Q on larger wheels and wider tires
10-09-2001, 08:57 PM
#1
Drifting
Thread Starter
Q on larger wheels and wider tires
Okay, I have a few questions about upgrading to larger wheels and wider tires...
1. people say that the same car with 18' wheels will be slower then the one with 16' wheels. If that's the case, why? Is it becuase of the weight on the wheels? or is it because of rotating mass? What determines the rotating mass?
2. If larger wheels provides better handling, won't that mean more grips? Then wouldn't that reduce the wheel spinning caused when laungh the car?
3. I have just read this article http://www.autospeed.com/A_0996/page1.html
Do you guys agree on what it is saying? I always thought that larger wheels/wider tires gives you more contact patch, therefore gives you better handling.......
1. people say that the same car with 18' wheels will be slower then the one with 16' wheels. If that's the case, why? Is it becuase of the weight on the wheels? or is it because of rotating mass? What determines the rotating mass?
2. If larger wheels provides better handling, won't that mean more grips? Then wouldn't that reduce the wheel spinning caused when laungh the car?
3. I have just read this article http://www.autospeed.com/A_0996/page1.html
Do you guys agree on what it is saying? I always thought that larger wheels/wider tires gives you more contact patch, therefore gives you better handling.......
10-09-2001, 09:55 PM
#2
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18's are slower due to the rotating length. its the moment of inertia and the classic moment arm. longer distance (diameter requires more power to rotate). there is also a larger contact patch with larger wheels which creates greater friction and drag. larger diameter wheels may also weigh more which as you mentioned results in a loss of power from mass.
its not the larger wheels that provide better handling, it's the accompanying lower profile tires. lower profile tires have stiffer sidewalls that make for improved grip in cornering. but there is a limit to this. autocrossers for instance usually prefer a 45-50 profile to give them a little more flexibility to avoid spinouts. there is no give on low profile stiff sidewall tires...turn into a corner too hard and you don't have that flexibility resulting in a total loss of traction.
its not the larger wheels that provide better handling, it's the accompanying lower profile tires. lower profile tires have stiffer sidewalls that make for improved grip in cornering. but there is a limit to this. autocrossers for instance usually prefer a 45-50 profile to give them a little more flexibility to avoid spinouts. there is no give on low profile stiff sidewall tires...turn into a corner too hard and you don't have that flexibility resulting in a total loss of traction.
10-09-2001, 10:58 PM
#3
Racer
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I originally posted this on another thread, but it might help here (paraphrased):
While reducing rotational mass has a big effect on acceleration (think lightweight racing flywheel) and reducing sprung weight has a big effect on handling (think titanium springs and carbon rotors on race cars), there will probably not be a huge difference unless you make a drastic change. Some very high end wheels may possibly be a little lighter than the stock wheels (1-2 lbs max), but the wider tires (235 vs. 215) are probably heavier even though you have less sidewall, so it should be a wash, especially if the new tires are VERY close in diameter.
Another thing to consider is where is the weight located on the wheel? Lets say you have two wheels that both weigh 26 pounds (without tires), one with a heavy center or hub and light rim, and one with a light hub and a heavy Rim. Both will affect handling very similarly compared to a 22 pound wheel, but the one with the heavy rim will greatly lag acceleration when compared to the one with the light rim.
The most noticeable changes usually occur when Civic and Integra owners go from pizza-cutting (175-width) 15's to wider (205 or 215) 17's or 18's and have a MUCH heavier wheel/tire combo (7-10 lbs) which is also as much as 1-2" larger in diameter. The diameter is the real killer when weight stays comparable. It's like putting a lower (numerically) gear ratio in your differential. Top speed is great, if you have the HP, but acceleration sucks, especially on low-torque Japanese engines.
As far as handling is concerned, it's all about the right balance of sidewall flex versus stiffness, too much of either and you're screwed, it has nothing to do with wheel diameter. Granted 215/35/18's do not have enough sidewall to prevent the go-kart effect ("skipping"), but that is an extreme situation and typical 235/40's should be fine.
As far as friction is concerned (I think Jimster216 meant rolling resistance), wider is NOT better, but how often will you be over 130mph, and if you were, and a soon to be dead rabbit ran out in front of you, would you want to take evasive maneuvers with 215's or 235's? I vote for 235's.
As far as your web article, everything seemed to be factual, but confusing, as trying to explain how tires work is nearly impossible. Hopefully my little take on the situation helped shed a little light on the subject for you.
While reducing rotational mass has a big effect on acceleration (think lightweight racing flywheel) and reducing sprung weight has a big effect on handling (think titanium springs and carbon rotors on race cars), there will probably not be a huge difference unless you make a drastic change. Some very high end wheels may possibly be a little lighter than the stock wheels (1-2 lbs max), but the wider tires (235 vs. 215) are probably heavier even though you have less sidewall, so it should be a wash, especially if the new tires are VERY close in diameter.
