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DIY Cargo Bike – Part 1

KP’s home-grown cargo bike anyone with an angle grinder, old steel bike and welding machine can make without any special tools.

Firstly a disclaimer. As this bike was a personal experiment then I didn’t use the regular amount of planning and modelling. Many methods would not be used to make a proper product and currently I’m constructing a jig to hold everything in place when making this kind of bikes in the future.

With that cleared away, let’s dive into this DIY Cargo Bike project. It was actually started 2,5 years ago and I finished the bike roughly 8 months ago. I wanted a long john type cargo bike when we decided to move to Estonia, as there will not be a luxury of so many cycle paths. So already when still in Copenhagen I started the project.

  1. The geometry.
    Something that irritates me a little when people see my bike is they say – oh did you make a Bullitt replica. In part that is true. But also true is that long john type cargo bikes were used a hundred years ago, so you shouldn’t be afraid to make something similar. Of course most of the geomtery should be similar to an existing bike that has been tested and sold with success. So you can use a lot of the geometry here: http://larryvsharry.com/wp-content/uploads/2014/08/technical_wireframe_bg1.png
    Improvements for next time: a) Plan as much ahead as possible. If you have access to 3D CAD program then use it. Model everything, check that nothing collides when steering etc.
  2. Chopping an old bike into pieces. Welding a new down tube.
    I knew I wanted to do as little work as possible, so I found an old bike, dissembled everything and started cutting away. After cutting away the down tube I took a long 2 meter tube I wanted to use for the new down tube. Then I aligned it to the middle of the fork and welded to the bottom bracket. It is important to keep the fork on the bike at this point as I was not using a jig and needed some reference points. Keeping the new down tube long would also be giving me reference points for later alignment of the new fork. Before welding, I made sure the seat tube and new down tube were parallel by bolting both the welding table. PS! If tubing sizes are different then you need to use something for distance under the frame tubes if frame is of smaller tubes. Improvements for next time: a) I would consider building a jig even for 1 piece. b) If not then I would run another tube under the down tube to align the new down tube with the rear axle center. c) I would make the down tube from round tubing as it will have some rotational stress.
    DIY cargo bike
  3. Welding on a new top tube.
    Now I cut off the steering tube and cut the old top tube shorter, using it as a guide for the new top-tube alignment. This way I could make sure the new steerer would end up in the middle of the bike. Had I used a men’s frame I would have probably kept the original top tube. Note: keep the guiding tubes on the frame as long as you can. They help against heat distortion from welding. Improvements for next time: a) Make this from round tubing for more resistance to rotational forces / torque.
    DIY Long John Bike
  4.  Welding on the new head tube.
    Now this one was the biggest mistake and can also be for you, so pay attention and read improvements. Steerer postition will affect the whole handling. So what I did correct was to make sure the head tube is in position before welding the cargo bed. All the tubing in between the bottom braket and head tube can be misaligned without a problem – if the head tube, rear triangle and the bottom bracket are located correctly. So using the 2 meter long new down tube, I could be quite confident that the middle of the front hub would be in the correct position. But getting the fork exactly straight in relation to the frame is more tricky. I used an extra piece of tubing and welded it to the new down tube. The other end was bolted to the fork.
    DIY cargo bike 5
    Now I didn’t double check the alignment properly here. I would strongly suggest using an inclinometer here. Or at least a spirit level to make sure the seat tube and head tube are aligned. Next comes the head tube angle. You need to make sure you have proper amount of trail in order to keep the steering stable. I didn’t pay enough attention to this and ended up with almose half the trail of a Bullitt (more about trail and steering here). Improvements for next time: a) After setting up the fork take a photo of the frame as best as you can from the side. On your computer open the photo with image editing programme and calculate the head tube angle or just compare it to this blue print of a Bullitt. b) I would buy an inclinometer from the web to check all angles. They are quite inexpeniseve , starting from 10€ on the web.
    DIY Cargo Bike Trail
  5. The Problem.
    I mentioned a the steering will be where you can make the biggest mistake. What I ended up with is speed wobble when running over bumps at speeds over 30 km/h. Science is not exactly sure why it happens. In my case I think it is small trail combined with slightly misaligned front and back wheel and square tubing for top tube and down tube which make the frame flexible sideways. What I did to compensate is that I added a motorcycle steering damper. This worked, but I want to experiment further. This year I will cut the fork again and try to increase the trail. I will post an updated later this year whether this worked. I believe Bullitt actually also has trouble with high speed steering stability as they also now have a steering damper for as an extra option.

