Initial Ideas on gears and chain..

These are some initial ideas on how to deal with shortening the chain and easing the ride by creating more efficient gears.

At the moment the gear ratio is 1:2.

The first option is moving the whole tray forward.  This could work for a minimal length shortening of the chain, however the flipside is that the tray may overbalance with too much weight.

This is a birds eye view of the basic frame of the cycle rickshaw:

The next idea is using a gear train method.  That is adding in an extra chain and two gears to create more efficency.  By having two chains the rider only has to pedal half as much to get two wheel rotations (this does not take into account any forces at play).

One option of this would be:

This is adding two more of the same diamater gears in so should not be a problem for manufacture.  Some questions are raised such as…

How much resistance is there because of weight?

How much harder is it to initially pedal?  Is this noticeably different to the current system?…How does this change with more weight in the tray?

Is there any “drag” from the green gear transferring the rotation?

The trade off for the increase in rotations is the ease of pedalling.

To look at two different gear trains….

The next option is introducing a second axle closer to the pedals.  This involves incorporating 3 more gears and a drive shaft…  This shortens the chain.

This involves changing around many parts,  and at this stage the benefit of shortening the change is not defined.  The trade off is the cost and ease of manufacture.  Also the more parts the more maintenance required.

2 thoughts on “Initial Ideas on gears and chain..

  1. Hey Jess and co. how’s it rocking? It looks like an auesome project your working on! I was wondering what sort of stuff you’d be up to over there. I’m working on a bike transport project as well atm, but its set in 2030 as part of a proposed new green development in Melbourne. I’ve got a blog running too so you can have a look see 🙂

    I was thinking, earlier you where talking of incorporating suspension, and people where saying it’d add cost and extra maintance to the bike. Suspension on the front’s no go, cos it saps all your power, and having back suspension can as well.

    But could you incorporate some sort of rubber suspension for the back wheels? I was thinking you might be able to work out a way to recycle rubber products like tyres, to create rubber pads, that would absorb some of the bumps. Might be too much extra weight… I’ll keep an eye on how you go anyhow, its cool stuff!

    Catch ya’s Tim

  2. hi,
    so this is a really good project – and one that can be taken a long way..
    So onto gearing..
    last year I ran a studio on designing load carrying bikes – rohan can fill you in on the good and bad bits of it – but one of the things that I found was that the gearing required to get the vehicle moving when loaded was crucial – particually in stop start sitautions like Ahmedabad traffic.
    One system that might be worth looking at is using a schlumpf type geared bottom bracket – see
    Given it is an NGO project you may be able to convince the company to donate the bottom bracket system for a set number of cycles – email them and see if they want to become partners.
    Keep the system as a single chain if you can – the more simple the drive train the more reliable and servicable.

    Floating the load bed on some rubber bushings may make some difference but any suspension needs to be treated carefully as any flex between the legs and arms, the drive train and the rear driven wheels will demand more energy from the rider – I would look into using bushings as a way of isolating any hard knocks and rebounding weight of the heavy goods being carted rather than trying to float the rider – the best way of cushioning the rider is a sprung saddle and some thick rubber hand grips.

    re: load – it would be worth trying to drop the center of gravity for the load area as much as you can – this may mean that you need to use smaller rear wheels – say 20″ / 406 as opposed the the 29″ ones that are currently used. Smaller wheels are theoretically stronger, and require less energy to get moving as large wheels.

    more comments in other posts

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