just wondering.... do bigger wheels make the car accelerate slower and stop longer because of the greater rotational inertia??? yes I know big wheels make steering more responsive.. so maybe going from 15 to 16 makes sense.. but 17 and 18???? do some people sacrifice performance for look???

phil

in my opinon..

what u said in ur paragraph was correct. I belive that having over 16" wheelz can decelerate our cars at the get go...not too bad but you can feel it since our cars have a weak motor (talkin ST...not sure about the GT).

remember weight is a big factor in that equation too, and where the weight is centerally located on the rim, whether it be on the outer diameter or centered more in the middle of the rim... but your overall assumption is correct.

I've heard that you can go up to 17s without sacrificing exceleration.

--Neipas09+Apr 13, 2003 - 12:38 AM

QUOTE (Neipas09 @ Apr 13, 2003 - 12:38 AM)

I've heard that you can go up to 17s without sacrificing exceleration.

if you are willing to do the math and figure out what setup would relate to the ideal rim diameter/width/centripital force and acceleration/ tangential force and acceleration/ any other relivant equation and find a rim that matches the specs you are looking for then yes, you can go up to 17s w/o sacrificing performance... but to flat out say that you can go to 17s without sacrificing performance is false. i know first hand, i lost alot of acceleration when i went to my 17" enkeis.

There's an explanation for bigger wheels=slower cars that i've discussed with a shellow(female car enthusiast). I'll find it and post here if it's still there. gimme a moment

--K2_Celica+Apr 12, 2003 - 10:45 PM

QUOTE (K2_Celica @ Apr 12, 2003 - 10:45 PM)

--Neipas09+Apr 13, 2003 - 12:38 AM QUOTE (Neipas09 @ Apr 13, 2003 - 12:38 AM) I've heard that you can go up to 17s without sacrificing exceleration. if you are willing to do the math and figure out what setup would relate to the ideal rim diameter/width/centripital force and acceleration/ tangential force and acceleration/ any other relivant equation and find a rim that matches the specs you are looking for then yes, you can go up to 17s w/o sacrificing performance... but to flat out say that you can go to 17s without sacrificing performance is false. i know first hand, i lost alot of acceleration when i went to my 17" enkeis.

Man you sound like an extra from "star trek".>>

I'm wearing 17"s and I think my standing starts would
be compromised even more if it wasn't for my 4 wheel drive...

This post has been edited by jontechie: Apr 13, 2003 - 9:18 AM

Our cars don't have enough torque to sufficiently push 17, 18 and 19 inch wheels...so it slows us down..(talkin about STs here) >>

hey maybe I worry too much...

let me think about it again.. that little extra inertia at the perimeter of the wheel would be nothing comparing to the inertia of the 2700lb car acting on the tire..

just think about it... if you were to cruise down the road and drop the clutch.. what keeps the wheels spining is the inertia of the car acting on the tires acting on the wheels.. so what is that extra 20lbs for a beefier set of wheels??? you can compensate for that by losing weight.. (or picking a skinnier rider..>> )

phil

--pflau+Apr 13, 2003 - 11:21 AM

QUOTE (pflau @ Apr 13, 2003 - 11:21 AM)

hey maybe I worry too much... let me think about it again.. that little extra inertia at the perimeter of the wheel would be nothing comparing to the inertia of the 2700lb car acting on the tire.. just think about it... if you were to cruise down the road and drop the clutch.. what keeps the wheels spining is the inertia of the car acting on the tires acting on the wheels.. so what is that extra 20lbs for a beefier set of wheels??? you can compensate for that by losing weight.. (or picking a skinnier rider..>> ) phil

hahahaha, youre right about a skinnier rider....when i have 1 or 2 people in the car, i can feel the thing fighting like hell to speed up >> It's so much quicker feeling when its just me- im only 150 pounds.

--pflau+Apr 13, 2003 - 11:21 AM

QUOTE (pflau @ Apr 13, 2003 - 11:21 AM)

hey maybe I worry too much... let me think about it again.. that little extra inertia at the perimeter of the wheel would be nothing comparing to the inertia of the 2700lb car acting on the tire.. just think about it... if you were to cruise down the road and drop the clutch.. what keeps the wheels spining is the inertia of the car acting on the tires acting on the wheels.. so what is that extra 20lbs for a beefier set of wheels??? you can compensate for that by losing weight.. (or picking a skinnier rider..>> ) phil

i disagree. the best place to save weight is in moving parts on your car. so take wheels. your car will be faster if you lose 20 lbs in the wheels vs. 20 lbs in the hood, fenders, seats, gut, etc.
reason: if you jacked up your car and had no restriction on your wheels they would spin slower with heavier wheel that with lighter ones. the moment of interia increases with a heavier wheel. it also increases when the weight is concentrated farther from the center of the wheel. so not only does a heavy wheel slow you down just like a heavy hood or a heavy you does, but it also robs power straight from the engine.

