Larry Lem's recumbent bike Projects Page
Larry Lem's Unofficial 'Bent Projects Page
A forward by Warren Beauchamp: Larry Lem is an enthusiastic and prolific builder and racer of HPVs, and lives in SoCal. In this picture, Larry simulates going 100 miles an hour on Steve Delair's Battle Mountain training bike. 

The following is a compendium of email send by Larry over several years, which chronicles the projects and problems he has encountered. 

Pictures and text by Larry Lem

FWD Fork Project

I just finished my first attempt at making a fork. It came out okay, not the greatest, but I learned a few things and will know better next time.

I built a 406 wheel with an XT rear disk hub. I then took a 27" fork and made partial cuts (not all the way through) on the cassette side as I planned on bending and welding. One bend at a time. I cut the inside of the bend with a notch, then bent the fork (closing up the notch), and welded the cut area. That pointed one of cassette-side leg outwards. I then repeated the process to point the leg down to the axle. 
I took 1/8" steel plate and cut out my own dropout. I cut the dropout off of the fork, and fitted the new dropout, then welded it into place.

I repeated the process for the disk side. I should have made the narrow-to-wide fork transition closer to the disk. I then ground the caliper mounting bracket and welded it on to the leg.

These pictures can by clicked on for a larger image.

Problem areas:
getting the axle square so the wheel remained centered between the legs. You can bend the dropouts to align the wheel within the blades, but then the steerer tube no longer points straight up. Arrrrgh. Much trial and error after that. Cutting, grinding, and rewelding, repeat several times. Yech. Way too many trials and errors. Finally say "good enough".

Next up is an offset fork similar to Warren's. I've already build a wheel with an XT disk front hub, with the rim offset 1/2" toward the drive side. This will allow the fork leg on the drive side to be very
close to the wheel from hub to rim. This will give more chain clearance for a bike I've made that needs it.
Speed Trike Project
Slowly taking shape. Gotta stay away from those zinc fumes (3/4" conduit). Not really a jig per se, just stacked up wood and placed frame in progress on top to see how things should fit together.
I finally finished the first version of the tricycle on Friday and test rode it on Saturday. I drove a lot looking for a place to ride it. I ended up at an industrial park area 10 miles away. It was empty, but had a small hill with about 600 meters. The hill was in the middle, maybe 20 m high? Good enough for testing.

1. My helmet interfered with the seat and frame so I rode without it (not the greatest idea, but what the hell) I realized that I hadn't sat in the trike with my helmet on since I finished the seat late in the week. Earlier in the week, without the upper shoulder/head section of the seat, I had plenty of room with a helmet.)
2. I had derailment problems with the mid-drive.
3. The crank was about an inch too far away.
4. I slid up the seat when pushing. I think 3 and 4 were kinda related. Maybe problem #3 didn't really exist.
5. I also under geared it. I did that on purpose, as I kept 5 rear cogs together that were a set to avoid shift problems on the first test.
First run was maybe 17 mph, then derailled. 
Second run was maybe mid 20's, then derailled.
I then increased the distance between the crank and mid-drive to increase the tension on the chain. That kept it on better, allowing me to spin faster before it derailled.
Third run was maybe high 20's, no derail 4th run 32 mph (100 rpm), at which point I derailled.
5th run, about the same or faster, but max speed didn't record. I also derailled. I couldn't have gone much faster. 
I also ran out of road. My spin was pretty uneven at high speed which caused the derailment. When I had even tension on the chain, it stayed on. With different gearing, and a sticky seat, and clearance for my head and helmet (allowing me to see where I was going a little better, giving me more confidence to push harder), I might get to 35. But I think 40 is a pipe dream. 40 was the goal.
I am not sure what I will do at this point. I would like to install my Swanson fiberglass seat, but that would require major surgery. I would like to change the seat angle of the existing seat, but that would also be tough. Yesterday afternoon, after the test, I installed a different crank bracket, that put the crank about 1.5" closer to me, but then I sat on it and my heel hit my brake disk. I could remove the disk, but then my right heel hits my derailleur. So I have to keep the crank a minimum distance from the wheel. I think I'd have to cut 1" out of the frame to move the seat. 
And then I looked at the trike again this morning, and it is tweaked.  The front end is listing 3-4 to one side. I don't know how that happened. It must have relaxed to this position due to the test ride.

