Gear/Tire Wizard not showing tire size input

[LittleRedRacer]

I'm not sure if this is working by design, but on the attached tune for my 98' Camaro M6 I don't see an option for tire size input in the "Gear/Tire Wizard". I see where I can input values for the tune on my G8, but not the Camaro.

What I get is the following when I bring up the wizard..
Gear-Tire-Wizard.PNG

And here's the tune in question..
98 Camaro Z28 M6 Stock - Disabled AIR DTC's + MAF.hpt

I need to re-calibrate the speedometer for a new wheel tire combo. I'm moving from 275/40/17 to 275/35/19 which is about a 1" difference in diameter.

[LittleRedRacer]

I did some digging through the forum and I think I found the answer. Seems like tire size parameters are not available in the older ECU's. https://www.hptuners.com/forum/showt...-to-3-73-gears