High performance & durability Cannondale Semi Recumbent

[neptronix]

The KP058 arrived and appears to have the right diameters and lengths to be the right part.
I also bought some jb weld with the idea that i will fill in the grooves cut into the rear swingarm.

However, given that the disc brake side of the swingarm is where the damage is, i feel that i can never trust it to be as sturdy as stock.

What i would like to do with this bike is have a 22" rear and 20" front.. and run dual hub motors.. a 28mm wide DD in the rear and a geared motor up front that's wound for 3/4ths the speed, and the only use of the front hub would be to assist in climbing hills.

The bike now has to be sent off to a shop to have the new headset installed.

 

[neptronix]

The KP058 fit without a hitch and only adds about 2mm to the bottom of the steer tube. No sweat.

The real problem is getting a 20" fork with an appropriate rake and disc brakes. Sunlite sells a perfect cromo 20" fork but it is threaded, and the non-threaded portion is too short to get away with using a quill stem adapter. Bachetta sells a carbon fork for $300 but the offset/rake looks less than ideal.

I'm asking sunlite if they have a non-threaded version and also bugging maxarya to see if they have a spare cromo fork laying around.

otherwise i will have to use a fork with half the rake needed and that is not ideal.

 

[Chalo]

The real problem is getting a 20" fork with an appropriate rake and disc brakes. Sunlite sells a perfect cromo 20" fork but it is threaded, and the non-threaded portion is too short to get away with using a quill stem adapter.

For my cargo bike, I cut off the threaded portion, prepped a section of 1-1/8" tubing to fit to it, clamped the fork and the extension tube into a piece of angle iron to align them, and then had a very skilled welder attach them without a reinforcing sleeve. The weld was flush enough that I did not have to reduce it to fit the crown race over it.

If I had been working with a less skilled welder, I would have made a sleeve for the insides of the tubes, and I probably would have done some post-weld cleanup.

That fork you're talking about is very sturdy and thick-walled, and the increased offset versus a BMX fork cured my bike's handlebar flutter problem. I think it's worth the effort to modify it.

 

[neptronix]

I'm visualizing that and i see how it could work.. because the crown race is a larger diameter than the tube, a 2mm bulge at part of the tube is OK.

Now you have me wondering... if there exists a tube that nicely fits into a 1 1/8 steerer tube.. maybe a 1 inch tube would work as the reinforcement you're talking about. Making this as strong as possible would be ideal because the bike will do at least 40mph and i'd like the frontend to be ultra solid considering that a 20 inch unsuspended wheel is still gonna end up getting knocked around.

 

[Chalo]

I'm visualizing that and i see how it could work.. because the crown race is a larger diameter than the tube, a 2mm bulge at part of the tube is OK.

The difference is 1.4mm (28.6mm tube, 30mm crown race seat).

Now you have me wondering... if there exists a tube that nicely fits into a 1 1/8 steerer tube.. maybe a 1 inch tube would work as the reinforcement you're talking about.

1 inch liner sleeve should work fine for .058" wall tubing used as the extension, but the wall thickness of the recumbent fork at the bottom of the thread might be thicker than normal. The threads on that fork are ridiculously long. In the worst case, the sleeve would have to be stepped to fit two different diameters.

The weld would need to penetrate into the sleeve for the sleeve to add any integrity.

Making this as strong as possible would be ideal because the bike will do at least 40mph and i'd like the frontend to be ultra solid considering that a 20 inch unsuspended wheel is still gonna end up getting knocked around.

Mine has no liner sleeve, on a front loaded bike with no suspension, and it carries over 500 pounds gross weight very frequently. A few inches up from the crown race is a low stress part of the steer tube. Consider that cutting a thread on the outside of a thin walled tube is one of the surest ways to weaken it. Your welded steer tube will probably be stronger than the threaded original.

 

[neptronix]

Yah... looks sturdy enough.
So cool that you already have experience doing just this. If my other forks don't materialize, this is the way to go.

 

[ivonesh]

I've enjoyed reading over this entire thread, seeing the build process, and have some questions.

