Have a base 12 car. What benefit to 19 inch wheels? Traction? Handling? Etc? Or is it more important to consider the width of the rim?

 

Looks.

 

^ this & that's it.

edit: heavier wheels (of the same width) are usually detrimental to handling, acceleration, braking, & performance.

 

and a little extra bit of road clearance, which is moot if you lower your car anyway.

 

I thought the idea was to use a bigger wheel, lower profile / shorter sidewall tire, so the overall diameter is the same but you have more wheel and less tire; which should stiffen-up the handling.

But maybe that is cancelled-out by the heavier wheel???

 

i have to look for the article.. was a few months ago
they tested the same car with 16, 17, 18, 19, & 20's
perfomance leveled off around 17/18 then dropped, but weight was the main reason.
if you could find a 19 that weights the same as an 18 then the 19 would prob be better..

 

stiffening the handling and having a rough ride are 2 different things. if you are really looking to improve handling, go with Koni STR-Ts. 19s will fill up the wheel well a bit if you don't plan to lower your car.

you don't want to go bigger than 19's or it will really start to compromise ride quality.


keep in mind if you go with a different wheel size, the speedo will be inaccurate. you may have to have the control module reprogrammed for the new wheel size.
My premium came with 19s and I'm using 18s for winter wheels and I know my speedo is off by 5 MPH which also effect the odometer.

 

Wheel size is not the determining factor on speedo accuracy. It is the overall tire diameter....which can be covered by the correct tire size to match the original tire diameter.

 

The functional reason for larger wheels are to install larger brakes on the car. For example some 18" wheels will not fit over the Brembo brake calipers on the Boss and GT500 cars.

 

+1

..

 

18's will ride a little nicer over the 19's where as the 19's will handle a little better over the 18's that is with the same tire od

 

Not due to diametrical clearance; the physically large caliper requires lateral clearance which in most cases can be solved by using a spacer.

 

Incorrect. Try fitting a 16" on the front of your car and tell us if it fits. Reread what I stated...

 

I didn't say 16" wheels fit over the Brembo caliper. I was saying the reason why some 18" wheels didn't fit was due to lateral clearance.

 

As with all things it depends, someone posted a link awhile back where a magazine tested a few different wheels and the increasing unsprung weight and how the car handled better with a proggressively shorter sidewall on larger diameter and consequently heavier wheels (as you suggest).

I dont know if the article also tested acceleration times, but in drag racing reducing unsprung weight is a proven way to help cut times.

and I suspect that even though the heavier wheel/tire combo improved road holding, that was perhaps on a best case scenario of a smooth surface. Go someplace where you have alot of surface disruptions in the road (pot holes, heaves, sinking asphalt, et al) and those heavier wheels will work against the dampers leading to poor compliance.

 

to summarize;

-typically the lower the profile the less sidewall flex and the better the cornering (profile decreases as wheel diameter increases, assuming outside tire diameter remains the same). This also results in a harsher ride...tires don't give as much.

-the larger the wheel diamater, the heavier the wheels. This not only adversely effects handling as wheel weight is increased (more mass bouncing up and down), but also slows acceleration as rotational mass is increased...note how many times heavier wheels are mentioned in some of the better car reviews as slowing 0-60 and qtr mile times.

also;

-18" wheels and tires are less $

-the selection of tires is greater in an 18", unless you want wider than 275 all season or 285 summer...if that's the case you'll want to look at 19".

and some 18" wheels will fit over big brakes

first I'd suggest you decide how wide a rear tire you want to run and also whether or not you've a big brake concern (either OEM Brembo or aftermarket upgrade in the future)

I've read an old thumbrule that states 1# of rotational mass is ~= to 10# of stationary mass, when considering acceleration...don't know how accurate that is but consider....many rims, including most stock, are cast and weigh ~ 30#. TSW Nurburgrings weigh ~ 20#. Also note that the stock driveline weighs ~ 46#...Have seen a couple carbon fiber shafts listed at 15.5-17#...there's potentially ~70# of rotational mass that can be easily shaved.

Not everyone lists wheel weights, however. Tire rack is pretty good about it, and the TSW site is good about a couple of theirs...note the Nurburgrings are rotary forged....they state that during manufacture the wheel is forged at a high pressure while being spun, changing the molecular structure enhancing strength, which allows them to use less alloy.

Also note that more performance vehicles are coming out equipped w/19" rims.

Next time you're in the grocery store, pick up a 5# bag of sugar. Imagine removing two of those from each corner...then imagine removing 6 from your drive line.

Use this to figure out what you've got and what you want to end up with;

http://www.csgnetwork.com/tiresizescalc.html

 

I'm starting to hear Tarzan yelling and beating his chest....