To be continued…
KP

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Sunday read: Brooks Leather Saddle Maintenance & Care

Leather saddles have a ton of advantages over synthetic materials – they form to your anatomy, they get more comfortable with time, and if maintained well, they last forever and only look better as time passes. At the same time, if not looked after at all they might start cracking and loose their colour and character. Looking around Copenhagen shows you both ends of this line, the beauties and the beasts. No-one does leather better than Brooks, so we will share 4 easy ways of making your saddlle last a lifetime.

  1. Give it some grease – Even if you keep your bike indoors, never ride in the rain and only wear velvet pants, leather will have its natural wear. The saddle on the picture is a year old B17 that I’ve ridden in all sorts of weather almost daily. As you see, it is starting to look like someone rubbed sandpaper over the edges, this is to be expected. Easy medication against it is to take a piece of (clean) cloth and some leather fat. Brooks tells you to only use their saddle polish, but anything will do as long as it is natural and doesn’t have chemicals in it. Personally I would suggest bee’s wax, you can use it for saddle, grips, shoes, handbags etc.
    Leather fat for Brooks Saddle
    Natural leather fat
    Aged Worn Brooks Saddle
    A year old Brooks Saddle with signs of wear.

    Brooks B17 saddle care
    Same saddle after a layer of natural leather fat. Rubb it on, let it sit and rubb excess fat off with a clean piece of cloth.
  2. Cover from rain – Leather is not a huge fan of water. Just have a plastic bag in your backbag or under the seat for when it rains, pull it over the seat and keep your saddle in order and your rear end dry.
  3. Keep your bike indoors – This one is not a must, but a rule of thumb is that your bike will last longer the less sun and rain it seems. If you don’t want to keep it indoors then cover the seat with a plastic bag during the night so it won’t soak in the rain.
    The Bike Hanger by KP Cykler Odense
  4. Tighten your seat every once in a while – In most cases, it will be needed only once a year, but still, it is a good idea to do it. All Brooks saddles come with a special key to tighten them as leather stretches. If you’re not sure when to do it then jump into the closest bike shop and they should give you a good idea and probably do it for you. NB! Don’t tighten a wet saddle!

    Tightening Brooks B17 saddle
    Use Brooks saddle key to tighten stretched saddle. Quarter of a turn at a time, tighten until you reach desired tension.

And that’s as easy as it is. It is probably less than an hour of work a year that will keep your Brooks leather saddle looking good for ages, and who knows, maybe one day you’ll sell it on eBay for a nice dime.

 

*We’re happy to do the above steps for you for free in our Copenhagen shop 😉

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Leaning Sidecars

It’s been a little while since the last post – we’re looking to get back into it now as we’ve successfully moved the shop to Copenhagen (Ingerslevsgade 103, Kbh 1705 if you’re curious to stop by ;) ). Here’s a piece on something that’s been cooking for a while – leaning sidecar history.

Leaning sidecars were first invented by Freddie Dixon, an English motorbike racer, way back in the 1920’s. Dixon was the first to figure out that by having the sidecar passenger control the tilt of the car with a lever, instead of the sidecar being rigidly fixed to the bike, it was possible to take turns a lot faster, and he used this idea to great success in his motorbike racing career. Leaning sidecars were further popularized in the same decade in American motorcycle racing, although now the focus was on having the sidecar wheel tilt by itself, giving the bike rider control. The technology used in these tilting sidecars has come a long way, and we have now been able to come up with our very own leaning sidecar for a bicycle, allowing you to easily carry goods around without knocking the bike itself off balance.

Leaning motorcycle sidecar

Leaning sidecars have many advantages which they can bring to your bike-riding, that make them an excellent choice for anyone who wants to be able to carry things on their bike with ease. With a leaning sidecar, riding the bike feels normal, and you aren’t constrained by having to compensate for the added weight of the sidecar. You’re able to take corners as you normally would, leaning in and taking them faster, as the sidecar is able to tilt freely to match the curve of the corner. Furthermore, since the sidecar is able to move independently, you don’t have to worry about holes in the road knocking you off balance- the sidecar can move over these without affecting the stability of the bike itself. On a three wheeled bike, you might notice that the bike rocks around when moving over holes, but this is not a problem with a leaning sidecar.