Oh yeah, the steering is unstable. That would be problem #6. If you let go of the bars, the front wheel oscillates from side to side at a really high rate, about 10/sec. I have steering limiters with padding hanging from the bars and the frame hits them. You have to hold the handlebars with some force at all times. That dampens it right out.  Since I slid up the seat when pushing, I had to pull on the handlebars to push on the pedals. If I tested again, I'd need something for my shoulders to push on.

I would like to try my Swanson fiberglass seat with foam, as I think that would keep me from sliding, but to do that, I might have to build a lowracer bicycle. I was already thinking about doing that, so now I have it in my head that that is the next thing I will do. It might look similar to a Cobra (Ed Gin Photo), but with a longer wheelbase so I can vary the seat angle some more. It would be 2" dia steel. The hard part will be the custom fork - again.

 I can get a 60t chainring from Gaerlan. But I'd like something a little bigger - don't know where to get one - at a reasonable price.

Too many projects, too little time.

While watching the super bowl, I had an idea. My mid-racer is in my living room, on a trainer. It has my Swanson seat on it. I could raise the front wheel some more which would lay the seat back some more. That would be one way to try the seat angle that I want with the seat that I want. I could also install a 20" rear instead of the 26" rear. I could ride that configuration. But I don't want my crank to get too high in relation to seat height. I was looking for about 12", and that might push it up a lot higher than that.

I am going to wait awhile before I modify the trike. I'm kinda burned out on it. If it was the only thing I had to do, I'd be all over it.  Would you believe I am in the middle of reinforcing the crummy welding cart that I bought from Northern Tool & Equipment, and have been putting that off for 2 years?

For trike mods, I was going to make an idler, maybe out of a rear derailleur to keep the chain on. I was thinking about making shoulder supports/pads, but haven't thought too hard about them, yet. I also had
the idea of using shorter crank arms, but I won't try that until I stop sliding in the seat. Maybe the crank is in the right place. The Y in the frame idea above my head is great, thanks. I hadn't thought of that. I thought I was going to just have to make what was there taller. I have to find a way to prop my head up to see, with a helmet on, then determine how much room I need. I'll have to find a better place to test, too. (closer, longer, more level)

I only copied the Coslinger in terms of having the chain come down from the mid-drive to the wheel hub in front of the fork blade, instead of behind it. Some day I'll try mounting the rest of the gears up there at
the mid-drive, along with the rear derailleur, instead of having the gears down at the wheel. I think that's how Sam gets away with having a 24" wheel. His hub is so skinny, with one gear, that he can allow his
leg to pass by it. My leg is fully above the hub. I went back to some old pics of Sean and the bike; they have a really lax head tube angle.  It's like 50. You know, I don't even know what I ended up with...somewhere between 65 and 70 degrees.

I am really disappointed about the frame being tweaked, though. I spent a whole day doing nothing but straightening the frame a month ago, before I welded the front and rear together to tie the side rails

During construction, I was continually surprised that the rear suspension members did not triangulate as I had expected and the whole frame could rock and twist from side to side. I ended up welding the
two arms that come down from the top together. They are bolted to the frame in two places (at the top), so they are now part of the frame. I am still imagining/wondering how I will support the rear wheels for the
streamliner. It's gotta be clean, compact, precise and effective. More work to do.

This trike took 4 months. I predicted it would take two. I wonder how long it will take to make a full-up streamliner. I wonder how many I will have to throw away before I figure out what I'm doing and before I
get it close to being right that I can say that I'm done. Some friends are saying that I should throw a fairing on this prototype. I think there are too many things wrong with it, too many things to change,
lotsa cutting and replacing; I'd end up with a whole new trike in the end, anyway. But maybe I will make a frame and fairing instead of a monocoque. I don't have to decide right now.

