Endless Sphere

Is that the same Rohloff hub I remember, that you bought secondhand with a racing MTB attached? Yes, the very same one! It's really old, and it now has periodic skipping in 6 of the speeds, but I've been too cheap to send it back to Cycle Monkey / Rohloff for a rebuild. Aaron Goss's shop is a Rohlo...

I need those larger 50T+ rings that I can only get on a Cassette. My Quad (Jouta Blue Line) sits at ~14 gear inches [GI] (20x1.5; 24T front, 34T rear), weighs only ~1 pound more then the Rotovelo and it's not geared low enough to let me winch it up even the 12% grade hills in the area. Currently I'...

Must accept a standard Shimano Hyperglide 9-10 speed Cassette, no free wheels. You know that there are 9 and 10 speed freewheels now, right? They're made mostly for e-bikes, which have large enough axles to avoid the issues that led to cassette hubs in the first place. Mind you, using an 8, 9, or 1...

Man, I'd love to see a car go "pop" while attempting something like that.

[...]so it's time to upgrade to the Pinion 18 speed internally geared bottom bracket, which has an even greater range than the Rohloff on my current bike. Is that the same Rohloff hub I remember, that you bought secondhand with a racing MTB attached? I really like the idea of the Pinion gearbox. I'...

neptronix wrote: ↑

Dec 13 2018 12:03am

I had an a2b metro once. Wasn't a fan of it at all [...]the frame measured out to being 15lbs.

Funny... it's like people figured out how to make light strong bike frames a long time ago, and deviating more than a little from the formula results in inferior strength-to-weight ratio. Who knew?

Remember when you're doing your thermal limit estimates that the reduction gearing also suffers some power loss and heat accumulation. I'm guessing on the order of 10%. I got off track on plastic vs metal (confused with another thread). You are totally right gear loss needs to be added to motor eff...

Remember when you're doing your thermal limit estimates that the reduction gearing also suffers some power loss and heat accumulation. I'm guessing on the order of 10%.

Please keep in mind that gearhubs have rider weight limits and minimum input gearing ratios that are intended to limit the torque fed into them. When you stack reductions, you multiply the forces into the second hub, which may cause it to fail.

When NiXX cells reach full capacity, their voltage *drops*, and the cell heats up to get rid of this excess energy. That means that the current that's still flowing to charge other paralleled not-yet-full cells will now flow thru the already-full cell that's already hot will cause the cell to get h...

0.5 (primary chain) x 0.75 (first hub) x 0.75 (secondary chain) x 0.75 (second hub) x 0.833 (final chain) = 0.176. With both hubs in middle gear, 0.312. With both hubs in top gear, 0.488. Why the increasing sprocket sizes as you go back? It's only the ratio that matters; not the absolute size. It's ...

Red and black are almost certainly +5V and GND respectively. The blue and green wires that go with them are the "wipe", or signal wires.

The ones with bullet connectors might be an enable circuit that must be closed to operate. But that's a guess on my part.

NiCd cells don't need BMS-- under trickle charge conditions, the earliest cells to reach full voltage simply reject the extra current as heat while the others catch up. It's a luxury of NiCd chemistry that you should definitely exploit. For this reason (inherent self-balance on overcharge), it's not...

You still haven't eliminated the batteries as a cause, if you haven't had the batteries load tested. Just because the batteries are new, doesn't mean they're good. Go to an auto supply that can load test them for you; then you'll know. In the meantime, look at all along the main power circuit for si...

Size doesn't matter when energy is free. I've just put a deposit on a Rivian. I know I can power it from PVs. It matters when humans and other living things must share the road, and the world, with you. On top of the huge kinetic energy and accompanying hazard required to move a relatively small pa...

I was planning either a two-wheel trailer or perhaps a three-wheel trailer not unlike the Carla Cargo . I thought that the trike cargo configuration, at speeds not exceeding 15-18 mph, would make trailer sway a non-issue. Maybe I am wrong in this assumption? A three-wheeled trailer might eliminate ...

Pusher trailers can exhibit wheelspin resulting in the trailer stepping out in corners. Also, pusher trailers can induce a wobble in the tow bike. Attempts to mitigate one of these problems can often exacerbate the other. While I have only used a single wheeled pusher trailer, it was consistent enou...

actually i upgraded from the 400amp kls and have only noticed only changes at takeoff on acceleration was expecting double till top speed. If you insist on playing this high stakes game, you need to study the effects of voltage and current on motor output, and study the relationship between speed a...

Parallel connections balance the cells in each group at the same voltage potential. Series connections don't.

Parallel groups of cells act like a single larger cell. Series strings don't.

For that kind of weight and speed, the best retrofit is probably a motocross fork from a long term popular model. It will have much, much more structural integrity than any bicycle fork, but also plenty of aftermarket support for changing its travel, spring rate, and damping.

Resistance is a function of wire cross-section and length. I don't think very much heat will be generated (or energy lost) in the short piece of 16ga wire. Consider that the power traces and FET legs on our controller and BMS circuit boards are much smaller yet. They don't incur much loss because th...

Grautuefel wrote: ↑

Dec 09 2018 5:23pm

They're retrorefletive. Make you easier to see at night

The one in the picture doesn't look like a reflective stripe. It's partway into the knobby tread. My guess is that it's only a cosmetic feature.

What was the nature of the damage? Normal wear, bent teeth impinging on its neighbors, or something else?

I got a 14t outer position sprocket for my BBS02 bike. I would use a bigger outer sprocket if I could get my hands on one, because 46/14 is too high a ratio to be of use to me.

So after finally getting a replacement half link chain here in the netherlands, where nobody sells them, I've put my motor kit back together and it's still slipping under even light acceleration. If your old chain was worn and elongated, then the chain in turn wore out your sprockets. Worn sprocket...

If they are low due to being drained by the damaged BMS, then you can simply leave the pack on the charger continuously for a few days (or more likely a few weeks), and the BMS will rebalance the pack. In the past, I was led to believe that BMS often run their continuous processes from the power of...