I am considering the purchase of this Cannondale recumbent locally. I'd like to electrify it, but more for pedal-assist than moped-like needs/speeds.

I like the idea of a front hub on recumbents for more even weight distribution. My concern on the Cannondale is with the front only being 16". There's a lot of hub motor choices at 20", but 16" seems like a strange area for hub motors and bicycle wheels in general.

From what I am reading, it does not seem like there is an easy fix/bolt-on replacement for the front fork to get a 20" wheel on it? If there is a solution, does it drastically change the geometry of the bike?

Ignoring the concern over the front hub motor and going with a rear hub motor, it seems like there are many more options.

What is the dropout width and what's the widest bicycle wheel and tire that can fit on the back?

What's the max weight one can expect to support on a rear wheel with a hub motor?

I hadn't seen anyone post this guy's awesome battery setup. https://youtu.be/KRgSQVAaHDg?t=180

The other recumbent I am considering is a RANS Rocket, which according to many, is a classic. It's a short wheel base with 20" wheels in front and back. It's a longshot, but anyone here have experience with both of these recumbents and have an opinion?

Thanks for anyone willing to respond...

 

[rowbiker]

The other recumbent I am considering is a RANS Rocket, which according to many, is a classic. It's a short wheel base with 20" wheels in front and back. It's a longshot, but anyone here have experience with both of these recumbents and have an opinion?

I've got two Rans Rockets, and don't ride either one anymore. I electrified one and put lots of miles on it, but I crashed too many times to keep making it fun. My perception was that it's handling was way too skittish for me. I've likely got more than 50,000 miles of recumbent riding under my belt, so I feel very comfortable with recumbents in general. One crash occurred on flat, dry pavement while I was adjusting a light on the back of my helmet with one hand -- the bike was on the ground before I had a chance to blink. (I live in MN, so if you want a Rocket for local pickup, I've got a deal for you.)

I don't like 16" wheels for the reasons you mentioned (parts availability), but mostly because of road safety issues. Even a 20" wheel is significantly more likely to be either damaged or lose control when hitting potholes or obstructions, but you can at least minimize this with BMX style wheels/tires. I'm in the process of moving to a full-suspension recumbent (HP Velotechnik StreetMachine), after many years on Bacchetta recumbents (both high racers with 20" and 26" wheels).

I definitely am a fan of all-wheel drive: a direct drive front hub coupled with a human drive rear wheel. I've found this to provide all the assist I ever need, plus a completely reliable backup system of non-stressed chains and sprockets. Take a look at the "eG20" page on my website in my signature line below.

 

[neptronix]

On these types of bikes, you have the worst weight distribution possible, so your front wheel has very little traction. I really would not recommend putting a motor up front for this reason. And a 16" wheel really screws up things because very few hub motors are designed/wound for that high of RPM.

Due to the frame design of a CLWB though, even if you lose some traction on your front wheel, it's much more forgiving than any other kind of bike.

The rans rocket, or anything like it.. is not a very stable bike by design. It also has small wheels and no suspension. I wouldn't even want to ride one un-electrified. I've ridden a few SWB/high racer type bikes and never felt stable or safe on any of them.. because you cannot use your upper body to control the handling so well.

 

[Warren]

I owned and rode an original 20/20 Rocket, a 26/26 converted original V-Rex, and rode this rowing 700c high racer 3,552 miles. Much of that was in the Blue Ridge mountains of Virginia. Rode down to Vesuvius, and back up. It is considered the steepest, hardest climb on the entire Trans America Bike Route. These bikes rode like a dream. I ride my RANS Screamer converted to single seat electric assist cargo bike for 40 miles at a time, no hands.



Maybe it is just me. I did ride my FWD, RWS recumbent for over a hundred miles, thirty years ago. But I can't do a track stand, even on a fixie, and I can't dribble a basketball, so I don't think I am exceptionally coordinated.

 

[neptronix]

I don't get how you do it. I found those kinds of bikes very unstable at low speeds, downright scary at 30+mph downhill canyon carving. And totally unsuitable for my pothole and irregularity littered roads.

