The Carrygo Bicycle

All you ever wanted to know about the Carrygo Cargo Bike (hopefully one day - ask your questions to @CarrygoBikes on Twitter).

Design decisions

posted 18 Dec 2011, 05:23 by Jocke Selin

When venturing onto something as mad as trying to build a practical cargo bike out of an old bicycle you have to scratch your head quite a bit. There's many more design decisions than you can initially think of. Here's a few noggin' boilers that I've encountered regarding the steering on the Carrygo.

Longevity means common parts

Because the Carrygo is personal and customised to your requirements, it can't be made as a throw-away-bicycle. It has to have a long life, this in turn means that all parts and all design decisions have to be selected and made with the objective of either being indistructable or repairable with common parts. If a part is specially made and it breaks, it means that the owner will either have to source a new custom part from me, or have someone make a one-off part, or the worst; have a broken bicycle. Neither of these options are viable. Should something break or wear out, I want the owner to be able to take the bike to the local friendly bike shop and purchase a part off the shelf.
To me as the builder and designer it means I must stay away from anything that's exotic or hard to come by. In fact, I should buy all the parts from the same ecosystem where my customers would buy from. In practical terms this means that the local DIY shops, the local bike shop, etc, become my good friends. The downside of this is that some parts of the design will have some of that DIY look and inevitably will not look as "factory" made as if I would have opted for custom made parts. The image is of the steering rod and the "Rose joint" ("Heim joint" in the U.S). This is a standard part available from shops that sells ball bearings etc.

Dream steering as an example

Let me tell you about a design decision that I've had to refrain from. My friend, Mike Tryphonos, builds hub-steered motorcycles, see his website. I've been fascinated with those bikes for a very long time. Better handling and lighter weight. Then I saw Elian Cycles cargo bike with hub steering and it blew me away. The design is simple and very robust, just beautiful.
I started sketching on a hub-steered version of the Carrygo, and the benefits were obvious. I could remove about 200 - 250mm off the height of the front cargo rack. That would mean that the heavy load would be lower and thus the centre of gravity would be better and the handling would improve. It would also mean that you could carry higher loads without obscuring the view for the rider. This is all thanks to not requiring to have the fork's head tube.
The drawback is clearly that it would require a custom made steering front hub. Not only would that have required a lot of effort to design, prototype, and test, but once that stage would be complete, they would be expensive and/or time consuming to manufacture. Finally, if it would break, it would leave the customer in the aforementioned pickle; most likely with a broken bike. I really didn't want that to happen, so I've had to shelf that idea. Maybe I can revisit it as a design exercise one day.

More steering issues

Steering version 1. Not a very good option. Fixed now.
With my "organic engineering" approach, I will encounter issues that need to be improved, after they have been created. The first version of the steering was such an issue. I built the frame and the steering as I was progressing. I quickly noticed the reason why most (well, all!) front loading cargo bikes have a long steerer tube that goes all the way to the bottom, such as the Bilenky Cargo bike. However, that requires a custom frame or quite extensive modifications to an existing frame, so I didn't do it. I can laugh now, but I must admit I felt quite stupid when I couldn't get the steerer tube into the head tube. After a bit of "modifications" I had fixed the problem, but it was ugly. Ugly I could have lived with, but the way the steering worked, didn't feel right. The "problem" was that the steering rods crossed the bottom tube, and it required the "rear" steerer tube to be created in two parts. More parts, more failures. Not good. An improvement was required.

Steering version 2

This is a much better way to handle the steering. Version 2 works.
The solution was to create a "hole" in the bottom tube so that the steerer tube could fit into the headtube without any problems. This also allowed me to put the steering rods below, and parallell to the bottom tube. This made the steering a lot more pleasing to the eye and because of the improved parallellness (warning; not a word!) the steering was also improved.
By using two steering rods, I've not only improved the robustness of the steering by doubling the fail-safe, but also because the rods now push-pull, there's no requirement for a centre fixed point (such as a bearing) at the bottom of the rear steering arrangement.
The steering is now working perfectly and it's much kinder to the eye.

That's how it goes

I hope this little article has given you a bit more insight into the development and manufacture of the Carrygo cargo bike. What seems simple on the surface might have a complex story behind it. Solving these issues and making the decisions, are part of the fun. If you have any questions feel free to give me a shout on Twitter; @CarrygoBikes.

The Carrygo Criteria

posted 9 Dec 2011, 11:40 by Jocke Selin   [ updated 9 Dec 2011, 11:42 ]

When I started thinking about making a cargo bike, I did a lot of research. I probably read every article on cargo bikes two or three times. It quickly dawned to me that there's lots of big cargo bikes and there's lots of normal bikes, but there seems to be a distinct lack of suitable, appropriately sized cargo bikes. After a lot of thinking I came to the following criteria of how my ideal cargo bike would be configured.

