Supraman Posted February 15, 2005 Share Posted February 15, 2005 Advice on this one would be appreciated...I've got 265*40*17 on the rear BBS wheels. Could I go to 275*45*17 without the tyres sticking out past standard wheel arches or rubbing against anything? Cheers Quote Link to comment Share on other sites More sharing options...
SilverMachine Posted February 15, 2005 Share Posted February 15, 2005 You might need to roll the arches, not completely sure though. Be aware that if you change the depth of the tyre wall, it will affect your speedo reading! Gaz Quote Link to comment Share on other sites More sharing options...
Supraman Posted February 15, 2005 Author Share Posted February 15, 2005 You might need to roll the arches, not completely sure though. Be aware that if you change the depth of the tyre wall, it will affect your speedo reading! Gaz Reason I'm wanting to change to 45 is that the front are 45*17 and I'm concerned at the different depth between front & rear. Should it be 40 or 45 all round? Quote Link to comment Share on other sites More sharing options...
Ibrar Jabbar Posted February 15, 2005 Share Posted February 15, 2005 The 275 should be OK depending on the offset of your wheels you will however need 40 series to keep the rolling radius as close as posible to the fronts (don't know what size you have). Also to my knowledge there isn't a 275/45/17 tyre made. Quote Link to comment Share on other sites More sharing options...
Thorin Posted February 15, 2005 Share Posted February 15, 2005 It's normal to have different profile size front to back. Stock 17" sizes are 235/45/17 and 255/40/17 IIRC. Quote Link to comment Share on other sites More sharing options...
Homer Posted February 15, 2005 Share Posted February 15, 2005 40 profile rears and 45 profile fronts is normal. I think it works something like this: The profile is the high of the sidewall, but its stated as a percentage of the width (i.e. 265 width with 40 profile will have 106mm sidewall height). So, as Supras have a wider rear wheel size than the front, they need to have a lower profile rear tire Stock cars with 17in wheels have 225/45 front and 255/40 rear, this makes the overall diameter of both wheels approximately the same. If you fitted 265/45 rears the overall rear wheel+tire diameter would be too high and therefore affect handling, acceleration, top speed, fuel economy, steering (PAS adjusts with speed), active spoiler activation and possibly more. Here is a great excel sheet that show the best fitment sizes (Hosted by Thorin ) http://www.kulthea.net/fitment.xls Quote Link to comment Share on other sites More sharing options...
Lez Posted February 15, 2005 Share Posted February 15, 2005 I agree with Torin, the stock wheels are 17s on 8JJ 235/45/17 and 9.5JJ 255/40/17 making the rolling diameters 643mm & 636mm respectively. For info, the best size for 18s are 235/40/18 = 645mm and 255/35/18 = 636mm However the recommended deviation is 2.5% so the max oversize from the stock 17s is; Front 245/45/17 = 652mm +1.4% 245/40/18 = 653mm +1.56% 245/35/19 = 654mm +1.71% Rear 275/40/17 = 652mm +2.52% 275/35/18 = 650mm +2.2% 275/30/19 = 648mm +1.89% Use this calculator to determine your wanted size, tyre size that is!! http://www.tyresave.co.uk/tyresize.html Quote Link to comment Share on other sites More sharing options...
Supraman Posted February 15, 2005 Author Share Posted February 15, 2005 Guys thanks a lot for the info. Quote Link to comment Share on other sites More sharing options...
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