What are the effects of a thinner sidewall?
07-24-2010, 08:00 PM
#1
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What are the effects of a thinner sidewall?
I'm trying to decide between 18" or 19" wheels. If I were to go with 18" wheels, the tires would be 235-40-18. If I were to go with 19", the tires would be 235-35-19. While the 18" tires seem to have a pretty healthy sidewall height, the 19" tires are kind of thin. To get a better idea of the difference, you may just want to type the tire sizes in on Google Images. My question however is will going with 19" wheels affect the ride comfort and/or performance of my A6? I rarely drive up to the snow, but occasionally we go on a ski trip, so will 19" perform poorly in the snow compared to the 18" wheels?
07-24-2010, 10:11 PM
#2
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I have actually decided to go with 18's, but would like to hear anyone's opinion on what tire size to run. The manufacturer of the wheels recommends 235/40/18, but is there any other I could run? The wheel is 18x18.5. Thanks
07-25-2010, 04:35 AM
#3
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17". Stock (optional) 4.2 wheels are 8" width, ET35 running 255/40-17 tires. Base 4.2s even came with 16" wheels!
Chances are your suspension is incorrect/incapable of keeping the 18" or 19" tires flat on the road anyway, inhibiting cornering.
Of course if you don't care or are incapable of understanding or appreciating handling and only care about bling, knock yourself out.
It doesn't matter if you feel good, it only matters if you look good.
Chances are your suspension is incorrect/incapable of keeping the 18" or 19" tires flat on the road anyway, inhibiting cornering.
Of course if you don't care or are incapable of understanding or appreciating handling and only care about bling, knock yourself out.
It doesn't matter if you feel good, it only matters if you look good.
Last edited by SloopJohnB@mac.com; 07-25-2010 at 04:36 AM. Reason: change for change sake...LOL
07-25-2010, 05:42 AM
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Oddly enough, I've been running the '02 4.2 on 18x8.5" wheels initially with the C5 RS6 original equipment 255/40-18 size (26.03" overall diameter).
Now I'm going with the C5 4.2/S6 friendly and XL load rated 255/35-18 size (25.03" overall diameter--identical to the OE 255/40-17 size) just to correct an annoying 4% speedometer error since it turns out that the C5 RS6's final drive gearing is quite a bit shorter (3.197:1) than the C5 4.2/S6's which are both identical (2.727:1) and that's considering that all three V8 models sport the same forward and reverse gear ratios.
Just remember that with 18" and larger tire sizes, one really should mind the tire's load rating. Why? Because C5s are notably heavy cars, especially the V8 models which are real fuggin' heavy (as in two tons heavy). Speaking of which, any tire with a load index of at least 94 is recommended and some 18" and larger low profile standard load rated tires usually won't meet this recommendation but XL (eXtra Load) rated tires in the same size usually will.
Now I'm going with the C5 4.2/S6 friendly and XL load rated 255/35-18 size (25.03" overall diameter--identical to the OE 255/40-17 size) just to correct an annoying 4% speedometer error since it turns out that the C5 RS6's final drive gearing is quite a bit shorter (3.197:1) than the C5 4.2/S6's which are both identical (2.727:1) and that's considering that all three V8 models sport the same forward and reverse gear ratios.
Just remember that with 18" and larger tire sizes, one really should mind the tire's load rating. Why? Because C5s are notably heavy cars, especially the V8 models which are real fuggin' heavy (as in two tons heavy). Speaking of which, any tire with a load index of at least 94 is recommended and some 18" and larger low profile standard load rated tires usually won't meet this recommendation but XL (eXtra Load) rated tires in the same size usually will.
07-25-2010, 06:59 AM
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of course it will affect it.
It will be stiffer. The unsprung mass will likely be higher. The load rating will likely be lower. And the margin for compression before you damage a sidewall or dent the rim will be less.
The question is whether you care.
I barely tolerate 17" 255/40s.
G
It will be stiffer. The unsprung mass will likely be higher. The load rating will likely be lower. And the margin for compression before you damage a sidewall or dent the rim will be less.
The question is whether you care.
I barely tolerate 17" 255/40s.
G
07-25-2010, 09:17 AM
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Oddly enough, I've been running the '02 4.2 on 18x8.5" wheels initially with the C5 RS6 original equipment 255/40-18 size (26.03" overall diameter).
Now I'm going with the C5 4.2/S6 friendly and XL load rated 255/35-18 size (25.03" overall diameter--identical to the OE 255/40-17 size) just to correct an annoying 4% speedometer error since it turns out that the C5 RS6's final drive gearing is quite a bit shorter (3.197:1) than the C5 4.2/S6's which are both identical (2.727:1) and that's considering that all three V8 models sport the same forward and reverse gear ratios.
Just remember that with 18" and larger tire sizes, one really should mind the tire's load rating. Why? Because C5s are notably heavy cars, especially the V8 models which are real fuggin' heavy (as in two tons heavy). Speaking of which, any tire with a load index of at least 94 is recommended and some 18" and larger low profile standard load rated tires usually won't meet this recommendation but XL (eXtra Load) rated tires in the same size usually will.
Now I'm going with the C5 4.2/S6 friendly and XL load rated 255/35-18 size (25.03" overall diameter--identical to the OE 255/40-17 size) just to correct an annoying 4% speedometer error since it turns out that the C5 RS6's final drive gearing is quite a bit shorter (3.197:1) than the C5 4.2/S6's which are both identical (2.727:1) and that's considering that all three V8 models sport the same forward and reverse gear ratios.
Just remember that with 18" and larger tire sizes, one really should mind the tire's load rating. Why? Because C5s are notably heavy cars, especially the V8 models which are real fuggin' heavy (as in two tons heavy). Speaking of which, any tire with a load index of at least 94 is recommended and some 18" and larger low profile standard load rated tires usually won't meet this recommendation but XL (eXtra Load) rated tires in the same size usually will.
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07-25-2010, 12:07 PM
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However, the overall length of a C5 from bumper cover to bumper cover does vary slightly depending on engine and, at a quick glance of all the specs, it looks like C5s come in four distinct overall lengths:
189.4" = allroad 2.7T and 4.2
191.3" = RS6 sedan or Avant
192.0" = 2.7T, 2.8 and 3.0 sedan or Avant
193.4" = 4.2 and S6 sedan or Avant
Of course, one'd surmise that all of the V8 models should be longer than their V6 equivalents based on the notion that a V8 engine is a bit longer than a V6, but apparently that's not the case.
07-25-2010, 01:06 PM
#9
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And then there is the wide body 4.2....