But its not the wheel diameter that matters, its the overall height (and weight) of the tire/wheel package, an 18" wheel with a 35 series tire could be the same overall height as a stock 205-55-15 and might weigh more or less, depending on brand, as long as the weight and overall diameter are the same, it should make no difference in acceleration. (other than maybe better traction with a hi-perf tire) there is a lot of variation in weight between brands of both tires and wheels. thats how Centerline got so popular in the streetrod market, they had one of the lightest, strongest wheels available, (ugly though),,,The old original Cragar Mags looked good, but they were HEAVY!
You also need to remember, the wheels are UNSPRUNG weight, vs the body/eng/trans being SPRUNG weight (meaning they sit ON the springs), the less UNSPRUNG weight the better. Say you hit a bump, if the wheel/tire/spindle assembly weighs 50lbs rather than 40, more of the energy from the bump will be tranferred to the body thru the spring, giving a rougher ride, worse handling. with lighter wheel/tire setup, the shocks and springs can control the bumps better since there is less moving mass. (this is actually where drilling the rotors started, they were looking for less unsprung weight)

i have tenzoR's apex-5 18's and i cant really tell a difference besides in my handling. i did have 15's b4.

What about 16s ?? I have the gts rims. I used the miata calculator thing and i only have a 1.3% difference in the speedometer. I'm just curious; would getting 17s or 18s make the car handle differently?

--97GTinKC+Apr 18, 2003 - 9:40 PM

QUOTE (97GTinKC @ Apr 18, 2003 - 9:40 PM)

(this is actually where drilling the rotors started, they were looking for less unsprung weight)

what are you talking about.. drilled rotors are for heat dissipation.

--97GTinKC+Apr 18, 2003 - 11:40 PM

QUOTE (97GTinKC @ Apr 18, 2003 - 11:40 PM)

But its not the wheel diameter that matters, its the overall height (and weight) of the tire/wheel package, an 18" wheel with a 35 series tire could be the same overall height as a stock 205-55-15 and might weigh more or less, depending on brand, as long as the weight and overall diameter are the same, it should make no difference in acceleration. (other than maybe better traction with a hi-perf tire) there is a lot of variation in weight between brands of both tires and wheels. thats how Centerline got so popular in the streetrod market, they had one of the lightest, strongest wheels available, (ugly though),,,The old original Cragar Mags looked good, but they were HEAVY! You also need to remember, the wheels are UNSPRUNG weight, vs the body/eng/trans being SPRUNG weight (meaning they sit ON the springs), the less UNSPRUNG weight the better. Say you hit a bump, if the wheel/tire/spindle assembly weighs 50lbs rather than 40, more of the energy from the bump will be tranferred to the body thru the spring, giving a rougher ride, worse handling. with lighter wheel/tire setup, the shocks and springs can control the bumps better since there is less moving mass. (this is actually where drilling the rotors started, they were looking for less unsprung weight)

very true, except the crossdrilled/slotted rotor part.

--hioctane+Apr 19, 2003 - 1:01 AM

QUOTE (hioctane @ Apr 19, 2003 - 1:01 AM)

What about 16s ?? I have the gts rims. I used the miata calculator thing and i only have a 1.3% difference in the speedometer. I'm just curious; would getting 17s or 18s make the car handle differently?

it all depends what kinda rubber you get, and what the change in width is.

This has to be the best tech discussion 6gc has ever had! hahaha!

--K2_Celica+Apr 19, 2003 - 7:47 AM

QUOTE (K2_Celica @ Apr 19, 2003 - 7:47 AM)

This has to be the best tech discussion 6gc has ever had! hahaha!

LOL. I had the same thought while reading this thread.

just remeber that if change you wheel you have to get a tire that make the wheelandtire the same height as your stock tire and wheels. cause if you don't your speedomiter will be off.

--K2_Celica+Apr 19, 2003 - 7:47 AM

QUOTE (K2_Celica @ Apr 19, 2003 - 7:47 AM)

--hioctane+Apr 19, 2003 - 1:01 AM QUOTE (hioctane @ Apr 19, 2003 - 1:01 AM) What about 16s ?? I have the gts rims. I used the miata calculator thing and i only have a 1.3% difference in the speedometer. I'm just curious; would getting 17s or 18s make the car handle differently? it all depends what kinda rubber you get, and what the change in width is. This has to be the best tech discussion 6gc has ever had! hahaha!

