So after my success of my rat rod rebuild with great reception, it's time build a new bike. I'm revisiting an old concept: hybrid. Since I do not have the tools required to build from the ground up frame like I want, I have to grit my teeth and build from a mountain bike. But don't forget, I'm doing major frame modifications. Including 3/16 or 1/4 dropouts. The hybrid drivetrain consists of a 212cc (stock for now) and a hub motor mounted as mid drive. This bike is a test mule for for my production bike BA (badass). The frame design for BA is totally different from what I'm building.
Yep, it's about that time
- Thread starter jazz2561
- Start date
wheelbender6
Well-Known Member
Interesting. Most hybrid motorbikes I've seen use the hub motor in the front wheel. I'll be following this one.
BarelyAWake
New Member
I've a few questions ifn' ya don't mind 
Why the HF 212?
Why a hub motor mounted as mid drive?
Assuming a plug-in, parallel hybrid - what batteries?
If it's a "test mule for (a) production bike" what's your customer base?
Build what you will for the love of tinkerin' I figure, but as a hybrid owner myself I'm just wondering if you've fully explored all your options is all. I built for just myself & it's designed for comfort, reliability & efficiency - but were I to go for speed, I don't think I'd have chosen the 212 for that either as it's a rather large, bulky & heavy engine for it's HP... and both size & weight gets to be a serious concern with hybrids in particular.
Hub motors are one of my favorites, I love their simplicity & compact design - but they're RPM limited, they'll create quite a lot of drag if pushed beyond their maximum via another motor, which means it would need be freewheeled and provide only low speed assist, off the line & no more. They're also an odd shape as they're supposed to fit between the stays, thin and tall it'd be awkward when they've standard side-shaft motors available designed for mid-drives, of which would also aid low-speed acceleration but would be unlikely to reach the speeds you're looking for. They've motors that will ofc, but they're somewhat exotic & very hungry.
Which brings up the electric power supply, a problematic endeavor with any hybrid no matter the application. The HF 212 is ideally suited to serve as a generator in a series hybrid as it's a utility motor, but it's a massive & heavy unit to squeeze into a bicycle to begin with, let alone as a full genset. A plug-in parallel eliminates the generator as both the gas & electric are drives, but this necessitates batteries & with these weights/speeds, that's either costly or very bulky & heavy, perhaps even both.
Which brings up the customer base - no matter how it's done, it won't be what most consider inexpensive. Essentially two motorized bicycles built into one it's at best twice the complexity & cost for not twice the preformance... which gets difficult to market as there's likely simpler, lighter bikes that would meet or exceed it's capabilities for the same price or less.
Power to weight is everything, despite advances in the automotive application I'm not sure I'd use a hybrid platform for maximum speed as a motorized bicycle - if I were, I'd likely explore light, small preformance two strokes (KTM clone or horizontals) which have an equivalent HP output as he HF for a fraction of the weight & size yet cost about the same (depends on redrive choices). They haven't the torque it's true - but that's the electric's strongest aspect, it's "instant torque" complementing the ICE's HP output for hybrid harmony.
If you're just buildin' for the joy of it - have at & no worries, hybrids are a great concept to experiment with & I love mine. If however like you've said it's a "test mule for (a) production bike... top speed should be in the 90s" I've gotta caution what you may well be aware of, it's likely going to be an expensive novelty difficult to recoup your investment from, particularly as a homebuilt motorcycle.
Just as an example, one that admittedly is quite different in concept & application - my "tribrid tadpole" took three winter seasons to design & build, for about $3500 invested. Granted, as a recumbent trike w/lots of shiny toys your overhead/cost would be less... but perhaps not as much less as would be ideal for retail as aside from shocks & one extra wheel, most our components are similar. I think my lil toy is defo worth what I spent in time & monies, but I wouldn't dream of being able to turn a profit with it lol: http://motorbicycling.com/showthread.php?t=24210
Why the HF 212?
Why a hub motor mounted as mid drive?
Assuming a plug-in, parallel hybrid - what batteries?
If it's a "test mule for (a) production bike" what's your customer base?
