How mountain bike wheels could go full carbon

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The Spengle tri-spoke mountain bike wheel looks like the future, but is it? (Photo: Spengle)
The Spengle tri-spoke mountain bike wheel looks like the future, but is it? (Photo: Spengle)
  • If carbon-fibre is so great, why do mountain bike wheels still have steel spokes?
  • Full carbon-fibre wheels are available, but they have constraints
  • Scott’s latest mountain bike wheelset, could be what premium off-road cycling wheels might become, by 2025

Wheels are the most important component of your mountain bike. Their influence on ride quality, stability and steering accuracy is immense.

Although the mountain bike wheel has evolved from aluminium rims to carbon-fibre, it still uses steel spokes. The sheer strength of carbon-fibre rims has allowed wheel designers to reduce spoke count. Whereas many mountain bike wheels from the mid-2000s had 36 spokes, that number has dropped to 32, 28 and now, even down to 24, for a modern lightweight wheelset. 

With fewer spokes, you reduce rotational mass, but shouldn’t steel spokes have been replaced altogether? In an era where most core mountain bike components are now carbon-fibre, why do we remain steadfastly committed to steel?

Tuneability and replaceability are two issues. Steel spokes can be easily adjusted, to create the perfect amount of tension in a wheelset. If you do manage to break a steel spoke, it is quite simple to replace.

This could be the decade where the transition to complete carbon-fibre wheels might happen and the Swiss are primary innovators in this regard.

Spengle mountain bike wheel
Spengle uses only three large spokes to carry a bike and rider’s weight (Photo: Spengle)

Not a new idea

Back in the late 1980s and 1990s there were tri-spoke mountain bike wheels, marketed by Spengle. These wheels never became popular but with the advances in carbon-fibre shaping technology, they were reintroduced in 2017 and despite a wonderfully futuristic appearance, limitations remain.

There are a few issues with the Spengle tri-spoke wheels. Firstly, they are a touch too narrow. The rims are only 24mm wide, which is way under the current ideal tyre standard of 30mm. Another problem is the lack of hub choice.

One of Switzerland’s most famous cycling brands is Scott. The company has multiple cross country world champion, Nino Schurter, as its professional team lead and this season he will be riding on some very interesting wheels.

From a distance they might look like traditional carbon-fibre mountain bike wheels, with blackened steel spokes, but upon inspection, you’ll notice they aren’t. These are Scott’s Syncros Silverton SL wheels, first shown in concept form, during 2018.

Scott carbon mountain bike wheel
The Scott Syncros Silverton SL wheel looks traditional but has carbon spokes (Photo: Scott)

Does Scott show us the future of mountain bike wheel design?

Like Spengle’s wheels, the Silverton SLs are a singular (monocoque) carbon-fibre design: the rim and spokes are all joined and constructed from carbon-fibre. There are no steel spokes present, nor the possibility to ever tension these wheels.

They are intricately fabricated and built with perfect tension. If you do, by great misfortune, manage to break a spoke, it will have to be repaired by a professional composite technician. This makes it a lot more labour intensive when things go wrong, although compared to a conventional carbon-fibre rim with steel spokes, the seasonal maintenance is zero, as these Silverton SL wheels never run out of ‘true’ alignment.

A huge advantage the Silverton SL design has over Spengle’s tri-spoke wheel, is that it offers a greater selection of hubs. These are supplied by DT Swiss, another Helvetic brand celebrated for its engineering quality, durability and ease of maintenance.

When they were originally brought to market in the Silverton SL wheels only had one real weakness, their 26mm internal diameter rim width. That has now been addressed, with Scott having developed a wider version for its professional mountain bike racers.

The redesigned Silverton SL wheels should come to market by winter, with rims that space to a generous 30mm of internal width. Amazingly, a complete wheelset weighs only 1290g.

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