recumpence wrote:I hope this does not come across as a criticism, but, this thing is really going to be HEAVY. I enjoy your build threads, but, is there any way to focus just a bit more energy on weight saving?
Well, mostly it just comes across as pointing out the obvious,
but FWIW, I am happy to get criticism! Especially from people that have proven they know what they're doing.
Mostly, I am after *sturdy*. Heavy, well, I'm already used to that.
If I could make a light bike and still fulfill the other requirements, which also includes spending virtually zero money (cuz I typically don't have any), I'd be more than happy to make it light.
If you (or anyone else) have ideas on how to do that, I'd be very happy to hear them.
I've already thought about it quite a bit, but mostly I simply don't have the right things to accomplish what I want it to do, in lighter versions. If it was just a racer, or even just a commuter, it'd be pretty easy to cut out a lot of weight, but it's more complicated than that.
Generally, the things I need to do with it require the frame be very stiff (whcih the already-heavy CrazyBike2 is not), and capable of carrying up to several hundred pounds of cargo on the frame itself, without a trailer, and without breaking the wheels, and be able to stop me really quick from 20MPH with that up to several hundred pounds of cargo still on there. (exactly how much cargo I need to carry is not possible to know exactly, but basically as much as physically possible--I don't know what I may run across that needs hauling home while I"m out riding, and there ahve been a lot of things I've missed out on because I didn't have the trailer with me and weren't there when I got back with it).
Theoretically a trike would be better suited to what I want, but I haven't got all the bits to do a FS tilting trike just yet, and if it doesn't tilt I can't ride in traffic and turn suddenly if required (which happens often enough to worry about, and is why I do not yet have a trike--the only way I could build one that wouldn't flip over like that when not loaded down would have to be very low to the ground, which makes it dangerous in traffic around here; this is part of why I built CrazyBike2 the height it is, compared to my abandoned ReCycle project).
It might turn out to not be possible to handle that much weight, but I'm on the way to trying...if it doesnt' work I'll have to figure out some sort of tilting bakfiets tadpole trike sort of thing for cargo, and stick with this one for a commuter (in which case it can be made significantly lighter).
Right now the actual bike frame itself is pretty light, but all the stuff to be added to it is going to be heavy:
--motor (mid-drive via NV)
--dirtbike rear wheel
--hefty suspension damper
The mid-drive motor is not yet determined; if it works with ebike controllers once the halls are installed, I am very interested in trying out that powerchair BLDC motor on here. Otherwise I have a 9C/GM 1000W hubmotor that is next on the list. I'd also like to test out whether a Fusin geared hubmotor motor would work well. I also have a few powerchair brushed motors with right-angle gearboxes that I've proven can work on CrazyBike2, and a couple of controllers that would work at 24-48V or so, if I get desperate.
The battery will probably be an experimental LiPo style I've been using on CrazyBIke2 for a while, but I might end up using one built up from those 18650 LiCo cells if I ever get to finish sorting/testing them. Or the Vpower/CammyCC LiFePO4 pack. I've also got 10 TS 60Ah cells, but that's only about 32V, and nearly 45lbs. Fortunatley it doesnt' matter for the speed of the bike since it's a middrive, and would probably be ideal for the BLDC powerchair motor, compared to my other options ATM.
Suspension will be lighter if I use the MTB springs with the Suzuki damper than if I use the orange damper I have on there now. I may find that I have to use the Suzuki's spring, too, which will add several pounds to it, depending on how it all acts under heavy load. I'd almost rather use airsprings, but I don't have any and haven't had the time to experiment with making my own.
Cargo frame could be lighter using Cromoly, but I don't have enough in single-lengths (just bits of bike frames that arent' all the same diameter tubing) to do it, so I currently plan to use that red square steel tubing to do it. It's not as strong as I would like, certainly not as strong as the similar stuff used on CrazyBike2's cargo rails, so I intend to triangulate it to make it stiffer/stronger. As I am not certain exactly how strong it needs to be, I'd rather overbuild it than later find out the hard way it wasn't strong enough.
The rear wheel is an issue. A bike wheel is not strong enough to deal with what I need to do--at least, not the wheels I have available, or can build from the parts I have available. The only thing I have that's strong enough is one of the dirtbike wheels, which *are* too heavy, but I dont' have any other options yet. I once considered "duallie" rear wheels, basically two complete wheels on the same axle with no space between them, but I don't think it would be as strong even on level straight road as the dirtbike wheel, and if I was turning or leaning it would definitely not be, as only one wheel would take any load then. Theoretically I might be able to interlace the wheels so the spokes are half from one hub and half from the other on either rim, but I'm not sure that would do anything useful, and might make the wheels weaker.
The swingarm off the Suzuki (minus it's pivot/crossbrace) is actually lighter than what I would have built from the treadmill steel, and probably stronger. I'll still be using some heavy steel for the pivot/crossbrace replacement, but it will be lighter than the Suzuki version, and shoudl still be lighter overall than what I would ahve built of all-steel.
Anyhow, that's a "few" thoughts on the matter for now.
Harold in CR wrote:
Instead of cluttering up your build thread, I put the new photos in my own updated thread. It shows what I have done. Maybe something there will give you some ideas. You surely don't seem to need much input on your ideas.
Oh, I need lots of input--just because I have a lot of what seem like well-thought-out ideas doesn't mean they're any good!
I'll go take a look at your thread and pics--thanks!
I'm not sure about the link--mine just tend to show up that way automatically? There is a checkbox when you post for "Do not automatically parse URLs", whcih is always unchecked for me. What is it for you?