In what ways does wheel size matter?
 

I got a 04 wrx a few weeks back and cant stand the stock tires. I'm wondering if i should get 17" wheels also? Im not to concerned with looks but performance. Could i get some feedback on the different size wheels? Pardon my car ignroance I am quickly trying to learn =)

Bigger = BETTER
 

When you go to a larger dia wheel you gain a whole lot of lateral stiffness. I recently went to a 18x8 with a 45 series tire and was more than pleased with the performance gain. You end up looseing some of the ride comfort (becomes more harsh) but if performance is the issue. Bigger wheel = better cornering performance. Just make sure your offsets are right and you should be in there.

Well, a bigger wheel usually means a bigger tire, which means a larger contact patch. That will give you better traction. It will also seem like you've changed your gear ratios, but not enough to notice. Also, if you get low profile tires, the sidewall is stronger since it is shorter. That helps cornering and turn in, due to the fact that the tire isn't going to give as much as it would on a tire with a larger sidewall. It really depends on your intentions though. I've 'heard' that the 16" setup is the best choice for gravel and dirt rally driving. I personally didn't buy the car to play in the dirt, but many people did. If that's your intention, you may want to stay with the stock size.

17x7's - 17x7.5's have been a popular choice among folks with WRX's. It's an excellent mix of ride comfort & performance. Popular tire sizes are 215/45/17 & 225/45/17. Personally, I have 17x8's with 225/45/17 Pirelli PZero Neros. I'm very happy with the set up.

- Kean

thank you all for the feedback, any recomendations on wheel brands. Also pardon my ignorance but what does 215/45/17 and 225/45/17 mean? Never actualy bought tires for any type of preformance.

[QUOTE][i]Originally posted by Lagwagon56 [/i]
[B]thank you all for the feedback, any recomendations on wheel brands. Also pardon my ignorance but what does 215/45/17 and 225/45/17 mean? Never actualy bought tires for any type of preformance. [/B][/QUOTE]

first number is the tire width (in milimeters)

second number is the sidewall height (given as a percentage of the tire width)

third number is the inner diameter (in inches)

[QUOTE][i]Originally posted by Lagwagon56 [/i]
[B]thank you all for the feedback, any recomendations on wheel brands. Also pardon my ignorance but what does 215/45/17 and 225/45/17 mean? Never actualy bought tires for any type of preformance. [/B][/QUOTE]

Wheel selection will greatly depend on your personal preference as well as your specific application (this goes for tires as well). Try [url]www.tirerack.com.[/url] Even if you decide not to buy from them, their website is a good source for some basic information.

Here's their "Tech Section". You'll be able to find more info about the size/dimensions I mentioned regarding tires as well as useful tips when selecting wheels:

[url]http://www.tirerack.com/about/techcenter.html[/url]

Hope this helps,
- Kean

There was a sport compact car article a few years back comparing wheel sizes. They took three wheels of the same types, with same tires, and gave them a run of performance tests.The results are...

when you go to a large wheel you need to realize that tire selection is very important. The performance you recieve is more related to tire tread pattern and compound, as well as tire structure. A low aspect ratio (the second number in tire size) can actually pull the tire away from the pavement. The suspension will not be level with the pavement all the time.

Also the larger wheel size will lower accelleration due to greater rotiational inertia.

Now you're asking what's rotational inertia.

when you try to spin something, the mass of that item resists the spinning. The farther the mass is concentrated from the axis of rotation, the greater it resists. For an example, take a dumbell and a barbell of the same weight. If you try to spin these items, the dumbell will be easier.

If you have a 16" wheel with tire, and a 17" wheel with tire, and they both weigh the same- the 16" would accellerate quicker.

If you are going to get a larger wheel (on a WRX, anything more than 17 would be just for show) make sure you buy a light wheel, and DO NOT cheap out on the tire.

i dotn know if weight affects it much...as long as its not over like 25lbs or so you should be okay. IMO-derbagley may know more about me but im just telling you what ive heard. i went to that side. now ofset is...uh... perfect if the tire is directly centered? can someone explain how to pick the correct ofset cuz i still dont fully understand it

With bigger wheels, you get to fit large brakes.

[QUOTE][i]Originally posted by jerry 1 a b [/i]
[B]It will also seem like you've changed your gear ratios, but not enough to notice. [/B][/QUOTE] interesting. how so? also, would the speedo/odometer be affected as well?

if the circumference of the new wheels/tires is different than the OEM yes the spedo will be affected...but if they are close it will only be off by a mile or two/hour. there is no way to reset the ecu or anything to fix this

offset refers to the relation of the inside of the wheel where it contacts the hub and brake rotor, to the rim. I beleive it is to depth of the inner surface to the inner portion of the wheel.

Don't worry about what the offset is, just let the shop that you buy the wheels from that it's for a WRX, they have all the measurments from the manufacturer.

a wheel transfers spinning forces to linear motion. spinning motion is measured on revolutions. linear motion is measured in length. one revolution will give out a certain distance of the circumference of the tire. if the cicumference is greater, it will change the ratio of rotation of the wheel and the distance covered by that rotation.

circumference is pi times the diameter (I beleive).

cool, understood. :) but what about jerry's gear ratio comment?

also i was talking to a friend who recently bought fn01c' for his car, and he told me to not worry too much about wheels. tires are more important. he said "wheels are like socks, tires are like shoes. get better shoes."

what do u guys think about this?