High performance & durability Cannondale Semi Recumbent

[neptronix]

The 6.5lb shengyi is looking appealing in my configuration. That's pretty high efficiency for a geared hub. And the power/weight ratio in a small wheel is fanstic.



I added a 5kph wind against me to try to account for the motorcycle tires and add 100 watts of load ( hopefully a pessimistic case )

Maybe this is a half decent answer to offset the added weight of the moto tire in the back.

Thermal characteristics of a small motor matter though, because i have 7% grades here and strong winds. Let's compare it to the MAC on the flat.

Both motors at 40mph on flat cruise:
MAC: 1731w - 1486w = 245 watts of heat to shed ( a lot )
Shengyi: 1712w - 1499w = 213 watts of heat to shed ( also a lot )

Going 40mph on both of these motors for extended periods of times is certainly out. But a couple miles are OK.
The fact that a 6.5lb motor can handle that for a period of time is astounding!

The MAC/GMAC, being a slightly bigger motor, is 1% more efficient on a 7% grade hill climb and these numbers get reversed. But climbing a mondo hill is rare.

I think the Shengyi is the better motor for what i want: 25-30mph cruising, a burst to 40mph here and there to avoid getting killed on fast roads with no bike lanes.

Maybe i need to pick one up and see what it's limits are. I'm thinking it's efficiency makes it a nice power surprise like the leafmotor was. This sounds like an OK powertrain plan for now.

 

[neptronix]

An update for those wondering why one the bigger builders on this forum is not a builder anymore..

My $250/month small dark dusty warehouse corner with no air conditioning or protection from pollution's effects on me turned out to be the deal of a lifetime compared to what's out there now, which i can only find ~25 miles away, thanks to the real estate boom over the last year doubling the cost of space and real estate.

The cost of the lease for the company who rented me part of their warehouse has become so high that the company is moving to a totally different area and can't host me or my workshop anymore.


I have decided to abandon the idea of doing some really good recumbent conversions for now and sell most things off. Not just because of space issues, but because of these roadblocks i can't clear without specialist help ( or space + elbow grease ):

This cannondale needs a fully custom 20" chromoly fork and another rear swingarm. I cannot find another used jekyll swingarm where the bolt holes are not rounded.. and forget finding someone to fabricate a new one or resize the current holes to snugly fit a 1mm wider bolt.

The maxaraya has steerer tube issues that a machinist and welder is needed to sort out. It also needs machining to properly mount a battery.

All 3 recumbents have weight balance issues due to my long legs, and 100% need the motor and battery up front. There is no suitable front-mounted motor for me to help cure the wheelie issue. ( been waiting on the lightest.bike kit for a year now, i'm not sure at this point if i'm getting what i paid for. )


At the end of the day, i just need a bike to ride that doesn't start with major design considerations and roadblocks.. so.. sigh.. i'm in the market for an upright bike frame :/

 

[calab]

Yeah thats just it you just need a bike that gets up and goes. You do not have to think about anything, Hop on and ride, the air over your face with that cross wind thats got a bit of a snap to her.

Welcome back

i'm in the market for an upright bike frame :/

 

[maiz]

An update for those wondering why one the bigger builders on this forum is not a builder anymore..

My $250/month small dark dusty warehouse corner with no air conditioning or protection from pollution's effects on me turned out to be the deal of a lifetime compared to what's out there now, which i can only find ~25 miles away, thanks to the real estate boom over the last year doubling the cost of space and real estate.

The cost of the lease for the company who rented me part of their warehouse has become so high that the company is moving to a totally different area and can't host me or my workshop anymore.


I have decided to abandon the idea of doing some really good recumbent conversions for now and sell most things off. Not just because of space issues, but because of these roadblocks i can't clear without specialist help ( or space + elbow grease ):

This cannondale needs a fully custom 20" chromoly fork and another rear swingarm. I cannot find another used jekyll swingarm where the bolt holes are not rounded.. and forget finding someone to fabricate a new one or resize the current holes to snugly fit a 1mm wider bolt.

