- 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.
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.
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.