2.low transmission in Capra with flat skid

[NScaleJason]

Long lurker, first post.

I got a 3d printer, printed a flat skid for the 2.low transmission, and it printed off nice. Then I found that I needed a riser to prevent the motor from hitting the link attachment. Downloaded a riser file, printed it, and mounted the transmission. Everything was looking good until I got it all mounted up in the Capra frame. The rear drive shaft rubs on the tube frame.

I didn't find anything on an internet search, so I wanted to post something to help others before they go through so much.

I know this is the knockoff transmission, but still not really happy with it in any situation. It's just awkward to try and fit straight between chassis rails, have to chock it sideways to fit, get smaller motors, make risers, doesn't fit well with the upper links, etc. I know there's too much out there to make things universally "plug and play", but slight changes in the "engineering" would help bring it closer to a universal fit.

 

[MVRCA]

Unfortunately you picked the wrong transmission for this platform. Because the Capra is a portal, you really want to do the gearing adjustments in the portal housing, and then the ring gear as needed. You don't need to have reduction in the transmission.

Here is the version we used: https://dluxfab.com/HamBerger-Transmission-p80064413

 

[TeknoJ]

you said it.

 

[MVRCA]

For sure!

We we design crawlers, the conversation is always the same:

1. What axles are we going to use?

2. What is the frame layout?

3. What is the transmission?

Once we answer those three questions, then the detailed work begins.

One of the biggest reasons transmissions are not standardized is the ring and pinion gearing as well as the tire size. There is such a crazy wide range that a "standard transmission" is nearly impossible. Gearing, overdrive, rotation direction, axle ring and pinion location, and link position all cause their own unique headaches. We have a 2.2" Capra build in the showcase, and if there are any questions you may have, please let me know and I will help where I can.

 

[NScaleJason]

Thanks for the responses. I was hoping to slow the output down through the transmission. Seeing others install the 2low in portal axles and then finding the purpose designed 3d file for the flat capra skid with 2low transmission mounting holes made me think these things would work/go together.

The 2low is wide so it seems it would be well suited for a wide skid plate like the Capra. It doesn't really fit unless you have a shorty motor in skinnier frames or unless you install a riser. Even then, sometimes it has to be mounted on an angle to work. Raising the gears up so they could go over the side of a typical C-chassis frames-meaning the motor could then shimmy inside the frame rails (and out of the way of the links) would have been a potential solution to making it more "universal." Or having the mounting holes more towards the outside edges and therefore the placement on the skid plate could be shifted (right now a good place for the mounting screws happens to be where the lower links are located).

Some engineering annoyances for me:
Capra 4WS crawls well, but the included ESC/receiver is already maxed out so adding a servo for the dig function means $$$ (Vanquish, Redcat, RGT among other brands actually have open channels for some expansion)
Long ago I got an Injora chassis for the Jeep 4dr hardbody. The forward motor mount was in the way of the steering servo if it was axle mounted. Chassis mounted made the servo hang well in front of the chassis frame to avoid the motor.
I just bought a RGT Challanger Pro. Tried to open the body shell only to find that the new plastic bed insert hits the frame and prevents it opening.
Redcat Ascent Fusion runs well for me, but the battery strap doesn't hold the battery in place on steep slopes.
I know nothing is going to be perfect, but it's these little things that make me wonder who's pushing these things into production either saying "I see that as an acceptable issue" or have never picked up the model in person.

Side note. I installed mini servos into the two figures' heads. Driver's head turns with the front steering, passenger with the rear. It's neat in idea, but hard to notice when you're driving around.

 

[MVRCA]

Well, as you can see the 2 Low is not the ideal option. Our Capra creeps mighty slow, so I'm curious as to the math behind the gear reductions in the 2 low Capras. Other than finding a great way to increase torque lift of the front passenger tire ( not good), the 2 low is a solution looking for a problem in the Capra.

The Capra has centered diffs and an axle mounted servo ( 4 link all around ), so the offset output on the 2 Low is also going to give you fits.

The 2 low can be made to work, but I can't fathom a single reason why to use that transmission in the Capra.

 

[WickedFog]

Well, as you can see the 2 Low is not the ideal option. Our Capra creeps mighty slow, so I'm curious as to the math behind the gear reductions in the 2 low Capras. Other than finding a great way to increase torque lift of the front passenger tire ( not good), the 2 low is a solution looking for a problem in the Capra.

The Capra has centered diffs and an axle mounted servo ( 4 link all around ), so the offset output on the 2 Low is also going to give you fits.

The 2 low can be made to work, but I can't fathom a single reason why to use that transmission in the Capra.

I really wish Horizon Hobby would wake the hell up and bring the kits back. I so wanted to build a Capra.

Yeah, that doesn't seem like it would be an upgrade huh.

 

[MVRCA]

I really wish Horizon Hobby would wake the hell up and bring the kits back. I so wanted to build a Capra.

Yeah, that doesn't seem like it would be an upgrade huh.

The RTR is $100 off on sale. Why not grab that, shell it out, and then build up something slick?

 

[WickedFog]

The RTR is $100 off on sale. Why not grab that, shell it out, and then build up something slick?

View attachment 210069

Yeah, that's my plan, one of these days. But it's just not the same. And the kit was a lot cheaper. I kinda hate buying electronics I don't want. I'm just gonna wait til you sell yours

 

[MVRCA]

Yeah, that's my plan, one of these days. But it's just not the same. And the kit was a lot cheaper. I kinda hate buying electronics I don't want. I'm just gonna wait til you sell yours

That's terrible!!

 

[MVRCA]

And no way I'm selling this..!

 

[WickedFog]

And no way I'm selling this..!

View attachment 210415

Yeah, I didn't figure you would. I wouldn't either. I might grab one one of these days. Probably about the time Horizon discontinues them

 

[MVRCA]

Yeah, I didn't figure you would. I wouldn't either. I might grab one one of these days. Probably about the time Horizon discontinues them

Do it! We can get you lined out with all the custom parts we developed. Our Capra eats up regular Capras with ease.

 

[WickedFog]

I'd be all over it if we had even a pile of dirt to climb here. When I bought the Ryft there was a gravel quarry right next door. The mountain of dirt had weathered into the perfect rock bouncer hill climb. I bought the Ryft and they closed the quarry and turned it into a field right before we got the kit together. We were pretty bummed.

 

[MVRCA]

Well crap.

 

[WickedFog]

Well crap.

It's ok. I like building them and looking at them more than anything. When my kid gets old enough to drive, there's a place north of us about 45 minutes that just might even make you jealous. It's just south of Attica, where Axialfest is held. And all the area up that way looks like this when you get off the beaten path. This is Turkey Run State Park.

 

[MVRCA]

That's lovely indeed, but me and wet rock don't mix. I have the grace of a water buffalo.

 

[WickedFog]

That's lovely indeed, but me and wet rock don't mix. I have the grace of a water buffalo.

You will get wet on this ride