Performance difference between 18" and 19" wheels
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Performance difference between 18" and 19" wheels
Just wanting to know what everyone thinks. I just bought my 05 daytona blue z last week and considering either 18x8.5 front 18x9.5 in rear or either 19x8.5 front 19x9.5 rear. I like the way the 19's look and feel up the fender well, but was curious if you can tell that much of a difference in performance? I also want to get a billet grill for it, but was curious if anyone knows; do you have to cut out the stock grill or does it unbolt from the inside? I haven't took the bumper off yet, but it looks like it will need to be cut out?
Thanks
Thanks
Last edited by 150flyingace; Nov 3, 2005 at 11:56 PM.
get 19s they look nicer, but they are probably heavier so performance would most likely go down, its not that much of a difference a few more pounds than stock.
the billet grill most of them dont drill away the orignial grill, but just bolt or clip on.
the billet grill most of them dont drill away the orignial grill, but just bolt or clip on.
I’m not going to comment about looks, but there is an incremental difference moving from 17 to 18 to 19 to 20 wheels. First is weight. Generally, bigger wheels weigh more. Second is sidewall: bigger wheels have a shorter sidewall, and are more apt to be damaged by road hazards such as pot holes.
Originally Posted by davidv
I’m not going to comment about looks, but there is an incremental difference moving from 17 to 18 to 19 to 20 wheels. First is weight. Generally, bigger wheels weigh more. Second is sidewall: bigger wheels have a shorter sidewall, and are more apt to be damaged by road hazards such as pot holes.
Some 19" rims weigh less than the stock 17" rims, or 1-2lbs more... Volk CE28 & LE28Ns & possibly the TE37 & LE37s as well so if you were to get a lightweight 19" rim then performance would be negligable.
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I think light weight 17" rims are the best for track but daym they look crappy. Aren't NSX-R rims 17"? That car is all about light weight.
I think 20's are too big for our car, esp. from a performance perspective. I see more bling in a 20 and wouldn't respect a Z with 20's as far as being a serious performer. Too heavy for our power output. Real sports cars just don't go that high unless they got the serious (500+HP) to spin it.
19's are as high as you would want to go; the new Nismo LMGT4's are 19. Mine are 18. 18's are easier to brake, too.
What is probably the best of both worlds is to stagger a 19 rear and an 18 front. That's how the '06 Tracks are set up.
I think 20's are too big for our car, esp. from a performance perspective. I see more bling in a 20 and wouldn't respect a Z with 20's as far as being a serious performer. Too heavy for our power output. Real sports cars just don't go that high unless they got the serious (500+HP) to spin it.
19's are as high as you would want to go; the new Nismo LMGT4's are 19. Mine are 18. 18's are easier to brake, too.
What is probably the best of both worlds is to stagger a 19 rear and an 18 front. That's how the '06 Tracks are set up.
The issue is not really weight alone. But also where the weight is located.
An object's "moment of inertia (I) " (Think of it as resistance to torque) follows the following relationship:
(I) is proportional to (mass) x (radius)² . I=MR² might be true for something like a uniform metal disc, but wheels do not have uniform weight distribution. They are heavier towards the outside, where the tire is located.
So you are putting rubber out at 9.5" Radius compared to 9" radius, which is essentially a 10% increase in moment of inertia (rough estimate) even at the same mass.
You can feel it, going from 18 to 19. (Even if the wheels are about the same weight as stock). It feels slower. I can't vouch for the FI guys, but for a stock motor Z like mine, you can feel it.
Especially since my tires are much much wider than before, so even if the metal from the rims was lighter (and volks shouldn't be all THAT heavy...) then the extra rubber weighs a TON. To top it all off, all that extra rubber is at the MAXIMUM radius, which corresponds to a big increase in moment of inertia.
[/physics lesson]
An object's "moment of inertia (I) " (Think of it as resistance to torque) follows the following relationship:
(I) is proportional to (mass) x (radius)² . I=MR² might be true for something like a uniform metal disc, but wheels do not have uniform weight distribution. They are heavier towards the outside, where the tire is located.
So you are putting rubber out at 9.5" Radius compared to 9" radius, which is essentially a 10% increase in moment of inertia (rough estimate) even at the same mass.
