i wanna do road/ auto-x and looking for best wheels for handling. everyone says 17's will slow you down cuz theyre bigger. my friend just put his 17's on 45 tires next to his 15's on 55 tires and looked to be the same diameter. maybe im missing something but can someone explain why theyre slower?

 

weight is one factor.

 

is that it weight? theyre are penty of lightweight wheels out theyre... please tell me that not it....

 

Its the weight in relation to the center of rotation. The further away from the center of rotation, the more it effects you for the worse.

And its not only the wheels themselves that add weight further away from the center, but the tires you put on them as well are much further out as well.

 

well if thay are same overall diameter, then why would it be different?

ex: a 15 in. wheel and tire weighs 25lbs and a 17 in. wheel and tire weigh 25lbs. your saying that the 17 in. will still hinder performance over the 15??
edit: these are with the same diameters too

 

simply put, its more rotating mass.


Rob

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rjardy &raquo;</TD></TR><TR><TD CLASS="quote">simply put, its more rotating mass.Rob</TD></TR></TABLE>

that doesn explain anything. how is it more rotating mass if they are same weight and diameter?

 

u can get 17 inch center lines that weigh 12 pounds, or some hx 13's that weigh 11.5, but if u have 17's that weigh 25 pounds, and 13's that are 11.5 pounds,, u will loose about 3 hp with the 17's, it was in sport compact car,,, better yet get a hatch with ls/vtec or a h22a trubo n get some 26's slicks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JunIntegra &raquo;</TD></TR><TR><TD CLASS="quote">well if thay are same overall diameter, then why would it be different?

ex: a 15 in. wheel and tire weighs 25lbs and a 17 in. wheel and tire weigh 25lbs. your saying that the 17 in. will still hinder performance over the 15??
edit: these are with the same diameters too</TD></TR></TABLE>

In most cases yes, as the weight from the 15" is going to be closer to the center of rotation. In a 17" rim, most of the weight is going to be on the outer loop of the rim. That outer edge is much further away from the center. Where the 15" the weight is going to have the weight tucked closer in to the center.

 

yep listen to style teg. its all about rotational inertia. i wont get to indepth, but look at it this way
torque = force x distance
if the wheels weigh the same then they require the same amount of force to rotate
but with a larger rim, the majority of the wieght is further away from the center of rotation - hence a larger distance
therefore you need more torque to turn the larger wheel, so instead of the torque from you motor going to accerate you car, you have to use some of that torque to overcome turning the larger rim - hence less torque is bring used to accelerate your car
does that make sense. if not lemme know, im sure i can explain it some other way
later

 

it has to do with phisics. research inertia

 

does this also relate to the design to flywheels? why some flywheels will have drilled holes on the more outer portions of the flywheel so that the weight is more near the center?

 

smaller wheels/tires = more torque and less to rotate
larger wheels/tire = harder to get going, but once in motion they keep you going, (possibly have a better top speed) its almost the same as flywheels. If you stick with the stock flywheel it weighs more. But once in motion its to your benefit. Light weight flywheels, you have to rev higher coming off the line and your rpms will still drop sometimes when engaged.

 

ok thanks guys, i understand better now. so what do you guys think is the optimal sized wheel and tire? i want probably a 16" but if 15's are better then ill get.

 

what that guy said about flywheels is completly wrong i hate all this misinformation a lightweight flywheel is harder to launch(debatable not gonna argue though) then a heavier flywheel because a flywheel stores this inertia basically think about it like this if you had a 20lb rock tied to and a rope and you spun it above your head to throw it as far as possible well say then you pick up a 10lb rock with the same length rope to make it go as far as the 20 lb rock your gonna have to start spinning the **** out of it before throwing (stored energy and launching the car) but once the car is underway you have to waste power to rotate something heavy for no reason slowing you down.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JunIntegra &raquo;</TD></TR><TR><TD CLASS="quote">ok thanks guys, i understand better now. so what do you guys think is the optimal sized wheel and tire? i want probably a 16" but if 15's are better then ill get.</TD></TR></TABLE>

Go with the 15s if you are planning to race. They will be lighter (in most cases) and have a better tire selection as well.

 

15's

 

i got 99 ex my suspension set up is eibach springs of 1.3 in alla round wit kyb agx and i have a rear suspension technique sway bar i got the factory 14in wheels on it. i wanna upgrade the wheels for better handling which would be better 15s or 16s? thanx guys and what else would u guys recommned to make the handling better

 

ya i never realy thought about how much of a diff light er wheel/tire combo would do .....
there just cheap *** 15s but they weight in at 8 pounds each...and wow what a diff from my 15 lude si wheels....by far the best mod for power ive done.....ever

 

so what rims do you guys recomend i look into? dont mean to be a jdm ***** but most of these american wheels i see look so ricey. some wheels so far i like are volk te-37's, ce28n's, advan rg's, enkei rpf1's. any others? naybe more affordable?

 

Style teg and burke are both very right. I balance turbine engine parts for a living (much like clutch disks only about$35k each!). Using the radius of the circle (the wheel's diameter divided by 2) times the weight it grows exponetially. One ounce at one inch from center of wheel still weighs one ounce. One ounce at 6 inches from center weighs 6 ounces when spinning. Now use pounds and what Teg and burke says really takes on weight (pun intended!)

 

sounds like you got ahold of it now
check out rota's - cheap, lightweight, and not nearly as expensive to replace as a volk or something.
good luck

 

i just bought some speedmaster rims from marcus @ heeltoeauto.com. look for his thread in the sponsor's section. 15" rims that weigh 10.5 pounds for about $480 a set. i think he said there are only 3 sets left. good luck

 

are u refering to me?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integ 1983 &raquo;</TD></TR><TR><TD CLASS="quote">are u refering to me?</TD></TR></TABLE>

What you said about flywheels is probably right. Removing weight from the outer edge is more effective than removing weight from the center if you want a lower moment of inertia in a flywheel. Lighter flywheels have advantages and disadvantages over heavier ones. Nevertheless, whether or not a lighter flywheel hurts the launch during a drag race is not the point. It is absolutely irrelevant to what everybody's talking about. I'm not sure why omega11855 even brought it up

For heavier wheels, I can't really see them being good for anything. They would not increase top speed, probably just decrease it by an unnoticable amount.


Modified by Lsos at 9:40 AM 11/10/2003