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-   -   Fully Suspended Tribrid Tadpole (

BarelyAWake 08-06-2011 06:11 AM

Fully Suspended Tribrid Tadpole
Howdy folks :D

First off, this is still a "project in progress" yet, I was hoping by posting my madness, some of the fine folks here may contribute their experience & suggestions...

What I'm trying to achieve with this "tribrid" is quiet comfort with a combination of range/efficiency and improved acceleration - both of which are somewhat questionable what with the added weight & mechanical drag. The advantage of experimenting with an electric hub is should the results be less than satisfying I can always just put the hub on another bike - but I'm really hoping it'll not come to that.

Overall this build is mostly for the sheer experimentation, an excuse to tinker w/both a four stroke 49cc Lifan and a 'Magic Pie' 48v 1000w electric drive and a recumbent tadpole configuration. My "best case scenario" is something that uses little fuel for my commute, offering comfort & reliability for the long hauls (daydreamin' of cross country trips & camping adventures ofc) - but really more than anything else, just the fun & education of tryin' ta make all the pieces fit lol;

...and it appears the pics will hafta wait ;)

BarelyAWake 08-07-2011 10:20 AM

Yay pictures :D

Build log: The Bent Zombie Tribrid Tadpole (build phase)
Photo album: Tad pictures - Photobucket

mcrews 08-07-2011 05:22 PM

oh my!!!!!!!!!!

please, post more madness!!!!!!


Frank Lee 08-07-2011 05:30 PM

I like it~

cfg83 08-07-2011 05:33 PM

BarelyAWake -

Marvelous execution. With all the man-hours you must have put into it, no wonder you are sleepy!


Patrick 08-07-2011 06:06 PM

How many MPGe do you get in human-power mode? :D

Ryland 08-07-2011 06:09 PM

So what problems are you having with it? it looks like it should be road worthy right now.

My guess tho as to what kind of troubles you have or that you will have, is that your free wheel (ratchet on the rear sprocket) is not holding up and that the Lifan engine has a pile of it's own issues, as they tend to.

My reasoning for bringing up the free wheel issue is that years back when I was working on super mileage vehicles for high school competitions we found that a chain drive from a gas engine to a bicycle free wheel would rip it apart, that it was like putting an impact driver on it, gas engines do not turn at a consistent speed and the pulses in their rotation will make the free wheels only last a few hours at best, the solution for this is the same as what is done on motorcycles, big chunks of rubber or springs that dampen the pulses, on motorcycles you find these dampeners under the rear sprocket in the rear hub, for this project you might even be able to get something like a love-joy coupler to work with a small fly wheel on the dampened side.

A friend of mine who owns a motorcycle shop has talked alot about how much he hates Lifan engines and pretty much any engine made in China, Lifan are a bit better then alot of them but they are still a knock off of a Honda engine only they use lower quality alloy and their quality control is sketchy, replacing worn out parts with Honda parts can help, if you can get them to fit, that is sometimes the case but not always.

Otherwise it looks like an awesome project! nice fabrication skills and it looks like you have a decent shop and are good at improvising on the parts that you don't have.

BarelyAWake 08-08-2011 02:34 AM

More madness mcrews? Mk heh: wait, that's "addiction" not madness, my bad lol ;)

Thanks Frank Lee & cfg83... I try not to think of two things too much however, man hours would be one, silly stuff like the budget being t'other heh

MPGs in pedal mode Patrick? Well, hopefully the miles per grin will be unprecedented... I s'pose there's... naw, we'll not talk about burrito power :rolleyes:

BarelyAWake 08-08-2011 02:35 AM

Ryland - Problems? lol - too many lil ones to regal ya with. No worries however, they're mostly fabrication & learning curve related, I joined this fine forum mostly to peruse other's projects & experience - I posted here to get w/e feedback folks felt like sharing and to offer a sample of mine insanities... I'm not sure there is help for that :p

You have brought up some good critical feedback & I thank you for it! They're concerns I hope won't be too dire but only time will tell I s'pose. First, although it may look "road worthy" it is not nearly as close to completion as it may appear. I'm at the "pesky details" stage, which is ofc the most time consuming for the least profound changes - given that and the season, I've decided to take my time and attend to such during the fall & winter - it's relatively complex electrical harness would be an example as I hope to "marry" the two motors (charging & accessories) as well as full lighting - and I've not even picked out what lights I'll be using, let alone figured out how & where to mount them heh

The cassette/freewheel & potential pawl failure is another valid observation, the concern compounded by it's intrinsic nature to my electric hub, fortunately it's one I'm somewhat prepared for... There's been extensive testing of 49-66cc two stroke engines (aprox 2hp) being routed through a bicycle's power train via jack shaft & interestingly pawl/freewheel failure seems to only occur with those that have chosen to run older, used internally shifted hubs. New, quality hubs don't seem to have this issue - the '43 Rollfast pictured above has a lil over four thousand miles on it's jack shaft through a (modern) Sturmey Archer x-rd3 (3sp drum brake hub). Cassette users have reported no freewheel failures that I've seen - but some distortion of the sprocket's teeth (twisting, sometimes referred to as looking like a turbine) - but those individuals have always admitted to some abuse, as in "speed shifting" (leaving it at wide open throttle while shifting).

Admittedly, those low cost, piston ported two strokes don't have squat for torque compared to their four stroke brethren so there is some cause for concern. Backup plans include ridding myself of the rear disk brake and using it's six hole mount for a sprocket (retaining the electric hub) or worse case, ridding myself of the electric hub & batteries and using a jack shafted Nuvinci CVP from Fallbrook Technologies - which has been shown to be able to handle up to about 9hp before failure (using Morini Franco two strokes).

Insofar as the "power pulse" issue, that's been the subject of much debate. A number of folks have suggested that the momentary peak torque load of a human actually exceeds that of the motors typically used to power a bicycle and that it's actually the sustained "high speed" engagement that appears to cause some premature wear, when in actuality it isn't premature - the miles accumulate much faster at a constant 25-30mph than the typical & variable 5-15 while pedaling.

As I lack access to a dyno small enough to be accurate & both sides of the disagreement seem perfectly rational, I've chosen to shrug it off and go with what I've experienced... and that's most quality bicycle hubs are capable of transferring up to roughly 4hp (conservative) from an internal combustion engine w/o undue failure (electrics w/the "instant torque" may fare differently)... I s'pose I'll find out lol

As for the quality of the Lifan, I chose it over other Chinese variants of the Honda CRF50 as it's a true "clone" and not merely a copy, as in all Honda parts are fully interchangeable. I knew it might be a compromise in quality when I purchased it, yet it was one I was willing to make as this ...erm... "vehicle" is a prototype to say the least heh. When I received the Lifan I was pleasantly surprised to find that in actuality it's castings are gorgeous, the milling of machined parts done w/precision and even it's fasteners seem of equal quality to it's Honda equivalent... but again it's a case of "we'll see" heh - should the taddy itself prove a success but the Lifan problematic, I'll happily replace it w/a real Honda :D

Frank Lee 08-08-2011 03:17 AM

When I was a kid I made a trike go-cart with bicycle wheels and a typical go-cart drivetrain consisting of centrifugal clutch and chain, direct with no jackshaft. I had a driven sprocket welded right to the bicycle sprocket on the old "Mattatuck" coaster brake hub which survived the 2hp B&S "N" and the 3 1/2hp Tecumseh, but the hub split under the mighty 5hp B&S' torque.

I think these days I'd like to go with belt drive- built in rubber cushioning AND no fooling around with messy lubes.

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