Introduction: TIMBER CHILD’S BIKE / BICYCLE SEAT
I am living in Bhutan for one year as my wife is working as a volunteer teacher through the Bhutan Canada Foundation. I have taken a year off work to spend more time looking after my two sons, a 5 year old (who attends school here) and a 3 year old that I look after on a daily basis. [For further information on our story, refer to my wife’s blog here http://downundertothetopoftheworld.blogspot.com/].
However, we don’t have a car, and it’s good to get away from the same 200 metre stretch of road through our village where we tend to spend a lot of time. I also wanted a way to get around with my 3 year old son, that’s faster than walking. So I decided I needed a child’s bike seat that could attach to my mountain bike. It also had to be removable so I could use my bike on my own for longer rides (Bhutan is an amazing place for cycling).
As there was no commercial product available here in Bhutan, and difficult to buy one and have it posted here, I made the child’s bike seat out of timber. So now I can easily and quickly take my son to the child care centre about 4 km away, where he has lots of fun playing with kids his own age and doing craft activities. It’s also fun riding there, as I get to talk to my son along the way.
Following are instructions for how I made this bike seat, which is based on the concept of a Wee Ride bike seat. I recognise that it may be open to improvements, depending on how much you ride and how old your child is. I have thought of ways to improve it but I only have 4 months left here in Bhutan so I think that it is good enough for us the way it is. You may wish to add a head rest to give your child a place to rest his/her head when he/she falls asleep, which will ensure they don’t fall off the bike. I also make no claims as to the safety of this bike seat. I am comfortable that mine is made sturdy enough to keep junior on the seat whilst I am riding but if you make one of your own, you may wish to add some side supports or other safety improvements.
The first photo is the child’s bike seat minus the foot rest, which was installed later.
The second photo is of our first test ride with the child’s seat.
Step 1: DESIGN DRAWINGS AND SEAT POST TEMPLATES
Prepare some design drawings of your bike seat, showing dimensions of the seat post, seat, seat back, handlebar upright, and handlebars. For my seat, I used dimensions of 155 mm wide x 165 mm long, which is based on the size of my 3 year old boy. It is just wide enough to fit on most of his bottom, and not so wide that it makes it difficult to pedal. If you make it too wide, you have to pedal with your legs sticking out at an angle, which gets quite tiring when pedalling long distances.
Make a template of the seat post upright using stiff cardboard or other suitable material. I used some wire to wrap around my bike frame to try to capture its shape. I then used the wire to mark on to the cardboard the section that was to be cut away. I had to make two different templates, one for the rear and one for the front of the seat post, as the bottom frame meets the seat post at a different height towards the front of the timber post. I found it useful to mark on to my templates, front left, front right, rear left, and rear right.
I found this task to be quite tricky to get right and in the end the seat post does not fit perfectly on to the frame. However, it is close enough that it fits tightly without moving, once bolted together. I am lucky in that my bike has a frame with a triangular shaped cross-section. I’m not sure how snug the seat post will attach to frames of a circular cross-section. Note that you may also have to cut away sections to allow your brake and gear cables to operate without being hindered by the seat post. Ensure that there is enough surface area of the seat post touching the frame so that it won’t slide along the frame.
The photo shows my early design drawing, seat post templates, seat post, and tools used. Note that the design changed over time, with a bit of trial and error methodology. The main change is that the seat post had to extend to the bottom frame to ensure that it wouldn’t rotate - the template on the right is the one I made before I realised I needed to lengthen the seat post.
Step 2: MAKE THE SEAT POST
Use your template to mark out the section to be cut away from your two lengths of timber that form your seat post. The height of the seat post above the frame will depend on the size of your child and where you want their feet to rest. It may also depend on the height of the rider. I arranged my child’s seat so that the seat-back leans against my bike saddle, for the usual height I have it set. So in this respect, there may be some limitations with who can ride the bike and the size of the child that can use the child’s seat.
I used two lengths of relatively light soft-wood timber. I actually sourced all my timber from lengths that were lying around the yard, as the building in which I live was only recently finished construction. The dimensions of each side of the seat post are as follows: Length from top to bottom at rear of seat post 393 mm; Cross-section 56 mm (along the frame) x 42 mm (across the frame). I allowed a height of 120mm above the top of my bike frame to the top of the seat post. These dimensions will vary depending on your circumstances – the size of your child, the rider’s size, the strength of the timber, and your bicycle frame size.
For each side of the seat post, cut away the sections using a saw, hacksaw, hammer and chisel, rasp/file, sandpaper or other suitable tools. Cut carefully so that you don’t cut away too much as the seat post must fit snugly onto your bike frame. This step took me a long time as I don’t have a great selection of tools (a piece of timber is my hammer, my screwdriver is used as a chisel, and my hacksaw is just a broken blade without a handle attachment).
Once you have the top section cut away, mark out the cut away for the bottom frame, with consideration of where you want the seat post to sit with respect to your bicycle saddle. As I said before, I positioned my seat post so that the back of the child’s seat rests against my bike saddle. So you will need to know the dimensions of the child’s bike seat before you cut away the section that wraps around the lower part of the bike frame. To mark out the lower cut away, I used wire again to capture the shape of the bike frame, and marked this shape on to the templates, then onto the timber seat post. I marked the front of the seat post and the rear of the seat post, and then joined these markings up along the side of the seat post. The sawing required a series of saw cuts at odd diagonals, which again took me a long time, and required quite a bit of tidying up using a hack-saw, file, and sandpaper.
