Help understanding/converting gear ratios (HPI & Axial)

[HumboldtEF]

I'm working up some ideas for a new scratch build I'm doing and so far I have the axles selected and thats it. I'll be using a set of narrowed SCX10.2 axles (by Beef Tubes).

I dont plan to run a SCX10.2 tranny but I might, anyway I'm leaving my options open and right now I'm more curious about how well the HPI Venture Tranny and transfer case would pair with the SCX10.2 axles ratio wise?

I found the ratios of both axles

SCX10.2 3.75:1

HPI Venture 3.31:1

These seem close enough that they might work but I'd love to hear others opinions on this. and I suppose thats only part of the picture, theres the trannies too, which I'm struggling to compare.

SCX10.2 has a FDR of 40.44 which I believe is a typo (range is 33.69-54.15)

HPI Venture is (drivetrain ratio) 7.6:1

But I dont know how to convert or compare the decimal value to the fractional value (?)

Any guidance would be appreciated.

Picture of my mock up for the heck of it

[Voodoobrew]

Basicaly the scx10 2 axles will be a little bit slower with slightly less torque twist and more torque.

The HPI transmision is married to the spur gear,
The spur gear can be either 60t (stock) or 56t.
The HPI transmission ratio is 1.53:1 but it also uses a divorced transfer case which is 1.5:1
Together the HPI transmission and transfercase have a gear ratio of 2.3:1

The Axial transmission can use a massive variety of pinions and spur gear combos
The axial scx10 2/wraith/ax10 transmission is 2.6:1 so again slightly slower and more torque then the HPI 2.3:1

there is a link in my signature where you can mix and match transmissions and transfercases and calculate gear ratios and speeds.

Originally Posted by HumboldtEF

SCX10.2 has a FDR of 40.44 which I believe is a typo (range is 33.69-54.15)

This is not a typo, stock axial 13t pinion and 56t spur is 40.44:1 FDR
HPI Venture is (drivetrain ratio) 7.6:1, this drivetrain does not include the pinion and spur. so 7.61*4=30.44 or 30.44:1 (pinion and spur is 4:1)

40.44 is the same as 40.44/1 or 40.44:1 for every 40.44 times the motor turns, the wheel turns one time. To change the decimal value to a fractional value just divide by 1 4.5 is the same as 4.5 over 1 or 4.5/1

[HumboldtEF]

Thanks Voodoobrew! That was very helpful