20 inch rims = Loss of power
07-04-2005, 12:50 PM
#21
RE: 20 inch rims = Loss of power
ORIGINAL: t3000
20"+ rims are for anyone who wants to buy them, not just for gangsters and white people who want to be black.
20"+ rims are for anyone who wants to buy them, not just for gangsters and white people who want to be black.
07-04-2005, 01:00 PM
#22
2nd Gear Member
Join Date: Oct 2004
Location:
Posts: 485
RE: 20 inch rims = Loss of power
ORIGINAL: jdaniel
You are incorrect. It isnt just the size of the tire its the size of the rim and tire together. Why do you think I race on 275/60/15's instead of 275/60 17's? The longer it takes that tire to go around then the more rotational mass you have thus reducing gear size. There is no way to put 20's on a car and keep the stock demensions reguardless of what size tire you go with.
ORIGINAL: Blue70
Only if he has huge tires on those 20s
(I agree I would lose them too, they are just not my style, but if the diameter is kept close the effective gearing should not change)
ORIGINAL: jdaniel
You wont lose power but you will lose some gear.
You wont lose power but you will lose some gear.
(I agree I would lose them too, they are just not my style, but if the diameter is kept close the effective gearing should not change)
Hello..Maybe you missed the above post...go back a few and read, I listed 3 20" tires that have almost the same diameter, and one was almost exact.
Tell me how a tire with the same height and diameter takes longer to go around???
Talk about stock demensions........You are going against what you are saying by listing your tire choise......
Stock.....25.68 tall.....you....27.99 tall.....now you tell me which one takes longer to get around.
Lets keep going
Stock Radius....12.84....you....13.99
Stock Circumference....80.67....you....87.93
revolutions per mile stock.....809.9.......revolutions per mile you.....743.1
Speedo at 60 with your tire will show 55.0
Who is turning over slower......YOU
I won't even get into the 275/60/17 you listed, that thing is 30" tall, what are you lifting your Stang?
Do the math before you decide someone is incorrect. [>:]
You should be running 15's instead of 17's because they have more sidewall and should give you better bite because of the flex..
07-04-2005, 01:05 PM
#23
2nd Gear Member
Join Date: Oct 2004
Location:
Posts: 485
RE: 20 inch rims = Loss of power
ORIGINAL: BicketyBam
Agreed - that was a pretty stupid comment to begin with.
ORIGINAL: t3000
20"+ rims are for anyone who wants to buy them, not just for gangsters and white people who want to be black.
20"+ rims are for anyone who wants to buy them, not just for gangsters and white people who want to be black.
The world would be bretty bland if every mustang was silver with one style of stock wheels.
07-04-2005, 01:24 PM
#24
2nd Gear Member
Join Date: Oct 2004
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Posts: 485
RE: 20 inch rims = Loss of power
jdaniel
Check out this site. It does all the calculations for you, like speedo correction factors and percentages. You put in the original tire size and the new tire size and it will say something like "your speedometer will read 1.8% fast; at 60 mph, you'll actually be going 58.9 mph." That percentage is the same percentage you use to calculate your effective difference in gear ratio. With this example, you would take your ratio (lets say 3.42) you can multiply by .018 and add the answer from 3.42 giving you an effective ratio of about 3.48.....but your tire size shows it is reading 8.99 slow not fast, so you just went from a 3.42 to a 3.12 gear.....wrong direction man......
Keep in mind that "plus size" only implies larger wheel and maybe treadwidth. It never means larger diameter. The "plus size" concept was developed by aftermarket companies so they could sell tire and wheel packages without messing up your speedo and odometer or having fitment issues.
The website is: http://www.1010tires.com/TireSizeCal...?action=submit
Check out this site. It does all the calculations for you, like speedo correction factors and percentages. You put in the original tire size and the new tire size and it will say something like "your speedometer will read 1.8% fast; at 60 mph, you'll actually be going 58.9 mph." That percentage is the same percentage you use to calculate your effective difference in gear ratio. With this example, you would take your ratio (lets say 3.42) you can multiply by .018 and add the answer from 3.42 giving you an effective ratio of about 3.48.....but your tire size shows it is reading 8.99 slow not fast, so you just went from a 3.42 to a 3.12 gear.....wrong direction man......
