# Building a Recumbent



## Night Train (1 May 2008)

Always one to save money when I haven't got it I have been thinking of building a recumbent. Has anyone here done this before?

I am still thinking about a cargo vehicle that I can use for work so it will probably be along the lines of an AVD Stablemate. However, despite having some engineering background I only have a wood workshop and some heavy engineering tools. I am sure that I could build one that weighs 400kg but that would be pointless.

Are there any specific parts that I would have to buy? I am figuring I will need brakes, gear sets, pedal and chainset, general cycle components, etc. Are there wheels that would be easy to convert to single side mounting or are they specials?

If there is anyone in the Manchester or North West area who is happy for me to measure up their recumbent so I can get some dimensions that would be really helpful.

Any advice would be much appreciated.

Thank you.


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## byegad (3 May 2008)

Visit the BHPC site for details on how to build a 'bent.


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## Night Train (3 May 2008)

Thanks for that pointer, saved in my favorites now.


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## mickle (3 May 2008)

If you can make it over to York we have 15 or so recumbents you may try.


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## Night Train (3 May 2008)

Thanks Mickle, I am sure I can get over there at some point. I've been several times but have only driven around droping off and picking up, I've never managed to park yet.
Where am I looking for?


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## Night Train (3 May 2008)

Found this on building a recumbent.


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## ufkacbln (3 May 2008)

WISIL

A good base for all things recumbent!


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## Night Train (3 May 2008)

Thank you Cunobelin, looks a very extensive site.


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## PrettyboyTim (6 May 2008)

I like the look of this recumbent, if only because it doesn't require any welding


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## Hilldodger (7 May 2008)

Building a recumbent is easy and we've built loads at Cyclemagic.


Basically, you weld loads of stuff together and then angle grind off anything that doesn't look like a recumbent.

Hope that helps

Seriously, try and ride as many as you can before you start building and expect to make several alterations until you're happy.


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## Night Train (7 May 2008)

I want to collect the essential bits first. Chain rings and pedals, front wheels, rear wheel(s) and then start mocking up in wood.

Once I have the form worked out I can then look at the structural requirements and see if I can do it all in wood or if I start looking for nice bits of tube.


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## mickle (7 May 2008)

Wood! He said wood! Pssshht! Fnaar!


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## Night Train (8 May 2008)

Nothing wrong with wood. Wood is good.


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## tdr1nka (8 May 2008)

Oh Mickle,

Hows about a funky wooden motor cycle?


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## Night Train (8 May 2008)

I was thinking more along these lines.


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## tdr1nka (8 May 2008)

Night Train said:



> I was thinking more along these lines.



I thought you might be thinking more along these lines?


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## Wobbly John (14 May 2008)

That's my one.


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## NickM (16 May 2008)

Hilldodger said:


> ...Basically, you weld loads of stuff together and then angle grind off anything that doesn't look like a recumbent...



LOL!   

To avoid re-inventing the wheel recumbent and avoid all those mistakes that others have been generous enough to make before you, you need a copy of this little book.

Or there's this one, with some intriguing designs that can be put together after a trip to your local tip...

One BHPC member rode Paris-Brest-Paris (1200km in 96 hours) on a recumbent of his own construction last year - now that's what I call a real cycling achievement.


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## Night Train (16 May 2008)

Thanks for those recommendations NickM. I will have to sort myself out and get a look at the books.

I am hoping to be at the Tour de Presteigne & Green Wheels 2008 tomorrow to see what I can learn from there too.


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## Night Train (19 May 2008)

I think I have come up with the 'client specification' for the build.

I am thinking of a long wheel base trike, probably wide track and preferably folding, with cargo capacity around the rear wheel and a trailer to match for when extra cargo space is needed. There will need to be some electric assist, probably assist only as I think it will make better use of gears and reduce useage to conserve batteries.

I will need to think about the build materials though to balance cost / weight / what I can work with in my workshop.


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## NickM (20 May 2008)

Night Train said:


> ...I am thinking of a long wheel base *trike*, probably wide track and preferably *folding*...


Whoa!! You don't like to make life easy for yourself 



Night Train said:


> ...There will need to be some electric assist...


I can see this machine becoming a bit of a behemoth - is there any point making it a folder if it cannot be lifted by one person?


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## Night Train (20 May 2008)

I've already had the folding bit thought out for my own requirements of storage for a while now. Doesn't make it much smaller but easier to move about in tight spaces.

I have a cunning plan with the electric drive.

Anyway as a client spec it is open to adjustment as the design unfolds.


Many years ago I wanted a Land Rover to play with off road and got a long wheel base that never got better then second place in trials due to its length. So I rebuilt it for something different. The finished truck was 18' long, 6'6" wide and 8' tall. It had six wheel drive, 5 speed main gear box and 3 speed transfer box (which I designed and built myself). There was over 18" of wheel travel, up and down, on the suspension and it was able to tow almost 60 ton. 

Some of my toys get a little on the large size but I think I need a weight limit on the trike.


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## Night Train (19 Jun 2008)

I've made a start on a mock up using an Aluminium rear triangle from a dead MTB and a few pieces of softwood scrap in my workshop. The seat is two sheets of hardboard laminated together to give an idea of the seat location.


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## PrettyboyTim (20 Jun 2008)

Sweeeeeeet!


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## Night Train (20 Jun 2008)

Not so sweet just yet. Just sorting out clearances. I am figuring on having a set of chain rings on the BB under the seat and then an electric drive could be added there. There is a 4 ring chain wheel on Ebay that I am going to use there, one ring for the electric drive, another for linking up to the front BB and the other two selectable as extra hill climbing gears.

The seat needs shortening as the head rest is a bit too high, then I can remake it in multiply laminations. I will need to make a vacuum press to do that though.


