Opinion: Is carbon worth it?
Are we drunk on carbon?
I’ve owned, ridden and competed on carbon bits and bobs since they were available, here’s my take on the purchasing decision many face: carbon or alloy?
The truth is carbon frames and parts are almost always lighter than aluminum and in any Endurance format, carting a lighter beast about will help an athlete achieve their best possible performance. There’s no rocket science or grey areas there. If it’s lighter, it’s faster. Period. And just to clarify, my definition of Endurance is performances that are more than 30 minutes and under 10 hours in duration. If you are looking for the ultimate performance in this style of riding, then rest assured that lighter is faster (mostly) and that’s usually carbon. Shifting the conversation away from the Endurance space and zooming to Trail, eMTB and the more gravity-orientated sides of mountain bike riding, the Cost Vs. Benefit analysis of carbon, can be foggy. The confusion stems from multiple factors like evolving technology, rising costs, a change in the way we play on bikes and more. I’ve owned, ridden and competed on carbon bits and bobs since they were available, here’s my take on the purchasing decision many face: carbon or alloy?
When it comes to strength, weight, appearance, tuneability and repairability, how does carbon compare to aluminum?
Gram for gram, a carbon part can be more than 3 times stronger than its aluminum equivalent. That is not insignificant. Over a decade ago when GT introduced a full carbon framed downhill bike, the world watched in wonder, waiting for a trailside catastrophe. We all believed there was no way carbon could be as strong as aluminum. How wrong we were. Very soon the likes of Santa Cruz, Trek et al launched their own carbon machines and race victory after race victory, world title after world title, they quickly changed everyone’s opinion on the material. The reality is the catastrophic failure point of carbon is far higher than aluminum. Carbon is in fact ‘moer’ strong.
If you look at some of the bigger bike brands like Trek, Giant and Specialized who produce carbon and aluminum editions of the same bike, the weight variance between their carbon and alloy frames is probably less than you expected. Consider Trek’s 160mm Slash (reviewed here) which has a listed weight of 3.7kg, including shock. That’s very light for an Enduro bike. Now guess how much their aluminum equivalent weighs… okay wait, I’ll tell you – it’s only 600 grams more. That’s equivalent to a small orange, small avocado and two average-sized bananas. See what I mean? The takeout here is that good manufacturers not only produce incredibly light carbon bikes but that their alloy versions are also light.
As an example of this, I’ve owned three Trek Sessions (a Downhill bike) in the last 12 years. Two of them were carbon and market leaders at the time when it came to weight and perhaps even performance. The one aluminum model I owned weighed a mere 400 grams more than the carbon boyjies. In this genre, that is insignificant. Then when it comes to eMTB’s, I’ve noted the difference between carbon and aluminum frames is generally around 1000g, which as a percentage of the total weight is kind of low, especially considering there’s a motor to assist you. The point is, aluminum frames are not always hefty farm gates….
On appearance alone, there is no denying that carbon frames and parts outscore their aluminum counterparts. The appeal and pure bling of the seamless finish are not up for debate here. In my opinion, carbon wins the fashion show, every time. However, surely we are buying bikes to have fun, be healthy and connect with others, not to parade around town and win the games of bling.
Then there’s compliance. Carbon frames and parts can be ‘tuned’ to flex and comply to deliver a better ride. Manufacturers do this by using different types of carbon and varying the layups. This tunability comes in handy when engineers are trying to improve things like grip and ride characteristics. You see, flex or compliance in certain directions (for frames, wheels and bars) can dramatically influence the ride performance – and durability. However, the wizards of aluminum construction have a few tricks of their own that influence ride feel. The overall design, smart positioning on bracing the stays, linkages, gussets, tube sizing, tube shapes and choice of aluminum all impact compliance. Leading the charge here is the Andorran bike brand Commencal, who completely canned their carbon construction in favor of aluminum, for their entire range. Few would argue when I say Commencal is leading the ‘re-birth of aluminum’ in trail and gravity mountain biking. Locally, there’s also that SA bike wizard Mr Patrick Morewood creating some top-performing aluminum bikes.
There are other factors to consider. When carbon cracks or breaks it is often repairable. In most cases that is not possible with aluminum. Carbon also has a damping effect on certain vibrations which can translate into a smoother ride, with less pilot fatigue. If you are racing technical trails against the clock be that on Strava, an Enduro or Downhill race, unless you are a well-conditioned specimen of an athlete, you will fatigue more with a heavier bike, especially in the last half of the race. When it comes to wheels, many top-end aluminum rims deliver a superior ride feel to that of a super stiff carbon rim. They might not match the outright durability of the carbon rim and will need more maintenance, but their softer feel does wonders for traction and calming rowdy trails. As you can see, there’s a lot at play here.
What’s the answer?
Going for the carbon frame usually means an extra R20k, at least. That’s a chunk of change. Is it worth it, you ask? The answer is both yes and no. Here’s my advice.
If you are shopping on a strict budget then chose an aluminum-framed trail bike. Down the line upgrade to top-of-the-line brakes, suspension and maybe a lighter wheelset. Then you’ll have a dope machine. If you are really riding the bike aggressively then insurance is a must, especially after the manufacturer’s warranty is up.
Shopping without a budget you could still be better off going for aluminum – but it would depend on the bike in question and where you are riding it. Let me drill into this a bit. If it’s an eMTB – carbon is not a necessity and you’ll be fine on an aluminum frame and aluminum wheels. Put some extra cash into an electronic shifting system, (reviewed here) the accuracy in shifting under ePower really makes a difference. If it’s a trail bike that you’re after and you intend on doing a lot of climbing (to descend) I’d think you’d get more laps in if you go for carbon, everywhere. If it’s a big line gravity bike that you’re not pedaling then look for aluminum wheels and don’t be fussy about the frame material.
The big takeout which is my opinion based on both personal experience and group research is carbon parts and frames may not always improve performance and we shouldn’t all be ‘drunk on carbon.’ Buy what you can afford. And ride, lots.