Component Help - Identification on Homebuilt Recumbent?

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Kerosene-Tin
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Joined: Tue Dec 02, 2014 9:47 pm

Component Help - Identification on Homebuilt Recumbent?

Postby Kerosene-Tin » Thu Oct 25, 2018 9:51 pm

Ive got my recumbent that is not only long but a mismatch of components, the story was shes the work of an engineer.. but looks as though as he got sick he just wanted it on the road while he still had time maybe.

6 speed shimano shifter, 7 speed cassette matched with some odd brand cranks and wellgo pedals..3 ring front chain ring and wheels that look like they come from a mountain bike.. and an unknown 20 inch wheel that contains a lizardskin tyre
infact its probably a mating of 2 mountain bikes with a tandem under the aging blue paint

She works though, I had to adjust the limit screws of the derailleur so it'd shift gear properly and not jam in the frame or spokes.. the brakes were non existant and not tensioned at all.. handlebar grips look like they came from somewhere in the 1980s along with a massive motor plate that seems to be in the right spot for some early mid-drive. I dont have much information on it other than it'd been sitting in a garage for 2 years after the builder got sick.. when it was originally built I dont know.. maybe before hub motors existed

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her components though puzzle me, the drive is complex and prone to failure as far as I can see

its driven by 2 small cogwheels that im not sure what they are, other than if either of them fails, breaks off or gets too old (unknown age) the bike is effectively disabled.. with its imposing size, its already taken a truck to get it here from where I brought it from a few weeks ago

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The drive chain to the single drive wheel it has, is prone to being crushed during a rollover, as evident by the bolt it has with no paint.. its not exactly straight already.. but not bent alarmingly so. just warped

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if anyone can help me identify the 2 cogs and where i'd find a replacement it'd be greatly helpful.. the chain that goes from the cranks to the center underseat sprocket that eventually drives the other side to the wheel is tensioned by what looks to be a newer shimano derailleur?

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theres no cable to this though so it lives its life tensioning the chain and sometimes not very well in the smallest gear

On another note too, the seat fabric seems brittle and fragile with a few small holes in that get bigger each time I touch it in the wrong place, likely originally strong material thats perished with age.. i'll have to cover it again. any recommendations?

Any help would be great. shes quite a puzzle.. a much loved one though :)

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Duck!
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Re: Component Help - Identification on Homebuilt Recumbent?

Postby Duck! » Fri Oct 26, 2018 12:31 am

It's difficult to tell exactly, but it appears the sprockets on the intermediate shaft (connecting front & rear chains) may be small chainrings from a MTB triple crankset, likely a mid-level 8- or 9-sp. model with replaceable rings, custom modified to suit, AKA welded onto the transfer shaft and not easily replaceable..... It may be a trick of perspective, but at some angles it appears the sprocket for the rear chain is smaller than the one for the forward chain, making for a reduction gear on the final drive.

There's not a lot you can do with that forward derailleur/tensioner given that it needs to be able to allow the slack for the triple chainrings. There are better specific tensioners, but they're not designed for multi-ring systems. Given that it's only dealing with the chain length for the three front rings, and not having to deal with a rear cluster, your best bet is to adjust the chain length so it's quite taut, with the cage pulled a fair way forward when on the big ring; when on the smaller rings it will take up the slack but not be too floppy. It will never be perfect, but should at least be acceptable.
I had a thought, but it got run over as it crossed my mind.

John Lewis
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Joined: Tue Oct 02, 2007 7:12 pm
Location: Albany. 400km South of Perth

Re: Component Help - Identification on Homebuilt Recumbent?

Postby John Lewis » Sat Oct 27, 2018 12:30 am

Are those sprockets bolted?
Appears so but one bolt missing and perhaps a weld in its place.

I'm wondering if they are just sprockets that have been drilled to take bolts.

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