Decreasing rolling diamater for speed
10-21-2007, 12:54 PM
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I currently have 18 inch tires and was going to go to 19s but have decided against that in order to save some dough and just keep my current 18 inch rims. However how would it look to go with a lower profile tire-say a 245-30-18 instead of the 245-40-18 in order to give it a more sleek look around the tire and actually make a small diamater in order to increase acceleration.
1. Would that really make the tire/rim look small within the wheel well?
2. How much would it be noticable in acceleration-in essence it is like creating taller gears
1. Would that really make the tire/rim look small within the wheel well?
2. How much would it be noticable in acceleration-in essence it is like creating taller gears
10-21-2007, 01:17 PM
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Originally Posted by redwhiteblue' post='484251' date='Oct 21 2007, 09:54 PM
I currently have 18 inch tires and was going to go to 19s but have decided against that in order to save some dough and just keep my current 18 inch rims. However how would it look to go with a lower profile tire-say a 245-30-18 instead of the 245-40-18 in order to give it a more sleek look around the tire and actually make a small diamater in order to increase acceleration.
1. Would that really make the tire/rim look small within the wheel well?
2. How much would it be noticable in acceleration-in essence it is like creating taller gears
1. Would that really make the tire/rim look small within the wheel well?
2. How much would it be noticable in acceleration-in essence it is like creating taller gears
10-21-2007, 01:32 PM
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stock 18" setup already looks small to me on the E60 body, so if you want to go even smaller in diameter on the 18's that would look worse. The car is really made for a 19" set up.
10-21-2007, 04:34 PM
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actually with 19s people get a lower profile tire so the overall diamater is actually the same-so not sure how it looks worse to you considering it is the exact same diamater overall with the same amount of space between the wheel well showing.
10-21-2007, 04:52 PM
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Originally Posted by redwhiteblue' post='484311' date='Oct 21 2007, 07:34 PM
actually with 19s people get a lower profile tire so the overall diamater is actually the same-so not sure how it looks worse to you considering it is the exact same diamater overall with the same amount of space between the wheel well showing.
10-21-2007, 05:25 PM
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Originally Posted by redwhiteblue' post='484311' date='Oct 21 2007, 05:34 PM
actually with 19s people get a lower profile tire so the overall diamater is actually the same-so not sure how it looks worse to you considering it is the exact same diamater overall with the same amount of space between the wheel well showing.
You're right... forgot about that.
But yes its the visual that you get...
10-21-2007, 06:16 PM
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I'm no physicist but I don't think that acceleration will increase just because the tires are a smaller diameter. The speedometer might indicate a faster speed than actually travelling but something tells me that it won't change the effective acceleration...
10-21-2007, 06:54 PM
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Originally Posted by Rudy' post='484337' date='Oct 21 2007, 10:16 PM
I'm no physicist but I don't think that acceleration will increase just because the tires are a smaller diameter. The speedometer might indicate a faster speed than actually travelling but something tells me that it won't change the effective acceleration...
Thus, adding more milieage on your speedometer than what your really traveling.
10-22-2007, 03:14 AM
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Originally Posted by slickrick' post='484359' date='Oct 21 2007, 10:54 PM
Thus, adding more milieage on your speedometer than what your really traveling.
10-22-2007, 03:25 AM
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Originally Posted by Rudy' post='484337' date='Oct 22 2007, 03:16 AM
I'm no physicist but I don't think that acceleration will increase just because the tires are a smaller diameter. The speedometer might indicate a faster speed than actually travelling but something tells me that it won't change the effective acceleration...
As you say, it will also make the speedo read fast too.
This of course applies to new tyres Vs old tyres because the diameter reduces as the tyres wear. It is however so small of course that no one would notice.
If you lowered the gearing enough, you would end up having top speed dictated by the revs rather than what the engine could deliver. This used to be the case when you tuned 4 speed manual cars in the 70s but with todays 6 speed boxes is not really an issue as top is so high.
A friend tuned a 1966 Ford Cortina that did 115mph at 7000 rpm and used to spend his weekends changing diffs to change the overall gearing.
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