You can feel it, going from 18 to 19. (Even if the wheels are about the same weight as stock). It feels slower. I can't vouch for the FI guys, but for a stock motor Z like mine, you can feel it.
Especially since my tires are much much wider than before, so even if the metal from the rims was lighter (and volks shouldn't be all THAT heavy...) then the extra rubber weighs a TON. To top it all off, all that extra rubber is at the MAXIMUM radius, which corresponds to a big increase in moment of inertia.
[/physics lesson]
Last edited by Wired 24/7; Nov 4, 2005 at 11:23 PM.
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^ what he said
it's a common misconception that just because the static weight of a +1 or +2 wheel is less than stock that you will not notice a performance difference... you WILL
best and only way to offset increased wheel diameter is to buy a light-weight tire, in which case you will offset some (and perhaps ALL if your tire is very light) of the performance impact
it's a common misconception that just because the static weight of a +1 or +2 wheel is less than stock that you will not notice a performance difference... you WILL
best and only way to offset increased wheel diameter is to buy a light-weight tire, in which case you will offset some (and perhaps ALL if your tire is very light) of the performance impact
Originally Posted by Wired 24/7
The issue is not really weight alone. But also where the weight is located.
An object's "moment of inertia (I) " (Think of it as resistance to torque) follows the following relationship:
(I) is proportional to (mass) x (radius)² . I=MR² might be true for something like a uniform metal disc, but wheels do not have uniform weight distribution. They are heavier towards the outside, where the tire is located.
So you are putting rubber out at 9.5" Radius compared to 9" radius, which is essentially a 10% increase in moment of inertia (rough estimate) even at the same mass.
You can feel it, going from 18 to 19. (Even if the wheels are about the same weight as stock). It feels slower. I can't vouch for the FI guys, but for a stock motor Z like mine, you can feel it.
Especially since my tires are much much wider than before, so even if the metal from the rims was lighter (and volks shouldn't be all THAT heavy...) then the extra rubber weighs a TON. To top it all off, all that extra rubber is at the MAXIMUM radius, which corresponds to a big increase in moment of inertia.
[/physics lesson]
An object's "moment of inertia (I) " (Think of it as resistance to torque) follows the following relationship:
(I) is proportional to (mass) x (radius)² . I=MR² might be true for something like a uniform metal disc, but wheels do not have uniform weight distribution. They are heavier towards the outside, where the tire is located.
So you are putting rubber out at 9.5" Radius compared to 9" radius, which is essentially a 10% increase in moment of inertia (rough estimate) even at the same mass.
You can feel it, going from 18 to 19. (Even if the wheels are about the same weight as stock). It feels slower. I can't vouch for the FI guys, but for a stock motor Z like mine, you can feel it.
Especially since my tires are much much wider than before, so even if the metal from the rims was lighter (and volks shouldn't be all THAT heavy...) then the extra rubber weighs a TON. To top it all off, all that extra rubber is at the MAXIMUM radius, which corresponds to a big increase in moment of inertia.
[/physics lesson]
it takes more power to initially turn a 25 pound wheel-tire combination than it does 20 pounds. I think he said that.
Originally Posted by Wired 24/7
The issue is not really weight alone. But also where the weight is located.
An object's "moment of inertia (I) " (Think of it as resistance to torque) follows the following relationship:
(I) is proportional to (mass) x (radius)² . I=MR² might be true for something like a uniform metal disc, but wheels do not have uniform weight distribution. They are heavier towards the outside, where the tire is located.
So you are putting rubber out at 9.5" Radius compared to 9" radius, which is essentially a 10% increase in moment of inertia (rough estimate) even at the same mass.
You can feel it, going from 18 to 19. (Even if the wheels are about the same weight as stock). It feels slower. I can't vouch for the FI guys, but for a stock motor Z like mine, you can feel it.
Especially since my tires are much much wider than before, so even if the metal from the rims was lighter (and volks shouldn't be all THAT heavy...) then the extra rubber weighs a TON. To top it all off, all that extra rubber is at the MAXIMUM radius, which corresponds to a big increase in moment of inertia.