The right size

In UK a bike that's too big won't work. We have narrow streets, we don't have many wide cycle lanes. Many houses don't have wide access to front or back gardens. We also have staggered gates at the end of some cycle paths to prevent us from riding straight into traffic. Finally, many houses have very limited outdoor or shed storage space.
This means that a long cargo bike, like the bakfiets/long-johns can't make it through the staggered gates, or perform tight turns. It also eliminates the cargo trikes. They're simply too wide for the staggered gates, they're too wide for the narrow back garden gate and to park them you need something more like a car parking spot than a cycle rack. Quite unfortunate.
The Carrygo solution is a bike that's not too long, or too wide, but still capable of carrying a very substantial load. The length of the Carrygo isn't much longer than a normal bike, in fact the wheelbase is not too different from a normal bike thanks to the smaller front wheel. You can ride the Carrygo wherever you can ride a normal bicycle, you can park the bike wherever you park a normal bike. Agile! And that's, to me, the right size.

The right cargo capacity

The CarryGo cargo box loaded with our shopping.
I spent a lot of time wondering what's the right size when it comes to how much stuff you want to carry. I wasn't going to pretend that the Carrygo would compete with a medium size car when it comes to what it can carry. I did want the bike to carry enough to replace many of the car journeys we think we need a car for. These trips are the trips to the super market, to the DIY shop, to town centre for shopping, etc. The criteria that I settled for was a half-week's shopping or 2-4 bags of compost or other material from the DIY or garden shop. I didn't want to stretch to a weekly shop for a few reasons. First one is that I'd like to think that more frequent shopping gives us fresher products. Then I'd also like to think that two cycle rides are better than one when it comes to excersise. The Carrygo can easily take this amount of cargo. We have completed several trips to the super market and we have filled the cargo box to the brim and used the rear luggage rack to great success.

Your bike, adapted to you; personal.

One obvious thing after reading all the information on the web was that there's a wide variety of sizes when it comes to cargo bikes. It was quite obvious that different people will have different requirements. Some have children that they need to carry, some have heavy stuff, some have odd shaped stuff, some need to attach things, etc. I decided that the best solution is to build the bike for the customer. That way, you can dictate what you want, and you can be sure you get to use your bike for what you need.
You will also be able to specify the exact components you want. The number of gears, the type of brakes, seat, handlebars, wheels, accessories, etc, etc.

It needs to be robust, convenient and practical

The front disk brake on the Carrygo cargo bicycle.
We are all lazy, and I try not to be, and many others do too. But we all know that the path of the least resistance is the one we're most likely to take. If your bike is locked up, behind doors, and it's cumbersome to get out, and it requires special this-or-thats, then the likelyhood that you're going to use it is much lower. If the bike's accessible, inviting and ready to ride, the chances are you'll enjoy it more. It also needs to handle the day-to-day tasks without getting in your way - in fact, it should make them easier. The lock, for example, shouldn't have you wrestle with a wire and spend time locking the bike. It should be easy. Every bit on the bike should be aimed at reducing the effort you have to make to use the bike. The Carrygo demo bike will come with a horseshoe lock that allows you to quickly lock the bike's rear wheel, and attach a wire or chain to the same lock. One key, two locks. And the key stays in the lock whilst you're riding. Convenient and practical
Another thing that gets in our ways is broken things, and a fact is, the less things you have, the less things can be broken. Cables on bicycles are the most common nuisance. They get stiff, they rust, they need oiling, and finally they snap. Hopefully it's not your brake cable that snaps in that critical moment. The Carrygo solution to this is to use a rear coaster brake (that's one of those built into the rear hub and it's activated by pushing the pedals backwards) and a front hydraulic disk brake. It's hydraulic because it doesn't have a cable that can snap, it's also more powerful and gives better feel. The only cable on the Carrygo is for the internal hub gears. Should it break or seize, it will not be a catastrophical failure. Please note that every Carrygo is built to your specifications, so if you want other components, that's how it should be.
The rest of the Carrygo is built with the same philosophy, strong and hardy - so it's ready to help you, not hinder you.

Why start from scratch?

When you can use a bike that already exists? It saves time and it certainly saves another bike from the scrap heap, and perhaps a smidge of the planet. I felt so strongly about using an existing bike that I wanted to make it one of the criterias for a Carrygo. It makes your bike personal. If you want, you could use a bike that you already own and love. Regardless, it's almost certain that there will not be a bike exactly like yours.
But don't think it's a junk bike just because the frame had a previous life. Every bit has been scrutinised and checked over. The only way to guarantee the highest quality is by servicing all the components or fitting new parts where required.
What's not to like; your personal recycled bike?!

The result is the Carrygo

The appropriately sized cargo bike that's personalised for you. The way you want it. Ready to serve and help you.

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