The maxaraya has steerer tube issues that a machinist and welder is needed to sort out. It also needs machining to properly mount a battery.

All 3 recumbents have weight balance issues due to my long legs, and 100% need the motor and battery up front. There is no suitable front-mounted motor for me to help cure the wheelie issue. ( been waiting on the lightest.bike kit for a year now, i'm not sure at this point if i'm getting what i paid for. )


At the end of the day, i just need a bike to ride that doesn't start with major design considerations and roadblocks.. so.. sigh.. i'm in the market for an upright bike frame :/

this is a bummer. I follow your builds and have learned lots from your approach. there's no other workshop space available? a shared space or a maker space perhaps?

 

[Bullfrog]

Neppie...I recently bought a Schwinn Axum from Walmart. Aluminum frame and 29" wheels. I got the "Large" frame for two reasons...enough leg room and enough room in the forward triangle for a decent sized battery. And yes it does come in different size frames from Walmart :thumb: . I installed a stem riser and handlebars with a little rise so my riding position is upright.

We both know what a hazard going slower than the cars/trucks around us can be...I figured sitting upright on a bike with 29" wheels will at least allow me to be seen a little better :wink: .

And of course you know I am a huge MAC/GMAC fan but the Shengyi does look interesting "if" you can keep it from over heating. With the smaller size, it is going to have less surface area to reject heat to the atmosphere. You may be able to install a 26" rear wheel to reduce the overall gearing without screwing up the geometry too much...always better to get your speed from the motor winding than using a larger diameter wheel to do it. I plan to eventually install a SR Suntour Raidon fork.

 

[neptronix]

This is a bummer. I follow your builds and have learned lots from your approach. there's no other workshop space available? a shared space or a maker space perhaps?

I'm glad you learned something from my builds even though the last 3 have been a fail.

I did call up anything resembling a 'maker space', and not one of them in a 20 mile radius had any suggestions on where to find space.
Having to transport a 70lbs bike in/out of a makerspace and in/out of a small car ( eventually damaging the bike and/or car ) is a dealbreaker.

We both know what a hazard going slower than the cars/trucks around us can be...I figured sitting upright on a bike with 29" wheels will at least allow me to be seen a little better :wink: .

I eliminate that hazard with high speed. But an upright 26er is still plenty visible, unless you're in a tuck

I can't do large bike wheels because i require a motorcycle tire in the rear as a bare minimum for handling the road environment here. That means i need to start with an extra large ( long wheelbase ) 26er again and use a 22" rim and jam a 18" moto tire on for a total bike tire diameter of 23", then adjust the geometry accordingly for the 1.5 inch difference.

The right frame for this is probably another extra large Turner from the 2000's.

 

[Bullfrog]

Nep...do you want a rear suspension?

Nothing you don't know...but a rear suspension is nice from the comfortable ride perspective but it can complicate things a little bit with more movement for the wiring going to the motor and the weight of the motor being "unsprung"...the Shengyi would be nice because it is one of the lightest "good" motors available.

Back when Plus size bikes were popular, I bought three Mongoose Terrex bikes just because the frames would accept a 27.5x3.8 Maxxis FBR tire on the 52mm internal width rim that came on the bike. Plus they had a head tube angle of ~70 degrees and I liked the quick steering. The lower angles used on head tubes today steer waaay to slow for me.

That Turner frame looks nice :wink: .

 

[neptronix]

My environment necessitates a front and rear suspension above 20mph, so i won't ride a bike that doesn't have it.

I've solved the suspension problems you're talking about before with a custom blockoff plate and well thought out wiring. Not hard to solve the problems again. The problem i ran into was the absolute need for a motorcycle tire. But we didn't have 22" BMX rims back then.

These are also way easier problems to solve than recumbent bike problems :lol:

The ideal next motor for a high power upright is a lighter DD like the ebikes.ca RH212. It's almost power equivalent to the leafmotor, but the extra power density offsets the weight of the motorcycle tire i'll slap on it. Also, the 23" diameter vs the 26" plus the fact that the RH212 has a couple more poles may = a torquier and lighter wheel despite the motorcycle tire drag. IDK. Worth a shot.

