kipibenkipod

Hi,
Is there a gearing system like rohloff, but for the bottom bracket?

Thanks,
Kfir

Speedo

Something like this one by Schlumpf?

Speedo

kipibenkipod

Thanks for the link.
This is a good progress, but still you need to have internal gear hub on the back wheel.
I'm looking for a regular hub in the back with one cog.

Thanks,
Kfir

Thasiet

Kfir,

Something similar to what you want can be found in a few exotic freeride/downhill mountain bikes, such as the GT IT-1, Honda RN-01, and Nicolai Nucleon. But if you're looking for a touring bike, this really isn't what you want.

kipibenkipod

Hi,
I have seen those, but they are heavy and just 7 speeds.
It looks like they will survive after we fade from the planet
I said Rohloff because its very lite compared to those gearboxes, and also have 14 speeds.

Thanks

rhm

Apparently there is/was a five-speed internally geared crankset called a Miyata FM-5 or something; in the folding bikes forum someone posted a Strida that had been modified with one. Very hard to find, at any rate.

Thasiet

Kfir, the Nicolai uses a rohloff as the gearbox. Also requires a proprietary rear hub for left side drive. Also costs 4800 euro for frame and gearbox.

kipibenkipod

Yes, now I understand. I saw this thing and didn't bother to read that its rohloff inside.
This is a nice adaptation of the rohloff hub as a front gearbox.
This is what I was looking to find, but, hehe, maybe 1/10 of the price
But it certainly nice to see people adapt known technology and use it differently then intended.
Why does it weights 6.3 kg? My guess it related to downhill where everything should be very stiff.

Thanks,
Kfir

kipibenkipod

Well, now I understand that 6.3kg is for the frame and the gearbox together.
I wonder what is the weight of the gearbox itself.

kipibenkipod

My intentions when I asked for gearbox like this, was, that it will let the rear wheel be lite without the rohloff hub inside. Also stronger. Was that the intention in the design of the Nucleon?
Thanks,
Kfir

kipibenkipod

Ok ok, hehe
People did think about this concept before and also went forward to standrize it
https://www.g-boxx.org

Regards,
Kfir

vik 

How would the rear wheel be stronger without the Rohloff? A Rohloff wheel has shorter spokes and is not dished which is the equivalent to a 36H/40H dished wheel. People use 32H Rohloff wheels on touring tandems which has to be a pretty brutal application for a bike wheel.

kipibenkipod

I do respect the way things are developed. But now
rohloff hub make the wheel heavy.
It should be in the crank or above like gbox, and let the wheel be lite.
Also then, you will be able to run the belt drive above the crank/chainstays and avoid the opening of the frame for replacing belt.

Kfir

vik 

The difference in weight of a Rohloff wheel and a Shimano hub/cassette/der is about 1.75lbs. I'm not sure I could tell the difference on a touring bike - especially once loaded up.

Another thing to consider is that my keeping the gearing in the hub you can quickly move the Rohloff to a 2nd or 3rd bike in minutes by just buying an extra shifter. I'm doing that and it means you suddenly get a whole lot more for your $$$ if you can run two bikes with the same Rohloff.

kipibenkipod

I agree with what you say.
I think you didn't understand what I said.
Its a single speed hub at the back and have the rohloff in the crank or somewhere near.
Apperently this was thougt about here: g-boxx.org Techtalk/FAQ's page
If this concept can be cheap, this is a great option for touring bike.

Oh, and again, the concept of sharing rohloff wheel between frames is good, and the g-boxx concept will not have it.

One other thing. Rohloff should be in g-boxx. Its better for a part that cost 1200$. Also it shouldn't be also a hub. Divide and concur. Rohloff will be gearbox and the hub will be a hub. Much better.

vik 

I think I am understanding you, but I don't see the advantage of trying to stuff 14 gears into the BB area and I don't understand how that would be any cheaper than a Rohloff. Ultimately if you want a wide gear ratio transmission you are going to use the same parts regardless of whether they are in the BB or a hub so the cost will be the same. Since the Rohloff is a proven product with a track record for touring applications it doesn't seem like there is a lot of motivation to change to something else that is unproven unless there are significant benefits.

tcs

If you go back to the formative days of bicycle gearing, 1900 to WWI, you'll find a number of bottom bracket multi-gear schemes. They lost out to internal gear hubs because they were on the wrong side of the speed ratio/torque multiplication and had to be stronger (larger, heavier, more expensive).

tcs