[CEPupper]

I was curious what the speed at redline in 1st gear for Z51 and non-Z51 given the different gear ratios.

I found an on-line calculator: Speed versus RPM calculator but I wasn't sure if the differential ratio was the same as the rear axel ratio.

Sorry if this is basic stuff but I'm not really a car person...

 

[LT1xL82]

Different names for the same thing. In this case rear differential ratio is the same as rear axle ratio.

 

[rdslon01]

Just be aware that the rear differential on the StingRay is also different (I think) based on if you have an automatic or manual. Check the specifications on the official Corvette website from GM.

 

[rdslon01]

CEPupper, also, do you know how to compute the tire's outer radius? This is NOT the number following the "R" in your tire's specification.

 

[Fdxpilot]

Both base and Z51 have rear ratio of 3.42 for manual tranny. Base A6 has 2,56 and Z51 A6 has 2.73 rear end.


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[rdslon01]

Both base and Z51 have rear ratio of 3.42 for manual tranny. Base A6 has 2,56 and Z51 A6 has 2.73 rear end.

Sent from my iPhone using Corvette Stingray Forum

Thanks for the definitive answers, FedEx Pilot!

 

[Randy WS6]

Don't the Z51 M7 manual trannys have a differant ratio than the non Z51 M7 , but with the same rearend ratio ?

 

[Fdxpilot]

Don't the Z51 M7 manual trannys have a differant ratio than the non Z51 M7 , but with the same rearend ratio ?

I'm not sure about all the ratios, but IIRC, the 1st gear in a Z51 MT is 2.97 while 1st in the base is 2.66

 

[rdslon01]

Randy, I am sorry: I was so wrong! I am going to delete my post above, and then give the information straight from a Corvette publication from Chevy's website. Hold on.

 

[rdslon01]

Here is the specification sheet directly from Chevy:

I hope that worked to upload the image that way. We shall see.

 

[rdslon01]

Okay, that seems to have worked.

Moderators, would one of you mind to take the above image about the specifications and sticky it somewhere? Thanks!

 

[rdslon01]

Finally, to finish off the last question about wheel radii, the equation to compute it is:

radius = zz/2 + xxx/25.4 * yy/100

where Pxxx/yyRzz are the tire sizes. Multiply the radius by two to get the diameter. By the way, these are for the overall wheel outer diameter (or radius).

For example, on the StingRay front, using the specification sheet given above for P245/40ZR18 we have:
18/2 + 245/25.4 * 40/100 = 12.85827 inches radius = 25.71654 inches outer diameter
For the SingRay rears with P285/35ZR19 we have:
19/2 + 285/25.4 * 35/100 = 13.427 inches radius = 26.854 inches outer diameter.

For the StingRay Z51 fronts with P245/35ZR19 we have:
19/2 + 245/25.4 * 35/100 = 12.87598 inches radius = 25.75196 inches outer diameter (note how close this is to the Base StingRay's fronts!)
For the StingRay Z51 rears with P285/30ZR20 we have:
20/2 + 285/25.4 * 30/100 = 13.366 inches radius = 26.732 inches outer diameter (again, note how close this is to the Base StingRay's rears!)

By the way, this is why Glen E. and others were telling someone last night in another thread that you can put the Z51 rims + tires on a Base StingRay with no problems: the outer diameter for Base versus Z51 is SO CLOSE!

 

[Randy WS6]

No problem , we're all learning this car. Ive worked on cars most of my life and never seen a car so complex , U.S. cars any way

Randy, I am sorry: I was so wrong! I am going to delete my post above, and then give the information straight from a Corvette publication from Chevy's website. Hold on.