unless you drill through the wheel’s thane you will have trouble finding wheel gears for 70mm wheels.
The common wheel gears are setup for Kegels or the more common Abec 11 Flywheels and clones (beware of thick “spokes” on clones vs normal/thin on original flywheels). Abec FW’s come in a wide range of sizes (76mm, 83mm, 90mm, 97mm, e-fly 107mm) - the smaller your wheel the lower your speed, but better torque. I just test fit a 40t on 76mm and there is not much room below the gear/belt - so not much ground clearance w/ the smaller wheels - just FYI and be careful.
83mm is usually the recommended starting point. the bigger the wheel the better it absorbs and rolls over rough roads/cracks/etc. So if you have really crappy roads going larger helps - but then be aware of wheel clearance and wheel bite. A symmetrical deck w/ cutouts for wheels works well (like Vanguard or similar), where a regular top mount (like a kick tail) with big wheels usually means you need risers to avoid wheel bite. It’s a preference thing - i like my board as low as possible, with as little risers as possible.
I would start with your ESC - figure out what voltage (#s battery) you want to run, then select gears to hit the speed you want with a speed calc (Calc RC app, multiple online calcs, etc.).
your example - 70mm - 190kv - 8s - 16/32:
first the 70mm is going to be a PITA. so i’d go to 76 or even better 83mm. Your gear ratio of 2:1 is good for speed, but not for hills or acceleration.
A “standard” setup like Enertion has w/ their pulley kit is 15/36 (for flywheels or clones).
So same setup w/ 83mm - 190kv - 8s - 15/36:
better 2.4:1 ratio for sure.
I’d also look at a 13/40 or 14/40 setup if you want a bit more acceleration, lower top speed and better hill climbing. It’s all a trade-off. Going up in voltage to 10s would help give more power, more speed, and still gear lower for hills and accel.
Some basic info you didn’t include - how heavy are you? Hills (and what %), or flats? What kind of riding do you want to do (cruising, commuting, hauling ass/racing)?
HTH - GL!
