Building a Recumbent

[tdr1nka]

I was thinking more along these lines.

I thought you might be thinking more along these lines?

 

[Wobbly John]

That's my one.

 

[NickM]

...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.

 

[Night Train]

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.

 

[Night Train]

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.

 

[NickM]

...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

...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?

 

[Night Train]

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.

 

[Night Train]

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.

 

[PrettyboyTim]

Sweeeeeeet!

 

[Night Train]

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.

 

[Riding in Circles]

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

 

[Night Train]

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.

 

[Riding in Circles]

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

 

[Arch]

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.

 

[Night Train]

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...