Cheap Electric fatbike

[yugi]

I wouldn't use an Alfine or rohloff hub on a beach. I'd stick to derailleur and rinse with fresh water after every ride.

Maybe on the beach once of those wax based chain lubes is smarter as sand won't stick.

[Dwight (DW)]

Look at all that sand on my bike. A big set wave almost took me out. It broke over the seat height when it hit me. Still not sure how I kept from washing out to sea.

Beach was narrow where it got me.

Waves were awesome. So worth it.

[Dwight (DW)]

I would point out that your 30T puts more tension on the chain, not less.

Yeah, my main concern was lack of power. If it had been more windy, no way the bike could have made any headway.

[Dwight (DW)]

I love singlespeed. The downside is limited top speed. The upside is big badass chain that’ll never break. I love the simplicity of singlespeed.

This appeals to me because the Bafang only seems right in one gear anyway.

Is it easy to replace 7 sprockets with one, then get a big hoss chain.

[yugi]

you will lose top end. As long as you realise that.

People think singlespeed is hard. No it isn't. It's super cruisy. You just shouldn't be in a hurry.

I'd have thought a huge advantage of eBike is speed.

[Dwight (DW)]

I'd have thought a huge advantage of eBike is speed.

It is, but doesn't need gearing to go fast. Just twist the throttle and fly!

I'd like to set gearing for the beach. On the road, I can use the throttle for any extra speed I want.

[Beasho]

Picture is worth 1,000 words.  This is titled:

I Think I'll Stop Here 

First Tracks Half Moon Bay Style 

The Gumbi sticks are my legs against the sunrise.  No vehicles allowed on the beach.  The sand with a rising tide just too soft for human power.  Only an electric fatbike can pull this off.

[PonoBill]

Probably singlespeed makes great sense on a mostly-beach bike. I tend to ride mine everywhere, and I have this mentality that tells me I must pedal effectively, so multiple speeds are needed to satisfy my Calvanist ethic. Of course, that's a pragmatic Calvinism or I wouldn't have an electric motor.

My three-wheeler had an alfine hub for the last four or so years, and it was pretty bulletproff. I currently have a Nuvinci hub in it that I'm probably going to toast. the Alfine is still working perfectly. I thought I might have grubbed up the gears, so I took it apart to check it out. Not recommended. took me about 30 tries to get it back together and working. But it was fine, gears looked good, the inner housing was unscored. this trike probably has somewhere in the neighborhood of 5K miles on it, so I was surprised to find the hub looking so good. I just cleaned it, replaced the grease, replaced the seals and called it good. I think the alfine would be fine for a beach bike--it's well sealed.

Rohloffs look to be a bit more fragile, but they are rated for tandem use, which means one hell of a lot of torque. Picture two two hundred pounders standing on seven inch cranks. That's 200+ foot pounds of torque. Admittedly low RPM, but it has to be torque that smokes these things, not power.  Nuvinci's are rate for 350 watts. I hear there's a torque rating somewhere, but I haven't found it.

[Dwight (DW)]

More problems found..

Tore things apart. Found a bent rear axle. It's a 10mm axle. Do they make stronger axles? This axle, the loose balls just fall out. Now I'm wonder if something better can even be fit to this old school design.

I put calipers on a single chain. The side plates are the same cross sections as a 7 speed chain. That means no difference in strength, unless someone offers harden steel side plates. I only see hardened pins. Worthless for my issue.

What kind of rabbit hole did I go down 

At this point, I'm not even sure a higher end bike would have prevented these issues. Am I wrong?

[yugi]

yes

next question?

[PonoBill]

I've pounded the heck out of my Mongoose without any issues--doesn't mean they won't jump out and bite me. I assume all the stuff is crap, but it's been adequate crap so far. You can beef up what you have or swap to something more expensive. I'd try a good single speed hub and axle laced up to the rim and tire you have. that would probably put an end to your problems.

[yugi]

sorry to be harsh

will answer my opinion with time. merry Christmas

[PonoBill]

Not harsh at all, it's nice to have someone actually knowledgeable talk about this stuff. I'm just bumbling along, "inventing" shit that's probably been well understood for ten years.

[Dwight (DW)]

Ok lets discuss more.

I would assume higher end bikes can be had with hardened steel axles? But figuring out if the bike comes with one, easy, hard?

The chain issue really bugs me. Until I see thicker side plates, I'm worried.

Lighter bike by 10 lbs would be easier on axle, but guys jumps these things, so seems like bike weight can't that big a deal.

And the sand, oh my, when I tore it apart, everything was grinding in grit. Washing it after each use didn't seem to help at all.

As you can tell, I'm not a bike guy. I don't know squat. My other bike is an Electra  townie.

[yugi]

I learned some good stuff from Keith Bontrager, (Santa Cruz). One of the main influencers of modern mtn bike design. Smart guy but even more mad scientist. Tested stuff to find limits.

I remember a conversation about potential of carbon wheel rims to be stiff. [in those days they tried to make strong rims with 4 huge carbon spokes]. His answer: "why? A wheel is incredibly strong along it's plane. From the side it is very weak. You could build it be strong from all directions, but why? Basically: if you aren't pretzleing a wheel from time to time it is too heavy."

I bet you think same same when building a surfboard, DW. No?

My guess:
you had some freak weird high stress from an oddball direction on your axle and/or chain. Thus comprimised. An axle or chain, uncomprimised, would normally not break under circumstances that yours broke under. In layman terms: they were tweaked.

Think of it as some guy complaining that a surfboard you made wasn't strong enough because he had fallen on it. Then it snapped while he was riding the wave of his life.

My [totally uneducated] guess: your axle and chain underwent some freak stress, maybe even when you weren't there.

My recommendation: stick w the cheap stuff and replace as the world dishes out random funny crap. And laugh about it. [precisely because you didn't get suckered into buying the high end stuff]

merry chirstmus