[JSH]

Originally Posted by cjperformance

Ordered NT555R2s in 305/30/20 to go on my 20x11s.

I've never looked for 305, but I can't find 325 or 345 . . . anywhere.

[cjperformance]

Originally Posted by JSH

I've never looked for 305, I can't find 325 or 345 . . . anywhere.

I wasn't sure about fitment, and heard lots about rub on the inner rear fender with anything larger than 305's, so I just spec'd out the 1LE sizes for wheels/tires.

[JSH]

Originally Posted by cjperformance

I wasn't sure about fitment, and heard lots about rub on the inner rear fender with anything larger than 305's, so I just spec'd out the 1LE sizes for wheels/tires.

Member EDFHOBBIES runs Nitto 345 on his car without issues, and I currently run a 325 Toyo, but I can't speak to whether the SS is different.

The Hoosier A7 is a really good DOT radial tire, but you would need to swap them on/off at the strip because they basically have zero tread.

[KingLT1]

Originally Posted by cjperformance

Ordered NT555R2s in 305/30/20 to go on my 20x11s. I can vouch that the NT05s were a poor choice. The 555R2s are back ordered for a month or so.

WWT has no drag events, at least no WOW or MM until July. Prob still cleaning up from the Enjoy Illinois 300. So will get back after they open and when I've got my new tires. I might try a few runs with the NT05s and then the 555R2s. I like comparing small changes to see the difference. Between last time and the next time out I'll have the Trans tune, converter, and DS different already.

Why the 305/30/20 and not the 305/35/20 ?

The 305/35/20 is a better match for the stock 245/40/20 front. The 30 will be shorter unless you changed the fronts to something else.

[cjperformance]

Originally Posted by KingLT1

Why the 305/30/20 and not the 305/35/20 ?

The 305/35/20 is a better match for the stock 245/40/20 front. The 30 will be shorter unless you changed the fronts to something else.

I changed the front wheels to 20x10 w/ 285/30/20 NT555G2s.

I just went with 1LE spec all the way around... according to the nitto site, a 275/35/20 (original rear) is 27.56 inches and a 305/30/20 is 27.24 inches. The 305/35/20 is 28.43 inches.

I figured I was safe mimicking the 1LE sizes... it drove me nucking futz looking at all the different options and eventually just rage ordered something safe.

Now that you mention it, the 285/30/20 may be 3/4 inch smaller in dia than the 245/40/20's... so back stayed about the same dia and front may have gotten smaller

I had just removed my wheel/tire combo from my sig trying to clean it up Guess I'll put it back.

[cjperformance]

Just went out and measured. The 285/30/20 fronts are smaller in dia by about 1" than the 245/40/20, but I think with the addl width, they had to get smaller in dia to clear the strut. In any case the stock rear 275/35/20 and 305/30/20 are really close in dia.

[wnta1ss]

Originally Posted by cjperformance

Just went out and measured. The 285/30/20 fronts are smaller in dia by about 1" than the 245/40/20, but I think with the addl width, they had to get smaller in dia to clear the strut. In any case the stock rear 275/35/20 and 305/30/20 are really close in dia.

Here's what Chevy put for the front tire sizes in the regular SS and the 1LE (non-driven tire circumference). Note how the 245/40-20 F1 runonflat was listed as 2164 mm circumference, then the 285/30-20 F1 Supercar 3 was listed as 2123 mm circumference. Rears list the same for both, but really they are not, the 305/30-20 is slightly shorter than the 275/35, and makes the speedo read a little higher in my experience. Screenshot of stock SS vs 1LE below:

[laynlo15]

I didn't want to run the 275-35-20 as it is shorter then the 245-40-20. I still like the big tire look, I've never had a rub on my 305-35-20s. They just fill out the fenderwell much better. Not into the short tire look.

[lt4camaro]

[QUOTE=wnta1ss;11185356]Here's what Chevy put for the front tire sizes in the regular SS and the 1LE (non-driven tire circumference). Note how the 245/40-20 F1 runonflat was listed as 2164 mm circumference, then the 285/30-20 F1 Supercar 3 was listed as 2123 mm circumference. Rears list the same for both, but really they are not, the 305/30-20 is slightly shorter than the 275/35, and makes the speedo read a little higher in my experience. Screenshot of stock SS vs 1LE below:


Attachment 1101202[/QUOTE
285 35 20 = 27.9 inch diameter
275 35 20 = 27.6 inch diameter
245 40 20 = 27.7 inch diameter
305 30 30 = 27.2 inch diameter
285 30 20 = 26.7 inch diameter

[lt4camaro]

Originally Posted by laynlo15

I didn't want to run the 275-35-20 as it is shorter then the 245-40-20. I still like the big tire look, I've never had a rub on my 305-35-20s. They just fill out the fenderwell much better. Not into the short tire look.

the 275 35 20 is 27.6 inches in diameter, the 245 40 20 is 27.7 inches in diameter. the 305 35 20 is 28.4 inches in diameter, that tall of a tire should rub... lucky you they do not.

[KingLT1]

Originally Posted by lt4camaro

the 275 35 20 is 27.6 inches in diameter, the 245 40 20 is 27.7 inches in diameter. the 305 35 20 is 28.4 inches in diameter, that tall of a tire should rub... lucky you they do not.

They don't rub if you relocate the harness on the driver side rear.

[lt4camaro]

Originally Posted by KingLT1

They don't rub if you relocate the harness on the driver side rear.

I hear ya King, but to close for comfort for me anyway. That tall of a tire also hurts the 450- 475 horse cars as it robs some needed gear ratio LOL.

[cjperformance]

Originally Posted by lt4camaro

the 275 35 20 is 27.6 inches in diameter, the 245 40 20 is 27.7 inches in diameter. the 305 35 20 is 28.4 inches in diameter, that tall of a tire should rub... lucky you they do not.

I think laynlo put them on 9.5" wide rims too, instead of 11" wide, so maybe that tucks it in a bit.

[lt4camaro]

Originally Posted by cjperformance

I think laynlo put them on 9.5" wide rims too, instead of 11" wide, so maybe that tucks it in a bit.

A skinnier wheel doesnt have too much of an affect on the tread width, but does on the sidewalls. I believe it also makes the tire a little taller. Back space is critical to keep the tire/wheel out and away from the inside lower front section of the wheel house.