2005SilverGT

I have a 2005 GT with a Roush stage 1 package. I'm thinking about upgrading it to a stage 3 in phases by adding a suspension and supercharger. The suspension lowers the car by an inch but I believe the diameter of the tires is the same (27 inches) so it should not impact the stance of the car. I really prefer the look of the 17 inch 5 spoke GT wheels over the 18 inch selections (more of an old school look). What are the pro's and cons if I were to stick with the 17 inch wheels?

bigstick

First mod I did to my 2006 GT was a Roush Stage 3 suspension and still had my stock 17" wheels. LOVED the ride and handling and got compliments from people who were used to Steeda and Eibach suspensions. You won't have any problems.

The only reason I switched to BMR lowering springs and D-specs is that I can switch back and forth between road course and drag race set ups. Roush is more tuned for road course/daily driver.

The only downside I can think of to sticking with 17"? Cosmetic: 18's fill out the wheel well better.

CMcNam

That's about it as I can think of as well. If you're looking for performance, that's a whole different can of worms and various wheels sizes will affect your performance differently. I like my stock 17s too, but couldn't find the exact style and tires I was looking for to fill out the wheel well, so I'm going up to 18s when I can afford it. When I lowered the car it became really obvious to me just how small the 17s are in that well.

Norm Peterson

Exactly what improvements are you shooting for with your proposed suspension upgrades?

In 17", you're limited to only two tire sizes (235/55-17 and 255/70-17). Three, if you're willing to run the slightly shorter 245/50-17. The OE 17" wheel is only 8" wide and will not properly support anything wider than 255. Keep in mind that there may be fewer tire mfrs producing those sizes, meaning that your choices could become somewhat limited over time.

For the same tire OD, a 17" size will generally ride a little smoother/nicer. The 18's will tend to have sharper cornering response and probably a little more ultimate grip.


Don't try to make 55- and lower profile tires look exactly like the 70- and taller profile tires of the 1960's and 1970's where the sidewalls bulge/belly way out past the rim flanges. These tires aren't supposed to be fitted to too-narrow rims like that and would run somewhat hotter due to the additional sidewall flexing that will happen if they were (not a good thing).



Norm

2005SilverGT

To answer Norm's question, I don't really have any specific performance goals in mind. I bought the car as weekend driver - just to enjoy and possibly make some upgrades. It came with a stage 1 package and I've already had a couple people ask if it's "real Roush or not" - so I thought maybe I'd go ahead and start the upgrade process with the new suspension, then add the supercharger next year to get it up to a stage 3 and then possibly put it in some shows or something. The suspension upgrade recommends 18 inch wheels, but I like the look of the stock 17's, the tires only have 30K on them, so if there are no major performance or safety issues, I'd rather defer that until later.

Sounds like the ride would be better with the 17's, but the handling and response would be better with 18's, and the 18's might look better because they fill the wheel well out better.

Again, thanks for all the info.........