Tire Size vs. Performance (More Info?)

rickyrickster25

09-18-2007, 10:10 PM

I know we all had a big conversation on this not too long ago, but noone ever really got into details with how much performance would be lost, with 17's vs. 18's... I was just wondering does anyone have some ideas thay can throw out there, because it will effect what i do in the near future, and im sure other people might be wondering the same thing. Is it even possible that somone might even have some HP comparisons? Any info would be great, thanks.

nofear39427

09-19-2007, 11:51 AM

2of9

09-19-2007, 11:55 AM

^^^great info indeed

defiancy

09-19-2007, 12:06 PM

I wish we had a rep system here because I would be pushing it for you nofear!

nofear39427

09-19-2007, 01:12 PM

HAHA your making me blush lol.
Just trying to help with whatever I can.
This is the best forum I have ever been on and you guys
have been most helpful on your part.
BTW maybe this should be posted under STICKY NOTES
There may be more people with the same question later
on down the road.

SilvrEclipse

09-19-2007, 03:37 PM

http://www.nerocam.com/SCC_TAPnew.asp <-Thats the best one. LMAO

Some of your links dont work...

TalonEclipseMixGsx

09-19-2007, 04:18 PM

http://www.nerocam.com/SCC_TAPnew.asp <-Thats the best one. LMAO

Wow that was great. All of that to knock 2 seconds off. Makes me wonder how my car would do with all that weight reduction. Of course I'd never do it, but it would still be interesting.

nofear39427

09-19-2007, 04:52 PM

Sorry about some of the links not working.I just didnt have time to go through all of them at the time to see if they where up or down.
Yeah that site was halarious...poor car:lol:

david-b

09-19-2007, 05:26 PM

http://www.nerocam.com/SCC_Images/image033.jpg

Best Pic Ever. I can't believe they actually did that.

Man I hate when I had my 17s on. They were lighter, but I lost a ton of power on them. Once I put my 15s on, it felt great again. There's a difference between them for sure.

Thor06

09-19-2007, 06:00 PM

If you care about performance and not looks much, get 16's (not sure if 15's will fit 2g AWD big brakes, and if you dont have those you should :p). If you want a mix, go 17's. If you dont care that your car is slow, go 18+. Personally though, I think 16's fit our cars fine.

And that poor car :(. All for a gay internet article. I totally would have taken that car if thats all they were going to do to it.

TalonEclipseMixGsx

09-19-2007, 06:52 PM

My eclipse has the stock 16's from the GS-T, I didn't really notice much of a change when I made the swap, but I'm sure it helped a little, which the results would only be seen with a run at the track. On the other hand, the ol 1.8 is sporting the 17's, and i thought it was slow before putting those on there.

nofear39427

09-19-2007, 07:21 PM

Yeah I didnt ever realize that rim size would affect performance.
Then I thought about it some rims weight a hell of alot.
On the other hand some cars have to have heavy ass rims to
keep em on the road.Like the Mini Cooper those rims weight a ton it seems.

vanilla gorilla

09-20-2007, 01:44 PM

My car came with 16's. I swapped them to 18's. But the tires I put on the 18's made the wheel/tire combo the same overall height as the the factory tires. I made sure not to put a taller tire on the new rims because I didn't want to have any performance losses. But just by the added weight of the 18's I lost 2mph in the quarter mile than with the lighter 16's.

rickyrickster25

09-20-2007, 03:51 PM

Dies anyone have a pic of their eclipse with 17's on it, im just curious what it will look like.

david-b

09-20-2007, 04:17 PM

http://files.automotiveforums.com/gallery/watermark.php?file=/503/107097DSCF0057_Custom_.JPG
http://files.automotiveforums.com/gallery/watermark.php?file=/503/107097DSCF0016_Custom_.JPG

Thor06

09-20-2007, 04:24 PM

defiancy

09-20-2007, 06:30 PM

Weight is not the only performance robbing thing associated with bigger rims. I did the same thing with my 17's they are exactly the same height as my stock rims/tires were and they were a good couple pounds lighter and the car got a lot slower from that. It has to do with the moment of the wheel, its hard to explain so just trust me, the bigger them rim, the worse the performance will be.

