hans_wiren

Now that the 2006´s have started to get delivered I´m curious about how the upgraded suspension (that comes with the 18" wheels) compares to regular stock? Is it stiffer or softer or about the same? Also, is the ride height about the same (meaning way too high...) ?

According to the limited info that I´ve found about the upgraded susp. the setting of the shock (rebound) is softer on the upgraded one. Isn´t this bad if you like driving aggresive and or would like to lower your car?

While I´m at it I´m also wondering if the 18" fanblades really are 8" ET45? Judging by the pics I´ve seen they look pretty close to the lip of the fender (which the 17" stock don´t!!!)

Please give me some input!

withinavoid

From what I can tell, the 18in does feel a bit stiffer than I remember from my test drive of a 2005 with 17s. Particularly on a new highway by my house, the Mustang seems to bounce all over it. It is also pretty noisy inside from rattles on bumps so I think it's not as soft. Just my opinion.

Dan

The 18" fanblades are 8.5" rims. They are a bit farther out than the 17's but not as far out as the 9" rims which I don't think is so bad since you're less likely to throw stones down the side of your car.

The upgraded suspension is likely softer. I put the fanblades on my own car without any upgrades and its a touch stiffer but the ride is still great. Don't worry about it.

rhumb

I believe the 18" wheels come with lower aspect ration tires -- shorter sidewalls -- and that might explain a good part of the difference in feel, i.e. less sidewall flex = stiffer ride and sharper steering response. Also, and I don't know this to be so, the 18" tires might be a different model or make than the 17ers, which could account for some difference, even if the suspension were unaltered. Even just differences in tires pressure can make a readily noticeable difference in ride and handling, so make sure you control for that variable in your assessments.

RadBOSS

Rebound on the softer side can actually be good. If its too stiff, then the wheel does no want to return to ride height quick enough. Bumps in quick succession will then progressively cause the car to get lower and lower before getting out of the bumps ... could lead to bottoming out against the bump stops which really upsets the car balance. The slow rebound can also cause / aggrivate wheel contact loss, most disturbing in a hard corner.

The tendency I have read / seen of most owners with adjustable shocks is to crank them down. The problem is, they are only increasing the rebound resistance. The perception is the car is stiffer, and I guess it is, buts its not necessarily stiff in the right way.

I am pretty convinced the 05 has too much bounce and rebound resistance on the rear axle. I find it readily looses contact hitting even small sharp bumps while cornering. This really upsets the car balance in the corner and require throttle and steering correction to keep it going the direction you want.

rhumb

You hit on the achilles heel of a live axle design, which is basically its immense unsprung weight. Good suspension tuning can ameliorate some of the negative effects of all this mass flailing about, but alas, in the end, physics win and you end up with a rather compromised suspension (when actually called upon to suspend rather than sit still as on a drag strip).

Too little shock valving and too soft springs and the beast flails about on anything less than a creamy smooth road with only incidental pavement contact (so much for the supposed superior traction characteristics often cited as a live axles raison d'etre).

Dial in enough shock damping and firmed up spring rates to reign the flailing beast in and you end up with a punishing ride (for a given level of handling capability) and can start ending up with the whole **** end of the car leaving terra firma, with predictable dire consequences for handling.

IRS system, by dint of their far lower unsprung weight and inertia, are far better able to follow the road surface contours over a far greater range of conditions with much less degradation of ride quality and suspension compliance for any given level of handling capability. Basically, you can have a whole lot more cake and eat it too. Of course, that IRS cake will cost a bit more than live axle corn pone.

Of course, all this is moot for street/strip racing where very little is asked of the suspension other than to hold still and hold together. And for better or worse, seems like many if not most Stangers take this rather constricted view of vehicle performance (straight line myopia) with all other dynamic elements coming in as a distant after thought after their wallets are bled dry stoking the engine bay with 20 gizillion horsepower.