Yeah i put in the width, wheel size and everything in the calculatator thing.

QUOTE

what are you talking about.. drilled rotors are for heat dissipation.

maybe now it is, 25 years ago we were drilling them for less weight, on bikes mostly...dont remember anyone doing it for better heat dissipation, not sure anyone had realized that aspect of it yet. even had a few guy want me to cut their new rotors down to the minimum thickness to save a few extra ounces. (Kinda thought that was going a little too far myself)

think of it as a 21 speed mountain bike

first gear= really easy to get going but no top speed that is good
21st gear= really hard to get going but once you do, LOOK OUT!!!

that's my tech for the day.. i'm to the bar.

THE WHOLE REASON FOR BIGGER RIMS IS SO THAT YOU CAN CLEAR BIGGER BREAKS SO YOU CAN STOP FASTER BUT ALONG WITH THIS YOU NEED A ENGINE THAT COMES WITH HIGH HP/ TQ I HAVE 18 AND THEY ARE HEAVIER THAN MY 15'S I COULD SPIN THE CRAP OUT OF THE 15'S NOT THE 18'S WITH 2153518 FALKENS ON THEM IT STICKS TO THE ROAD LIKE GUM

There's no need for the all caps man, just a thought

Anyway, as much as you all are enjoying this tech discussion >>, let's not forget some people put new wheels and tires on their car simply for a different, unique look.

Do most wheel websites show the weight of the wheel? I haven't been able to find that information. I'd like to get some bigger wheels (got little 14" ones now) but I don't want to sacrifice any speed on my powerful ST.

on www.1010tires.com, you get the weight of wheels you buy.
Just make a few searchs, you'll find sites with wheels wheigt.

So from what I've read on all this wheel talk, I would be on the safe side to just get 16's right? I want wheels for a new look, but I am more for speed than a look. Also isn't there something about the less hp you have the skinnier you want the wheel? Like 6.5 would be good for our cars?
By the way whats the wight of the stock wheels on the Celicas?

This post has been edited by 94Toy: Apr 24, 2003 - 11:41 PM

If you want speed, go with Super lightweight wheels such as ssr competition, OZ superleggeras ,rota ...and others, in 15 inchs...mouhahahaha, you'll gain performance over your stock wheels. I think our stock 15 wheels weight around 15 lbs, not sure. Many 17 weight 23 lbs. Superleggeras in 15 weight around 10 lbs...
As I said, when I put my 23 lbs 17s on my gti, I lost around 4 cars length on a 0-160. And this with 180hp-180lbs/in.

http://www.seanet.com/~jgtang/wheel.txt

http://www.jimsnodgrass.com/wheels[1].html

This post has been edited by hi_rider: Apr 25, 2003 - 5:27 AM

I think the stock 15x7 GT wheel is closer to 18 lbs., I sold a set recently and seem to remember 18. I am getting ready to swap a couple of tires around, will post the weight of the stock wheel then.
On my wife's digital bathroom scale, the stock 15x7 wheel with worn Michelin Pilot 205-55-15 is 34.2 lbs. while one with most of its tread left (had one tire replaced) comes in at 36.0 lbs. so wear can change things by a couple of pounds also.
Michelin doesnt list weight on their web site, but Continental does, their Extreme Contact 205-55-15 is 21 lbs. while a 215-40-17 is 20.9 lbs. and the Conti Sport Contact in 225-45-zr16 is 18.9 lbs. while the 265-35zr18 (which is 24.3" tall) is 23.7 lbs. (all tires have the same approx diameter 23.9 for the 1st 3 and 24.3" on the 18), so weight can vary between models and same approx. sizes even in the same brand.
36 lbs is probably a good baseline to start from. If a person stays in the same height range as stock(23.9" diameter) , and the same approx stock weight (36 lbs wheel and tire combo) they could run 17 or 18 inch and probably not lose any performance. As far as the weight being concentrated farther out from the center affecting anything, I think it would be too hard to calculate. does it really make a difference accelerating 2 differently shaped masses of the same overall diameter and weight? I agree if you go taller, you will take a performance hit, (even 1 inch will make a noticeable difference and affect the speedo)
And remember wear can account for a few pounds of rubber, so a few pounds either way probably wont make a noticeable difference.

hey the stock GT 15x7 wheel is about 16lb each. I just weighted it