I feel like i am floating on the air with very little control over where the bike goes until i hit 15mph+. But even still, you cannot make a twitch decision at high speeds. A long wheelbase CLWB is the least twitchy type of bike i have ridden, on the other hand.

And this is coming from a guy who has ridden a dual suspension mountain bike at 60mph... and the only thing that made me nervous about that is the possibility of an unintended power wheelie.

We probably have some big differences in body configuration, terrain, etc!

I can't get the hang of SWBs!

 

[thundercamel]

This is quite interesting to read your different experiences. There must be some magic geometry to be able to ride a recumbent with no hands. My SWB needs very little steering input and more leaning to get through a curve, which requires a little planning in the approach. It doesn't feel tricky, until you get under 10 mph, and at 5 mph a lot of steering input is needed for balancing.

That 20" front tire is where all of my confidence comes from though, so any squirminess and I feel like I'm going to die. A couple times I had the wrong tire on for the conditions. Hit some muddy patches in the grass, and like rowbiker said the bike dropped before I had a chance to blink. Thankfully I dropped my feet off the pedals just as fast, and caught it. Haven't crashed the bike yet thankfully.

No, I can't make a twitch decision at high speed, but yes I could do some 30+ mph downhill canyon carving, if the curves are a large enough radius without too tight of transitions.

Bike for reference:

 

[neptronix]

Sorry to hear you took a few falls, buddy. Good thing they weren't from a taller height!

Your view makes a lot of sense to me. Your bike is a midway point between my CLWBs and his highracer type bikes.
You sit lower and the wheelbase is close to an upright bike's, which is where you get that added stability.
Your bike has better aerodynamics than mine, but the cost of that is a bit worse handling.

I do have to plan a little for big turns before i take them at high speed, but there's lots of room for error.
More planning is needed on the 'medium' size bikeE than the cannondale or Maxarya, which are both 'large' size CLWBs with massive wheelbases.

I think this is why the trike is the most popular recumbent these days. It doesn't trade aerodynamics for handling abilities. But then, you don't fit on a sidewalk or bike lane well. An excellent handling trike has a tilting mechanism which makes it heavier, more complex, and more expensive though. The financial barrier to entry is steep.

I feel that the CLWB is a nice middle ground between all recumbent approaches. In some ways, i feel safer on mine than a regular bike, since the front wheel can't get upset so easily. On the other hand, the sluggish and uncertain handling is concerning and makes me want to add a safety bar or wear elbow/knee/shoulder pads in case of a fall.

 

[Warren]

Trikes are most popular because most recumbent buyers are old farts who have lost their sense of balance, and can stop half way through a climb, and rest without falling off. Trikes are, and always will be, less efficient than a similar single track vehicle.

 

[thundercamel]

Sorry to hear you took a few falls, buddy. Good thing they weren't from a taller height!

Don't feel bad, they were just close calls that I managed to catch by putting my feet down and pulling the handlebar up!

Trikes are most popular because most recumbent buyers are old farts who have lost their sense of balance, and can stop half way through a climb, and rest without falling off. Trikes are, and always will be, less efficient than a similar single track vehicle.

I got a good smile out of this :lol: I had thought about a trike before I found the Lynx, and still wouldn't mind trying one someday.
These 4 reasons were mostly on my mind:
1. Figured the third wheel would add more friction
2. It's impossible for me to afford one with full suspension
3. Want to fit through narrow places
4. Figured balancing is part of the fun of cycling
5. Didn't want my viewpoint to be too low. I like viewing the scenery as I ride, and the Lynx is already low compared to my upright bicycle

 

[neptronix]

Same reasons i don't like trikes.

Don't care about the non-cool factor.... cool is what you make it.

Anyway the cannondale still lays in pieces in my garage and needs a fork. Maxaraya has been slow to get me any parts.. i wanted to use one of their old stock chromoly forks for the cannondale. But i'm asking a favor here.

