Wheel size? wth

ok why does almost every race car/most spo-coms run on 17" wheels? everyone with 18+ always seem to be jsut for show . cause my stock wheels are 14's and when i mentioned upgrading someone was all like youll go slower with those....so why isnt every race car running on like 12's or something

btw i have a slow ass RS eclipse

Im just gonna speak my mind on this.Seems to work in my head.Here goes,

I think that if you have bigger tires,you might go slower,IF you have a really weak car.And if you have small tires (13 in.) you will go make the tires spin faster. with a weak engine.Its all really in the power that your making in the vehicle.If your making lots of low end torque and horsepower,and your vehicle is capable of putting in some 17's,then go for it.See,its like a bicycle,if you have a really huge rear tire,it will require more power to push right? And you will go a long way with just one revolution of the pedal. Now imagine if your bike had a training wheel for the back tire( about 5 inches ).Wouldnt it be easier to push? But all that easy pushing comes at a price,you wont cover that much area.So when a race car is very powerful,it gets the 17/18 inchers.Its like the middle of tire sizes.They will cover a good area,and they will be easier to turn with the engine.Here is an example.

Get your little brother/sister to get on your adult sized bike.Their bike will have like big 20 inch tires right?
Now,you get on your small child sized bike(About 10 inch tires there).Now imagine that your the big powerul race car with 10 inch tires.And your bro/sis is the little weak engine with huge monster tires with big chrome spinning rims.Both of you get side to side,and start to race,if you notice,you will be pedaling like a mofo but not making much progress.And your little bro/sis will be trying really hard but will barely be moving.That there is your example.I think you got the point I was trying to make.Now you (Being the huge 600+ horsepower engine) get back on your adult bike and go for a spin.As you may notice,its not hard,to speed up.All thanks to your powerful engine.

Hopefully you got what I meant.It all made since in my head.

Im just gonna speak my mind on this.Seems to work in my head.Here goes,

I think that if you have bigger tires,you might go slower,IF you have a really weak car.And if you have small tires (13 in.) you will go make the tires spin faster. with a weak engine.Its all really in the power that your making in the vehicle.If your making lots of low end torque and horsepower,and your vehicle is capable of putting in some 17's,then go for it.See,its like a bicycle,if you have a really huge rear tire,it will require more power to push right? And you will go a long way with just one revolution of the pedal. Now imagine if your bike had a training wheel for the back tire( about 5 inches ).Wouldnt it be easier to push? But all that easy pushing comes at a price,you wont cover that much area.So when a race car is very powerful,it gets the 17/18 inchers.Its like the middle of tire sizes.They will cover a good area,and they will be easier to turn with the engine.Here is an example.

Get your little brother/sister to get on your adult sized bike.Their bike will have like big 20 inch tires right?
Now,you get on your small child sized bike(About 10 inch tires there).Now imagine that your the big powerul race car with 10 inch tires.And your bro/sis is the little weak engine with huge monster tires with big chrome spinning rims.Both of you get side to side,and start to race,if you notice,you will be pedaling like a mofo but not making much progress.And your little bro/sis will be trying really hard but will barely be moving.That there is your example.I think you got the point I was trying to make.Now you (Being the huge 600+ horsepower engine) get back on your adult bike and go for a spin.As you may notice,its not hard,to speed up.All thanks to your powerful engine.

Hopefully you got what I meant.It all made since in my head.

You've got the right idea but you're really over thinking the whole thing.

Take two tires. One twice the diameter of the other. The smaller one will have to spin twice as fast as the larger one to reach the same ground speed.

What this does is indirectly affect your final drive gear ratio. With a smaller diameter tire, you are able to apply more torque to the tire and (traction not withstanding) to the ground. Therefore, the car will accelerate faster with a loss of top speed.

The opposite is true when you switch to a larger diameter tire. When your friends are telling you that your car will be slower with the larger diameter tire, what they're really talking about is you will lose some acceleration.

Now, of course with the larger tire you will improve your handling and looks so you need to figure out if the trade-off is worth it. (Most of the time it is). Just be aware that ANY change from your stock tire diameter, bigger or smaller is going to throw off your speedometer and it will need to be recalibrated.

Also, I don't know what your plans are for this car but there is a car-club in WA state called Northwest DSM that I used to race with. There's a member (possibly president by now) named Sam Crawford that built an all motor GS Eclipse that hit 14.9 at Seattle Int'l Raceway. He knows Eclipses better than anone that I know. Good bunch of guys and they will most likely be willing to help you get some more power out of your RS.

Good Luck!

Whew.Thanks for helping me out there,I was getting stressed.

And theres an important factor that the others are missing. its very hard to squeeze some 310mm brembo's into a 13 inch wheel. generally, a bigger wheel can mean a bigger brake which can run cooler (because of the longer swept area, and the available space in general), and have greater leverage on the wheel (cause of the larger rotor - der).

and who can tell me that those gold calipers look bad...show of hands?...didnt think there was many.

Because the race cars are so fast that they would have a top speed of like 120mph, & it would be very hard to control the car.

For any street driven car, you want shorter gearing, which is the height of the rims + the heightx2 of the sidewall. around 22" is optimal.

17's are for show, not go. They can go through a turn faster if they have a shorter sidewall, but you can have a shorter sidewall on a 15", & you could exit the curve faster.

You add a lot of weight & lose a lot of tq w/ big rims. Rotating weight is everything.

People always say well this 17" only weighs 15lbs, & then i show them my volk ce28n's that weigh 7lbs.
I have 14" skinnies in the back & 15" w/ drag radials up front.

It's not a matter of if you have the power, go for 17's, it's a matter of no matter how fast you may be, you'll always be faster w/o the bling bling.

Dude, check the dates on posts before you post on them. Just passing along a friendly "reminder" that I got.....

wheel size... as long as your rolling raduis is the same it don't matter how big is your rim.. Lets sey you have a 16 in rim with 55 tires now go with the 17 and 45 tires.... so your rolling raduis is the same since your tire arent that tall... have you ever notice those 20 in rims? u see most of the rim and not the tires.... you hit the curb and sey bye to those nice rims. 17in rims will slow your car down if it weights more than stock rims, other than that 17 in will be better in every aspect. But light rims won't be good for crappy roads... they are for nice race tracks.

And theres an important factor that the others are missing. its very hard to squeeze some 310mm brembo's into a 13 inch wheel. .

jackpot. Technically speaking, the moment of inertia of a 13" is less than that of a 17" wheel so its going to take more work to get that 17" wheel moving, not to mention it probably weighs less too. But a smaller sidewall tire on a larger wheel, will help give better performance in cornering.