So.. Does it.. I've decided that within the next few months .. i will be purchasing the 17" Tenzo-R AV-7's in GM... i believe they are 19lbs ea. Will I be able to notice a very large difference in overall power to the wheels?
K
p.s. here it is in the form of photochop..
yes wheel weight does matter. I wish I never got mine. I have 17's, they weigh 18.5lbs..may as well be 19lbs. They suck. My best 1/4 mile was 15.5 with i/h/e (intake is cai) when I had stock wheels/tires with sri and hp header I got a 15.5 at a higher mph than with the 17's.
Not only does weight matter, but size, more size, more rotational mass=slower acceleration.
damn.. thats depressing.. i really dont want to sacrafice performance a great deal, yet i love the look of the 17" rims.. and is the difference only going to be a .5 sec at the track? if so im willing to sacrafice..i think
Last edited by Vivid-Cruz; 10-12-2003 at 10:35 PM.
if you keep the same diameter as stock will it be okay?Originally posted by 02SilverSiHB
yes wheel weight does matter. I wish I never got mine. I have 17's, they weigh 18.5lbs..may as well be 19lbs. They suck. My best 1/4 mile was 15.5 with i/h/e (intake is cai) when I had stock wheels/tires with sri and hp header I got a 15.5 at a higher mph than with the 17's.
Not only does weight matter, but size, more size, more rotational mass=slower acceleration.
Formerly known as Plainol2k2si
no, the more rotational mass you get from the 17" rims will still slow you down compared to a stock size rim. as an example...a totally stock si with falken azenis was catching up with me at the end of the 1/4 mile just because the 17's I have. If the 1/4 mile had been longer he would have eventually caught up.Originally posted by plainol2k2si
if you keep the same diameter as stock will it be okay?
But if you don't care about .5 sec in the 1/4 mile go for it. It won't be that noticeable. people will argue that for autocrossing that a 17" doesn't hurt as long as it's light weight.
Overall, I stick with what I said before, I wish I had just stayed with 16's at the most.
what about a 17" wheel and tire combo that weighs less than a stock 15" wheel and tire combo? :D who's mass is higher, then?Originally posted by 02SilverSiHB
no, the more rotational mass you get from the 17" rims will still slow you down compared to a stock size rim. as an example...a totally stock si with falken azenis was catching up with me at the end of the 1/4 mile just because the 17's I have. If the 1/4 mile had been longer he would have eventually caught up.
But if you don't care about .5 sec in the 1/4 mile go for it. It won't be that noticeable. people will argue that for autocrossing that a 17" doesn't hurt as long as it's light weight.
Overall, I stick with what I said before, I wish I had just stayed with 16's at the most.
the problem then is finding inexpensive sticky tires at 17"...
Last edited by glw; 10-13-2003 at 11:06 PM.
There's three factors to consider.
One, obviously is the wieght of the wheel/tire combo (regardless of size) does matter a bit. When I put my stock setup back on, I almost stall because I have to give it more gas to get going, compared to my aftermarket set. You will notice a difference if you drop say 5 or more lbs from the stock wheel/tire weight.
Two, is overall diameter. Anyone with 15" azenis is running almost 1" shorter overall diameter (hence they look somewhat winky) because thats the only 15" azenis offered. That shorter diameter will give a boost in accleration because it alters the gearing of the car, however it also sacrifices the tops speed by about 4%. With Azenis, when your speedo says 100mph, you're actually going 96mph. That same factor also means you shift at a 6% lower speed, too.
Finally, there's grip to consider. Though the Azenis are not drag tires, thier grip rating makes them a better-than-average tire for occasional 1320's, especially in launching.
My advise is to plan your wheel/tire combo around maintaining at the most the same of the stock setup.
how much does the stock wheel/tire combo weigh?
About 40 pounds. The wheels are heavy (about 19.5 pounds), but the tires are relatively light, because of their size. Also, because the wheels are 15s, most of their rotating mass is closer to the center. A 19 pound 15 is not going to feel the same as a 19 pound 17.
My 15" Superleggeras are 10.5 pounds each, 32 pounds with tire. Plus, there's enough rubber that I'm not worried about denting a rim.
Just adding on... a lightweight 17" wheel may be better than a heavy-ass 15" wheel. But what if you got a similar lightweight 15" wheel? What if you got a 15" and a 17" that weighed exactly the same? Your rotational mass is farther out on a 17" wheel than a 15" wheel. I think that affects your performance as well.
Not too sure that the Azenis would make for a good drag tire. They have incredibly stiff sidewalls which may make traction at launch a bit trickier than a tire that flexes a little more to give you that contact patch you need. I don't drag race, but I think that this is why dragracers run really low pressures in the front. What the Azenis are good for is turn-in response and max lateral grip.
nicely put:)Originally posted by bobdobbs
Also, because the wheels are 15s, most of their rotating mass is closer to the center. A 19 pound 15 is not going to feel the same as a 19 pound 17.
wouldn't it be similar to inertia ... say like if you were spinning on a disc. you spin faster with your arms close to your body than you would if you spin with both arms extended. you weigh the same, but the more mass you put further away from the axis, the harder it is to get that mass spinning. or am I way off base here?Originally posted by 02SilverSiHB
no, the more rotational mass you get from the 17" rims will still slow you down compared to a stock size rim. as an example...a totally stock si with falken azenis was catching up with me at the end of the 1/4 mile just because the 17's I have. If the 1/4 mile had been longer he would have eventually caught up.
But if you don't care about .5 sec in the 1/4 mile go for it. It won't be that noticeable. people will argue that for autocrossing that a 17" doesn't hurt as long as it's light weight.
Overall, I stick with what I said before, I wish I had just stayed with 16's at the most.
Originally posted by Tenacious G
wouldn't it be similar to inertia ... say like if you were spinning on a disc. you spin faster with your arms close to your body than you would if you spin with both arms extended. you weigh the same, but the more mass you put further away from the axis, the harder it is to get that mass spinning. or am I way off base here?
Definately... Spinning wheels also act as a sort of "gyroscope" on the car. The gyroscopic effect of big, heavy wheels would also offer a small amount of inertial resistance when the car wants to change direction.
Also the rotational inertia of larger, heavier wheels affects braking too. Big brakes are great, but the fact that you have to run 18's to fit them steals away some of the extra braking power.
One more thing. There is still some debate as to whether or not our 4-lugs can even handle wheels 17" and bigger.
My personal opinion on the whole matter: I'm going with a set of lightweight 16"s.
buy the 15inch spoon rims they are mad light, but mad expensive....
i wouldn't dwell over wheel weight as much. After a week or less driving with the 17's you probably won't notice a difference. Even if it would make .1 or less in a 1/4 mile.
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