Rims size, change in performance Options

[gnetik]

hey guys, I was just wondering, how much difference would you feel between using stock 15 inch rims and 17 inch rims (not chrome or lightweight performance) such as the adr gt sports? Anybody who switched from stocks to 17 inchers, please tell me what difference you felt (how much slower). Also, anybody with track experience, what is the difference in quarter mile from stock 15 inchers and 17 inchers? Anybody with input please........uh.. input? haha! yeah, well thanks! (sorry if this is stupid question)

[jgreening]

If you keep the outside diameter of the tires the same, there is no difference in gearing or speed. The biggest difference in larger wheels is that the smaller sidewalls on the tires make the feel stiffer which is great for the corners but does give a little bit more bumpy ride on marginal roads.

P.S. Its not a stupid question.

[Coomer]

There is actually a difference in speed, since some rims are lighter than others. That's why people often spend large amounts of money for lightweight rims for their cars.

[jgreening]

True but he didn't mention weight - only size.

[gnetik]

oh, I see. The reason I asked was because I want to raise( yes I said raise haha!) my car a bit since it is lowered 1.75 inches in the front and 1.5 in the back. Where I live,
It is not fun driving a lowered car anymore. The problem is that I want to raise my car, but not have an ugly gap. If I get bigger rims, I'm concerned of my performance, cuz I'm just happy the way it is it right now.

[CheesyLobster]

Actually, acording to physics and the laws of enersa, if you have 2 wheels, both th exact same weight, and accelerate them, the wheel with the majority of its mass located at the center will accellerate faster. This is because the weight is at the center and is easier to start to move. So, you will have higher speeds with lighter tires, but also with smaller tires, even if they were the same weight.

I just got the Mortegi rx5s, which are 17inch, 19lbs rims, about 6 ponds lighter than stock (i believe) and i think that i notice a bit more speed.

[jgreening]

Cheesy, your science is correct but the "more speed" is likely in your head. The "theory" we are talking about here translates to negligable effects in a low powered, street driven car. The weight game is played by serious draggers who are looking for a few tenths or even a few hundredths at the track. Do you really think that losing 24 lbs off your a stock ST is going to make it run noticably faster? I think sometimes we get a part to mod our car and we want so much for the performance to be better that we fool ourselves.

I am sure the rims look good though

P.S. its "inertia"

[Coomer]

Cheesy, your science is correct but the "more speed" is likely in your head.  The "theory" we are talking about here translates to negligable effects in a low powered, street driven car.  The weight game is played by serious draggers who are looking for a few tenths or even a few hundredths at the track.  Do you really think that losing 24 lbs off your a stock ST is going to make it run noticably faster?  I think sometimes we get a part to mod our car and we want so much for the performance to be better that we fool ourselves.

I am sure the rims look good though 

P.S. its "inertia"
[right][snapback]254550[/snapback][/right]

It's not just losing 24 lbs. though. It's losing 24 lbs. of rotating mass, which equates to bigger gains than removing 24 lbs. from the rest of the car.

[jgreening]

Cheesy, your science is correct but the "more speed" is likely in your head.  The "theory" we are talking about here translates to negligable effects in a low powered, street driven car.  The weight game is played by serious draggers who are looking for a few tenths or even a few hundredths at the track.  Do you really think that losing 24 lbs off your a stock ST is going to make it run noticably faster?  I think sometimes we get a part to mod our car and we want so much for the performance to be better that we fool ourselves.

I am sure the rims look good though 

P.S. its "inertia"
[right][snapback]254550[/snapback][/right]

It's not just losing 24 lbs. though. It's losing 24 lbs. of rotating mass, which equates to bigger gains than removing 24 lbs. from the rest of the car.
[right][snapback]254558[/snapback][/right]

I understand. But its still a ST... Lets return from theory and enter the real world here.

[Coomer]

Cheesy, your science is correct but the "more speed" is likely in your head.  The "theory" we are talking about here translates to negligable effects in a low powered, street driven car.  The weight game is played by serious draggers who are looking for a few tenths or even a few hundredths at the track.  Do you really think that losing 24 lbs off your a stock ST is going to make it run noticably faster?  I think sometimes we get a part to mod our car and we want so much for the performance to be better that we fool ourselves.

I am sure the rims look good though 

P.S. its "inertia"
[right][snapback]254550[/snapback][/right]

It's not just losing 24 lbs. though. It's losing 24 lbs. of rotating mass, which equates to bigger gains than removing 24 lbs. from the rest of the car.
[right][snapback]254558[/snapback][/right]

I understand. But its still a ST... Lets return from theory and enter the real world here.
[right][snapback]254559[/snapback][/right]

Regardless of a car's power, removing 24 lbs. of rotating mass is a good thing that will result in quicker acceleration/braking.