Another thing to consider is where is the weight located on the wheel? Lets say you have two wheels that both weigh 26 pounds (without tires), one with a heavy center or hub and light rim, and one with a light hub and a heavy Rim. Both will affect handling very similarly compared to a 22 pound wheel, but the one with the heavy rim will greatly lag acceleration when compared to the one with the light rim.
The most noticeable changes usually occur when Civic and Integra owners go from pizza-cutting (175-width) 15's to wider (205 or 215) 17's or 18's and have a MUCH heavier wheel/tire combo (7-10 lbs) which is also as much as 1-2" larger in diameter. The diameter is the real killer when weight stays comparable. It's like putting a lower (numerically) gear ratio in your differential. Top speed is great, if you have the HP, but acceleration sucks, especially on low-torque Japanese engines.
As far as handling is concerned, it's all about the right balance of sidewall flex versus stiffness, too much of either and you're screwed, it has nothing to do with wheel diameter. Granted 215/35/18's do not have enough sidewall to prevent the go-kart effect ("skipping"), but that is an extreme situation and typical 235/40's should be fine.
As far as friction is concerned (I think Jimster216 meant rolling resistance), wider is NOT better, but how often will you be over 130mph, and if you were, and a soon to be dead rabbit ran out in front of you, would you want to take evasive maneuvers with 215's or 235's? I vote for 235's.
As far as your web article, everything seemed to be factual, but confusing, as trying to explain how tires work is nearly impossible. Hopefully my little take on the situation helped shed a little light on the subject for you.
10-10-2001, 06:00 PM
#4
Drifting
Thread Starter
Thanks a lot......... althought I am still a bit confused...
I will try to make sense out of it... and if not... then I will seek for help again...
anyone else got something to say............. please enlight me on this one........
I will try to make sense out of it... and if not... then I will seek for help again...
anyone else got something to say............. please enlight me on this one........
10-10-2001, 09:15 PM
#6
Drifting
Thread Starter
1. so, with higher profile tires, you have more warning before go out of control and with a lower profile tires you just lost your grip without much warning?
2. Now I understand that outter/inner weight on the rim and tires will affect the acceleration. Larger diameter will also cause that.
So, it is NOT ture to say that 18' wheel with low profile tire will cause more wheel spin during the launch compared to a 16' wheel with higher profile tires? Cuz all the drag cars I see got SUPER HIGH profile tires, there's gotta be a reason with that...
3. So can I say that lower profile tires will provide better handling, while higher profile tires will give you a better launch in 1/4 mile?
4. A good set of 18' rims that's actually lighter then stock rims, with some low profile tires. Assume that the Diameter is the same as the stock with the 18s with tires. Then it should not affect my accleration on the highway or rolling start, am I rite?
Sorry for so many questions.... but I am just a bit too confused by that article.....
I always thought that bigger is better because of more contact patch and bababa............
2. Now I understand that outter/inner weight on the rim and tires will affect the acceleration. Larger diameter will also cause that.
So, it is NOT ture to say that 18' wheel with low profile tire will cause more wheel spin during the launch compared to a 16' wheel with higher profile tires? Cuz all the drag cars I see got SUPER HIGH profile tires, there's gotta be a reason with that...
3. So can I say that lower profile tires will provide better handling, while higher profile tires will give you a better launch in 1/4 mile?
4. A good set of 18' rims that's actually lighter then stock rims, with some low profile tires. Assume that the Diameter is the same as the stock with the 18s with tires. Then it should not affect my accleration on the highway or rolling start, am I rite?
Sorry for so many questions.... but I am just a bit too confused by that article.....
I always thought that bigger is better because of more contact patch and bababa............
10-10-2001, 09:46 PM
#7
Burning Brakes
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The high profile tire on a drag car is a completely different principle. You will notice that as the wheel of a dragster begins to spin, the rotation of the tire lags begind the rotation of the wheel, kind of twisting the tire around the wheel. Eventually the potential energy that has built up in the tire (much like what would be built up in a twisted rubber band) is overwhelmed by the kinetic energy of the spinning wheel, changing the potential energy into kinetic causing the tire to spin faster than the wheel itself as the tire tries to regain its original shape on the wheel, giving you faster acceleration. Also, as the wheel expands during acceleration, its diameter increases thus allowing the wheel and tire to travel a greater distance with each rotation of the wheel.
Did that make any damn sense?
Did that make any damn sense?
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10-11-2001, 02:42 AM
#8
Drifting
Thread Starter
Pretty technical, but makes sense.......
So, that means the 16' will not be better on the drag strip? Passanger car that I am talking about... not crazy dragster......
So, that means the 16' will not be better on the drag strip? Passanger car that I am talking about... not crazy dragster......
10-11-2001, 06:48 PM
#9
I shoot people
I've also heard that changing the wheel/tire size throws off the ABS or some computer stuff... is that true?
10-11-2001, 06:55 PM
#10
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Originally posted by is300eater
I've also heard that changing the wheel/tire size throws off the ABS or some computer stuff... is that true?
I've also heard that changing the wheel/tire size throws off the ABS or some computer stuff... is that true?
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