I still don't know wtf happened... *noob failures/tale

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azneinstein   100 mW

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Joined: Jun 10 2013 11:24am

I still don't know wtf happened... *noob failures/tale

Post by azneinstein » Mar 14 2017 11:57pm

So I really should have planned ahead as my build slowly got less and less ambitious, but I thought my first real posts would be showing off my build but I don't even know what happened on my first test ride.

A little background, I do work in a shop and I've probably built over 30-40+ bikes from scratch and tuned hundreds- so I think this is where my ego took a hit and why it took about a week before I finally decided to look at the damage. I was so ready for hair in the wind adventure that day...

The kit is one of those front hub 1000w kits from ebay. I finally find a guy selling a brand new Nashbar Steel fork off CL with reviews saying the fork worked great with a ebike build, etc... Now using a Ping 48V 16ah battery.

At this point, the bike is finally finished- the dropouts seems good, the wheel is straight and the bolts are definitely tightened. At this point I have only picked up the wheel and opened up the throttle fully, and all seems well. Wheel spins fast and no shaking/vibrations or anything loose and done this a dozen times.

So now the test ride, I ride the bike around the block several times to make sure the mechanics of the bike is fine and get a little speed, as I open up the throttle (which I swear was pretty lightly) I eat it. I'm still not sure what happens as I'm more concerned about the back of the bike which just threw itself almost over, I only had tiny bungees for the battery, it was in a basket but I wasn't expecting an upside down catastrophe. Luckily I caught the bike and all is well except the electric part and part of the back of my leg.

From the damage- I'm guessing the torque itself spun the wheel out of the axle cause I remember the wheel axle out of the fork which had jammed the vbrakes causing the sudden stop and back flying over. The dropouts on the forks are now not as rectangular and now a bit widened and the spacing itself got spreaded out when the wheel went crooked. (I did verify right now to make sure I didn't get shafted with an aluminum fork) Also huge scrape marks on the inner fork legs from where I think the bike fell out of the wheel and scraping the axle.

I think the problem I have is that this was suppose to be a simple install and go. Tons of people have done it, everything was dandy during testing, I used the torque nuts not arms but I didn't think that would be an issue with a rigid steel fork.

The damage to the wheel- currently one of the blue tiny/thin wires got frayed and cut during the process, the rest looks find but it's a pain cause the part is right where the wires run into the axle and there's barely any wire to repair/crimp/solder as they're so thin.

The wheel also doesn't spin now where it did before, I don't think the disconnected blue wire (Hall) would cause that.

So what's next? I'm so disappointed in myself right now- but I had won a ebike.ca ebay kit from somebody that never used it so hopefully that one works out.

Recumbent Bicycle Source   100 W

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Re: I still don't know wtf happened... *noob failures/tale

Post by Recumbent Bicycle Source » Mar 15 2017 12:10am

Torque Arms are your friend.

Ebikes.Ca "Grin" makes some of the best.

I own a bunch of them. Money well spent.

But the good news is at least (apparently) you suffered less damage than the bike.

A high torque motor, and weak, loose mounting can result in disaster. You want tight tight tight and STEEL.
Recumbent Bikes - My Recumbent Bike site for people who want to know more about them.

boytitan   100 W

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Re: I still don't know wtf happened... *noob failures/tale

Post by boytitan » Mar 15 2017 12:12am

This is why you use a torque arm and insert the tabbed washers properly. Your kit should have came with tabbed washers that sit in the fork that are a little wider then the axle of the hub fork.That go in first. What happened was your drop outs slowly widened over time happened with my first bike before I tossed the bike out since it was one of my cheaper bikes and bought the most durable front steel fork bike I could find. I mean I was running in the rear when my drop out widened and didn't fall but still made sure to make sure my next build was done right. Also I use torque arms. Hell I want a second a torque arm. After reading again I think torque washers are those tabbed washers I was talking about and yeah those aren't enough you need a torque arm especially from acceleration from a stop which generates the most torque. Running 1000 watts no issue.
Last edited by boytitan on Mar 15 2017 12:22am, edited 1 time in total.

DAND214   1 GW

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Re: I still don't know wtf happened... *noob failures/tale

Post by DAND214 » Mar 15 2017 12:17am

I started with a frt kit. I didn't make it out my driveway. I'm /was a cert auto mech. I thought It was tight too but it wasn't. I also cut a hall wire. Short to the axle but managed to repair it. Fixed the fork which was also steel. I added some washers as needed to fill in the lawyer lips on the fork and tightened it tight this time. It lasted for a couple years till I sold it. I have had 1 other frt but that was it, all rear now, about a dozen I think.

1000w on the frt is even more trouble than what I started with. I sure hope the battery is ok. In most cases when then hit the pavement there is damage.

Good lick on the next project. get it right and when you get that ride in you will enjoy it.

Dan

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MadRhino   100 GW

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Re: I still don't know wtf happened... *noob failures/tale

Post by MadRhino » Mar 15 2017 1:26am

That is one of the reasons why I don't like front motor. A failure on the front is not a good experience. Because of that, you need to be very careful building it, and inspecting it often. Most who started with a front build, did build the next on the rear.
Make it fool-proof, and I will make a better fool.
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