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09-27-2009, 04:08 AM | #1 |
yodog
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aspect ratios and comfort
I've been wondering about this for a long time.
Let's say there's a tire that's 265mm with an aspect ratio of 35 and a sidewall size of 3.7 inches, and a 305mm tire with aspect ratio of 30 with the same sidewall size of 3.7 inches. Would the 305/30 tire be less comfortable even though both have the exact same sidewall size?
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09-27-2009, 10:59 AM | #2 |
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It also depends on what size wheels they're on and what brand tires each is. Both of those factors will make more difference than the width of the tire, but assuming same brand and that neither one is too stretched out, the narrower tire will probably be a bit more comfortable, but maybe not even enough to notice.
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09-27-2009, 02:38 PM | #3 |
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The wider tire has to have a little more robust sidewall, even if they're the same height, but as Tlud said, the difference might not be enough to notice.
Last edited by JCtx; 09-27-2009 at 03:00 PM.. |
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09-27-2009, 09:33 PM | #5 | |
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By the way, if you don't know how to calculate tire circumference, find a calculator online to determine the aspect ratio needed to match stock circumference for the widths you want. Good luck. |
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09-28-2009, 02:05 AM | #6 | |
Titanium TCP
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09-28-2009, 02:43 AM | #7 | |
yodog
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I have Nitto INVOs and 255/35/19 does rub when locking it full left. I'm going 245/35/19, 295/30/19 for my next set.
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09-28-2009, 04:18 AM | #8 |
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I am actually thinking of going with 255/35/19 in the front and 285/35/19 in the rear. I just don't know whether I should go 285/30 or 285/35. Anyone have any recommendations?
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09-28-2009, 10:13 AM | #9 |
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Comfort and 19" wheels do not mix...
Unfortunately you won't find any 19" tire size to be "comfortable". Different tires will have different sidewall compliance but they all will be pretty harsh. That being said I though my PS2's were comfortable for what they were-just really loud. An M3 won't ride like a Mercedes CL, ever, and thats ok with me.
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09-28-2009, 12:30 PM | #10 |
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Are you lowered? I don't think 285/35 will clear depending on the offset of your wheels but most don't. 285/30 is actually closer to stock size than 285/35. As far as the 255/35, the clearance will depend on offset too. Also, the exact tire you plan to use will make a difference because if at the same size, some tire brands will be wider than others. I believe Nittos are known to have very squared sidewalls so they tend to be a bit wider than most brands.
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09-28-2009, 04:38 PM | #11 | |
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Thanks man! That was very informative! I know these threads get redundant, but you just want to be safe when it's your tires you're ordering. I just ordered a set of 255/35/19 front & 285/30/19 rear Michelin PS2 (was thinking about the Yokohama Advan Sports though). I'll post a an update once I get them mounted onto my new wheels.
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09-28-2009, 05:28 PM | #12 |
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Stock 19's
You are getting the tire size I'm thinking about but I want to put them on the stock 19's. Does anyone know if i'll have issues with that?
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09-28-2009, 05:52 PM | #13 |
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255,285 will fit on stock wheels. I believe that is the max.
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09-28-2009, 06:29 PM | #14 | |
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Now to the math. A 265/35/19 tire has 82.634" of circumference. You need circumference to calculate speedometer error. But for clearance, you need RADIUS. It gets simpler here. Every 10mm larger width (275 vs 265, etc) with equal aspect ratio, increases radius by 3.5mm (10mm * 35%). So any size above stock with the same 35% aspect ratio will reduce fender gap by 3.5mm by every 10mm of added width, so tire would look even bigger than stock, and car would travel faster than with stock tires. But if you only go +1 in width (275/35 vs 265/35), you're talking a 1.04% increase in circumference (and 3.5mm less fender gap), which equals 79.2 mph speedo vs 80 real (IF it was accurate ). Hardly anything. If you go to 30 series, the 305/30 is virtually identical to stock, so anything in-between will be smaller. The next size larger than stock, 275/30, has 3.17% less circumference (82.5 mph speedo vs 80 real, plus factory error ), and is 10.25mm smaller in radius (added fender gap). The 285/30 would add 7.25mm of fender gap; 295/30 4.25mm and 305/30 1.25mm (almost like stock). Hope this helps. |
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09-28-2009, 10:32 PM | #15 | |
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09-28-2009, 11:26 PM | #16 |
yodog
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So 295/30 is probably a better option than 285/35? I checked, I don't think I'll rub with 285/35 even lowered on H&R springs but I'm afraid the tall sidewall and overall diameter may throw off the DSC/MDM
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09-29-2009, 12:56 AM | #17 | |
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09-29-2009, 06:52 PM | #18 | |
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09-29-2009, 06:59 PM | #19 | |
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I can't comment for certain about your concerns regarding DSC and MDM, but I think those electronic systems will do what they do, regardless of tire size. Hopefully, there is already a thread about it somewhere, or somebody listening in on this thread knows for sure.
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09-29-2009, 10:23 PM | #20 | |
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We recommend using the 245/35-19 front and 285/30-19. The 285/35-19 is way too big on the rear and tends to rub with some tire brands. The best that we have seen is going with 245/35-19 and 265/35-19 YOKOHAMA Advan Sport tires. They are so much more square than the PS2, that they sit very flush. Hope this helps. Cheers!
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09-30-2009, 04:29 AM | #22 |
yodog
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My lighter wheels are compensating for the added weight in the rear. 285/295 tires are around 30-31lbs each.
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