 

[APL]

OK, I'm already cringing at your response,.. but don't the Stealth "style" frames fit most of your needs?
Big square battery space, big MC wheels space, steel, re-configurable seat placement, etc.
Change the tires and some suspension heights and make it a roadie?

 

[neptronix]

Not fun to carry such a heavy frame up stairs. I don't need the battery space ( i will utilize efficiency to the highest degree instead ).
It also looks way too much like a motorcycle. I want the bicycle to look as much like a bicycle as possible. I may even go so far as to hide the rear wheel motor with panniers or some sort of aerodynamic aid designed to make it look like there's a 26" out back.

The best kind of fast bike is one that doesn't look like one.

 

[Bullfrog]

"The best kind of fast bike is one that doesn't look like one"...very true :wink: .

You want to fly under the radar and not get stopped like I did.

APL...last time I checked, HPC would not sell just the frame and I have not found another one like the one you have pictured. If there is another source, please let us know.

 

[Chalo]

The best kind of fast bike is one that doesn't look like one.

Yes, definitely. But the best bike of all is the one with nothing to hide, that does everything well and abides by the formula.

I'm still waiting for the commercial e-bike that lays down a full, calibrated 750W at the wheel from say 1 mph to 20.0 mph and then calls it a day. I think that would satisfy most folks' needs and wants from a bicycle. No motorcycle parts or riding gear required.

 

[APL]

Well, I don't know too much about them, but thought there was a selection of Asian copy's of the Vector and Stealth style frames to be had for cheap. Not everybody likes the looks, but functionally they solve most of the problems that the diamond frames don't. (placement of batteries and e-parts) Maybe not light though.

Edit; I guess the deal braker is the looks, (and $$),.. can't fight that, most of us are very particular about what we want to see in our bikes. I'm no different,.. totally understandable.

 

[qwerkus]

An update for those wondering why one the bigger builders on this forum is not a builder anymore..

My $250/month small dark dusty warehouse corner with no air conditioning or protection from pollution's effects on me turned out to be the deal of a lifetime compared to what's out there now, which i can only find ~25 miles away, thanks to the real estate boom over the last year doubling the cost of space and real estate.

The cost of the lease for the company who rented me part of their warehouse has become so high that the company is moving to a totally different area and can't host me or my workshop anymore.


I have decided to abandon the idea of doing some really good recumbent conversions for now and sell most things off. Not just because of space issues, but because of these roadblocks i can't clear without specialist help ( or space + elbow grease ):

This cannondale needs a fully custom 20" chromoly fork and another rear swingarm. I cannot find another used jekyll swingarm where the bolt holes are not rounded.. and forget finding someone to fabricate a new one or resize the current holes to snugly fit a 1mm wider bolt.

The maxaraya has steerer tube issues that a machinist and welder is needed to sort out. It also needs machining to properly mount a battery.

All 3 recumbents have weight balance issues due to my long legs, and 100% need the motor and battery up front. There is no suitable front-mounted motor for me to help cure the wheelie issue. ( been waiting on the lightest.bike kit for a year now, i'm not sure at this point if i'm getting what i paid for. )


At the end of the day, i just need a bike to ride that doesn't start with major design considerations and roadblocks.. so.. sigh.. i'm in the market for an upright bike frame :/

Sad to read but understandable. Your build inspired a lot here. I ve nearly finish a semi, based on a german utopia pheonix. That frame is all hand welded and all steel. Put a small shengyi x1 in the front wheel and a nice igh hub in the back and I was pretty much done. I still have controller issues to fix (the shengyi wont work properly with cheapos) but the bike basically works. I had the motor custom winded from shengyi to account for the super small wheel, and I must say that I m not disappointed. Not as strong as a heavy dd hub, but torquey enough to climb any hill without overheating, and super duper silent.

