Capra build

[atyler14]

Hey guys! I am new to the RC crawler world. I am tackling a Capra build out of a 4ws RTR. I have selected hobbywing fusion pro for my motor. I want to run an axial 3 gear transmission. Where I am getting lost is matching pinion and spur gears, then the internal gears. I do not want to gear down so much that I start having overheating issues but I do want to get more gear reduction out of this rig. I know there is a compromise with low gearing and speed but don't know where I need to be to make this rig a mean crawling machine. Any guidance would be helpful.


This is the 3 gear transmission clone I am thinking about using to save some cash on my first build.

(https://www.amazon.com/Metal-Complete-SCX10-Gearbox-Transmission/dp/B08L7R4DFJ?ref_=ast_sto_dp)

 

[HumboldtEF]

The KV of your motor is also pretty important to the overall speed, what KV are you going with?

I know the Capra transmission isnt the most popular as its geared a bit high. However I've had no complaints about using it with a 1800 KV HH Revolver setup. Going with a slower motor can help to slow down a fast transmission. Have you considered keeping the Capra transmission?

You could use a gear calculator to run numbers on the gearing so long as you have an idea of what ratio you wanted. Personally I dont bother with that as I have a box of pinions and spur gears to play around with. I know thats not exactly budget friendly but neither is buying a new tranny that you want different gears for. By the way the only gears you'd potentially be changing is the pinion and spur, the internal gears in the transmission are set ratios.

Everyone likes slightly different gear ratios. On the rocks I like it slow-ish, for trail running I want more wheelspeed so I can bump it up obstacles. Terrain will also dictate what ratio you'll be best off with.

Anyway I think if you go this route you might just need a larger pinion to speed it back up a bit. There probably arent a ton of options for a faster spur gears out there, more options if you want to slow it down.
EDIT: nevemind you seem to want slow it down even more, you might not need a thing. Maybe just start with the 3 gear trans and test it out as is.

As far as overheating goes gearing down= cooler gearing up=hotter. You can gear down all you want!

Oh and one last pointer Amazon (IMO) is the absolute worst place to shop for RC parts. If you dont already use them check our RPP and Amain.

 

[Speedy-Triple]

I built a 3 link straight axle capra with the stock transmission and the smallest pinion (10t IIRC) with a fusion se 1200kv and is fantastically slow and runs pretty cool ... no overheating issues and very good low end control... it is pretty slow crawl. I would imaging that with the stock portal axles you can throw underdrive gears in the portals if you wanted to go even slower. The 1200 Se still has a lot of punch to make the capra jump and bust out when needed ... 2 in 1 is a plus for space saving... my understanding is that you will loose or must mod the interior to fit a 3 gear ... plus the skid needs to changed and still put weight higher ... my 3 link straight axle sits pretty low and has incredibly LCG so it gained a lot in performance since the swap.

 

[atyler14]

The KV of your motor is also pretty important to the overall speed, what KV are you going with?

I know the Capra transmission isnt the most popular as its geared a bit high. However I've had no complaints about using it with a 1800 KV HH Revolver setup. Going with a slower motor can help to slow down a fast transmission. Have you considered keeping the Capra transmission?

You could use a gear calculator to run numbers on the gearing so long as you have an idea of what ratio you wanted. Personally I dont bother with that as I have a box of pinions and spur gears to play around with. I know thats not exactly budget friendly but neither is buying a new tranny that you want different gears for. By the way the only gears you'd potentially be changing is the pinion and spur, the internal gears in the transmission are set ratios.

Everyone likes slightly different gear ratios. On the rocks I like it slow-ish, for trail running I want more wheelspeed so I can bump it up obstacles. Terrain will also dictate what ratio you'll be best off with.

Anyway I think if you go this route you might just need a larger pinion to speed it back up a bit. There probably arent a ton of options for a faster spur gears out there, more options if you want to slow it down.
EDIT: nevemind you seem to want slow it down even more, you might not need a thing. Maybe just start with the 3 gear trans and test it out as is.

As far as overheating goes gearing down= cooler gearing up=hotter. You can gear down all you want!

Oh and one last pointer Amazon (IMO) is the absolute worst place to shop for RC parts. If you dont already use them check our RPP and Amain.

The fusion is a 2300KV. I like the slowish on the rocks but with enough get up to it if I need to punch out I can.

 

[atyler14]

I built a 3 link straight axle capra with the stock transmission and the smallest pinion (10t IIRC) with a fusion se 1200kv and is fantastically slow and runs pretty cool ... no overheating issues and very good low end control... it is pretty slow crawl. I would imaging that with the stock portal axles you can throw underdrive gears in the portals if you wanted to go even slower. The 1200 Se still has a lot of punch to make the capra jump and bust out when needed ... 2 in 1 is a plus for space saving... my understanding is that you will loose or must mod the interior to fit a 3 gear ... plus the skid needs to changed and still put weight higher ... my 3 link straight axle sits pretty low and has incredibly LCG so it gained a lot in performance since the swap.

I found a 11T and 12T pinions that I am going to try in the stock transmission. The beauty of this hobby is the tinker with the setups and getting it dialed in with whatever the driver wants to do. I didn't take into account the skid. that's good information.