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[CJBimmer]

So wheels seem to be more of an aesthetic mod for most people. Im running completely stock now but in the next couple months will probably start addressing performance things like intake, exhaust ... etc.

My question is what are the TRUE advantages of going with a bigger wheel? Ive got the stock 17" sport package wheels on my 328 and defaulted to wanting 18s but Im not sure why. Here's my understanding.

Lighter is better. Period. Unsprung weight reduction is significant. This suggests a smaller wheel, both assuming the same wheel smaller will weigh less as well as the tire to fit it needing less rubber, ie weighing less. Smaller wheel has less rotational inertia (mass is more centered relative to larger wheel). Again, +1 for smaller wheel.

Larger wheels can run smaller sidewalls, giving less deformation in the tire when accelerating. +1 for bigger wheel.

LeBron has 22s, so I need them too. +1 for big wheels.

I dont want to spend cash on performance mods just to move backwards so I can look like a baller.

Id rather run smaller wheels (17s) and get lowering springs to close that ridiculous gap between the tire and fender well.

Thoughts. Please.

[cb4]

18s sound like a good compromise for you. You won't find a lot of choices in 17 inch anyway. Best selection in 19s. Plenty in 18s.

[Gavin@MMW]

a 17" setup would be your best bet, but you would be looking at a custom set to get something that looks good and performs.

The Work MeisterS1 would be something to look at in 17" and can be custom tailored to you needs.



Or the Work Emotion 11R, it is a low pressure cast 1 piece but comes 17" in a wide range of fits

[IMG][/IMG]

The SSR SP3-R can also be custom done for a 17" fit



And the SSR SP1 can be made into an awesome 17" setup



But you wont find too many off the shelf options, so if you want 17" performance it does come with a price tag.

[2M]

Originally Posted by CJBimmer

Lighter is better. Period. Unsprung weight reduction is significant. This suggests a smaller wheel, both assuming the same wheel smaller will weigh less as well as the tire to fit it needing less rubber, ie weighing less. .

roflllll smaller wheel means more rubber ...bigger wheel means less rubber , wheel+tire need to keep the same diameter

[Stuart@BMRAutowerkes]

Here's a good comparison on 18inch vs 19inch wheels for track purposes. Whilst the 19s actually proved to be slightly faster, the tester felt that the 18s were a lot more stable.

For the street, you're not going to notice the difference in performance though.
You WILL notice the difference in comfort though. That said, I have no issues running 19s and experiencing a slightly bumpier ride.

It's up to you though, 18s seem like a good compromise in your situation, but if you have 17s already maybe it's not worth spending the money for a 1inch increase - just get it lowered via your choice of springs or coils.

[michaelthepsycho]

18" is the "standard" compromise. 17's might be lighter but usually have too much sidewall unless you go down several aspect ratios and drop a lot of ride height.

[TSM330i]

This is an extreme test going all the way from 15" to 19" on a VW Golf.
http://www.caranddriver.com/features...sted-tech_dept

Notice the difference in acceleration is the biggest difference. The lower profile tire proves to have superior handling and the widest tires have the shortest stopping distance.

I went with 18" because it was a good compromise in both design (ie looks) and light weight. My wheel/tire combo saved 11lbs per corner on my car over the stock 162 wheels. I also decreased my tire diameter and increased the width. The best of all worlds (less weight, wider and lower profile).

Yes, I do feel a difference in everything I do. Acceleration, braking and handling.

[CJBimmer]

Originally Posted by Alpine3

roflllll smaller wheel means more rubber ...bigger wheel means less rubber , wheel+tire need to keep the same diameter

No. As you can see from the cross section, the majority of a tire's mass is in the contact patch, not the sidewall. The increase in sidewall thickness to maintain the same diameter is negligible relative to the increase in mass due to all of the other components in an 18" tire.

[CJBimmer]

Im thinkin the 18 is the way to go.

I had planned on putting a set of winter's on the 17s and leave them there. BUT, if I was going to run 17s all year I was going to look for another option.

[ModBargains.com]

18" wheels gives you a good compromise between looks and performance. Most aftermarket wheel manufactures today don't make anything under the 18" size as well. If one of your main goals for the vehicle is to improve the performance aspects, I would recommend for you to check out the Forgestar F14 Flow Form wheel. Flow form wheels are much lighter than cast wheels. The Forgestar F14 wheel in 18x8.5 weighs an amazingly light 17.6 lbs, where a cast wheel of this same size would weigh anywhere from 23-27 lbs. This saving of roughly 6-10 pounds per wheel makes a BIG difference in regards to handling and drivability. Reducing unsprung weight (weight that is not supported by the car's suspension, i.e wheels, tires, brake rotors, and brake calipers) is one of the easiest ways to improve your car's handling, braking, and acceleration. As a general estimate 1 pound of unsprung weight is equal to 10 pounds of static weight. (weight that is supported by the vehicle's suspension). By using this ratio if you were to replace your stock wheels that weighed 25 lbs with Forgestar wheels you would be saving 320 lbs. in static weight! I'll shoot you over a PM with more details! In the meantime here are some pics of the Forgestar F14 in 18" for you to check out!

[img]http://www.**********s.com/images/Products/Forgestar%20Wheels/Gallery/E90-335xi-23092010-02-LowRes.JPG[/img]

[img]http://www.**********s.com/images/Products/Forgestar%20Wheels/Gallery/E90-335x-23092010-03-LowRes.JPG[/img]

[cb4]

I believe the latest 18 inch f14 is 18.5 lbs. They increased the load rating.

[Ben Richards]

i've got some 18" f14s on the way - don't buck the trend!