Build what you will for the love of tinkerin' I figure, but as a hybrid owner myself I'm just wondering if you've fully explored all your options is all. I built for just myself & it's designed for comfort, reliability & efficiency - but were I to go for speed, I don't think I'd have chosen the 212 for that either as it's a rather large, bulky & heavy engine for it's HP... and both size & weight gets to be a serious concern with hybrids in particular.
Hub motors are one of my favorites, I love their simplicity & compact design - but they're RPM limited, they'll create quite a lot of drag if pushed beyond their maximum via another motor, which means it would need be freewheeled and provide only low speed assist, off the line & no more. They're also an odd shape as they're supposed to fit between the stays, thin and tall it'd be awkward when they've standard side-shaft motors available designed for mid-drives, of which would also aid low-speed acceleration but would be unlikely to reach the speeds you're looking for. They've motors that will ofc, but they're somewhat exotic & very hungry.
Which brings up the electric power supply, a problematic endeavor with any hybrid no matter the application. The HF 212 is ideally suited to serve as a generator in a series hybrid as it's a utility motor, but it's a massive & heavy unit to squeeze into a bicycle to begin with, let alone as a full genset. A plug-in parallel eliminates the generator as both the gas & electric are drives, but this necessitates batteries & with these weights/speeds, that's either costly or very bulky & heavy, perhaps even both.
Which brings up the customer base - no matter how it's done, it won't be what most consider inexpensive. Essentially two motorized bicycles built into one it's at best twice the complexity & cost for not twice the preformance... which gets difficult to market as there's likely simpler, lighter bikes that would meet or exceed it's capabilities for the same price or less.
Power to weight is everything, despite advances in the automotive application I'm not sure I'd use a hybrid platform for maximum speed as a motorized bicycle - if I were, I'd likely explore light, small preformance two strokes (KTM clone or horizontals) which have an equivalent HP output as he HF for a fraction of the weight & size yet cost about the same (depends on redrive choices). They haven't the torque it's true - but that's the electric's strongest aspect, it's "instant torque" complementing the ICE's HP output for hybrid harmony.
If you're just buildin' for the joy of it - have at & no worries, hybrids are a great concept to experiment with & I love mine. If however like you've said it's a "test mule for (a) production bike... top speed should be in the 90s" I've gotta caution what you may well be aware of, it's likely going to be an expensive novelty difficult to recoup your investment from, particularly as a homebuilt motorcycle.
Just as an example, one that admittedly is quite different in concept & application - my "tribrid tadpole" took three winter seasons to design & build, for about $3500 invested. Granted, as a recumbent trike w/lots of shiny toys your overhead/cost would be less... but perhaps not as much less as would be ideal for retail as aside from shocks & one extra wheel, most our components are similar. I think my lil toy is defo worth what I spent in time & monies, but I wouldn't dream of being able to turn a profit with it lol: http://motorbicycling.com/showthread.php?t=24210
silverbear
The Boy Who Never Grew Up
Do what you want, but in my opinion 90mph on a home built bike or trike is nuts. I'm not saying it can't be done, but why would you want to?
I have a hybrid trike in progress (slow progress) using a golden motor front wheel and a gas motor in the back and I'm figuring a top speed range around 30mph. Even with fat tires (2.45) disc brakes in back and a suspension front fork from a light weight Harley Davidson motorcycle a delta trike is inherently unstable at speed, or so I'm told anyway. To make one roadworthy at 60+ mph would be an endeavor, let alone at 90 mph. I'd think real hard on this one before you invest much money and put your life at risk. Of course, that's your business and not mine.
SB
Lol thanks for all the replies, the main reason I'm doing this is: a it is a experimental test mule for my badass btr that will have a hopped up 212cc or a stock Briggs v twin, and the electric motor will way more powerful than the hub motor I'm using. This will help me develop what I like the call "the best beast", which the motto is 100 hp at a 100 lbs. Call me insane, but I'd like to be the Carroll Shelby of board track racers. Since the bike will be geared really low, take off is going to suck. This is where the electric motor steps in. Believe me the electric motor won't be play play because there is either one powerful one or what I'm considering, two.
KCvale
Well-Known Member
OK, that's insane ;-}