you want and how wide. A taller and wider tire on that rim will most likely hit the wheel lip. 4 Quote Link to comment Share on other sites More sharing options...
Canuck Posted January 24 Share Posted January 24 That is not an ideal rim for a Monte. An 8.5" wide rim would need more backspacing to fit a Monte properly. For example I have 15x8 with 4" backspacing and 245 tires rub the quarter panel. Your rim will be even further outward and not sure any tire will fit without rubbing unless you jack the rear end up high. 4 Quote Link to comment Share on other sites More sharing options...
Michael Boyte Posted January 24 Share Posted January 24 I would definitely consider a different wheel ! Go with a wheel that has 5 in of backspace in order to avoid tire rub. 4 Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted January 24 Share Posted January 24 My 15x8 wheels have 5 inch back space with 255-60 tires no problems but I do have my rear end a little higher than most but don't think they would rub even it was an inch or so lower. 4 Quote Link to comment Share on other sites More sharing options...
70white402 Posted January 25 Author Share Posted January 25 Thanks for the replies. I figured as much. Even a g70-15 would stick out. Quote Link to comment Share on other sites More sharing options...
MCfan Posted January 25 Share Posted January 25 Jeff, you are correct, even a G70-15 would be moved 1.3" further outboard (see first illustration below). Here's some numbers and illustrations to back up what others have said and you have also concluded about those wheels on the rear of a first gen Monte. A stock rally wheel is a 7x15 with 4.3" backspace (+8mm offset). The wheel you mentioned is an 8.5x15 with -25mm offset. The difference in positioning of the tire/wheel combo is 8 + 25 = 33mm or 1.3" further outboard with a G70-15 equivalent tire. If you were to consider running a larger tire on the rear, such as a 275/60-15 (which many of us currently run), it gets even worse with 2.45" of reduced outboard clearance compared to a stock rally wheel/G70-15 tire combo.(see second illustration below) If you were to compare a 275/60-15 on your proposed wheel to something we all know works, a 275/60-15 on an 8x15 wheel with 5" backspace (+12mm offeset), you can see it would still have 1.46" less outboard clearance. (see third illustration below) The current outboard clearance with the known combo is right at .75" without trimming the wheel well lip so I seriously doubt it could fit even if the wheel well lip was completely trimmed off. All illustrations were produced by the Tiresize.com Wheel Offset Calculaton Tiresize Offset comparisons.pdfTiresize Offset comparisons.pdf 2 Quote Link to comment Share on other sites More sharing options...
70white402 Posted January 25 Author Share Posted January 25 6 hours ago, MCfan said: Jeff, you are correct, even a G70-15 would be moved 1.3" further outboard (see first illustration below). Here's some numbers and illustrations to back up what others have said and you have also concluded about those wheels on the rear of a first gen Monte. A stock rally wheel is a 7x15 with 4.3" backspace (+8mm offset). The wheel you mentioned is an 8.5x15 with -25mm offset. The difference in positioning of the tire/wheel combo is 8 + 25 = 33mm or 1.3" further outboard with a G70-15 equivalent tire. If you were to consider running a larger tire on the rear, such as a 275/60-15 (which many of us currently run), it gets even worse with 2.45" of reduced outboard clearance compared to a stock rally wheel/G70-15 tire combo.(see second illustration below) If you were to compare a 275/60-15 on your proposed wheel to something we all know works, a 275/60-15 on an 8x15 wheel with 5" backspace (+12mm offeset), you can see it would still have 1.46" less outboard clearance. (see third illustration below) The current outboard clearance with the known combo is right at .75" without trimming the wheel well lip so I seriously doubt it could fit even if the wheel well lip was completely trimmed off. All illustrations were produced by the Tiresize.com Wheel Offset Calculaton Tiresize Offset comparisons.pdfTiresize Offset comparisons.pdf 195.25 kB · 6 downloads Thanks dennis Quote Link to comment Share on other sites More sharing options...
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