[jgreening]

Cheesy, your science is correct but the "more speed" is likely in your head.  The "theory" we are talking about here translates to negligable effects in a low powered, street driven car.  The weight game is played by serious draggers who are looking for a few tenths or even a few hundredths at the track.  Do you really think that losing 24 lbs off your a stock ST is going to make it run noticably faster?  I think sometimes we get a part to mod our car and we want so much for the performance to be better that we fool ourselves.

I am sure the rims look good though 

P.S. its "inertia"
[right][snapback]254550[/snapback][/right]

It's not just losing 24 lbs. though. It's losing 24 lbs. of rotating mass, which equates to bigger gains than removing 24 lbs. from the rest of the car.
[right][snapback]254558[/snapback][/right]

I understand. But its still a ST... Lets return from theory and enter the real world here.
[right][snapback]254559[/snapback][/right]

Regardless of a car's power, removing 24 lbs. of rotating mass is a good thing that will result in quicker acceleration/braking.
[right][snapback]254613[/snapback][/right]

You're right Coom.

I don't mean to be argumentatitve but let me put this another way. Lets assume gnetik was interested in some Racing Hart CR's (I heard they look good ). Racing Hart makes both one piece regular weight CR's which you can get for about $1000 shipped and forged three piece light racing rims for about $2500 shipped. Assuming he had $2500 to spend on performance upgrades, would you recommend the three piece (minor cosmetic differences aside) or would you recommend the one piece and putting the other $1500 into other performance modifications (e.g. turbo)?

My point here is that everything needs to be kept in context and an owner of an ST that isn't going to be HEAVILY modded with a price-is-no-object mentality should not be encouraged to spend money on light racing rims for "performance" reasons. I am curious if you agree.

Jay

This post has been edited by jgreening: Mar 8, 2005 - 10:02 PM

[Coomer]

Well yeah, I wouldn't drop $2,500 on those wheels. But they do make cheap, light wheels, like Rotas.

[Mr_E]

Removing rotational mass is a very very very good thing indeed. Removing unsprung mass is also a very very good thing indeed.

Light wheels are excellent, and well worth the money for a performance car.

Well yeah, I wouldn't drop $2,500 on those wheels. But they do make cheap, light wheels, like Rotas.
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I did.

They didn't fit.

[Coomer]

Why didn't they fit on your car Mr. E?

[Hanyo]

remember coomer.. it had problems clearing the gt4 calipers

[gnetik]

Oh, I see, so what all you guys are sayin is that it takes less torque or twisting force to rotate lighter wheels which leads to better acceleration, but lightweight wheels just cost too much? Also, Cheesy, you said -"I just got the Mortegi rx5s, which are 17inch, 19lbs rims, about 6 pounds lighter than stock (i believe) and i think that i notice a bit more speed." - You meant motegi right? And they are 6 pounds lighter than stock(even though it's 17 inch?)? Can anyone confirm this?- would the 19 pound motegi rx5 17 inch count as a perfromance wheel?- Ohhhhh I like this, this is interesting.

[Coomer]

remember coomer.. it had problems clearing the gt4 calipers
[right][snapback]254809[/snapback][/right]

Oh yeah...I wish I had that problem.

[Mr_E]

remember coomer.. it had problems clearing the gt4 calipers
[right][snapback]254809[/snapback][/right]

Oh yeah...I wish I had that problem.
[right][snapback]254879[/snapback][/right]

Heh. At the time I was rather annoyed. Tried a 10mm spacer, and no joy.

[Consynx]

well i dont know if motegi's are the best for things such as autocrossing because i dont recall anyone using them there.

19lbs is not too light, but it is a step in the right direction.

there should be many more 15lb wheels out there now, and it's not always the diameter that matters, but also the width
the stock wheel is a 7"
try getting a 8"

oh yea, although www.wheelmax.com has good prices and such, if you are raising your car due to road conditions you may want to ask around before you buy, or search google because i've read about certain wheels from there bending easily

[Kwanza26]

I don't know where you guys are getting your stock wheel weights from... but stock 15in alloys probably doesn't weigh more than 18 pounds a piece... and that's the very max. I'd bet they're only about 15-16 pounds.

Basically... if you're getting wheels over 17 inches... they're not gonna be performance lightweight wheels unless you're paying over 2g's for them... the cheapest may be some kosei k1s which can still weight as much as 17-18 pounds in 17 inches. If you want lightweight wheels... 7th gen GTS wheels are nice and light... that, or get some 5x114.3 camry hubs pressed onto your spindles and buy some Rotas.