The two sides of the seat post are to be joined by bolting them together. Drill holes through the seat post in three positions, sized to fit the bolts and nuts that you will use. The three drill hole positions I used are above and below the top frame, and above the bottom frame. I recessed my bolts and nuts inside the seat post, actually because I couldn’t get bolts long enough to go right through. Whether you recess the bolts and nuts is up to you. You can do this easily using a drill (be sure to drill only to the required depth) but due to a limited number of drill bits, I had to do this using a hammer and chisel (i.e. a block of wood and a screwdriver).
I actually added the foot rest as a later improvement. The foot rest is just a length of timber (mine is 235 mm long), which is screw fixed to the seat post at the appropriate height for your child. I found that this length allowed enough room for my son’s feet, yet didn’t extend out so far that it got in the way of my own feet or legs whilst pedalling.
The photo is of the seat post attached to my bike frame, with the foot rest attached to the seat post.
Step 3: MAKE THE SEAT AND HANDLEBARS
The seat is fairly simple, consisting of a seat bottom and a seat back. The dimensions of my seat bottom are 155 mm wide x 165 mm long x 25 mm thick. The seat back is 140 mm wide x 165 mm high x 22 mm thick. It was not as wide as the seat bottom, which was tapered in towards the rear. The seat back is simply nailed to the seat bottom through the rear of the seat back, using three nails spaced equally. You may wish to pre-drill with a smaller size drill bit to avoid splitting the timber.
I also placed foam padding on the seat bottom and seat back, then fastened some material over the top using small nails. [The material on my child’s bike seat is actually an offcut from a gho, the Bhutanese National dress.] I fastened the padding on the seat bottom such that it could be lifted up towards the front, to enable the seat to be fastened to the seat post.
The upright/stem for the handlebars has proved the biggest problem for me as it needs to be a fairly narrow piece of timber, as the child’s legs will fit either side of the handlebar stem. The dimensions I used for my first version was 42 mm wide x 25 mm thick x 140 mm high. Unfortunately, this piece of timber split (not whilst riding) as it was a poor piece of timber. I will make another handlebar stem using a sturdier piece of timber, once I can borrow a few tools.
I had trouble firmly attaching the handlebar stem to the seat whilst maintaining rigidity. I suggest that an angle bracket would assist here (unfortunately I couldn’t find one of these in shops in my area). You could put one leg of the bracket on the bottom of the seat, with the other leg running vertically up the handlebar stem.
Another alternative would be to use a longer piece of timber for the handlebar stem, such that it also extends downwards to the top of the bicycle frame. Going a step further, you could also chock the bottom of this handlebar stem against the seat post using a short length of timber, and nail or screw the chocking piece to the handlebar stem. You would need to do this in a way such that the seat is still removable from the seat post.
For the handlebars, I used a length of polyethylene pipe which I found in the yard. You could also use some plastic pipe or a length of dowelled timber for the handlebars. I cut out a curved section at the top of the handlebar stem to accommodate the circular cross-section of the handlebars, then nailed the handlebars onto the stem with two nails.
One final attachment to the seat is an old leather belt, which I nailed on to the back of the seat, such that it can be used as a safety strap. The belt is fastened by hooking the end over a nail partially embedded in the rear of the seat back. I’m not sure if it would really hold my child on to the seat if he fell asleep, but it is at least an improvement on not having a safety strap. If you made your seat back higher, you may be able to fashion an over the shoulder safety strap, perhaps with recycled webbing straps and plastic buckles, which would improve safety.
The photo is of the seat with handlebars attached shown next to the seat post whilst disassembled.
Step 4: ASSEMBLY
Attach the seat post and bolt it together, tightening the bolts such that the seat post sits firmly on the bicycle frame and won’t slide. To attach the seat to the seat post, I used a combination of nails and screws. I pre-drilled a hole for the nails, and used one 80 mm long nail through the seat bottom into each side of the seat post (ensuring the nail was roughly middled in the seat post). The pre-drilling was done such that the nail fits in fairly snugly, but must be able to be pulled out. I used what I had available and it works OK but this attachment may be better done with screws (of suitable length), to make it easier to disassemble. I also used one screw through the seat bottom into each side of the seat post, to ensure that the bike seat attaches firmly to the seat post. I recessed each nail and screw into the seat bottom so that the child can’t feel the tops of these nails / screws whilst seated.
So once you’ve done this, give everything a good wriggle and shake to ensure that everything is fitted firmly. Now you should be ready to take your child for a ride. Take it easy to start with until you get a feel for your child’s ability and confidence level. I still don’t get up too much speed out of a respect for my child’s safety and we always wear helmets. But it’s definitely quicker than walking, and great fun as we can see the same things and talk about them as we ride.
I hope that this idea may benefit others who also don’t have access to a commercial product or who just want to build their own child’s bike seat.
The first photo is of the bike seat about to be fitted on to the seat post with snugly fitting nails.
The second photo is of the bike seat showing the attaching nails and screws hidden beneath the seat padding.
Step 5: POTENTIAL IMPROVEMENTS
The sketch shows some potential improvements to the bike seat, including a head rest to allow your child to sleep whilst riding. There is quite a bit more building work involved but if you use the bike seat a lot or if you have a young child, it will be worth it. Note that I haven’t yet constructed this, it’s just an idea that I sketched up. If you take away the head rest and the extended handlebar stem, this represents the bike seat that I made.