I ve 2x 212 dds here, one front and one rear and am quite happy with them. Note if you get them from the factory in china, you can also order custom windings. Now Im lurking towards a lighter model, the shengyi dgw09 at only 4kg though I read some underwhelming things about it. I still think it s possible to build a true 1kw dd hub under 5kg that s not a glued piece of plastic like the bionx D...

 

[Bullfrog]

An update for those wondering why one the bigger builders on this forum is not a builder anymore..

My $250/month small dark dusty warehouse corner with no air conditioning or protection from pollution's effects on me turned out to be the deal of a lifetime compared to what's out there now, which i can only find ~25 miles away, thanks to the real estate boom over the last year doubling the cost of space and real estate.

The cost of the lease for the company who rented me part of their warehouse has become so high that the company is moving to a totally different area and can't host me or my workshop anymore.


I have decided to abandon the idea of doing some really good recumbent conversions for now and sell most things off. Not just because of space issues, but because of these roadblocks i can't clear without specialist help ( or space + elbow grease ):

This cannondale needs a fully custom 20" chromoly fork and another rear swingarm. I cannot find another used jekyll swingarm where the bolt holes are not rounded.. and forget finding someone to fabricate a new one or resize the current holes to snugly fit a 1mm wider bolt.

The maxaraya has steerer tube issues that a machinist and welder is needed to sort out. It also needs machining to properly mount a battery.

All 3 recumbents have weight balance issues due to my long legs, and 100% need the motor and battery up front. There is no suitable front-mounted motor for me to help cure the wheelie issue. ( been waiting on the lightest.bike kit for a year now, i'm not sure at this point if i'm getting what i paid for. )


At the end of the day, i just need a bike to ride that doesn't start with major design considerations and roadblocks.. so.. sigh.. i'm in the market for an upright bike frame :/

Sad to read but understandable. Your build inspired a lot here. I ve nearly finish a semi, based on a german utopia pheonix. That frame is all hand welded and all steel. Put a small shengyi x1 in the front wheel and a nice igh hub in the back and I was pretty much done. I still have controller issues to fix (the shengyi wont work properly with cheapos) but the bike basically works. I had the motor custom winded from shengyi to account for the super small wheel, and I must say that I m not disappointed. Not as strong as a heavy dd hub, but torquey enough to climb any hill without overheating, and super duper silent.

I ve 2x 212 dds here, one front and one rear and am quite happy with them. Note if you get them from the factory in china, you can also order custom windings. Now Im lurking towards a lighter model, the shengyi dgw09 at only 4kg though I read some underwhelming things about it. I still think it s possible to build a true 1kw dd hub under 5kg that s not a glued piece of plastic like the bionx D...

Have you seen this video from Justin at Grin Tech: https://www.youtube.com/watch?v=Ub4EP2_mAds

You probably already know this but Justin/Grin Tech host this forum and by "host" I mean "pay for" :lol:

 

[neptronix]

Sad to read but understandable. Your build inspired a lot here. I ve nearly finish a semi, based on a german utopia pheonix. That frame is all hand welded and all steel. Put a small shengyi x1 in the front wheel and a nice igh hub in the back and I was pretty much done. I still have controller issues to fix (the shengyi wont work properly with cheapos) but the bike basically works. I had the motor custom winded from shengyi to account for the super small wheel, and I must say that I m not disappointed. Not as strong as a heavy dd hub, but torquey enough to climb any hill without overheating, and super duper silent.

Glad i was an inspiration!
How much power are you putting through the little shengyi?

 

[qwerkus]

How much power are you putting through the little shengyi?

Cruise 500w; peak 1kw when climbing loaded. Top speed around 40km/h but I usually stay well below that.

 

[neptronix]

I have a tough question about this frame and fork and recumbent geometry..

I have a yellow jekyll frame with a 26" fork.
The front and rear end of both bikes is actually interchangeable with the cannondale bent.