The garage has been simply too cold to use epoxy to repair the frame. I have a decent match paint for the cannondale to hide the fixup. Most epoxies specify they want to be cured at 70F, so i don't want to try to cure one at the 30f my garage has been hanging around at. The epoxy may also expand when the frame is operated up to 70 degrees hotter.

I'm not going to take a risk when i cannot find information on the thermal expansion properties of these epoxies. I don't have reliable heating in my garage either. Well, we'll get back to this closer to spring.

 

[thundercamel]

I used to use one of these heaters in my old garage. Do you have a tank from a grill perhaps?

 

[neptronix]

Watching some videos about real world test. The channel 'project farm' on YT does a fantastic job of these types of tests.

[youtube]XObmZIbHOzY[/youtube]

In all tests of putties, epoxies, etc.. JB weld tends to come on top.

[youtube]aVLoJe3JbFI[/youtube]

JB weld seems to handle vibration and extreme changes in temperature well. This is my big concern about epoxies - about the long run.

I will simply have to trust this epoxy to fill the ~5% of material that is missing. There will be paint over the epoxy.. and if there is any

I feel that i cannot really trust this repair to handle high power. So this build needs to be shifted from a high power to low power, high efficiency bike. The Maxarya Ray 2 will be the high power bike from now on.

 

[neptronix]

I used to use one of these heaters in my old garage. Do you have a tank from a grill perhaps?

Hm, you know.. i have a 'mrbuddy' heater which would be adequate to provide continuous heat, but it only takes a very small propane tank.

Perhaps it could be modified so that it could use the larger propane tank using a hose etc.
I'll have to look into that, since i don't want to bodge up the epoxy settings and expose it to heat/cool cycles during the >24 hr curing period.

 

[amberwolf]

Hm, you know.. i have a 'mrbuddy' heater which would be adequate to provide continuous heat, but it only takes a very small propane tank.

Does this help? It's a bunch of pics of propane "can" adapters to tanks:
https://www.google.com/search?q=propane+can+to+tank+adapter&tbm=isch
Maybe it will show you the right thread/gender combination to do what you need to?

 

[neptronix]

Thanks for the help AW.

I did a lot of research on JB weld and it's long term rigidity and decided to say no to that idea.

What i would like to do with this frame is build a custom rear swingarm that's a hair longer, so it can be my big, fast, heavy tank of a bike and not be resigned to light duty. And corner better. Currently researching welding options.

 

[neptronix]

Maybe there's some hope for the bike without building a custom swingarm.

View attachment 4

View attachment 3

In looking at many pictures of the cannondale jekyll from 2003-2005, the swingarm appears mostly identical and has matching mounting specs other than the stroke length. I imagine 'stroke length' is more of a function of the interface between the rear shock and bike, which is different on the jekyll ( the mounting point is in the middle.. )

Here's a 2005 jekyll swingarm.



Here's a 2002 - seems to be a better match.

View attachment 1

And here's mine.




The Jekyll sold a bazillion more units than this bike and i think it would be worth throwing $500 at a used frame to see if the swingarm fits.
If it doesn't, i'll just resell the bike.

I need to call Cannondale today to see if i can find some info.

It would be killer to get this bike back on the road. The Maxarya has way more battery fitment and crank fitment issues to solve.

 

[neptronix]

OK, called Cannondale. They had an engineer that owned a Bent II and said the ~2002 swingarm fits.
The 2003+, which looks like a bit stronger design doesn't fit according to them.

Off to ebay/pinkbike to buy a jekyll frame.

 

[neptronix]

Jekyll frame incoming!




Also, how did the original damage happen you may wonder..

I had some big fat headphones on and was riding the bike and doing the single chainline conversion test and jamming out to this:

[youtube]oy3rEVAEAkk[/youtube]

Didn't hear it grinding the frame.. didn't feel it grinding the frame..

..i've actually missed occasional mechanical quirks due to this and do not want it happening again.
Ordered up some noise cancelling headphones that have a transparency function to pipe audio from the outside world into the headphones. Should work

 

[Chalo]

Cool. This is the kind of kitchen bike mechanicking I like.

Maybe one day it will become the basement level of your e-tallbike.