8/14/2006

Chinese tricycle retrodirect thingy

Most of the trikes I had the opportunity to inspect in China had some serious mechanical problems like this clapped out trike. Lots of them had no longer functioning brakes, and weird long droopy chains. There was obviously more going on with some of them than single speeds, but I was unable to crawl around under them long enough to figure it out.

When I went down to albuquerque to pick up the Flying Pigeon from Craig Degenhardt I got a chance to ride and inspect his chinese trike:

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It sports a nice two gear system mostly called retrodirect gearing. Two independent single speed freewheels are mounted on the rear wheel (or drive shaft in this case). The chain runs from the front chainring around one of the freewheels, around an idler, then backwards around the second freewheel and then back to the chainring. The effect is that you engage one freewheel when pedalling forward (while the other rotates backwards) and get one gear ratio. When you pedal backwards you engage the second freewheel (while the first one rotates backwards) and get a second gear ratio. Despite the fact that you are pedalling backwards, the bike still goes forwar, see? See some clean photos of a hirondelle retrodirect here with a different description if mine is too muddled.

Here is the whole drivetrain:

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The forward drive is the larger gear, the reverse pedalling drive is the smaller gear. The idler is at the bottom of the photo for reversing the chain over the second freewheel. The spring seen to the left of the freewheels are for disengaging the gears, which is accomplished by the orange tipped lever on the non drive side.



closer on the back bits:

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The pulley looking thing behind the freewheel is the brake drum.

Brake is operated by hand or foot via the lever here:

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The brake lever is attached to a rod going back to a leather strap which tightens down on the drum to slow the bike:

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Ah! It is all so clear now!

The reverse low gear is really really low, but the chain friction is really really high, so by pedalling backwards you can lump the trike up steep little hills or get it going while it is loaded.

Anyhow neat bike. Clear as mud?

9 comments:

Anonymous said...

Great pic's .....BUT you left out the second "D" in my name.

Craig Degenhardt

tnkey said...

Gee and the all these bikes I saw in China weren't all hammered junk after all. But I did think that it was neat how they all had 2 extra feet of chain so they would never need an add-a-link. Although this is the first non flat bed I've seen.

Anonymous said...

Great work on these bikes. I am looking to buy a new chinese tricycle like this one to take my daughter to school but haven't yet find a chinese manufacturer or exporter. Would you know of any, please? Thank you.

Tarik Saleh said...

Hey Latest Anonymous,
Thanks for reading. Here are my suggestions:
1. contact flying pigeon NYC they might have a lead.
2. Get a bakfiets through someone like clever cycles The dutch version is a bit more nimble than the chinese...
3. Contact Yellow Jersey in Madison, they bring in Indian bikes and may be able to find equivalent trikes from india.

Good luck and let me know if you have any luck

Nils said...

Thank you!
Great explanation! You can't imagine for how long I have been searching :-)

Zmeden said...

Hello! Do you know where I culd get one of theese (exept in China of course)? lol I don't want a new one why? XD It would only get wrecked up again in this country. I'm from Slovenia and so I'm wondering if you know anybody from (east) europe who is selling theese bikes (used ones like I said I don't need a new one lol)? Thank you ^^ ~Zmeden

Tarik Saleh said...

Zmeden,

No idea in your case. I would try to find an importer of chinese goods and see if you can convince the owner to import you a trike next time they are in china.

Good luck and let me know if you have success!

electric wire rope hoists exporter said...

Really very nice pics......

piloto said...

Thanks for this post... I`m searching for informations about those chineses trikes for long time.. thanks! I`ve a project to construct trikes for recycling collection in Brazil.... precious informations!