At KP Cykler, we’ve specifically designed our leaning sidecar bike to match the demand springing up for more efficient, effective bikes. With more and more households choosing not to have a car, it makes sense to enable your bike to carry goods such as groceries home easily. You’re sure to be impressed with how much weight it can cope with- in testing, we even managed to fit an armchair onto it! Stylish and functional, this bike makes a great choice for those who want to cut through urban congestion with ease, and carry goods around safe in the knowledge that they are still doing their bit for the environment. The only constraint on what you can ferry around is your imagination, so you’re sure to find that it adapts to your particular needs perfectly. If you have good balance, and hang on tight, you can even fit a person on it, so it really is suitable for everyone. We look forward to seeing what you can do with yours!

**Rasmus K, if you’re reading this and haven’t checked you inbox, then do so, you just won a set of magnetic lights.

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Why steel is still the king of frame tubing?

Steel is the material that has been on an irreplaceable position throughout the history of cycling. From the boneshakers of 1860s to modern custom builds, it has been the material of choice for many builders.

KP Cykler Boneshaker Animation

From the early 1900s to 1990s, steel was almost the only material used in producing bikes. In 1990s aluminium began its rise as the top choice in racing, only to be dethroned as the end of the decade saw a new material’s rise – carbon fiber. Composite materials have large advantages over metal such as aerodynamics, as it can be easily formed into any shape, and most importantly for racing – weight. Carbon road racing frames have been built as light as 642 grams with a ‘light’ steel frame being around 1400g. With carbon conquering most of the professional cycling, steel is not very likely to make a comeback to the performance world.

But if dreaming of the fastest time on Alpe d’Huez doesn’t give you a boner, then steel is most probably the best option for your urban bicycle. Sure the stiff aluminium gets you up the hill fast, but it also makes for a depressingly bumpy ride on most streets. Get into a crash on a carbon frame, and you better have a plastic bag with you to pick up the pieces – try to google shattered carbon bike frame. Steel frames give you a nice smooth ride on most city street with its lovely little flex. If you get into a crash, it will stay in one unit and hopefully still giving you a chance to guide your bike, or get to your destination once you get back up.

A shattered carbon fiber fork.

These are the exact reasons why at KP Cykler, we love steel  frames – their design is beautifully simple, they age gracefully, and they give you the most comfortable ride for the best possible price, what’s there not to like..?

KP Cykler bicycle 21
One of our steel framed bicycles

The lightest bike in the World: http://www.bikeradar.com/road/gear/article/the-worlds-lightest-bike-36902/

History of the bicycle: https://en.wikipedia.org/wiki/History_of_the_bicycle

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Sidecar Bike – How does it work?

A sidecar bike is a great way of extending the capabilities of your bicycle. By having a sidecar, you can easily transport cargo that is simply too large for panniers and racks. But have you ever wondered how a sidecar bike works? It seems like a miracle that it is able to stay attached without causing the bike to tip over. However, there are two simple methods which are used to keep everything balanced- sidecar lead, and toe-in. In this article, we’ll explain just how a sidecar bike works, so you won’t be left wondering anymore.

KP Cykler sidecar bike

The “sidecar lead” refers to the horizontal distance between the rear wheel of the bike, and the rear wheel of the sidecar. The greater this distance, the less of a risk there is of the bike and sidecar tipping over. However, a bigger sidecar lead will also cause the sidecar’s tires to wear out more quickly, so it’s important to get the sidecar lead just right.

KP Cykler Sidecar Bike Lead

The other way that a sidecar bike stays balanced is known as “toe in”. The weight of the sidecar means that the bike will be constantly pulled towards it- something that could pose a big problem if it isn’t dealt with. To counteract this, the sidecar will typically be tilted slightly towards the bike itself. The bigger the sidecar, the more toe in is required, both due to the increased weight and because of the wind resistance that could knock the bike off balance.

KP Cykler Sidecar Bike Toe In

As you can see, it requires a lot of skill to get the balance just right. We’ve worked hard to ensure that every measurement on our sidecar bikes is just right, so that you can be sure of a safe journey, every time.

 

Motorcycle sidecar setup: http://www.steves-workshop.co.uk/vehicles/bmw/sidecar/sidecaradjustment/sidecaradjustment.html

Our Sidecar Bike: http://kpcyclery.com/product/the-sidecar-bike-by-kp-cykler/