Sunday, October 12, 2014

My xtracycle

In this article I detail how I modified my xtracycle to cheaply carry two children. For the context of my decision to do it this way, please read my other article, cycling with two kids.


This article is for information only. If you decide to proceed with doing this, you take full responsibility for ensuring your arrangement is safe. Think carefully about what would happen if a child-seat detached from your bike with your child in it, and only proceed if you are confident you can install it safely! Off-the-shelf options are available! I accept no responsibility.

This shows the xtracycle, when it had only one seat attached


I bought two second-hand rear bike seats (topeak, I think they were). On their underside, they had two large metal bolts embedded in them, which attached to in-built suspension which attached to the carrier. I sawed off the legs of the seats with a hand saw, and then the bolts with a hacksaw. The seat around these bolts is very strong, so I drilled a hole through the centre of each bolt-stub, and used these to screw the seat through the xtracycle "flight-deck" (the top of its rack) and into the aluminium tubing that holds the flight-deck. I did this because otherwise the flight deck could easily detach from the tubing. I put a few other screws through the flight-deck and into the tubing to make sure it is secure. I put three other bolts through the seat, attached only to the now-firmly-attached flight-deck, and included large washers to spread the strain on the seat.
A detail of the underside of the seat. The legs protruded at the bottom and were sawn off. The two metal circles at the top are the remains of the "captured" bolts, which were sawn off flush with the bottom of the seat and then drilled through so that the seat could be screwed through the "flight deck" and into the aluminium tubing beneath it, anchored through the bolts themselves. Also visible are several holes through the base of the seat. I tried a couple of locations for these, and didn't use the first ones (I can't remember why). They were attached to the flight-deck using bolts and large washers to distribute the force across the seat's plastic so it didn't tear.

The benefit of this system:

  • cheaper (total cost of the two seats: $100, plus a few screws/bolts that I had anyway and will reuse when finished with)
  • the weight is lower to the ground than the off-the-shelf-xtracycle-seats', and so the bike is much better balanced (the off-the-shelf seats are at least 100 mm higher -- this would make a big difference to handling)

My kids on the back of the double-seater (faces smudged to preserve their privacy)

The down side is that the seats can't be easily detached -- they stay on the bike all the time. I have now removed the front seat and put some handlebars for my elder son to hold on (they are attached to my seat post)

On my xtracycle I now have two seats. For rear one has been there for about 18 months (since my youngest son was about 12 months old), and the front has been there for about 3.5 years. I had one nut come off one of the bolts on one seat, but because each seat has 5 bolts/screws it was still safe. I check them regularly to make sure they are safe, and feel that they are stronger, more rigid, better balanced and safer than the off-the-shelf child-seat-and-carrier-combo I use on my steel-frame racer.

Now that he's older, my four-year-old doesn't need a seat any more, and can hold onto the handlebars I've installed for him


It's not just kids that I can carry -- the carrying-capacity of the xtracycle is huge.
I've had 80 kg of wheat in sacks, plus my two-year-old on the back, plus my normal daily luggage (nappies, change of clothes, etc) on it and rode home in the rain. It was very heavy but still stable. Amazing.

I should note that my xtracycle is based-on a recycled bicycle that I bought from the nice guys at the bicycle revolution in Brisbane. It has a Rohloff hub, velocity rims, and some Magura hydraulic rim brakes that I salvaged from an old bike I broke. I love my xtracycle!

This article was written by Angus Wallace, and first appeared on

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