In our Tech Q&A series, we tackle cycling queries big and small with insights from the BikeRadar team and trusted industry experts. This time, a budding young shredder wants guidance on whether his next mountain bike should be carbon or alloy.
Which is better – carbon fibre or alloy for mountain bikes? I’m a teenager who loves riding bikes and spending quality time in the woods with my mates. I owned a carbon fibre Orbea Rallon and recently snapped it as I hit a tree front on, which cracked the frame on impact. I haven't got anywhere with the warranty. Before my Orbea, I owned an alloy Transition Patrol, which was great. Now I’ve had one of each, I personally believe that alloy bikes are much better. Should I let one bad experience with carbon bikes put me off? Liam, via email
Like trading stocks and shares, previous performance is not an indicator of future performance!
It’s not the case that one of the materials is ‘better’ than the other – they just have different properties and riding qualities.
Generally speaking, aluminium alloy bikes tend to be heavier and more affordable, whereas carbon fibre frames can be lighter, but pricier.
Focusing on the subtler differences, the ‘layup’ of a carbon frame (how the fibres are arranged and orientated, and how much resin binds them together) is entirely dictated by the designers.
It can be manipulated to give either a much stiffer (for precision) or more damped feel (for comfort and control) than an alloy chassis.
It can also be tuned to make key areas very torsionally stiff (resistant to twisting) – for example, the bottom bracket shell, for a snappier response when pedalling – or to give greater strength in the areas where it’s needed most.
In contrast, it’s less easy for designers to tune the feel of an alloy frame. They can tweak the ride characteristics by using different tube shapes, diameters and wall thicknesses, but, especially when working with off-the-shelf tubesets, don’t have the same level of control.
On a weight-for-weight basis, carbon fibre is stronger, so a lighter carbon frame is typically as strong as a heavier alloy one.
Neither material is bulletproof and both are susceptible to damage. Carbon can fracture and, to an untrained eye, any issues can be difficult to spot.
Alloy tubes can snap and, unlike carbon, can dent as well. Most damage to carbon fibre frames can be repaired relatively easily, but it’s an expensive, specialist job.
In almost all cases, alloy bikes can’t be fixed practically, but are typically much cheaper to replace.
In short, it’s up to you to make the decision based on what’s best for you and your budget.
Don’t discount your Orbea Rallon either – there’s a chance the frame could be repaired, so that’s definitely worth looking into if you still have it.
Do you have a cycling question you want answered? Every month, we’ll select the most interesting questions and bring you an expert-level response from our unparalleled access to the greatest minds in cycling, both on the BikeRadar staff and across the industry. Send your questions through to podcast@bikeradar.com
