17" or 18" aftermarket wheels?

[Track]

Hi Gang,

Specifically with regard to lightweight wheels & high performance tires, is there a general preference amongst LGT owners to choose one size wheel over the other? The reason I ask is that on my STI, I chose to stick with a 17" wheel, even when offered a deep discount on some forged Prodrives.

I came up with the following list of pros and cons and would like to hear people's opinions.

The pros and cons i came up with are:

17 Pros:

-Lighter, less unsprung weight/rotating mass

-Greater tire selection

-Cheaper tire prices

-Less chance of pothole damage

-Ride may be better (depends on tire selection I suppose)

17 Cons:

-Taller sidewall = more flex at the limit

-Cosmetically looks less cool

-Potentially less room for big brakes

18 Pros:

-Less sidewall flex

-Cosmetically looks betterhttp://www.legacygt.org/forums/images/smilies/smile.gif

-Potentially more room for big brakes

18 Cons:

-More prone to pothole damage

-Tire prices marginally higher

-Ride may be affected by shorter sidewall

 

Please chime in here with your opinion, especially if I've forgotten something important!

[ShadowImg]

I stuck with 17s, I think 18s look too big on our cars personally. As far as the amount of sidewall and impact from potholes, that's dictated by your tire sizing, not the wheel. You could adjust tire size on either and eliminate that one way or the other. Spedo would be inaccurate, but not a huge dela.

 

Brakes are the only thing I see on there that I would leave on the list, but if you aren't planning on upgrading I don't know that it matters.

[JoeFromPA]

Track -

 

17" if you are all about performance

18" if you desire the looks

 

You can find 17" that will fit a BBK....so that would take that off your list of cons.

 

Sidewall flex is a function of the sidewall itself (tire construction) and tire sizing you choose.

 

Just my take....

 

Joe

[Mines]

18' perfect balance between looks and performance

[Underdog]

Personally I would stick with the 17" wheels. Consider your "cons":

 

17 Cons:

-Taller sidewall = more flex at the limit

-Cosmetically looks less cool

-Potentially less room for big brakes

Sidewall flex should really only be a concern if 1) you are driving on the track, and, 2) you are planning on going to a much stiffer suspension setup.

 

Cosmetically they may look less cool, but meaty tires on 17's with a subtle drop look really good too. Function > Fashion.

 

The third one is a non-issue as our brakes are suitable for all street and some track conditions, although pads/rotors/fluid/lines should be replaced. As mentioned there are calipers that fit under 17's as well.

 

18 Cons:

-More prone to pothole damage

-Tire prices marginally higher

-Ride may be affected by shorter sidewall

These are all true and cannot be simply explained away. Your first and third points are even more exaggerated as you stiffen the suspension. Add to that list that a larger wheel hurts acceleration by being heavier (generally) and moving the moment of inertia further out from the axis of rotation.

 

 

From my experience:

 

As my first modification I bought UHP summer tires and put them on 18" wheels (w/ stock suspension). I noticed almost zero difference between my 17" winter tires and my 18" summer (225/40-18 vs 215/45-17, ~6mm less sidewall on the 18's) during hard cornering on the street, in terms of comfort and grip.

 

This past summer I modified almost every aspect of my suspension, with the most relevant additions being stiffer springs/shocks and swaybars. Now there is a more noticeable difference between my two sets of tires, with the 17's being more comfortable, yet I can still corner at hyper-legal speeds easily and with no drama. The difference is small, but a difference nonetheless.

[Track]

Thanks for the input, guys. I've been mulling this over in my head for awhile now and I have to say I really appreciate everyone's responses.