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A standpoint

posted 12 Apr 2012, 00:15 by Jocke Selin
There I was, merrily stripping the old paint off the Carrygo cargo bike. I only had a few more things to weld onto the frame before it was time for paint and then final assembly. But there was this niggling feeling.

The signs were there

During the test runs I did notice it, but I kind of had suppressed the gut feeling. Now in hindsight when I've realised what I've should have realised back then, it's absolutely obvious. The signs were there; first of all I had to consider the parking of the bike even when empty. I had to make sure that the ground was reasonably level, and that if it weren't, I had to angle the bike so that it would stay upright. But what really should have grabbed my attention was when my partner was holding onto the bike when we loaded it with our weekly food shopping. This should not be necessary. The bike should be rock solid as it stands on its own. It should also stand on its own on reasonably sloped ground. Regardless of how much load is on the bike.
If I would have been ready to face the facts I would have admitted it before, but now, closer to the end, it was harder.

The technicalities behind the instability

T
he Carrygo is what's called a front-loader cargo bike. It's got a big rack at the front, with the front wheel right beneath it. The majority of the load and weight will thus be located at the front. However, in my strive to make the bike as "common" as possible when it comes to parts, I opted for a standard centre kick-stand made by Hebie. It's rated at 60kgs so I thought it would be sturdy enough. Whilst the stand is well made it's has still got a tiny bit of flex in it, however, even if the stand didn't have any flex in it, the stability isn't enough. That is simply due to the fact that the stand is too far away from the load.

The solution

Having admitted that a bought stand is simply not sturdy enough, the only solution is to build my own stand. This isn't a problem, it's just a lot more work. Part of the complexity is due to that a stand has to move (up and down). Anything that moves is much more tricky than something that's fixed. Complexity means more time, time which I don't really have.
Still the solution I have in my head will consist of a sturdy front stand, that can be raised and lowered from the rider's reach. It will fold forward/upwards when not in use - something that I tried to avoid, due to the catastrophic consequences of it falling down whilst riding. The solution to that is simply that I have make sure it will not fall down.

And my standpoint is

That my Carrygo cargo bike has to, absolutely must, be sturdy and practical. It cannot have a compromise. As Dave Warnock (@dave42w) said on Twitter "Key test is being able to leave bike with kids loaded in strong winds!". And when it's put like that, there's no doubt that the Carrygo needs a sturdy stand, and I should have realised this weak point earlier in the development process.
I hope you will have patience for a bit longer whilst I tend to an important issue in the workshop. My plan is to crack on with the stand come Saturday morning.
Thanks for your understanding.
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