[/physics lesson]
An object's "moment of inertia (I) " (Think of it as resistance to torque) follows the following relationship:
(I) is proportional to (mass) x (radius)² . I=MR² might be true for something like a uniform metal disc, but wheels do not have uniform weight distribution. They are heavier towards the outside, where the tire is located.
So you are putting rubber out at 9.5" Radius compared to 9" radius, which is essentially a 10% increase in moment of inertia (rough estimate) even at the same mass.
You can feel it, going from 18 to 19. (Even if the wheels are about the same weight as stock). It feels slower. I can't vouch for the FI guys, but for a stock motor Z like mine, you can feel it.
Especially since my tires are much much wider than before, so even if the metal from the rims was lighter (and volks shouldn't be all THAT heavy...) then the extra rubber weighs a TON. To top it all off, all that extra rubber is at the MAXIMUM radius, which corresponds to a big increase in moment of inertia.
[/physics lesson]
When i went up to 19's (at the time my car was NA) I could feel a difference....as if I had a 400 lb passenger. Now that I have so much more power, I may go back to 18's to take even more advantage of the TT. It's a monster now, but will be even more so on 18's. 19's look great, but the right 18 can look damn good as well.
Originally Posted by davidv
What the professor said is...
it takes more power to initially turn a 25 pound wheel-tire combination than it does 20 pounds. I think he said that.
it takes more power to initially turn a 25 pound wheel-tire combination than it does 20 pounds. I think he said that.
The real point is that even if you were to DECREASE MASS, but also INCREASE RADIUS, it could be harder to turn as well.
With aftermarket wheels, you will most likely be putting a wider tire on the new rims. Then if you go from 18s to 19s, you are pushing that extra weight from the wider tires out approximately an extra 1/2" radius.
Even if the new mass of the rims is less than stock, the bigger difference occurs from the radius effect.
Originally Posted by Wired 24/7
The issue is not really weight alone. But also where the weight is located.
An object's "moment of inertia (I) " (Think of it as resistance to torque) follows the following relationship:
(I) is proportional to (mass) x (radius)² . I=MR² might be true for something like a uniform metal disc, but wheels do not have uniform weight distribution. They are heavier towards the outside, where the tire is located.
So you are putting rubber out at 9.5" Radius compared to 9" radius, which is essentially a 10% increase in moment of inertia (rough estimate) even at the same mass.
You can feel it, going from 18 to 19. (Even if the wheels are about the same weight as stock). It feels slower. I can't vouch for the FI guys, but for a stock motor Z like mine, you can feel it.
Especially since my tires are much much wider than before, so even if the metal from the rims was lighter (and volks shouldn't be all THAT heavy...) then the extra rubber weighs a TON. To top it all off, all that extra rubber is at the MAXIMUM radius, which corresponds to a big increase in moment of inertia.
[/physics lesson]
An object's "moment of inertia (I) " (Think of it as resistance to torque) follows the following relationship:
(I) is proportional to (mass) x (radius)² . I=MR² might be true for something like a uniform metal disc, but wheels do not have uniform weight distribution. They are heavier towards the outside, where the tire is located.
So you are putting rubber out at 9.5" Radius compared to 9" radius, which is essentially a 10% increase in moment of inertia (rough estimate) even at the same mass.
You can feel it, going from 18 to 19. (Even if the wheels are about the same weight as stock). It feels slower. I can't vouch for the FI guys, but for a stock motor Z like mine, you can feel it.
Especially since my tires are much much wider than before, so even if the metal from the rims was lighter (and volks shouldn't be all THAT heavy...) then the extra rubber weighs a TON. To top it all off, all that extra rubber is at the MAXIMUM radius, which corresponds to a big increase in moment of inertia.
[/physics lesson]
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[QUOTE=ZZtopp]Good post. It's not just about weight, but intertia.
Inertia, in the sense that we care, is how much power it takes to turn the wheels. If the weights of 2 given wheel/tires combos are the same, but the weight of one is farther out on the edge of the wheel/tire, then it takes more torque to spin that wheel than the one with the weight located more toward the center. So the "r squared" part of the equation has a huge influence due to the squared factor.
The more I look at this, the more I want to go with lightweight wheels and light tires.
