Small Wheels

By Small wheels I speak about wheels below 24". Those wheels are difficult to build because of smaller spokes lenghts, accessiblity of the tensiometer, choice of the number of crosses and other specials cases that might prevent you to build them nicely.

That's the easier part. You might need to cut them a bit for them to work on 36 holes wheels.

When working with small wheel you will need spoke lenght between 70 to 200 mm. They are almost impossible to find with double butted spokes like the regular DT Competition or Sapim Race. So you will need to use single butted like the DT champion or the Sapim Leader, or you can use oversized spokes at the J-bend like the Sapim Strong or E-Strong for stronger build or motor hub. All of those spokes can be cut down to your taste.

And you will need a spoke cutting machine or someone that can cut them for you.

Small wheels are often use for cargo bikes. In this case you will naturally go for the rim of the Andra Series from Ryde. The Andra Series are tough and work nicely, you can even cross three times with them with a round head nipple like the Sapim Polyax. 

However, be careful of the following things :

- Crossing on such a small distance will bend the spokes a lot, resulting in loosing a bit of spoke lenght, you might end with too short spokes.

To avoid that, I generally don't interlace the spokes. The line is direct, spokes lenghts correct and will be easier to use with plucking if needed, because when interlaced, both spokes resonate.

Some might say that you might loose some rigidity without interlacing, but a small wheels is very favorable in term of geometry, so I think that it does not matter. When breaking a spoke it might play around, but that's the same issue as radial building on road wheel. Nobody complains about that.

- I only cross 2 times maximum. It is a pain to cross more with small spokes, and it might help to use the tensiometer later with more spoke lenght available. With 3 crosses the angles is very favorable for torq transfer, but it does not really matter on cargo bikes.

Stress relieved by hand - 2 by 2 spokes squeezed - might be tough with small spokes, and very tough with very small spokes. Try to find a pliers that can help you without hurting the spokes, or stress relieved on a tube for canalisation. (Picture needed)

That's one of the main issue with small spokes. The tensiometer does not fit.

Cheap solution : 

1) Plucking the spoke.

2) Take a cheap tensiometer like the Park Tool. Cut it down to 60 mm and rise the tension of the spring to the maximum.