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## Riding in Circles (21 Jun 2008)

I will be interested to see how you handle the lateral load dynamics on the rear wheel.


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## Night Train (21 Jun 2008)

Catrike UK said:


> I will be interested to see how you handle the lateral load dynamics on the rear wheel.


I don't know yet. I might switch to a smaller wheel if I can find one to set up with. I like the big back wheel look but I can also see advantages in smaller wheels of the same size. I also don't know how much static load the rear wheel will carry yet, that will be determined by a number of things like load carrying, wheelbase, seat position, etc.
All I want to do for now is to see how the bits will fit around me and then see if the wheels need to be elsewhere or different sized, tubular, space frame or monocoque chassis. It s all up in the air and is as much an experiment to see why existing trikes are as they are.

The more I think about it the more I want to question the status quo and work out for myself some of the issues as a learning process. If I end up with something conventional then it means that either conventional design is right or I can't better it yet. It will be a slow process as I am also working on an electric car project too.


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## Riding in Circles (21 Jun 2008)

I'm building a carbon tailbox, that's enough bother.


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## Arch (23 Jun 2008)

Night Train said:


> I've made a start on a mock up using an Aluminium rear triangle from a dead MTB and a few pieces of softwood scrap in my workshop. The seat is two sheets of hardboard laminated together to give an idea of the seat location.




It's no good, Night Train old chap, you'll have to have wheels at the front, legs don't work...

Nice seat! I look forward to seeing future installments.


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## Night Train (23 Jun 2008)

Arch said:


> It's no good, Night Train old chap, you'll have to have wheels at the front, legs don't work...
> 
> Nice seat! I look forward to seeing future installments.



Wheels are old hat, I have this great system of cabriole legs with a claw and ball bearing foot...


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## Riding in Circles (23 Jun 2008)

Night Train said:


> Wheels are old hat, I have this great system of cabriole legs with a claw and ball bearing foot...



That should generate enough heat on the downhills to power the steam engine assistance.


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## Night Train (23 Jun 2008)

Now there's a thought! A small steam engine located behind the seat so the heat is left behind in the slipstream. Now what to power it with? Coal or oil would be messy...

Beans! I could eat lots of beans!


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## Riding in Circles (24 Jun 2008)

Night Train said:


> Now there's a thought! A small steam engine located behind the seat so the heat is left behind in the slipstream. Now what to power it with? Coal or oil would be messy...
> 
> Beans! I could eat lots of beans!




Then run it off methane? can you wear shorts with a hose pipe up your arse?


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## tdr1nka (24 Jun 2008)

Could in theory a tadpole trike be built with powered front wheels and a steerable rear wheel?


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## Riding in Circles (24 Jun 2008)

tdr1nka said:


> Could in theory a tadpole trike be built with powered front wheels and a steerable rear wheel?



Yes.


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## tdr1nka (24 Jun 2008)

Are there any examples that you know of?


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## Riding in Circles (24 Jun 2008)

tdr1nka said:


> Are there any examples that you know of?



I have seen a rear wheel steering tadpole trike, in fact I rode one once, I remember thinking it was potentially lethal!


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## Arch (24 Jun 2008)

Night Train said:


> Wheels are old hat, I have this great system of cabriole legs with a claw and ball bearing foot...



You need WEGS. Can't find it online but I've seen a great little video. It's wheels, made of legs (bit like the Isle of Man three legged thingy), for little robots, means they can climb steps etc...


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## Night Train (2 Jul 2008)

I've finally managed to pick up a dead KMX from Spandex (thank you very much) and rebuild it. It had a badly broken back and a number of other bits were either missing or broke. It does, however, give me a rolling chassis to build up on to trial mods on. 
So I have rebuilt the chassis with a replacement 50mm one piece round tube to replace the square section two piece tube. The tube is the leg from a steel frame bunk bed found at the scrappies. Not great but it serves its purpose.





I beat the ends of the tube square and welded it to the stubs of the original tube. It is straight to within 1mm so it is close enough. I will weld a square section to it to take the seat mount as it saves making a round seat mount that then swivels and pitches me off. Taken three hours of messing about to get this far.


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## mickle (3 Jul 2008)

Has Spandex been giving stuff away again?


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## spandex (3 Jul 2008)

Yep  you know me






And we do need the space do we not


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## Night Train (3 Jul 2008)

mickle said:


> Has Spandex been giving stuff away again?


I would hardly say 'given'.


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## tdr1nka (4 Jul 2008)

Oh my god! What indignities did you undergo to get the KMX??

BTW, if I bring my KMX to you can you make the same bunk bed conversion so I can avoid breaking the back of mine?


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## mickle (4 Jul 2008)

tdr1nka said:


> Oh my god! What indignities did you undergo to get the KMX??
> 
> BTW, if I bring my KMX to you can you make the same bunk bed conversion so I can avoid breaking the back of mine?



He's a total prevert that Spandex.

It's definitely worth welding the buggers up _before_ their spine breaks.


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## Night Train (4 Jul 2008)

tdr1nka said:


> Oh my god! What indignities did you undergo to get the KMX??
> 
> BTW, if I bring my KMX to you can you make the same bunk bed conversion so I can avoid breaking the back of mine?


The conversion is a sound bodge but very ugly. With hindsight, and with less damage, I would remove the plastics from the sliding joint and just weld the two parts together with flitch plates across the joint. Replacing the whole tube with round was a pain. as the steering didn't clear it and the seat mounts needed fiddly setting up. Also a jig is needed to ensure the chassis is straight. Mine had a very slight twist which was resolved with a bit of leverage.

The other option I had was to use a new piece of square tube but all I had in stock was 3.2 mm wall and weighed more then the whole KMX chassis.


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