Inertia, in the sense that we care, is how much power it takes to turn the wheels. If the weights of 2 given wheel/tires combos are the same, but the weight of one is farther out on the edge of the wheel/tire, then it takes more torque to spin that wheel than the one with the weight located more toward the center. So the "r squared" part of the equation has a huge influence due to the squared factor.
The more I look at this, the more I want to go with lightweight wheels and light tires.
[QUOTE=jjellyneck]
Yep... ever notice why the japanese tuners run not only lightweight wheel/tire combos but ALSO SMALLER OVERALL DIAMETERS? In the best motoring video testing the Z's from Boss, Mine's and Esprit notice that they all run wheel diameters more than 1" smaller than stock? The Boss and Mine's use 265/35/18
Performance impact of doing this is two-fold: lower diameter effectively increases final drive ratio AND there is significant savings in inertial resistance
Originally Posted by ZZtopp
Good post. It's not just about weight, but intertia.
Inertia, in the sense that we care, is how much power it takes to turn the wheels. If the weights of 2 given wheel/tires combos are the same, but the weight of one is farther out on the edge of the wheel/tire, then it takes more torque to spin that wheel than the one with the weight located more toward the center. So the "r squared" part of the equation has a huge influence due to the squared factor.
The more I look at this, the more I want to go with lightweight wheels and light tires.
Inertia, in the sense that we care, is how much power it takes to turn the wheels. If the weights of 2 given wheel/tires combos are the same, but the weight of one is farther out on the edge of the wheel/tire, then it takes more torque to spin that wheel than the one with the weight located more toward the center. So the "r squared" part of the equation has a huge influence due to the squared factor.
The more I look at this, the more I want to go with lightweight wheels and light tires.
Performance impact of doing this is two-fold: lower diameter effectively increases final drive ratio AND there is significant savings in inertial resistance
btw just wanted to mention - i don't practice what i preach since i run 19x8.5/19x9.5... but in hindsight, i would run 18s all around with small overall diameters
VDC will be fine as long as you preserve F/R stagger
Sure the speedo will be off, but what mod can help you change final drive, increase acceleration AND save money at the same time (18" wheels and tires are cheaper than 19s)
VDC will be fine as long as you preserve F/R stagger
Sure the speedo will be off, but what mod can help you change final drive, increase acceleration AND save money at the same time (18" wheels and tires are cheaper than 19s)
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I barely even noticed the performance difference between the 17s and 19s. I have 19x9F and 19x10R. Prob made a difference in mpg tho. Get some light weight 19s and u'll be fine.. Id avoid the crap brand tho.
Originally Posted by guppies211
I barely even noticed the performance difference between the 17s and 19s. I have 19x9F and 19x10R. Prob made a difference in mpg tho. Get some light weight 19s and u'll be fine.. Id avoid the crap brand tho.
believe what you will ... but i gurantee your car is slower than before in overall acceleration
Originally Posted by defex
Doesn't the extra grip with the wider tire help performance though? No one is taking that into consideration. This is the reason high performance cars go with wider tires..is it not?
unless of course your idea of acceleration is just 1/4 mile times and trap speeds
while traction is a great thing, wide tires presents another hinderence: rolling resistance... again, if you're talking 1/4 mile times there's going to be a "sweet spot" where 1/4 mile times are going to benefit from traction but after that, rolling resistance and tire weight will take over and your 1/4 mile times will go down
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From: new orleans
Originally Posted by Strife350z
tires improve traction... not acceleration
unless of course your idea of acceleration is just 1/4 mile times and trap speeds
while traction is a great thing, wide tires presents another hinderence: rolling resistance... again, if you're talking 1/4 mile times there's going to be a "sweet spot" where 1/4 mile times are going to benefit from traction but after that, rolling resistance and tire weight will take over and your 1/4 mile times will go down
unless of course your idea of acceleration is just 1/4 mile times and trap speeds
while traction is a great thing, wide tires presents another hinderence: rolling resistance... again, if you're talking 1/4 mile times there's going to be a "sweet spot" where 1/4 mile times are going to benefit from traction but after that, rolling resistance and tire weight will take over and your 1/4 mile times will go down