arod

I'm currently looking for a new XC mountain bike (around the entry 'race' level range) and trying to decide whether I want to go carbon or aluminium.

I know there are many factors to consider, but all things being equal, is a carbon frame always going to be superior (particularly stiffer) to an aluminium frame? In what circumstances (if any) is an aluminium frame better than a carbon frame?

Appreciate hearing people's thoughts and experiences.

Steve B.

Only advantage to aluminum, other then the obvious cost difference to manufacture, would be the material is more resistant to hits on the tubing. While carbon is designed to be strong in particular areas, the sides and strength of the tubing typically cannot resist a hit as well as metal tubes. Aluminum might suffer a dent, where carbon might see a hole punched. I actually know a guy I ride with had his (new) carbon Specialized take a stick into the down tube, made a hole. Either new frame time or sometimes a repair.

Very specific though as to the type of hit, damage resulting, etc.... some cases carbon might be better. You hear of aluminum wheels just folding from some hits where a carbon rim might bend and bounce back with good results.

Bigger question to me is can you get better wheels and components on an aluminum, where you would take lesser components on a carbon at a similar price point. When you consider that the aluminum frame can be built near the weight of carbon, means you might never notice a differences in ride quality, which in any event and for an HT would be as dependent on wheel design, tire size and air pressure in the tire.

Kapusta

IMO, until you get to the higher level price points, the extra $ you spend to get a CF frame is almost always better spent on something else on the bike.

I really din’t consider whether a bike is Al or CF. I look for the suspension design, fit, and geo first, then (if looking at a complete bike) what has the components I want. If The bike ends up being CF that is fine, but I would not let that be a driving consideration.

EDIT: the above is for FS bikes. For a HT I think CF can be a distinct benefit over Al.... though I always end up with steel.

Leebo

Steel.

base2 

To your post as a whole: Consider the whole thing as a complete package sort of deal.

Some of us here are still rocking mid-90's hardtails with bonded aluminum tubes with full XTR and RockShox Recon forks. (Cross country/single track is fun.)

To the first part of your post:
Frame material should be the least of your concerns in relation to all the other criteria. Full suspension? Rigid? Acera or XTR? Geometry? Is a dropper post important? Do you plan on jumping mad triples like the X-Games? Single track? Etc...

XTR is good stuff, but hardly necessary to have a good time. What terrain do you ride?

I guess what I'm saying is: Between good carbon with so-so components or good aluminum with great components...I'd pick Aluminum with great components. What I actually interface with to ride/control the bike matters more, to me.

To the second part of your post: "Always" and "Never" are absolutes. There are no absolutes in things like this. Blue is absolutly best. Period. No, Wait...Red is best.
So, seriously, though; The actual answer is: "Meh. Neither. Both."

You say: "Entry level race level"
Do you actually intend to race? Or do you want a bike whose capabilities would never hold you back? The answer to that question should guide your decision compass.

HerrKaLeun

Look at 10 year old neglected bikes that have dings and paint scratches. The aluminum bikes will look ratty with exposed aluminum, but will be fine.

The steel ones will be corroded, the fiber ones may have deeper unknown damage.

Obviosly you can repair all damages and scratches on steel and carbon, but only aluminum can be largely neglected.

Of course, if you have the cash and dispose of the every few years, CF had some benefits.

Mattyb13

Thanks for posting this.

PumpedUpKicks

You can always upgrade components but you can't upgrade a frame. If you haven't seen this video, it's worth 5 minutes of your time if your serious about shopping. It gave me piece of mind about spending extra $$ on a carbon bike.

gil_00000

If I were in your situation I would suggest looking at what you want and what you don't. Obviously. But, I mean, what do you want from the new bike your current bike doesn't do or have? Do you want a slack geometry? Full suspension? A different wheel size? Do you want a certain group set? 1x? Sram? Shimano? etc.

If you know what you want from your bike, you could then narrow your options to the bikes that offer those options in the price you can afford. From there you could find shops with those models. At that point you can decide whether carbon or aluminum in those builds are better for you.

If a frame specific characteristic is what you want most, I wouldn't personally be as concerned with the components. As someone earlier said you can upgrade parts easier than a frame. I will say, get a bike built so you can at least enjoy it, or tolerate it, until you're capable of switching things out.

I bought a Surly Karate Monkey 2 weeks ago. Rode it the first time and hated it. I truly mean Hated it. The Sram components are trash. I need to switch to Shimano. It being a rigid frame, I need to adjust my riding to accommodate a rigid frame. The reason I mention this is I wanted a 2017 or newer Karate Monkey frame because they can run 27.5+ or 29er wheels. I've never ridden a 27.5 or 27.5+ frame. I wanted a different and more slack geometry than the 2014 Specialized Rock Hopper 29er Comp aluminum. Once I threw the Sram garbage away and replaced it with Shimano, I had a ton of fun. But at the end of the day I wanted something more. Hence the new bike. I also got a great deal on the Karate Monkey. Good enough to switch out all the Sram and put on a new front suspension fork for at least $500 below retail.

eja_ bottecchia

It depends.

