17s vs 18s
1st Gear
Joined: Jan 2005
Posts: 128
RE: 17s vs 18s
ORIGINAL: Nickel_5000tq
When you change wheels you better (must) keep the same diameter. But 16 on small cars use already very low profile tires. And if you go bigger the tire should be lower profile to keep diameter .
See tire calculator http://www.miata.net/garage/tirecalc.html
So bigger wheels might need same profile tires then the diam ll be bigger. Bigger diam means you loss torque, Hp, cause it ll be harder to do the same work.
Bigger with smaller profile means you keep the same performance (same diameter) but the ride ll be harder and maybe less fun.
When you change wheels you better (must) keep the same diameter. But 16 on small cars use already very low profile tires. And if you go bigger the tire should be lower profile to keep diameter .
See tire calculator http://www.miata.net/garage/tirecalc.html
So bigger wheels might need same profile tires then the diam ll be bigger. Bigger diam means you loss torque, Hp, cause it ll be harder to do the same work.
Bigger with smaller profile means you keep the same performance (same diameter) but the ride ll be harder and maybe less fun.
for the most part your right, but at the same time your a bit wrong. if you go to a 17in that weighs say20 lbs to a 18 that weighs 17lbs you are losing weight(not counting tires) true, BUT the majority of the weight of the wheel is moved further from the center of rotation, the farther you move the rotating mass outwards(from center of rotation) the more power it will take to rotate the wheel. although the difference really is insignifigant(can't hardly feel it) you are still losing power.
just something to keep in mind.
1st Gear
Joined: Jan 2005
Posts: 128
RE: 17s vs 18s
on a dyno you can see a difference, but like i said you will probibly not even notice it at all.
you would have to figure it out mathmatically, compare the weight of the 17 compared to the weight of the 18, and somehow figure in the change of distance from the center of rotation, but i suck at math and i think the only real way to figure out specifics would be to take apart the wheel, which is really only possible with a 2(+) part wheel or with a sawzall.
but yeah its really not gonna make any noticable difference unless you went to like dubs that weigh 50lbs a corner lol.
you would have to figure it out mathmatically, compare the weight of the 17 compared to the weight of the 18, and somehow figure in the change of distance from the center of rotation, but i suck at math and i think the only real way to figure out specifics would be to take apart the wheel, which is really only possible with a 2(+) part wheel or with a sawzall.
but yeah its really not gonna make any noticable difference unless you went to like dubs that weigh 50lbs a corner lol.