Bacchetta Clone Project
This photo shows a 20" fork I was making into a 16" fork, reattaching the dropouts. I know that most of the fixtures aren't straight - the ones with the pieces of angle iron.... When I insert one into the jig, and put a long tube in it, the tube doesn't exactly point down the middle. If I have a fork in a different fixture 4 feet away in the main jig, the tube might miss the center of the fork by 1/2". So during construction of the bike, I ended up shimming the main tube in one of the fixtures using pieces of plastic cut from a sour cream container, until the tube pointed straight. 
More info on the bike jig
I aimed for a 48" wheelbase, but it ended up at 47". Seat height (Swanson fiberglass) for me is 25". BB hight is 34.5". Rear dropouts to BB is 61". Head tube angle is about 71. I have Terracycle 38 cm wide, 25 bars and Bacchetta bars on order from PowerOn. I have a heavy Burley bar on it now. I wonder what the superman position will be like with Bacchetta bars. Cranks are 155mm arm Doteks with a 40 and 52t chainring. I have an Ultegra triple with 165 mm arms waiting to go on, but this is the first time I'll be trying short crankarms. If I don't recline the seat much more, I can probably buy a Fastback seat pack or... The more I recline, the tougher it will be to touch the ground.
I just hope the all-thread "axles" in their fixtures are square with the main jig. The problem there was I drilled them on a drill press, but the 2x4s don't have perfectly flat sides; they rocked a little on the
drill press table. Oh well. Nothing stays straight, anyway, even if it's restrained in a straight fixture. When I tack stuff together, as the tack welds cool, they pull the tubes around and so I have to 
straighten as I go. I have to re-space the rear dropouts as they pulled in 1/4". So much for 130 mm. And here I was wondering, "should I make them 130 or 135 mm".

First test ride was tonight. Surprise! I can reach the ground okay and probably will not turn it into a dual 26" wheel bike. The boom is 18" long instead of 15-16 like the commercial bikes as I wanted to shift the cg further forward. From pictures I've seen of the Bacchetta Corsa and Aero, it looks like most of the rider's weight is over the rear wheel on those bikes.

Now I have to attach the front derailleur post and rear brake posts. I was considering using disk brakes, but I'll see how the bike works, first. Then if I find that the canyons of the Santa Monica mountains warrant bigger brakes, I'll add them. I'll have to switch to a heavy cromo fork, though.

Tonight, I slightly screwed up the front derailleur boom. I ground it, removed the crank and bb, tacked it, reinstalled the bb and crank and chain, found the angle wasn't right, removed the crank and bb, cut the tacks, ground the tube some more, etc. Way too much assembly and disassembly. 

When I finally welded it for good, after burning many holes in the tube, and after reassembling everything, I found that the post is rocked back maybe 5 too much. I still have to braze on a split cable stop so I can see if it shifts okay. But now I don't think I'll be able to get to it until Monday night.

So I took it out for another 10 minute test ride as it was getting dark. Boy is it fast. I wonder how much it weighs. I hope it's under 30 lb. I am used to my 45 lb commuter with fat tires. The short crankarms are a little strange, too. I probably should only try one new thing at a time.

I fall down...
I think the bike it too tall. I can't touch the ground well enough to be really stable at stops. I came to a section of road where I needed to cross 2 lanes of traffic to get into a left turn lane (no light), but there was never a break in the traffic, and I went slower and slower, waiting and waiting for traffic, I kept twisting and looking back (no mirrors mounted yet), went by my turn, and finally tried to stop, put my right foot down on a curb, and my cleat slipped on concrete, and I fell on my right side. Man, I can't recall falling in 2 years. Part of the height problem is the big wheels, and the other part is the
seat angle. I still want to lay it back 5-10 more degrees, too.

When I got home, I put some 26" wheels on it, and I think that would make it kinda acceptable if I wasn't going to lay the seat back anymore. But putting on 26" wheels (and fork) would lower the crank too, and I already want it 1-2 inches higher. I bet I wouldn't be happy with the Strada, Corsa, Aero, Volae, or Rans Force 5. At least I know now.

So I thought about cutting up the frame to put a jog in it (Z-frame) because I still really want to use 700C wheels, but then the head tube angle would be wrong, and I'd still have to make another cut to reposition the boom.

Now my latest idea is to put 24" wheels on it, leave it as a stick bike, and mount the bb on top of the boom. The only problem will be the head tube angle gets steeper. I'll have to try it and see. I just ordered a 24" fork. This is easier than putting a jog in it. If I try that someday, I'll try it from scratch so all the angles and distances make more sense.

But the good news is that I broke my record for the ride. I did it in 1:40, whereas my best time with the commuter bike is 1:50. Usually I do 1:55-2:05. And I still have part of a cold, and haven't ridden hard in
3 weeks. I haven't weighed the bike yet. I am guessing that I dropped 15 lb going from commuter to high racer. Now I can go to the bigger hills in Santa Monica.

I didn't have a front derailleur, so I rode in 40t front, and 11-34 9-speed rear. I needed one more gear for the hills today, and a bunch more for the down hills.

