MOTORED BIKEs, About to give up!!!!

[MOTOMTB]

Ok, guys. I've been doing the motored bike thing for a few years now and I don't know how I'd live life without one. My latest bike is a completely custom built frame and bike that is so awesome to ride.....when it's up and running......... but I have been avoiding an underlying issue with this whole motored biking thing this whole time. And that is......................wait for it................., the traditional drive train and derailleur system.

I think I've stopped counting the number of times I've had derailleur issues over the time I've been motor bicycling. Each time I get things fixed I continue with the hope that it won't happen again, that the random branch won't get stuck in my derailleur while I'm deep in the bush and completely twist everything to ****. But it happens again and again and now I'm done with it. The engineering testing and research that I've unintentionally been doing over the last few years has come to an end,.... and the verdict is, the traditional bicycle derailleur and drive train is just not reliable enough for motored power and is too susceptible to damage while on the trails.

So, I just don't see many alternatives to the standard derailleur system, at least that are cost effective. Sure, I've heard good things about the rohloff but cost wise, just not worth it. The only thing I can think of is an N360 hub but I have my doubts to the durability over extended time and I don't like how it increases friction in the drivetrain system. I'm about to give up, should I give up....what do you think? This motored biker is about to close shop and part everything out, I need some support....

 

[troyg]

Deep in the bush is one problem, trail and street is what a common MAB excels at.If you must stick with a standard DF bike, maybe look into an old sturmey archer 5 or 3 speed, lace it to your fav rim and no more snags.Even after decades of use those old AW's are near bulletproof, plenty of range (for most riding) and it sure is nice being able to shift while standing still.Other than that, a motoped sounds like what you need.

 

[MOTOMTB]

Dude, I basically built a motoped but with almost a full range of gears and way lighter, that's what kills me the most, when it works, it's the perfect motored biccyle. You mention motopeds, but they are not motored bicycles, they're just motorcycles with a ****ty pedal option with no gearing, not quite what I'm after.

lol, never even heard of Sturney archer, but just did a quick ebay search and they look too good to be true, IGH for 120$??? what is the ratio compared to a normal cassette? anyone have any experience with them? Give me the full scoop. I have my china girl modded but obviously it still doesn't put out a whole lot of power, I'd say maybe 3-5HP. Just enough to get me where I want to go. Can these things handle motored power?

A little more hopeful now....thanks

 

[troyg]

WOW WOW WOW! That's gotta be one of the coolest MAB's I've seen!!!I don't think a sturmey is going to fit your needs.It's probably just that a bike drive-train is a bit too dainty for your set-up, regardless of internal or external shift.Sturmeys (old ones) sometimes slip out of gear (neutral, freewheel, no resistance) if not adjusted perfect, with your bike that could be a bad scene.If you could hybrid moto and bike gearing somehow, but that's above my mental capabilities.
How much do you have in that beast?It's super cool man.

 

[MOTOMTB]

Eh Troy, how goes.

Thanks man, quite a bit of R&D over the span of a few years. Long story but the picture pretty much sums it up. Like I said, I have it engineered to the point of perfection, have been testing, breaking and fixing all the issues for the past few years BUT this stupid derailleur issue is going to basically kill everything. I'm just stumped. If I had the time and money, I'd set out to design a supeior IGH but that's not going to happen anytime soon. I'm pretty sure a Rohloff would work but at their price, just not willing to do it.

Well, it's just such a **** off because like I said, the drive train basically holds up fine, and I've beat the $hit out of it at some points, it actually surprised me how well the chains held up, cassette, bearings and all that. BUT what happens is that you'll be out in the trails, for instance in the fall on a rough trail and as soon as any little piece of debree, a branch, rock whatever get's into your casette and you don't notice it, things just rip to $hit in 2 secs and then your stuck. The derailleur and cassette are too exposed.

An IGH is what I need for this rig, but the problem is finding a nice balance of cost to reliability. The Sturney looks cool to me but would it hold up, for 150$ I'm doubtful?? The N360 I'm hearing is hit or miss and the Rohloff is basically a motorcycle transmission in a hub which is what I need but it's just too expensive.

So guys, chime in, let me know what you're thinking. Is the end for the "Motopedal" (that's what I call her ), am I going to have dismantle her and sell her for scraps? She's giv'n me a lot of love over the years, a lot of pain too but more love.

 

[troyg]

I believe you may be over thinking it, beside, you'll never get back the $$ and sweat you put in.
Exposed cassette/drivetrain is the problem, a plastic dish (cake pan style, lexan being best) some carbon fiber rods from
https://www.rcfoam.com/, balsa, zip-ties, epoxy, and you've got a cover.Look at the old oil-bath enclosed chains
on vintage city bikes for ideas.I'd do everything in my capabilities (yours appear substantial) to keep that ride,
currency is only losing value, you'll kick yourself if you sell that.The frame has many options.Good luck.

 

[MOTOMTB]

I believe you may be over thinking it, beside, you'll never get back the $$ and sweat you put in.
Exposed cassette/drivetrain is the problem, a plastic dish (cake pan style, lexan being best) some carbon fiber rods from
https://www.rcfoam.com/, balsa, zip-ties, epoxy, and you've got a cover.Look at the old oil-bath enclosed chains
on vintage city bikes for ideas.I'd do everything in my capabilities (yours appear substantial) to keep that ride,
currency is only losing value, you'll kick yourself if you sell that.The frame has many options.Good luck.

You know, I was thinking of that, some way to completely protect the drive train, some sort of cover. You're right, it's essentially the root of the problem. I'm a CAD designer so I can probably work something with 3D printing. Thanks for the input about selling the bike. The plan would be to part everything out anyway and keep the custom made bits . I never sell my prototypes, just the copies. Thanks for the input, helps alot! Cheers.

 

[troyg]

Dig this, no solution, but ideas galore addressing your exact prob.
http://www.bikerumor.com/2014/07/06...mountain-bike-from-national-champ-downhiller/

 

[HeadSmess]

derailleur...archaic gear shifting at its most refined just one step away from crash gearboxes and dog clutches

sturmey archers...awesome. heavy. compact. large. low maintenance. dont ever try and pull a 9 speed apart.you wont ever have to.expensive, initially

the internal gear hubs have come a lot further than the days of yore. what...up to 15 speeds or something? all ratios are usually listed.

but even a simple two speed kickback hub is more than enough on a motorised pushbike(extra low and low) and has a saving grace over standard hubs...or gear shifting in general... no linkages! no cables! no flimsy chunks of metal waving around, waiting to get smashed off!

the internal gear hub has a habit of reaching for high gear when this happens.
the derailleur can go either way, or be a complete write-off. worst are the frames with integral shifter mounts.damage that and the whole frames ruined!

the hub gear just needs straight chain, and a decent cage over the shifter crank assembly, be it sturmey archer or shimano or whatever...

the shifter adjustment is virtually set and forget, and is far simpler than a derailleur! not that theyre hard anyways

derailleurs self tension. hub gears need a separate tensioner.

the hub gear can be a completely different size to the existing dropout widths.

the higher geared ones could be a right pain in the butt for attaching sprockets to.

you gotta learn how to, or pay to have someone else, lace up the wheel and hub.

nothing preventing you from keeping a 3 gear chainring upfront other than the need for the tensioner jockey assembly off the derailleur on the rear still

 

[MOTOMTB]

Shimano Nexus looks promising....hmm.