Manual 2 speed hub for mini bike, without jackshaft?

I'm a victim of dumb luck. I was so successful in mating a 1 HP BLDC motor, and a Nuvinci 171 auto shift to a rescue mini bike frame that I have a real, really efficient, hill climber.

https://endless-sphere.com/forums/viewtopic.php?f=12&t=89188

But I'm greedy, and want some more top speed with it. All of the 2 speed shifters I can find involve the use of a jackshaft, and between chaining from my motor to a jackshaft to my Nuvinci to wheel sprocket, I don't have the room for another jackshaft. So, what I would like is a mini bike, manual, 2 speed IGH, with a drive ratio of between ~1.6 and 2.0. I find that I have enough twist to use such an IGH as a transfer case, with "high" and "low" settings, just like my 4wd truck. My Nuvinci only "sees" the speed of it's output sprocket, so it would shift at the same motor rpm it's programmed to shift at (explained in my link) , no matter the position of the IGH. Again, just like my truck.

Not askin' for much, eh? I know, I know....

No responses, which I understand. I've been looking.

So how'z about the next, best thing. Has anyone installed 2 rear sprockets, with enough spacing between them, and the ability to slide them back and forth, ~1/2"? Then, run a chain idler to accommodate the extra chain from the smaller sprocket? That would just be a lift and separate manual move, involving nothing more than greasy fingers. I'll be checking that out, and will share findings. Thanks for reading my questions, folks...

I think it's that your question is too unclear. When you say 'Hub' around here people start thinking hub motor. You have a shift, now you want a second shift? Overdrive. And you're right, this is too small a bike, (It would help to see a picture) so you have to abandon the idea. Can you simply come up with a bigger spread in the gear ratios?

There are some 2-speed "single" freewheels around; most of them have only 2 tooth differences between gears. Any of them will go on your N171-- but mind you, you'll need to have a set of special tools to remove the old freewheel.

The only 2-speed, manually shifted internal gear hub I have ever been aware of was made by Bendix. It was made in the 1950s.

Dauntless said:

I think it's that your question is too unclear. When you say 'Hub' around here people start thinking hub motor. You have a shift, now you want a second shift? Overdrive. And you're right, this is too small a bike, (It would help to see a picture) so you have to abandon the idea. Can you simply come up with a bigger spread in the gear ratios?

Click to expand...

There are 7 pictures of my bike and its innards in the link from my original post. As well as a complete description of it. And yes, I want a "second shift". Actually, more like the analog I described, a "transfer case", a "high/low", a "dual range" - get it? It's about as clear as I can be.

I think my lack of response is for the good reason that I am asking for something that does not exist. Dual range mopeds, mini bikes, and motorcycles were a thing 40-50 years ago, and they got what they wanted with either jackshaft shifters, or dual ranges built into existing transmissions. They both make sense as better alternatives to mini bike internally geared hubs. They can be stronger, easier to get at, and if you are suspended, they don't add to unsprung weight. Hence my last post of earlier today, asking about dual sprockets and a chain idler, changeable with greasy fingers (i.e. no derailleur).

And nope on the "gear ratios". The Nuvinci hub actually has a great "spread" of ~3.6. But as I said, I'm greedy, and want a dual range too...

Chalo said:

There are some 2-speed "single" freewheels around; most of them have only 2 tooth differences between gears. Any of them will go on your N171-- but mind you, you'll need to have a set of special tools to remove the old freewheel.

The only 2-speed, manually shifted internal gear hub I have ever been aware of was made by Bendix. It was made in the 1950s.

Click to expand...

Thanks, Chalo, but that doesn't really get me there. Yes, I have the tool to remove the 171 freewheel. but it goes on the input sprocket. If you click the link on my first post you can see that I am using the N171 as a transmission, not as a hub. I have it suspended on steel bars. The output sprocket is a 44 tooth, mounted to the right side spoke holes, using Staton Inc custom mounting hardware. I want to keep the ratio between my motor, jackshaft, and Nuvinci input sprocket constant because I have it programmed to keep my motor speed at a constant 350 r/m, from low to high ratio. Since my speed sensor is on my output, any change in input ratio would effect motor speeed. The ideal Macgyver for me would be steal the lessons learned from someone who has taken a Sturmey Archer 3 speed, and mounted it in a standard mini bike hub.

Basically, I want the ability to climb hills (including the side of an earthen dam) when visiting my brother in law's land, AND to be able to do 20-25 in the city so I can go grocery shopping electrically. All by flipping a lever...