Internal Gear Hubs as transmission?

[DougC]

I know this has been asked in the past but haven't been around for a while and want to know if anyone has tried doing it since.

I know it has been found that a Shimano internal-gear hub (used as the rear-wheel hub) will not withstand very much torque for very long driven straight off an engine, such as what motorized use gives it. What I am pondering is if anyone has attempted to use an internal-gear hub as a sort-of "jack shaft", in a GEBE-style system.

In the GEBE bikes, the engine has a toothed pulley about 1 inch across, and a belt that goes to the rear wheel sheave, that is about 16 inches across. Like many bike motor kits, it has a major problem with climbing hills, especially when starting.

If you took a 3-speed or 7-speed Shimano internal-gear hub (IGH) and geared it 1:1 with the engine's output, and then geared the IGH's output roughly 1:16 to the rear wheel however you had to, then the IGH is going to spin a lot of RPMs but it will not be under very much torque at all. From all I've read, it's high-torque use that kills IGH's more than anything.

The Nexus-7 has a 244% range (top to bottom) so it should be able to handle hills much better, yet still may add some speed on the top end.

?

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[GearNut]

I don't know how well the internals would stand up to high speed use.
Pedaling under human power is not that fast, and that is what these hubs were designed to handle.
I don't know, but I wonder?
Right now I have a question posted concerning the differences between 2 kits. Hill climbing power is important to me.
I really like the GEBE kit due to their simplicity. I now have one count of GEBE's do not like hills. Thankyou!

 

[Fabian]

Maybe this can be of help

Shimano now has a new cassette available - HG61bh which has a 36 tooth cassette sprocket.
Some bike shops will tell you it does not exist and they will be adamant it does not exist as i've been through this most frustrating and infuriating process with shop staff when trying to order the cassette.
Let me tell you though, the 12-36T DOES EXIST and you can purchase the optional 11 tooth lockring to make an 11-36T in a 9 speed cassette.

http://www.shimano.com.au/media/tec...02/SI-1ZX0A-002-ENG_v1_m56577569830677475.pdf



Now this company makes some serious specialist hill climbing cassettes and also sells the individual sprockets to make your own custom ratio cassette.
Scroll down to "titanium Cogsets - does an 11-39T (yes a 39 tooth cassette sprocket) take your fancy and they say (i've emailed actiontec) that the 39 tooth sprocket will work using a standard long cage Shimano Deore rear derailleur.

http://www.actiontec.us/prices.htm

Hope it's of help

Fabian

 

[DougC]

Maybe this can be of help

Shimano now has a new cassette available - HG61bh which has a 36 tooth cassette sprocket. ...

You seem to be talking about external-gear hubs (the ones with a number of exposed sprockets, and the chain flips back and forth between them). They're not as useful here because they have to be rolling in order to change gears.

The Nexus hubs can switch gears standing still, which (in order to start UP a hill) is what you'd need to have.

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Last I heard, the only kit that seems to do well climbing hills is the NuVinci hub.
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[Fabian]

Hi DougC

I agree with your comment and i did understand that you were talking about internal geared hubs.
Maybe i was wrong, but i got the impression you wanted a very low first gear, a climbing gear or crawler gear for standing starts up a steep hill.

I just gave an alternative method of solving a very low crawler gearing issue, that doesn't require the extra gear reduction of a geared hub.
A simple external sprocket is far more simple and achieves the same result as a super low first gear using an internal geared hub.

From my experience, every time you add complexity into the system, you add unreliability into the system.
Personally, the internal geared hub system really appeals to me, as it doesn't have all the filthy grease and mess associated with a chain and sprocket drive system.
Only one thing keeps me away from an internal hub - "what if something goes wrong 50 kilometers from home" - you are completely stuck, can't even pedal the bike home as the hub may have totally locked up of fails to transfer any drive at all.

At the worst case with a chain and sprocket system, you can pull out your chain breaker and bypass the rear derailleur and run the bike as a single speed unit till you get home for major repairs.
That's the only reason why i run a chain and sprocket system, because all the working parts are on the outside.

In no way am i saying an internal geared hub is inferior - if i could buy an ultra heavy duty hub specifically designed to be used with a Chinese motorised kit and heavy loads, it would be on my bike tomorrow.

Fabian

 

[give me vtec]

if you are thinking about an internally geared hub the nuvinci is the only way to go. A little pricey but you definitely get what you pay for. Its pretty much indestructible up to 7hp. I have one on my felt... amazing piece of technology.

 

[Fabian]

""""rated to 7hp"""" that incorporates a power saftey margin that gets my attention.

Going straight to google to check it out.

 

[give me vtec]

""""rated to 7hp"""" that incorporates a power saftey margin that gets my attention.

Going straight to google to check it out.

I would go to their site and read the instruction manual... I believe there is a .pdf you can download. There is also a .pdf of all the research, and results of their testing. There are quite a few people here that can vouch for this thing including me.

Here decide for yourself... I think you will be amazed at this thing. And the best part is its maintenance free.

http://www.fallbrooktech.com/Nuvinci.asp

 

[Fabian]

It's got me sold: The NuVinci CVP hub has an industry-leading six-year limited warranty

Thanks so very much 'give me vtec' for informing me of this product.
With the Nuvinci hub (if it's as good as the manufacturer suggests), all other internally geared hubs have become obsolete (like a 386 computer) and a complete waste of time; even giving any thought thinking about them.

Thanks again give me vtec for posting that information.
Can you please put up hi-res photos of the hub installed in your bike.

Cheers Fabian

 

[loquin]

BTW - Staton sells the Nuvinci kit.