View Full Version : Will 18s slow me down
darkgt
02-14-2006, 10:21 PM
im thinking about going for 17x8s to 18x9s. should these bigger wheels slow me down much?
BadBlueBird*
02-16-2006, 09:28 AM
Youve got a mustang, how much slower can you go? :rotfl:
:wall: They may help w/ spinning, when I had 18s on the rear I really didnt notice a difference..
darkgt
02-16-2006, 09:33 AM
how much slower can i go?... well i could buy an integra or sumthin.
jimbo98z
02-16-2006, 02:05 PM
Not at all. I know a guy with a 2001 GT that went from stock 16's to Saleen 18's and it really didn't make much of a difference in a straight line, but he already had some suspension mods to reduce wheelhop. It turns noticable better now though.
ss~zoso~ss
02-16-2006, 03:27 PM
it will tho, make your spedometer read slower, so you'll have to get it recallibrated
Vudu2000
02-16-2006, 05:36 PM
It's not the diameter of the rim that will slow you down its the weight. If you go to an 18' rim it takes more metal to make the rim increasing the weight. You will be ok if you use a light weight rim but expect to pay a lot more cash wise. I once had TT2's on my SS and they weigh a ton, my car felt noticably slower and it showed at the track in times and trap speed. The rear would bottom out easily with such a heavy combo of a 17x11 rim and 315's. The shocks and springs couldn't keep the rear tires from flying up in the wheel wells over certain bumps. I finnally payed out the ass for a set of Fikse rims and the problems went away.
darkgt
02-16-2006, 05:48 PM
uh ohh... how much did they slow u down?
Vudu2000
02-16-2006, 05:57 PM
It was a few MPH and a couple tenths. Also, if you don't go with a shorter sidewall on the 18" tire to keep the same diameter as your 17" wheel and tire combo this will also slow you down by effectively giving you longer gears in the rear.
jimbo98z
02-16-2006, 08:41 PM
Honestly, it was probably the fact that you had less give in the sidewall more so than the added weight. Stock wheels are already pretty heavy, I beleive the stock 16" wheel with a tire was right around 42 lbs. Width is also what kills you on weight more so than just diameter
Vudu2000
02-16-2006, 09:57 PM
Honestly, it was the weight. My TT2's and my Fikse were the same sizes. Take a look at rims made specifically for racing and you will find they are extemely light. Nothing kills performance more on a vehical than rotational weight, "unsprung weight". More mass means more horse power to turn it, and more brakes to slow it. For instance, just swapping a steel drive shaft for an aluminum one without any other changes and a car will show more rear wheel horse power on a dyno. Once I got rid of the TT2's for the Fikse I regained my lost performance. The width difference between a 275 and a 315 is only 1.8 inches, not much, where as the weight difference between the stock SS 275/40/17 17x9 wheel and tire combo vs a TT2 17x 11 315/35/17 was over 20lbs per wheel.
wabmorgan
02-17-2006, 01:31 AM
It is the weight of the wheels that counts. BUt that will not affect your speedometer. The speedometer will only get off if you change the diamater of the tire. In other words, the height of the time must stay the same to not throw off the speedometer.
Now, what the weight of the wheels will do will slow you down when it comes to accelertion and even dyno numbers.
Btw, the increased rotational mass will also increase you distance for stopping. (It makes stopping distances longer!!!!!!)
darkgt
02-17-2006, 09:36 AM
dammit.. there 18x9s... would switching to 17x9s help much?
Deeavi
02-17-2006, 09:52 AM
dammit.. there 18x9s... would switching to 17x9s help much?
I have Boyd Coddington Smoothie 2s, 18x9 in the rear and 17x8 in the front.
They are actually lighter than the stock rims. I would not be two concerned about it!
Deeavi
02-17-2006, 09:58 AM
Here you go! I also have a light weight driver. LOL
http://i33.photobucket.com/albums/d52/Deeavi/MyZ.jpg
darkgt
02-17-2006, 10:41 AM
the 17x9s im looking at are 23lbs. and the 18x9s are 28lbs.... would this make much of a difference between the two?
Vudu2000
02-17-2006, 01:46 PM
I doubt you will notice a 5 pound diff, I wouldn't be to concerned.
wabmorgan
02-17-2006, 03:36 PM
The bad news is it is really more like 5lb*8. (*4 for each wheel). In other words, rather than adding 5lb per wheel, you are in effect adding a total of 160lb to the car.
