Handling

[Norm Peterson]

No doubt the school has chosen their tire/wheel fitments to provide more progressive breakaway characteristics.


Norm

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[NightmareMoon]

9" is 9" (and is the bead to bead measurement, inside the flanges. Not the outside to outside overall width, which is about an inch wider).



Compared to what - 255/40's? Yeah, in that case you ought to have gained some ultimate grip. But you've given up a little turn-in response and precision/linearity along the way.



9.5" all around would be a bit better, unless you're operating under some sort of restriction against changing wheel widths from OEM.


Norm

yeah its inside to inside.

depending on the tire, in street class autocross where you can’t change the wheel width, many of us have run as wide as 285/35 on a 9” front. Yep, and reaults seems to bear out that tradeoff was not slower, even in a fast transition handling contest where transitional response or feel seems like it should affect things the most. (Unusually stiff shouldered tire tho). Grip is so important and the wider tire may take a bit more heat before it gets greasy I guess. Slower response feel can be learned.

even going from a 9” front to that same 285 on an 11” front, the feel changed only slightly for me. You could tell it was different but the car didn’t suddenly come alive on the front axle just through the larger wheels.

Try that with a different tire like a soft shouldered continental street tire and you might get different results

 

[Norm Peterson]

I get this.

It's probably because my own Mustang came with a max-recommended fitment as OE (235/50 on 18x8.5"), which first went to 255/45 on 18x9.5 (still for general use), and later to 285/35 on 18x11 once I got into HPDE. All max-recommended. My current "street" setup is 265/40 on those 18x9.5 wheels, which is a "measuring width" fitment - and substantially softer/more progressive in the upper lateral-g ranges than the 285/35 setup even though the tread width is listed as 10.2" for both the 265/40 and the 285/35.


Norm

 

[Norm Peterson]

yeah its inside to inside.

depending on the tire, in street class autocross where you can’t change the wheel width, many of us have run as wide as 285/35 on a 9” front. Yep, and reaults seems to bear out that tradeoff was not slower, even in a fast transition handling contest where transitional response or feel seems like it should affect things the most. (Unusually stiff shouldered tire tho). Grip is so important and the wider tire may take a bit more heat before it gets greasy I guess. Slower response feel can be learned.

even going from a 9” front to that same 285 on an 11” front, the feel changed only slightly for me. You could tell it was different but the car didn’t suddenly come alive on the front axle just through the larger wheels.

Try that with a different tire like a soft shouldered continental street tire and you might get different results

Even 15 years ago when I was autocrossing, people were running some really pinched fitments in search of grip above all else.

I was also looking at ***** being over in Europe that there might be some official DOT/Ministry of Transportation/whatever regulations being involved, at least for street duty.


Norm

 

[shogun32]

obviously you're not in USA but I've personally bought several new 19x9.5 and 19x10 wheels, flow-formed for $400-600/set. Got 19x10/11 for less than 800.

OE wheels are crap to begin with so there is no merit to using them even for DD, IMO.

No doubt the school has chosen their tire/wheel fitments to provide more progressive breakaway characteristics.

Or they signed a contract for a certain brand/size and quantity and it was cheaper to force-fit what they had on the rims they had irrespective of any educational benefits. Plus do you really expect the tire monkey to measure each rim to make sure the 9" got A tire and 9.5" got B tire? No, every wheel gets the same tire. No thinking required.

 

[accel]

obviously you're not in USA but I've personally bought several new 19x9.5 and 19x10 wheels, flow-formed for $400-600/set. Got 19x10/11 for less than 800.

lightweight wheels are costly, but $1000 can get you reasonably good one.

for me bigger issue is selling old wheels.

 

[baazooka]

Steeda anti-roll and bumpsteer kit (these make a big difference in steering feel, probably the most noticeable change as far as driving feel).

howdy, are you referring to steeda anti-roll bars or the roll center correction/bumpsteer kit. I have almost the same suspension and am wondering which one of these (sway bars or bumpsteer kit) would make the biggest noticeable difference. thanks

 

[shogun32]

if you are lowered >0.75" you'll want the bumpsteer kit and roll-center correcting lateral arms. They go TOGETHER but that was (is still?) NOT properly called out.

But they did at least make a packaged listing
https://www.steeda.com/steeda-555-4915-s550-roll-center--bumpsteer-correction-kit

 

[thompsje]

howdy, are you referring to steeda anti-roll bars or the roll center correction/bumpsteer kit. I have almost the same suspension and am wondering which one of these (sway bars or bumpsteer kit) would make the biggest noticeable difference. thanks

If you're a base GT, either the Steeda G Trac K Brace or the BMR CB006 Chassis Brace would make a significant difference as well. Personally, I like to go the route of extra bracing before I change springs/shocks/sways. The rack is still too slow and the steering wheel belongs in a bus... but the brace helped a lot with the "lazy" chassis response.

 

[baazooka]

If you're a base GT, either the Steeda G Trac K Brace or the BMR CB006 Chassis Brace would make a significant difference as well. Personally, I like to go the route of extra bracing before I change springs/shocks/sways. The rack is still too slow and the steering wheel belongs in a bus... but the brace helped a lot with the "lazy" chassis response.

Thanks for the feedback, heard good things about the front K brace in regards to steering feel. The bumpsteer kit and some of the smaller linkages seem pricey for what they are.

 

[dman]

Thanks for the feedback, heard good things about the front K brace in regards to steering feel. The bumpsteer kit and some of the smaller linkages seem pricey for what they are.

add the IRS bracing to the K-brace and complete the package. big difference...

 

[baazooka]

Steeda red differential inserts (still on the fence about this)

How are you liking the bushing inserts? Does it improve throttle/driving feel?

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