Why your next mountain bike might be aluminium

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Pyga is a South African mountain bike brand that blends skillful aluminium fabrication, with progressive geometry (Photo: Pyga)
Pyga is a South African mountain bike brand that blends skillful aluminium fabrication, with progressive geometry (Photo: Pyga)
  • Balancing weight, performance and price, might underline an aluminium frame as your best option
  • Carbon-fibre mountain bikes are amazing, but they are more expensive than a similar aluminium model
  • An aluminium mountain bike can give you the same advanced geometry - at a lower price

Aluminium was the wonder frame material when mountain biking became popular, back in the 1990s.

Although carbon-fibre has overtaken it in performance and price during the last decade, alloy bikes are making a comeback. If you need to balance budget and performance expectations, a modern aluminium frame is unbeatable.

Novice and experienced mountain bikers all pine for carbon-fibre. Composites are much stronger per gram, than metal, allowing engineers to design mountain bike frames that are robust and very light, but it comes at a price.

With the mountain bike industry keen on selling mostly high margin carbon-fibre bikes, most of the marketing theatre is geared to the desirability of a composite frame, as opposed to the relative merits of aluminium.

But does this mean that aluminium frames are only suitable for cheaper bikes? Not at all.

Pyga mountain bikes
Most mountain bikes start as aluminium prototypes (Photo: Pyga)

Angles matter the most - not weight

One of the great truisms in mountain biking is that geometry is for free. Cleverly selected tube angles, which have by far the biggest influence on how a frame responds to your inputs, should never be influenced by price or material choice.

Carbon-fibre mountain bikes don’t have a monopoly on geometry. In fact, most carbon-fibre frames start as aluminium test bikes, during the initial design iterations and geometry tests. This allows companies to easily produce aluminium twins of their carbon-fibre models, because much of the source R&D has already been done.

There is no question that an aluminium frame is heavier than carbon-fibre, but if you are on a budget, it presents great value.

Our advice? Find your carbon-fibre dream bike, scrutinize its geometry chart, and then look for an aluminium frame that has similar angles. As we’ve mentioned: geometry is for free, and should be a guiding principle in mountain bike frame selection, as opposed to counting grams.

Aluminium frames are weaker than carbon-fibre, but in some instances, they have better crash survivability. Carbon-fibre mountain bikes can absorb tremendous loads when you land a big drop or jump. Laboratory tests have shown carbon-fibre frames to be conservatively 50% stronger than an equivalent aluminium frame.

Pyga mountain bikes
Aluminium mountain bikes are simpler to produce, than carbon-fibre frames, which is a big deal in a lockdown supply chain (Photo: _Banks21)

The issue of rock and terrain impacts

Where aluminium can be superior to carbon-fibre, is impact durability. When you crash and your bike spirals into a rock garden, aluminium frames often resist those sharp point load impacts better than carbon-fibre.

If you long for that desirable new carbon-fibre mountain bike, but find the purchase price beyond your budget, settling for an aluminium version won’t be much of a compromise in terms of riding dynamics. With the same geometry, your descending experience should be similar, although the lighter carbon-fibre bike will feel sprightlier on a climb.

There is also the question of availability, which is a significant issue in the contemporary mountain bike market, with product inventory levels at an all-time low.

Aluminum mountain bikes are easier to mass-produce within specific quality tolerances, compared to the labour-intensive fabrication of a carbon-fibre frame. As the global supply chain struggles to realign, your chance of getting that desired mountain bike in aluminium, is better than the odds of a carbon-fibre one, at least for the next year.

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