What Thor said is true.

I am not a math genius but the bigger the wheel the more work(energy) required to turn it. If you were to get a small wheel attached to an axle and turn the axle the small wheel would move pretty easy. Attach a larger wheel to that same axle and the amount of force to turn the larger wheel increases.

To explain this mathmatically we take a look at a simple equation. Torque=RadiusxForce or Force=Torque/Radius

So for our cars we will use basic figures. Stock our cars our supposed to have about 190hp 190ftbs of torque and 16" diamater wheels. We will use this as a mesurement as well as the F=T/R forumula. For this we must convert the 16" diamater into radius also using ft as the measurement. So by that logic 16" becomes 1.3' ft meaning the radius is 1.3/2 which equals .65

Plug these into the formula and you get. F=190ft/.65 so F= 292.3 This is the force of the tire against the ground (Minus calculations for friction, which we won't go into.)

So for a 17" tire it would be. F=190/.71 Force = 267.60 (Diameter is 17 inches 17/12 = 1.42 rounded than 1.42/2 for radius)

Right there you can see that with a larger tire, less force is exerted on the ground as opposed to with the 16 inch tire. The problem lies in that the smaller the tire the larger friction plays as an acting force against the force of the tire. But we won't get into that because for what we are talking about friction would only be a detraction from the numbers and the end result in this case would be similar.

Hope this helps.

vanilla gorilla

09-20-2007, 10:07 PM

What Thor said is true.

I am not a math genius but the bigger the wheel the more work(energy) required to turn it. If you were to get a small wheel attached to an axle and turn the axle the small wheel would move pretty easy. Attach a larger wheel to that same axle and the amount of force to turn the larger wheel increases.

To explain this mathmatically we take a look at a simple equation. Torque=RadiusxForce or Force=Torque/Radius

So for our cars we will use basic figures. Stock our cars our supposed to have about 190hp 190ftbs of torque and 16" diamater wheels. We will use this as a mesurement as well as the F=T/R forumula. For this we must convert the 16" diamater into radius also using ft as the measurement. So by that logic 16" becomes 1.3' ft meaning the radius is 1.3/2 which equals .65

Plug these into the formula and you get. F=190ft/.65 so F= 292.3 This is the force of the tire against the ground (Minus calculations for friction, which we won't go into.)

So for a 17" tire it would be. F=190/.71 Force = 267.60 (Diameter is 17 inches 17/12 = 1.42 rounded than 1.42/2 for radius)

Right there you can see that with a larger tire, less force is exerted on the ground as opposed to with the 16 inch tire. The problem lies in that the smaller the tire the larger friction plays as an acting force against the force of the tire. But we won't get into that because for what we are talking about friction would only be a detraction from the numbers and the end result in this case would be similar.

Hope this helps.

Your figuring 16" 17" rims. What about the tires?

vanilla gorilla

09-20-2007, 10:16 PM

Thor06

09-21-2007, 12:21 AM

Ah..but the weight is the performance robbing thing associated with bigger rims....not even so much the overall weight of the rim....but where that weight is positioned.
Precisely, my dear Watson. :smokin:

defiancy

09-21-2007, 12:52 AM

Your figuring 16" 17" rims. What about the tires?

Even with the tires, the numbers would be proportionate to what is listed above. The numbers would just bit a bit larger in each case, but the difference would remain the same.

Black99GST

09-24-2007, 12:02 AM

hmm... i dont know what i think about all this, other then the fact that rims look F-ing SEXY on our DSM's in 17's or even 18's!!! (17's w/ 234/45 tires for me)

cantgo2fast

09-24-2007, 04:18 PM

Its actually a center of mass problem. You could have rims with the spokes and rim itself made of carbon fiber and the center made from say steel and it would turn much faster with the same applied force than an all steel wheel. Or a wheel that was reversed. When i get home ill post a little experiment that illustrates this.

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Tire Size vs. Performance (More Info?)