[CamaroJim56]

Any problems in using 5th Gen tire sizes (245/45-20 and 275/40-20) on a 6th Gen? Tire height issue with speedo?



I don't particularly like the harsher ride on the lower profile tires.


Thanks for any help.


Jim

[arpad_m]

I'm no longer on the stock SS sizes, so can't physically check it for you, but that setup is 1" taller overall and the fronts might not fit under the strut perch (you need to check the available space), plus your speedo will be 3.6% off.

Wheel speed sensors will read 60 mph when you're actually doing 62-62.5 mph, but since GM, like everyone else, adjusts the displayed speed upwards to compensate for inaccuracies, this is not a huge deal IMO, your display will actually be closer to reality. You just have to remember there is no longer any "protection buffer" in case you should speed, not that anyone here would ever exceed the posted speed limits (right? ).

Other than these two aspects, it should just work, the front/rear ratio remains almost identical, i.e. your rake won't change adversely, and in fact, the extra sidewall will help fill the wheel wells a bit better.

You can check and experiment with various configurations at www.tiresize.com and www.wheel-size.com yourself if you want to fine tune your selections.

[vtirocz]

That's a significantly taller tire than stock. I personally wouldn't run it for these reasons:

• ~1.1" larger diameter than stock
• Negative impact on gearing. For manuals it would be like swapping from a 3.73 to a 3.58 axle ratio. Not huge, but in the wrong direction for performance.
• Speedometer off by 4%
• Stability control (including competition mode) and ABS wheel speed feedback would be off. I guess the rev / mile difference would be a simlar change front to rear so maybe this is not that big of a deal if you're not exploring the limits of the car.

I'm surprised to you're finding the stock setup harsh. I have a 1SS with the base suspension (ie. non-MRC) and find it to be comfortable and well damped. Harsh is not a word I'd use to describe it, but opinions vary!

[JT Camaro]

I cant fit a 275/40 on my ZL1 as it touches the fender line resting. Driving I see even less good

[CamaroJim56]

It might be the Nitto Motivos the previous owner put on, they suck in the rain, or at least lose their grip easier than I would like.

Originally Posted by vtirocz

That's a significantly taller tire than stock. I personally wouldn't run it for these reasons:

• ~1.1" larger diameter than stock
• Negative impact on gearing. For manuals it would be like swapping from a 3.73 to a 3.58 axle ratio. Not huge, but in the wrong direction for performance.
• Speedometer off by 4%
• Stability control (including competition mode) and ABS wheel speed feedback would be off. I guess the rev / mile difference would be a simlar change front to rear so maybe this is not that big of a deal if you're not exploring the limits of the car.

I'm surprised to you're finding the stock setup harsh. I have a 1SS with the base suspension (ie. non-MRC) and find it to be comfortable and well damped. Harsh is not a word I'd use to describe it, but opinions vary!