Keep in mind that "plus size" only implies larger wheel and maybe treadwidth. It never means larger diameter. The "plus size" concept was developed by aftermarket companies so they could sell tire and wheel packages without messing up your speedo and odometer or having fitment issues.
The website is: http://www.1010tires.com/TireSizeCal...?action=submit
07-04-2005, 02:09 PM
#25
3rd Gear Member
Join Date: Mar 2005
Location:
Posts: 625
RE: 20 inch rims = Loss of power
[[/quote]
ORIGINAL: jdaniel
You are incorrect. It isnt just the size of the tire its the size of the rim and tire together. Why do you think I race on 275/60/15's instead of 275/60 17's? The longer it takes that tire to go around then the more rotational mass you have thus reducing gear size. There is no way to put 20's on a car and keep the stock demensions reguardless of what size tire you go with.
[/quote]
blue70 I was just thinking the same about this incorrect comment. This made zero sense. Size of the rim has nothing to do with gearing. Its the size of the tire. A 26" high tire has the same gearing effect no matter the height of the rim. 15" or 20", both with the same tire height will be the same gearing and same speedo readings.
ORIGINAL: jdaniel
You are incorrect. It isnt just the size of the tire its the size of the rim and tire together. Why do you think I race on 275/60/15's instead of 275/60 17's? The longer it takes that tire to go around then the more rotational mass you have thus reducing gear size. There is no way to put 20's on a car and keep the stock demensions reguardless of what size tire you go with.
[/quote]
blue70 I was just thinking the same about this incorrect comment. This made zero sense. Size of the rim has nothing to do with gearing. Its the size of the tire. A 26" high tire has the same gearing effect no matter the height of the rim. 15" or 20", both with the same tire height will be the same gearing and same speedo readings.
07-04-2005, 02:16 PM
#26
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Join Date: Oct 2004
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Posts: 485
RE: 20 inch rims = Loss of power
tomabram
Thanks
I have left this forum quite a few times (only to poke my head in now and again)
I get sick of all the bad info being thrown around and people getting mad, or just flat out calling others liar or getting personal when confronted with facts, numbers, math, physics, ect because they can not produce their own.
[sm=icon_rofl.gif] I just realized jdaniels tires are taller than every 20" tire I listed above and he has gone the wrong direction (even more than the 20's he was talking about) with his effective gearing he is so worried about....
So I can not answer his question.....I have no idea why he races on 275/60/15's. It does not appear any thought has gone into tire choice.
Thanks
I have left this forum quite a few times (only to poke my head in now and again)
I get sick of all the bad info being thrown around and people getting mad, or just flat out calling others liar or getting personal when confronted with facts, numbers, math, physics, ect because they can not produce their own.
[sm=icon_rofl.gif] I just realized jdaniels tires are taller than every 20" tire I listed above and he has gone the wrong direction (even more than the 20's he was talking about) with his effective gearing he is so worried about....
So I can not answer his question.....I have no idea why he races on 275/60/15's. It does not appear any thought has gone into tire choice.
07-08-2005, 12:20 AM
#27
Join Date: Jul 2005
Posts: 2
RE: 20 inch rims = Loss of power
Hello everyone. This is my first post but I felt the need to sign up right away since I have some useful information.
I just recently test drove some GT's and ended up purchasing one of them. The one I purchased has 20" boss wheels on it. They definitely make the car slower then the stock rims. Not only because of the sheer weight, but the gearing, and the way the mass is distributed.
I used to work at a rim/tire shop where we sold boss wheels. Let me tell you.. They took significantly longer to spin up on a balancer compared to Cobra wheels. The difference in power you're feeling is most likely because of the wheels. I wouldn't avoid buying the car because of it. I would sell the wheels though.. Boss wheels are junk. I plan on getting rid of mine relatively soon.
I just recently test drove some GT's and ended up purchasing one of them. The one I purchased has 20" boss wheels on it. They definitely make the car slower then the stock rims. Not only because of the sheer weight, but the gearing, and the way the mass is distributed.
