Introduction: The Four-Year Plan: a Long-Wheelbase Recumbent Bicycle

I built this recumbent partly as a test-platform for some ideas I had about recumbent design and partly just to see if I could during my senior year of college.  Since my school is in the mountains, I wanted the bike to have somewhat higher ground-clearance than some other recumbent bikes that I've seen.  I also built it with fat tires in mind, since some of the fastest routes across campus aren't paved the whole way.

The frame is MIG welded together from a pair of donor bikes and a length of 1 1/2" 14-gauge square steel tubing, which was overkill, but it was the best that I could get from the local metal supplier.  In its current configuration, I'm running it as a 3x7 using salvaged Shimano Acera components and a seven-speed megadrive freewheel which gives me 24x34 in my lowest gear, giving me the range to tackle anything that the Appalachians can throw at me.

The seat is still a work-in-progress, and what you see in the pictures is a temporary solution until I have the time and resources to build a new one.

Comments

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Farhana AkterR (author)2015-04-29

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author
Farhana AkterR (author)2015-04-29

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therishel (author)2012-03-31

Have you seen www.recycledrecumbent.com? The author of that site has a lot of free information on building your own long-wheel base recumbent including patterns, lots of pictures, materials, etc. I built a recumbent using his plans including a mesh seat that has proven very comfortable and durable. Check it out.

author
-insert dreams- (author)2012-02-27

Hey;

I am currently building my own recumbent bike from an old tandem and I wanted some pointers on how you set up the gears, some details about the seat, and also about setting up the steering. I appreciated your tip on chain length and I know each bike is different but if you had some other pointers or advice...
I was thinking that mounting the seat on a crane type thing would be great so I could change the seat distance, but I'm kinda scared of the complexity involved.
For the seetring under the seat, is that better than having them in front ? since its under don't you have a smaller turning radius?
A recumbent is great once you are rolling but needs more work for initial speed, I think. how did you set up the gears?

thanks a bunch

author

The seat is still a work-in-progress; real life has taken hold and I haven't been able to work much on the bike, so unfortunately I can't give you many pointers on that front; I would highly recommend taking a look at thesetwo instructables for seat design ideas.

As far as the gearing, I set my recumbent up with a pretty wide range of ratios, but I focused on the low end first because my college campus is very steep in places, and recumbents put you at a disadvantage on hills.

Where steering is concerned, if you're building anything with a long wheelbase, and tandems are just as long as my recumbent, your turning radius is going to suffer somewhat (get larger).  Under-seat vs. over-seat steering is really just a matter of preference as far as I'm concerned, and if you're going with a remote steering rig like I have (where the handlebars actuate a rod that's connected to the front fork), you're always going to have a slightly larger theoretical turning radius because you can't turn the front wheel totally perpendicular to the back wheel, but in real riding situations, this never comes up unless you've made a big mistake, and then you've got more pressing things on your mind, like the effect that gravity will shortly have on your body.

An equivalently-geared recumbent on flat ground might require slightly more work to get up to speed when compared to a normal bike, but that's pretty much just the first two seconds, when you're getting rolling.  After you're moving, there shouldn't be a noticeable difference as long as you're not going uphill.  Uphill, because you're not sitting over the pedals like you would be on a regular bike, you don't get the same sort of power, but downhill and on flat ground, a recumbent creates less drag and has the potential to go quite a bit faster.

I hope this helps.

author
drew.adc (author)2011-09-26

Have you had any problems with chain tension due to the long chain? Some bikes I have seen have a couple of guides or jockey wheels to try to keep the chain more supported. Seems like they could be useful but your design would be far simpler if it works alright. Nice job with the bike.

author
TheMadTinker (author)drew.adc2011-10-02

I haven't had any problems with chain tension, even during gear changes on steep slopes and under other difficult conditions. Before attaching the chain, I checked its length by putting it around the largest cog on the freewheel and the largest chainring without going through the rear derailleur, then cut the chain to be one pair of links longer than the minimum length required to make that circuit. That method usually results in optimal chain length and lessens the chances of having shifting problems.

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cjbikenut (author)2011-08-19

This looks nicely done! Enjoy it.

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mikeasaurus (author)2011-08-17

your bike looks great, have any pictures during the build?

author
TheMadTinker (author)mikeasaurus2011-08-18

Unfortunately, I was alone during much of the build, so I don't have any action-shots, and some portions of the build are completely undocumented, but I do have a bunch more pictures of all the little pieces that went into the thing.

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Bio: I'm a top-hatted, kilted, former-bike mechanic, sysadmin, and author with a fondness for silly things and delicious food. Holler at my Philly folks!
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