The bike's stock wheels are 20" rear, 16" front.
I am thinking of putting a 20" wheel on the front and the 26" suspension fork off the jekyll..
And then add a 23" in the rear.

So we're looking at a 1.5 inch taller in the rear and 4-5 inch taller on the front.

Two concerns:

1) Does the extra height up front even matter on a CLWB, handling wise?
2) On the 16" and the 26" fork, the offset from the center of the upper tube to the axle slot is roughly identical. I believe this measurement is called 'rake' and will greatly affect steering. Is it true that the 2x longer fork then has HALF the rake than the 16" fork, or do they have the same rake?


I understand that there may be detrimental effects from going taller, but.. it should be loads safer than riding the long wheelbase version of this tall boy:

[youtube]Sf0zOLOveYw[/youtube]

:lol:

 

[neptronix]

I have also considered a 20" no suspension chromoly fork up front.. my only concern is that i see a lot of long rakes on recumbent forks.. from what i understand, the more rake, the twitchier the bike is. The less rake, the more stable it as at high speed ( what i want! ).

So perhaps something more along the lines of a regular bike fork ( non-exaggerated rake ) is probably what i'm looking for, or no?

 

[neptronix]

Maybe one good clue is that the lightning bikes have super short rakes and are known to be very stable..



Sounds like i have my answer but check my logic on the idea that less rake = actually a good thing for this bike considering that i want it to go fast and am happy to sacrifice slow speed steering ( the motor will help a lot!).

 

[neptronix]

Okay i need another sanity check..

Chalo once recommended to me that a fork could be reduced in size safely like so:
1. Cut the fork legs.
2. Insert a metal tube that's just the right diameter and get the metal tube to support where the fork is broken.
3. Weld it.
4. Heat treat it ( it's aluminum )

Any potential for a loss of strength in the fork is OK because the 26" fork's tube diameter is at least 2x that of the 16" fork, plus the fork is supporting ~15% of the weight it was designed for.

Sounds feasible if i could find a skilled person to do the welding etc.

 

[qwerkus]

Seems to me that what you are looking for is a simple 20" mini bike with full suspension. I've been looking for that one for ages too. My solution: go for a hardtail and use a seatpost suspension. Combined with a good suspension fork, it works ok.

 

[Atos62]

Just found this discussion.
I had some similar thoughts about improving this bike, but came across the same questions.
IMHO this bike pros and cons.
On the pro side: super comfy and you can look around without stressing your neck.
On the con side: slow for a recumbent, pothole sensitivity due the small wheels and the very rearward center of gravity, this is my biggest trouble with this bike.
Going uphill with lots of weight behind the seat takes so much weight off the front wheel that the handling became tricky after fitting the Bionx for +100km rides

Fitting a 26" (fatty) fork modifed to 20" and a bigger rear wheel might work. Consider a longer rear shock with the same travel or some travel restrictors, otherwise the rear wheel will hit the frame. Bending the fatty fork to a conveniant geometry should not be a problem if you are unhappy with the handling.

When I bought the used Bionx, it was fitted to 18" rim - the handling was still OK.

Here in Germany the Cannondale bents are so rare that I have decided to live with the cons and preserve as much as possible the bike.

 

[neptronix]

Nice pic, and a damn clean build!

Yeah, you have the small size, the larger size i have would fix your weight balance problem.
I see you have your battery in an ideal place, maybe switching to a mid drive would help a little, but maybe not enough to move the needle.

I'm still waiting on the 'lightest bike' mid drive myself so that my motor weight is entirely up front.. even though it'll only be 2.5kg, at least the weight is on the far opposite end of the see-saw:



Now i need to find a way to get a battery up there also :lol:

 

[qwerkus]

I'm still waiting on the 'lightest bike' mid drive myself so that my motor weight is entirely up front.. even though it'll only be 2.5kg, at least the weight is on the far opposite end of the see-saw:

Check out this little jewel:

Riding position a bit more aggressive than a true semi like the cannondale, but it is still quite upright and solves the front fork issue and would allow for a powerful front hub, especially if you put the battery up front.