UrS4

Been considering going with a 19" rim and a 275/40/19 tire.

Tires would be Falken 452s which weigh 31.2lbs

The wheels are Motegi Touge wheels 19"

My question is should I go with the 19x9 (25.2lbs) or should I go with the 19x10 (26.3lbs)

So from purely a handling standpoint, is it better to save weight or go with a wider rim?

Pic of the rim



Pic of the tire

jayel579

From purely a handling standpoint it is always good to go with a wider rim, the more tire on the ground the better lateral traction. You also want the amount of tire down to be matched front to back, otherwise you will ruin the balance of the car. I dont think we can put a 10" rim under the front or these cars, so you are best to stay with a 9' rim on all four corners.

Norm Peterson

I'd go with the wider rim, assuming that it's available in a suitable offset/backspacing. I can't see the 1.1 lb per wheel (out of 56-ish total) making enough difference to feel in either acceleration or suspension response. Enough to measure with timing equipment resolution to 0.001 second, probably.Strictly speaking, you'd want a tiny bit more bump damping, but I doubt that you can get that set to within the 1% range that 1 lb in 50 represents. And a way to lose a half dozen lbs or so off the car as a whole. On the other hand, turn-in and other transient response is always improved with better lateral support for the tread.


Norm

UrS4

The 19x9 wheels have a 40mm offset and the 19x10 wheels have a 40mm offset too.

There shouldn't be a clearance problem on the front as putting a GT500 18x9.5 rim with a 50mm offset from americanmuscle.comwith a 255/45/18 tire is 15mmcloser to the suspension bitsas putting a 275/40/19 on the 19x10 with a 40mm offset.

So the added lateral support of going with a wider rim could show measurable improvement whereas the added weight has less of an impact?

Norm Peterson

That's the way I see it. A given percentage of critical damping, which is what you're sort of after with damper tuning, is a SQRT(MASS*STIFFNESS) thing, and I don't think the rotational effects aren't the 10:1 sort of thing that some have claimed (don't think I screwed the derivation up that badly, anyway).

But with the dimensions getting this close, you need to have a better estimate of tire section widths. Every inch of wheel wider than the "measuring width" adds about 0.4" to the section width. Measuring widths are different for those two sizes, so the corrections won't be exactly the same.

To which you'd need to add something (figuring it out as go here - the math is simple enough) to account for the added half inch and the difference in offset vs 45mm with the SVT 18 x 9.5 GT500 wheel that you know fits up front(and with an OE-acceptable amount of tolerance). The 5mm less offset almost accounts for the 1/4" extra on the inside(1/4" - 5mm = ~1/16"), so you should be OK on the back side from the wheel perspective. Front side would be almost 1/2" further out than the GT500 (1/4" + 5mm).


Norm

UrS4

Okay, thats good, as I think the GT500 wheels up front with the 255/45/18 are tucked in a little too much.

This 19" wheel should be more flush with the fender lip but may still be a little tucked underneath. Comparing this tire and wheel combo with another on of our members here, Black S197 who runs a 18x9 24mm offset with a 275/40/18 tire, it sticks out from the fender lip ever so slightly. My little wheel calculator has the 18" combo moving the tire section width (widest part of the tire) out 1.6". The 19x10 combo I am considering will only move out 1" so it should look good.

Thanks Norm for the advice.

ybnormal

I am running the 19 inch in 8.5 front and 9.5 in back with 295 x35 in back And I like it a lot good split from 18 or 20. no rubbing or clearance issues even with my vehicle lowered. Are you running on A track ? otherwise weight should not be that important. If you are racing it you just swap up to some drag radials and smaller rim.
good luck

F1Fan

Hi UrS4,

For lateral grip wide is better. For ride lighter is beter. The difference in the weight of these two wheelsis too small to significantly impact rideso I'd go wide if you can find wheels with an offset that fit and a tire that clears the strut speing seats, inner fender well and fender lip.

I'm running BFG T/A KD tires in 275/40x18 onforged Roush 18"x10" with a 50mm offset and the tire inside barely clears the D-Spec strut body by less than 1/4" with the maximum negative camber (-1.5 degrees)cranked into an Eibach camber bolt in the upper hole of the mounting bracket on the struts. I also have a set ofSaleen PJ wheels that measure 19"x9"with 30mm offset and 19"x10"with a 50mm offset runningYokohama Advan S.4tires in a275/40x19.Mounted on the 10"wheels theymeasure 11.3" at the widest part of the sidewall and on the9" frontwheels measured 10.9" wide.The Saleen PJ wheelsand Yokohama S.4 tires even though wider and taller comfortably clear the Steedacoilovers on my car even with -3.5 degrees negative camber on the Steeda billet camber plates I use on the coilovers.

HTH!