So, is it the end of the world??? No. It's probally going to add about the weight of another person in the car. So, it is probally not that bad. It will have one benefit, the wider tires will grip better:burnout:
csteingraber
02-17-2006, 06:42 PM
Although i agree with you about that 5lbs more per wheel will slow the whole car down about as much as an extra passenger which is about 1/10th on the quarter mile time(which is significant). But wider tires will not help in forward traction much, more in turning traction. the forward traction is more directly improved by length of contact patch front to back and tire compound(stickyness). I want to change wheels and will probably get some bogart road racing wheels with nitto road racing tires for light wheel and tire combo and sticky tires for best lateral and forward traction. If i'm spending on wheels and tires i think it should improve the feel and performance of the car not just the looks, after all it is a lot of money for any set of wheels and tires.
wabmorgan
02-17-2006, 07:12 PM
Sorry... did not relize that you were concerned about 1/4 mile. Yea.... I wouldn't want a "passanger in the car" either, so to speak. I agree with you about keeping the unsprung weight down.
What I really hate to see is some put on 20s or larger and not realize how it will effect braking!!!!!!!!!!!!!
oneBADDz
02-17-2006, 07:20 PM
Although i agree with you about that 5lbs more per wheel will slow the whole car down about as much as an extra passenger which is about 1/10th on the quarter mile time(which is significant). But wider tires will not help in forward traction much, more in turning traction. the forward traction is more directly improved by length of contact patch front to back and tire compound(stickyness). I want to change wheels and will probably get some bogart road racing wheels with nitto road racing tires for light wheel and tire combo and sticky tires for best lateral and forward traction. If i'm spending on wheels and tires i think it should improve the feel and performance of the car not just the looks, after all it is a lot of money for any set of wheels and tires.
wider tires are VERY significant in forward traction
lee1rbc
02-17-2006, 09:12 PM
If you are doing this for looks, go with what you like best. You are prob talking about loosing 8 to 12hp. On a LS1 You wouldn't notice, in a civic si it would feel like you left the emergency brake on, lol.
If you are concerned about 1/4 mile times you want the smallest tire, that still gives you traction. For me switching from 245-50-16 to 275-40-17 gave me a quiker 60ft time .04 avg improvement. But I also had a Dodge that ran a 15flat 1/4. I went to a bigger tire and my 1/4 dropped to 15.2. Since you have a Mustang I am not sure, but I would guess going to a 275-40-17 would be plenty of rubber for a stock car.
csteingraber
02-21-2006, 06:04 AM
wider tires are VERY significant in forward traction
a wider tire will help a little but you are adding a lot of weight of tire with only adding a little contact patch. it's better to get a stickier tire. That's why people running 9.5 inch wide slicks take off a lot better then vette's with street 325's. My point is that it you want your tires to stick get sticky ones! :burnout:
oneBADDz
02-21-2006, 10:30 AM
a wider tire will help a little but you are adding a lot of weight of tire with only adding a little contact patch. it's better to get a stickier tire. That's why people running 9.5 inch wide slicks take off a lot better then vette's with street 325's. My point is that it you want your tires to stick get sticky ones! :burnout:
Oh I agree, didn't mean to sound like I didn't agree about sticky tires you are very right. But why not get WIDER and STICKIER tires. . .mmmmmm. I can feel the whiplash now
Eugenio_SS
02-21-2006, 10:30 PM
fwiw, you get the same area of contact patch, even with a wider tire... the shape of the contact patch is different though.
If you want more traction, get a better compound (stickier tire).
But to answer the question, if you want performance, get the smallest diameter widest wheels you can, as long as it clears your calipers.
18s will slow down since the mass is further from the center... think of it as rotational inertia.
Snake Eater
02-21-2006, 11:44 PM
Does anyone know where I can get info on how much each of the Corvette rims weigh? Or does anyone know in general? zr1, z06, c6, c5?
Jon7I2
05-26-2007, 12:26 AM
Does anyone know where I can get info on how much each of the Corvette rims weigh? Or does anyone know in general? zr1, z06, c6, c5?
Good ?, i am also interested in this
Mr. Luos
05-26-2007, 07:12 AM
http://www.ls1.com/forums/showthread.php?t=51856
jimbo98z
05-26-2007, 11:42 AM
I guess the main thing is whether you will be carving corners or drag racing more often. The big problem with bit wheels is that they leave you with less sidewall to absorb the shock of launching, which means they spin more. An 18" rim on an f-body seems to be the breaking point as far as launching the car.
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