I have a Cannondale F400 aluminum frame mountain bike. I love that bike and wouldn’t trade it for a CF mountain bike.

I have two Colnago CF bikes. I love those bikes. I wouldn’t trade them for an aluminum road bike.

Different conditions different materials.

base2 

Ha, ha, HA! That's awesome!

I would've considered carbon to fail as soon as the first crackle because that indicates individual fibers/resin disbonding. Everything beyond that is a matter of degree. Catastrophic failure after that requires a duty cycle & time components. Nevertheless, the rider would've lived to fail at jumping again, & again, & again. The aluminum riders attempts at failing to jump would be much more limited.

Cool stuff.

You know how Boeing has wing failure test videos for all it's planes? It doesn't have one for the carbon winged 787.
Oh, they have videos of them doing the test.
They don't have videos of it failing.
You know why that is? They couldn't do it.
They failed at fail testing.
The testing rig didn't have enough travel to deflect the wings to failure.
It deflected the wings until they couldn't go anymore and that was that.

Carbon is cool stuff.

Cyclist0108

This is the correct answer.

Best of all, steel has carbon in it.

qclabrat

What's your budget?, carbon haters will always direct you to steel, lol. Also today's aluminum is great.
I've got all three and each have their benefits and negatives.
When you are naming it as a race bike, I assume weight would be the highest priority. But then the entry level threw me off.
Entry level and race bike terms should stay apart. Fast and lightweight can rarely be done on a budget.

PumpedUpKicks

Indeed it is! Thanks for sharing this. I was unaware.

Nessism

I'm no carbon hater but I wouldn't choose a carbon MTB frame unless I was an elite level racer for fear of damage. A nice aluminum frame will be cheaper and more durable. Steel would be another good choice but it would be heavier.

Canker

Surprised there is still so much carbon fear these days. The issue is the "entry level race" bit not carbon exploding. Bang for the buck you are probably going to be better off with aluminum and a better fork/wheels. And of coarse you can upgrade the frame. You just buy a frame and swap everything over but but but frames cost so much yeah so does a good fork and/or wheels. I guess what I'm saying is what does entry level race me to you? If it means $3k then that is a pretty damn nice light carbon hardtail. If it means $1k then it is aluminum for you. $1500-$2500 well it depends.

< 2 steel bikes and 2 carbon bikes currently
< several aluminum bikes in the past and the only bike frame I've ever busted was an aluminum one

EngProducts

Carbon frames feel amazing. If it's in your budget then it's always better.

PumpedUpKicks

Bottom line, If you can demo, ride everything on your prospective list and if you can try out the different frame materials and decide what feels best for yourself.
Carbon manufacturing has come a long way since the 90's. I was scared to death about buying a new carbon mountain bike after I'd seen others break like a crunchy taco. But after doing some demo's and renting different bikes and researching, I felt confident buying a carbon fiber bike from a reputable company. Plus I knew with all the new stuff constantly coming out, I might want to upgrade components so I wanted a nice frameset.

Something like this!

Kapusta

Yes, it gets old. CF MTB frames have been quite robust for a long time now.

qclabrat

Yep, that's why you find so many with long warranties. SC has been doing lifetime for some time and their still in business

Canker

One of my riding buddies is a bit heavy and his hardtail started off as an mid-level Specialized aluminum whatever model. He would crack those aluminum frames pretty much every year around the seat tube. Specialized finally got tired of it and just upgraded him for free to the carbon version and I think he is up to 3 years on that frame.

qclabrat

although the new hydroforming on aluminum is quite nice
My Banshee Prime looks fast and sleek. Big change over the rough stress plates they were welding not too long ago
I like both, but I've found fit is so much more important. just bought a Pivot 429SL and I'm having the hardest time with the fit due to the shortish reach.

Daspydyr 

I have a Santa Cruz Tallboy, aluminum and a Scott 20, carbon fiber. The best thing is to ride a ton and enjoy yourself. The details aren't that important.

Weresquatch

I used to be sponsored and a product tester for a carbon fiber company that made frames and components for several companies such as Scott and FSA. Carbon fiber is NOT uniform and as such there is quite a LOT of variance in how it can perform depending on mold and how the carbon is layered. RIDE the bikes you're looking at in as close to race conditions and terrain as you can before you buy. This is the ONLY way. I've owned high quality steel, Al, Ti, Mg, and carbon and they honestly all have their benefits. Carbon isn't necessarily some sort of wonder-product that is always better and you may find all else being equal, you don't prefer it.

BengalCat

Which is better? Depends upon what type of crash you have and what hits what.