Author Topic: Recumbent trike  (Read 2492 times)

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Offline toglhot

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Recumbent trike
« on: January 17, 2017, 07:09:49 PM »
Thought I’d share this, someone might find it interesting. I was moved to write this because I can no longer ride my recumbent and probably never will again, what a barrel of fun this thing was. It's pretty well worn out now after almost 10 years use, but it makes a good shed ornament.

I’d always wanted a recumbent bicycle, but when I saw my first tadpole about 14-15 years ago, I just had to have one and set about making one. All in all I made four of them, trying out different designs, wheel sizes, gear changing mechanisms, steering configerations, and so on. This was my final, Everything either came from the tip or from my box of bits, except the front hubs, rear rim, S/S spokes, three chains, brake levers, cables and tyres.

Main frame section was made from Square tubing and the rear from 20mm round tube. Bottom bracket was cut from a bicycle frame and welded to the non adjustable front extension. A short tube was also added for front deraillleur mounting and a modified rear derailleur mounted underneath the extension for chain tensioning, Behind the cross beam I mounted a threaded bottom bracket section about 20 mm long into which a bottom bracket bearing retainer is threaded and a modified rear cassette threaded over that for intermediate gearing. On the main frame above that is another short tube onto which is mounted a modified front derailleur. Seat brackets are welded to the mainframe and under that the handlebar mounting. Behind the seat bracket on the main frame are another couple of brackets for chain idlers. The rear wheel carrier is attached to the the main frame below and the seat support at the top. Axle mounts where cut from 3mm steel plate and welded in place, they include a threaded section for mounting the rear derailleur. I also welded short 6mm round cable retainers at various points around the frame.
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King pins are bushed with bronze bushings. Welded to the kingpins is a centre bored 12mm stub axle, tapped to accept a 6mm bolt for wheel security. Also welded to the kingpins are steering arms and brake support extensions. Six bronze bushings ride inside threaded mounts on both ends of three threaded linkage rods. Two connect each wheel to a central pivoting lever system, the third connects the pivot to the under seat handlebar. Gearing is provided by different sized levers on the pivot.

Wheels are double walled alloy rims laced to alloy hubs via S/S spokes. Front hubs are from a wheelchair, rear hub is a standard five gear bicycle hub.

Seat is made of three sections, the two sections for back support are shaped to wrap around the torso slightly and include lumbar support. Squab is flat. No padding required due to body hugging nature of the seat.

Gearing is via a five speed cassette at rear (13-26) operated by standard bicycle derailleur, twin chain wheel at front (52/42) operated by standard front derailleur, and three intermediate gears mid cycle operated by a modified front derailleur. Rear chain is approximately 2.5 lengths and routed through two idler wheels. Front chain is standard length and tensioned by a modified rear derailleur. Intermediate cluster is a modified four ring cassette and is mounted on a bottom bracket bearing retainer and threaded into a shortened bottom bracket welded to main frame.

Homemade bar end shifters mounted on top, each side of U shaped handlebar service front and rear derailleurs and a modified front deraillleur mounted in front of the seat squab services the intermediate cluster

Front brakes are modified alloy side pulls operated by alloy levers. No rear brakes required.

Features and specifications
Ackerman steering
Centrepoint steering
Adjustable toe in
Geared steering
Bar end shifters
Side pull brakes
Weight 22kgs
length 1800mm
Width 780mm
Height 600mm
Track 740mm
Wheelbase 980mm
Seat height 150mm
Ground clearance 90mm (Frame) 50-60mm intermediate cassette
Gears 5 rear
2 front
3 intermediate
Wheels 20”

Kilometers. Lots, used this one for around 8-10 years riding around 20klm 4-5 times per week. Front chain ring and intermediate cassette now worn out and slipping. Unfortunately I can no longer ride this trike and probably never will again due to crook hips. The trike now quietly hangs from the shed ceiling, slowly gathering dust.

Recumbent bikes. I also made two short wheel base recumbent bikes, 20“ front wheel and 27“ rear wheel, Both had standard 5 speed cassettes at rear, 52/42 chainrings at front as well as an intermediate cassette mid way to raise the gearing. Unfortunately, chains kept coming off and the intermediate cassette made it very uncomfortable. But, in tests these things, due to their light weight and very high gearing, were incredibly quick.

Recumbents were banned from racing under the UCI in 1934 due to their superior speed.
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Offline Alan Loy

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Re: Recumbent trike
« Reply #1 on: January 17, 2017, 08:08:41 PM »
I understand the mechanical advantage of the recumbent bike ,it's just that they look like you can't see where you're going being so low and they are wide.  Are these really issues or is it just my perception?

Offline toglhot

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Re: Recumbent trike
« Reply #2 on: January 17, 2017, 08:35:20 PM »
I ride recumbent bikes and trikes as well as MTBs and road bikes, so from my point of view obviously you can see more from a road bike or MTB by virtue of the height advantage, to what advantage though?   All styles of bikes/trikes have advantages and disadvantages, personal preference is key, I probably prefer the recumbents, simply because I made them. For touring and general road use the recumbent wins hands down, for off road the MTB and if speed is your bag, a racing recumbent.

Offline edz

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Re: Recumbent trike
« Reply #3 on: January 17, 2017, 11:27:42 PM »
Cool .. A mate has built an electric powered one from  bikes he got from council pick up days [ For about $200 all up ]  still has the pedals but they dont do anything ..
 Instead of costing him $60  a week in fuel to drive his V8 the 8 k's to work and back each day  in peak hour stop start traffic,  he uses the almost clear bike ways and recharges the batteries at work for free .
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Offline toglhot

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Re: Recumbent trike
« Reply #4 on: January 19, 2017, 01:22:11 PM »
Here's a couple of forerunners, the red one was very, very quick.   The black one probably could have been quick but the steering was a bit too quick for my liking so I stayed in the slow lane when riding it.   The seating also wasn't very comfortable, particularly the red one.   
« Last Edit: January 19, 2017, 01:23:59 PM by toglhot »

Offline DrewXT

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Re: Recumbent trike
« Reply #5 on: January 19, 2017, 10:52:19 PM »
I've always wanted a recumbent, but never found any plans or been able to justify the price of a name brand

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Offline edz

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Re: Recumbent trike
« Reply #6 on: January 20, 2017, 11:20:11 AM »
Youtube for the build thats what my mate did .not sure which one but could start here .https://www.youtube.com/watch?v=KSGIl90Hrno
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