I used to work at a rim/tire shop where we sold boss wheels. Let me tell you.. They took significantly longer to spin up on a balancer compared to Cobra wheels. The difference in power you're feeling is most likely because of the wheels. I wouldn't avoid buying the car because of it. I would sell the wheels though.. Boss wheels are junk. I plan on getting rid of mine relatively soon.
07-08-2005, 01:35 AM
#28
4th Gear Member
Join Date: Nov 2004
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Posts: 1,232
RE: 20 inch rims = Loss of power
your not losing any power, the wheels are slighty harder to turn. the weight of the rim is further from the axle, more rotational inertia. there is really no way to calculate how much harder they are to turn because i haven't seen any manufacturers list the required information.
07-08-2005, 02:22 PM
#29
4th Gear Member
Join Date: Aug 2004
Location: Philadelphia, PA
Posts: 1,654
RE: 20 inch rims = Loss of power
ORIGINAL: Shawn02GT
your not losing any power, the wheels are slighty harder to turn. the weight of the rim is further from the axle, more rotational inertia. there is really no way to calculate how much harder they are to turn because i haven't seen any manufacturers list the required information.
your not losing any power, the wheels are slighty harder to turn. the weight of the rim is further from the axle, more rotational inertia. there is really no way to calculate how much harder they are to turn because i haven't seen any manufacturers list the required information.
If the overall diameter of the tire changes (and thus the distance traveled per revolution), then yes, gearing/speedo are affected and it would simply be a matter of swapping to a different rear gear. I think this point has been beaten to death but big/heavy wheels need more torque to get up to speed quickly. As a turntablist, I often have to deal with this problem in cheaper record players.
Rotational inertia is another point. It will be harder to accellerate the wheel but this would mean it would be harder to stop the wheel turning which makes me wondering how much braking would be affected. This can't be calculated without knowing the material, and density distribution.
Certainly, you cant forget about the added (unsprung) weight. Not only does that slug the car down but it also makes the ride harsher (as if having rubber band tires isn't bad enough).
07-08-2005, 04:36 PM
#30
3rd Gear Member
Join Date: Mar 2005
Location: IL
Posts: 894
RE: 20 inch rims = Loss of power
ORIGINAL: Fallstar01
Pretty much.
If the overall diameter of the tire changes (and thus the distance traveled per revolution), then yes, gearing/speedo are affected and it would simply be a matter of swapping to a different rear gear. I think this point has been beaten to death but big/heavy wheels need more torque to get up to speed quickly. As a turntablist, I often have to deal with this problem in cheaper record players.
Rotational inertia is another point. It will be harder to accellerate the wheel but this would mean it would be harder to stop the wheel turning which makes me wondering how much braking would be affected. This can't be calculated without knowing the material, and density distribution.
Certainly, you cant forget about the added (unsprung) weight. Not only does that slug the car down but it also makes the ride harsher (as if having rubber band tires isn't bad enough).
ORIGINAL: Shawn02GT
your not losing any power, the wheels are slighty harder to turn. the weight of the rim is further from the axle, more rotational inertia. there is really no way to calculate how much harder they are to turn because i haven't seen any manufacturers list the required information.
your not losing any power, the wheels are slighty harder to turn. the weight of the rim is further from the axle, more rotational inertia. there is really no way to calculate how much harder they are to turn because i haven't seen any manufacturers list the required information.
If the overall diameter of the tire changes (and thus the distance traveled per revolution), then yes, gearing/speedo are affected and it would simply be a matter of swapping to a different rear gear. I think this point has been beaten to death but big/heavy wheels need more torque to get up to speed quickly. As a turntablist, I often have to deal with this problem in cheaper record players.
Rotational inertia is another point. It will be harder to accellerate the wheel but this would mean it would be harder to stop the wheel turning which makes me wondering how much braking would be affected. This can't be calculated without knowing the material, and density distribution.
Certainly, you cant forget about the added (unsprung) weight. Not only does that slug the car down but it also makes the ride harsher (as if having rubber band tires isn't bad enough).