Convertible Recumbent/folder
 

This was a conversation started within another thread that I thought was deserving of its own thread. It's a modification that allows a folder to be ridden upright OR recumbent. Done by BF poster Leigh Caines from Down Under. Truly remarkable!

http://i39.photobucket.com/albums/e1...h/DSCF5811.jpg

http://i39.photobucket.com/albums/e1...h/DSCF5787.jpg

http://i39.photobucket.com/albums/e1...h/DSCF5778.jpg

Hat's off to you, Leigh!

Leigh, that is quite an accomplishment. My hat is off to you. Thank you for posting those pictures. You have got the same general design elements in your project that I proposed using in my conversion project from an upright folder to a recumbent folder. I did not consider being able to switch from riding in an upright position to a recumbent position on the fly. I would certainly appreciate it if you explained how you routed your chain and managed to arrange your power transmission hardware to allow for pedaling from both positions. Also, I think that your seat looks very comfortable and quite adjustable. I would appreciate some in depth details on how you arrived at your seat design and mounting system. A question I have is do you have problems reaching the brakes and shifters in the upright position? How does your bike fold and how much more complex is it now that you have added on the recumbent kit? How much larger is the bike when in its folded position?

Thanks Leigh. It would be nice if there were more bikers willing to take the design plunge. I think the biking world would be better for it.

Oh, one more thing Leigh. How did you mount your bottom bracket boom to the bike? Is the boom adjustable? Does it fold with the rest of the bike and how?

Thanks.

Answer a few
 

To answer some of your questions.
Seat… yes is very comfortable … I’ve spent some long days in it and bounced up for more the next day…
By razing or lowering the seat post the recumbent seat is more or less reclined. I’ve come to like it quite layed back
The more I ridden it the more I’ve stayed in the down recumbent position but I still do get in the UP on some very long mountains and the other time I like the UP is riding though a strange town at slow speed and on very rough off road stuff.
I bought a length of mild steel rod then bent it around the front brick wall [pillar] till I got the right lumber support, welded the ends together. Then covered it and used elastic rope to pull it together then using slightly lager rod for the hinge… works well
Chain… this was some time on Sheldon Brown's gear sight to work out the right combination. I wasn’t as interested in having a very high gear in the UP position but I did want a high in the recumbent one and I wanted a low low in both UP and DOWN.
I’ve ended up with a 15 gear inch low in both UP and DOWN {not that I use the low low much even with a big load but is a nice feeling to know one has a lower gear if one wants itJ]
A 100 gear inch in the recumbent position and a 75 gear inch high in the UP position
Chain management… one chain from the front cogs back though a roller [made from hard plastic [neoprene] to the center. There is an old derailer to keep the chain tight.
The second chain from the center back to rear derailer
38/53 back to 39 then 30 back to 11/30 (with a 3speed hub] [the 3speed hub and getting it laced into a wheel cost more then the rest of the bike. Even though the hub was second hand. But worth it I think.]
Since those pic were taken I’ve changed the UP handlebars [by adding bar ends] and put the front brake where it can easily be reached in the UP position. [A friend is making me a “splitter” so I can run 2 brake leavers into one front brake and that should be on this week]
The gear changer is within reach from both positions.
More later as some friend have shown up and we’re off for a ride

Indeed it is, thanks for starting the thread, SesameCrunch.

I've been looking for sources for the Brompton kit, but read recently that the frame changed shape, so maybe that's why I can't find anybody selling one.

Your own Downtube conversion with the Cruzbike is also good inspiration, but it would be almost ideal if one could easily change from one position to the other.

I've done a couple of hundred miles on my recumbent in the last 3 weeks, & those very conditions are the only reasons I wouldn't ride it exclusively, apart of course, from not being able to fold my recumbent for multi mode travel.

So, Leigh, an inspirational effort, thank you; really looking forward to more details & pictures when you have time please! :-)

Back to my sketch pad now :-)

I wonder if this concept of a convertible recumbent/upright could be commercialized. It's really clever and useful.

It doubtless could, but interestingly whilst I was researching conversions, a Californian Brompton importer noted that there was much interest in the recumbent conversion until he actually obtained a supply, whereupon that interest evaporated, & I don't think he sold (m)any for quite some time.

Do you ride your Downtube recumbent much? I was thinking that the IX FS would perhaps be a good bike to base Leigh's ideas on. Based on your own experience, does that seem reasonable?

"Interest evaporated" because of what they were trying to charge. Put it this way: you can currently buy a Bike Friday tikit for what they wanted, and this was just for the kit sans bike. The Cruzbike is a much more sensible option.