This was also the first test of the 155 mm arm Doteks. I think they are too short. I am used to 165s, and when I ride those, I can kinda feel that they are either just right and a little bit too long. Maybe I'd
be happy with 160's also. That would only be a $29.99 + shipping experiment. I'll leave the 155's on for a month and see.
Here's a funny picture I took last night. This is the more crowded section of the garage. What a silly hobby.

After ordering and building a pair of 24" wheels, and ordering and receiving a 24" carbon fiber fork, I decided that I wasted a bunch of money.
The point of the dual 700C bike was to ride on weekends in the Santa Monica mountains where I used to ride my Softride bike. The problem with the Softride was that it needed better brakes. So the dual 700C high racer was supposed to eventually get disk brakes. I could not attach a disk mount to the 24" fork. I would have to make my own from a 700C steel fork. Also, my biggest gear would be 52/12 with a 24" wheel. (I was planning on using a 12-27 9-spd cassette.) So I really wanted to stay with a 700C rear wheel.
How to make it work? I thought about cutting the frame and possibly having to install a new head tube and to use a 20 or 24" front wheel. I think I would still have some heel-strike problems with the 24, so I decided to go with 20. Then drawing some more pictures and playing with the bike (removing the front wheel, blocking up the fork to get the seat height at 21", I figured I could chop the frame closer to the seat, and point it up 15.  That would get me close to 70 steerer angle again. But the bb wouldn't be as high as I wanted.
So here is the latest version, 21" seat, 28" bb. I will try riding this for awhile, then probably mount the bb on top of the tube to gain a couple of inches. I still have to weld on a disk brake tab to the fork. 

It is interesting that this bike becomes more like a tall 700C/406 T-bone with just one bend in the frame. Mine is different as I still have the chain going under the chainstay. If I did it from scratch, I'd
have the chain on top, like your bike. Then the chain deflection around the pulley wouldn't be as great. But I quit, I ain't cuttin' off the rear dropouts!
Now I see this CarBent comes out. It looks like a cross between a T-bone and a Swanson. I wonder if the seat can be reclined more. Maybe in a couple of years when I want to drop another 10 pounds. I don't feel very rich, right now.
Trouble with the chainline on the lowracer (as I expected). The pulley is mounted right against the head tube for best knee clearance, but that puts it in line with the innermost cog. The 9th cog gives some nasty chain deflection. So I will probably only use the innermost 5. And then I remembered that the 11t cog can only be mounted on the outside as
it can't slide on like the others. So my smallest cog will be 12t.  63/12 with a 406 isn't a very big gear. 
It might be okay for 20-25 racing, but not for sprints to 30. Even the chainring on the crank was too far out (away from frame centerline). I have a 107 mm bb, and had to mount the chainring on the middle position of a triple crank.

Hopefully, the first ride will be mid-week.
In 2007 Larry built the Beluga streamliner.

Beluga front view

Beluga rear view
Beluga side view.
The Beluga speedbike is tested on a smooth road in SoCal.
The Beluga at the 2007 WHPSC. Larry pedaled the bike to a speed of over 58 MPH, and teammate Tom Amick pedaled it to over 55 MPH.
He also built this back to back tandem, and Larry and Tom raced it a some local time trials.
September, 2008
In 2008 Larry built the Goliath back to back tandem speedbike.

Two Beluga top half parts were made, and then joined together.

The Beluga molds start to taper 5 feet from the nose, so a gap of 38" needed to be filled in the middle on the bottom.

Two parts were made from the 3 to 5 foot areas of the bottom female mold, then reinforced with plywood "bulkheads". They were then screwed together to make a male mold and Bondo'd smooth. Then a female female mold was made. Some difficulty was had keeping things square, getting separate parts to match, and minimizing gaps. The extra steps were made to minimize the number of parts and prevent fit problems.
Even tougher was filling in the center top fairing areas.

No vacuum on any parts. Just lots of epoxy.

 Here is Goliath II before painting.

Here is the Goliath after primer paint was applied.

Picture by Jim Iwaskow
October 2008
Larry Lem and Tom Amick get taped into Goliath II. Their MOALD (Mother of all launch dollys) allowed them to get perfect launches every time.
Larry and Tom in the Goliath II  back to back tandem during Battle Mountain 2008. Larry and Tom posted a top speed of 67.06 MPH during this event.
Picture by Brad Teubner
Larry begins the Scimitar speedbike project.

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