[getchapull]

https://tiresize.com/calculator/

According to this chart there would be a rev/mile difference of about 3 MPH at 70 MPH. Not a lot but still a difference.

What about a taller tire in the wheel well and rubbing cables at launch? Is that a concern?

I'm about to pull the trigger on some of these tires and the taller size has me curious if less than 1 inch sidewall height is worth the potential problems.

Anyone running 305/35/20s on a stock ZL1?

[JimGnitecki]

Originally Posted by getchapull

https://tiresize.com/calculator/

According to this chart there would be a rev/mile difference of about 3 MPH at 70 MPH. Not a lot but still a difference.

What about a taller tire in the wheel well and rubbing cables at launch? Is that a concern?

I'm about to pull the trigger on some of these tires and the taller size has me curious if less than 1 inch sidewall height is worth the potential problems.

Anyone running 305/35/20s on a stock ZL1?

When using a generic tire calculator, you risk errors because "same size" tires from different tire manufacturers are NOT exactly the same in exact width and exact height as the width / aspect "specs" imply. They vary. And, even when the UNloaded dimensions are the same, they can vary when loaded because one tire can have a softer sidewall than another, which results in that softer tire getting a bit wider, and a bit smaller in height, when LOADED with the car's weight, AND depending on what tire psi you run (e.g. 20 psi for dragstrip versus 30 psi for street).

All the tire manufacturers provide website charts that show the UNloaded diameter of each tire model and size, but also the tire's "revolutions per mile", which takes into account the circumferential EXPANSION with speed, and hopefully also at least a decent estimate of the countering REDUCTION in rolling diameter due to the flattening of the contact patch with the weight of the vehicle.

If your clearances are tight, and apparently they are on the Camaro, due to the wiring harness on one side for starters, you need to ask the experienced owners on the forum what they have found to be issues, as you have wisely done..

Jim G

[JimGnitecki]

Example of how 2 tires, the "generic" 245-40-R20 tire and 275/35-20R generic tire dimensions in the tire comparator referenced above do NOT match the the actual dimensions of the OEM LT1 Goodyear run-flat 245-40-R20 rear tire and the Nitto 275/35-20R:

Width of 245/40-20R tire in comparator = 9.60"
Width of 246/40-20R tire OEM actual Goodyear = 9.80"

Width of 275/35-20R OEM tire in comparator = 10.80"
Width of 275/35-20R tire Nitto actual = 10.94"

Be careful.

Jim G

[StanZL1]

I have a set of stock size 555R2 and love them on my ZL1. 4 years as my street set in Michigan, 25k miles. Driven 3 seasons, used in rain and even a little bit in light snow a few times. Also used them on track at road courses like Mid Ohio when wet, or when my SC3’s are corded. Good choice IMO.

[JimGnitecki]

Originally Posted by StanZL1

I have a set of stock size 555R2 and love them on my ZL1. 4 years as my street set in Michigan, 25k miles. Driven 3 seasons, used in rain and even a little bit in light snow a few times. Also used them on track at road courses like Mid Ohio when wet, or when my SC3’s are corded. Good choice IMO.

1. Did I understand your posting correctly - You've gotten 25,000 miles out of ONE set of 555R2 tires?

2. And the stock width of the rear tires on the ZL-1 is pretty wide at 305mm. That actually worked on "light snow"? At what ambient temperatures?

I am asking these questions because I am having my 275/35-R20 555R2 tires put on my car on 11-24, and we do get snow here in Alberta Canada!

Jim G

[laynlo15]

Originally Posted by StanZL1

I have a set of stock size 555R2 and love them on my ZL1. 4 years as my street set in Michigan, 25k miles. Driven 3 seasons, used in rain and even a little bit in light snow a few times. Also used them on track at road courses like Mid Ohio when wet, or when my SC3’s are corded. Good choice IMO.

I run the R2s on the street and I'm impressed with there ability to hook on most pavement. But, your mileage is pretty impressive, I've had several sets including on my C7 for the street and my drag pack for the drag striip. I was hoping to get 10k to 12k out of mine, I don't abuse mine on the street with 707 at the wheels so after your post of 25k I'm feeling pretty good about getting higher miles then I expected. Good job.

[KingLT1]

Originally Posted by getchapull

https://tiresize.com/calculator/

According to this chart there would be a rev/mile difference of about 3 MPH at 70 MPH. Not a lot but still a difference.

What about a taller tire in the wheel well and rubbing cables at launch? Is that a concern?

I'm about to pull the trigger on some of these tires and the taller size has me curious if less than 1 inch sidewall height is worth the potential problems.

Anyone running 305/35/20s on a stock ZL1?

If the height is less than 1" front to back then you are fine. I relocated the harness on driver side rear and put a push clip in the fender liner to give it more clearance on my SS.

[StanZL1]

25k miles on 2 ZL1’s in 5 years.
mostly street miles, half dozen 20min dry & wet track sessions.
They are on the car sitting on freezing cold garage concrete all winter while my SC3s are in the basement.

Driven a few times in abt an inch of snow at 30F.
Not by choice, kinda got caught, and wouldn't do it regularly.


Thus far, would buy again without question.

[Z OH 6]

Anyone used a 315/35/20 Nitto 555R2 instead of the 305/35/20 on the back of the ZL1?

[RobZL1]

Originally Posted by Z OH 6

Anyone used a 315/35/20 Nitto 555R2 instead of the 305/35/20 on the back of the ZL1?

FWIW, I'm running a 555G2 in that size.

EDIT- Scratch that. Mine's a 30-series, not a 35.

[JimGnitecki]

Originally Posted by StanZL1

25k miles on 2 ZL1’s in 5 years.
mostly street miles, half dozen 20min dry & wet track sessions.
They are on the car sitting on freezing cold garage concrete all winter while my SC3s are in the basement.

Driven a few times in abt an inch of snow at 30F.
Not by choice, kinda got caught, and wouldn't do it regularly.


Thus far, would buy again without question.

Wow! THAT's a testimonial! Just to clarify further: When you say 25k miles, do you mean "and still using" or "they are nearing a need for replacement imminently"?

Jim G

[zain]

Any 0-60 improvements with the R888R or 555R2 over the PS4S?

[SteveV]

Originally Posted by getchapull

https://tiresize.com/calculator/

Anyone running 305/35/20s on a stock ZL1?

Yes, I am running the 305/35/20 on a stock ZL1. I thought I was ordering the 30 series. But, when these showed up, I mounted them anyway.

Have to say, nothing rubs and they stick fantastic!

I have about 3500 miles on them now and am getting ready to order another set. Really don't think they will pass inspection this year.

[arpad_m]

Originally Posted by SteveV

Yes, I am running the 305/35/20 on a stock ZL1. I thought I was ordering the 30 series. But, when these showed up, I mounted them anyway.

Have to say, nothing rubs and they stick fantastic!

I have about 3500 miles on them now and am getting ready to order another set. Really don't think they will pass inspection this year.

Why wouldn't a tire with a higher than stock max load rating pass inspection? Or do you mean you wore the set out in just 3500 miles? (That would take some serious burnoutage, methinks.)