As it turns out, I don't ride it too much. I built it up to for a double century this year. I didn't realize how different recumbent muscles were from upright, so I never made the commitment to it. Now, I have too many upright bikes, so the Cruzbike conversion kinda sits there and is my child transport vehicle.

+1!

If I was starting again I’d pick a folder that had suspension …
While the spring I put under the seat dose take out a lot of shock a good suspension unit would be an improvement .

And it would be good to start with the lightest bike one can afford.

I started this home bike building with a Long [very long at 9 feet] Recumbent… I still ride it one day a week [50ks] but it is far to heavy to be a good Touring bike. It has full suspension and is a very comfortable ride.
The UPDOWN Bike is a great touring bike and until I come up with a better idea this is the bike I ride the most and I wouldn’t dream of touring on anything else.

I think anyone converting from a DF to a recumbent will need to ride every day for quite a few months before they will have the right “recumbent legs”. But I’m a bike nut and I ride every day.

To work on a few more questions.

Seat … base is plywood with upholstery grade foam covered with black vinyl.

Starting with the folder the first step was how to attach the seat.
Short bit of 40mm square was shaped to the backside of the headset. A “U bolt” was bolted into that from the front… and another “U bolt” was welded on the under side of the same square [40mm] and this went back the other way. So 2 “U bolts” with 6 nuts attaches both the boom and the seat. [Seat has one other bolt that holds the spring and bolts into the water bottle nut holes]
The front boom has another 40mm square that is shaped fitting around the headset and the whole thing is bolted together.
When the front boom and seat and front chain is removed you are back to what you started with.
So when folded it is the same size as the Dahon Boardwalk [32 x 66 x 75 cm] plus the seat and front boom…

My aim was not to make something that could be taken on a bus. I just wanted something that could be taken overseas so I didn’t mind if it took my half an hour to pack in a case and the same at the other end to put it back together.
But you guys have me thinking about making something [recumbent] small that would be good for commuting but that’s a different project for another time.

>Is the boom adjustable?<
At first I made it so…. One pipe sliding inside another [like on the Greenspeed trike]
But after trying it out [there was slight movement in it] and deciding this bike was for me alone …I set it up at my leg length. But if you want it to adjust then getting the right size pipe… it wouldn’t be hard [I was using what I’d got from the rubbish tip]

The chain adjustment was trial and error but now I have it perfect… it makes no noise and changes smoothly…. The roller is attached to the underside of the seat so when seat is removed it come with it. The chain tension [old rerailer] is also attached to the same bar.

The first handle bars were straight… but I found after a 100ks that this was not comfortable so I went with the longer one to bring the grips down and my arms stay by my sides…. This is great… did make it a bit harder to pack but once again [for me] worth it.

Wow look at that I just went from been a “Newbie” to a “Junior Member”
Not sure what that means…. But if I keep peddling who know what could happen

Here are a couple of new pictures from Leigh (I'm helping him post the pics 'cause he can build this convertible bike, but he can't figure out how to post pics on the Forum :D).

http://i39.photobucket.com/albums/e1...ch/YoYo003.jpg

http://i39.photobucket.com/albums/e1...ch/YoYo004.jpg

:roflmao:

I'm sure it's because he can't bolt or weld a pic to the forum, though he has probably tried. :)

Hey, that last picture with the kangaroo in the background got me thinking of a name for your creation Leigh. How about the Leigh Kangaroo or the Leigh Roo, since you can hop from upright to recumbent without much fuss. Those last pics were great. Can we have a couple of more close-ups or the other side of the bike. Is the boom welded to the front of the bike frame?

Certainly are different muscles! I find I can ride a lot further without getting tired on the recumbent though. Also it's becoming ever more windy over here, so the lower riding position makes it feel less like pedalling through treacle :-)

Sorry for the question on IX FS - I've just realised looking at your child seat pic' that you *did* use a IX FS. For some strange reason I thought you'd used a VIII.

The Cruzbike conversion was made on a 2007 Front Suspension model. I believe the frame is very similar, if not the same as the VIIIH. I swapped out the front suspension fork with a non-suspended one. Another BF poster, named Jack converted his VIIIH, and did a super job, as I recall.

Some more photos from Leigh, with some construction detail:

http://i39.photobucket.com/albums/e1...ch/Itsaway.jpg

http://i39.photobucket.com/albums/e1...h/DSCF5814.jpg

http://i39.photobucket.com/albums/e1...unch/rt006.jpg

http://i39.photobucket.com/albums/e1...ptsnaps237.jpg

Leigh, just one more complement. You have some awesome hair man. :-)
Thanks for the detailed photos.