# Carbon Fiber vs Aluminum frame for MTB



## RacerLex (Jan 20, 2010)

I've got an itch for a new hardtail MTB and have been doing some window shopping lately. I've typically owned my bikes 5-10 years and plan on doing so with my next purchase as well. I don't do any jumps or crazy stunts, my typical ride is technical single tracks with roots, rocks (not boulders), and lots of hills (up and down), about 5 miles in all. I also do a long flat dirt trail that's about 30 miles round trip so comfort is also important. Oh, and I'm 6', 190 lbs but I'll drop to 180 once I start riding again.

I did get to take a brief test ride on a 2009 GT Zaskar Expert (26") and really liked the way it fit and rode. I went to GT's web site found the same bike in a carbon fiber model - GT Zaskar Carbon Expert.

Performance sells both bikes with the carbon model costing a few hundred dollars more. The Performance bike shop I went to didn't have a carbon bike in stock and I've got no experience with riding or owning a carbon frame. Besides the potential weight savings and costing more, what are the pro/cons of going fiber vs aluminum? Is it worth purchasing the fiber model in this case? As far as I can tell the components on both bikes are exactly the same (Shimano SLX), the difference is just the frame.

To throw in another option, GT also makes a Zaskar 9r Pro, which as the name implies is a 29" but with Shimano XT components. This is an aluminum frame and costs a couple hundred more than the carbon model I referred to earlier.

If the consensus here is to go with an aluminum frame, my next question will be should I pay $600 more and go for 29" XT components over 26" SLX components? I did get to ride a 29r though not this exact one, but I"ll wait for some responses before this thread becomes a 26" vs 29" topic.  Oh and in case it matters, in the GT brand I fit a Large in the 26" frame and a Medium in the 9r frame.

*GT Zaskar Expert (aluminum) $1300*









*GT Zaskar Carbon Expert $1700*









*GT Zaskar 9r Pro (aluminum) $1900*


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## CaveGiant (Aug 21, 2007)

friking server too busy!!!

spent ages explaining all the benefits.

Get the 29er, miles better especially as it is a HT.


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## RacerLex (Jan 20, 2010)

CaveGiant said:


> friking server too busy!!!
> 
> spent ages explaining all the benefits.
> 
> Get the 29er, miles better especially as it is a HT.


Dang it! I know exactly what you mean, it's happened to me before on a different forum. I started typing out my long responses in Word or Notepad and copying/pasting the contents.

If/when you're motivated again I'd like to get your full feedback! Thanks! :thumbsup:


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## CupOfJava (Dec 1, 2008)

Carbon fiber has a softer ride and longer fatigue life than Aluminum. I would rather have carbon.


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## smilinsteve (Jul 21, 2009)

Carbon is cool, and XT is better than SLX. But, like so many things bike related, sometimes you spend a lot of dough for a very slight performance gain. 
I guess it depends on how much you want it, not if you need it. 
I would love to have a carbon frame, but don't really like the color scheme on the one you posted. 
You say you intend to keep it a long time, but you still might consider that the carbon resale value will probably always be better.


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## rockyrunner99 (Aug 13, 2009)

If it were me I would stick with the aluminum, and probably go with the 29er. Forgive me if I am wrong, but it doesn't sound like you are competitive biker, you just do it for the fun and exercise, right. I am not familiar with carbon bike frames, but I would imagine that even though it is strong in the shape of the frame. If you were to have a crash and the frame hit a rock, wouldn't it crack or puncture the frame easier. How much is a repair on a carbon frame over an aluminum? How does the warranty on the frames compare?


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## sanjuro (Sep 29, 2004)

Once in Bike Magazine, they mentioned this very relevant fact about carbon vs alu hardtails: they are both rigid bikes. 

This isn't like a road bike which you might ride several hours in the same position. You'll be in and out of the saddle the entire ride (unless you are riding it on the pavement).

Both frames are going to unforgiving compared to a full suspension bike, which is in your budget if you are thinking about carbon.

The two primary reasons why people buy carbon hardtails is the weight and the bling factor.


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## RacerLex (Jan 20, 2010)

No I'm not riding for competition but simply for pleasure. I do not mind spending a little coin on my hobbies but I never thought I'd consider buying a $2000 bike until now but I'd rather spend closer to $1000. This may sound shallow but how the bike looks (to me) is as important as the components. An ugly paint job or frame will turn me away quick. So yes the bling factor isn't a bad thing but I wouldn't spend $500 more for just bling.


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## sanjuro (Sep 29, 2004)

RacerLex said:


> No I'm not riding for competition but simply for pleasure. I do not mind spending a little coin on my hobbies but I never thought I'd consider buying a $2000 bike until now but I'd rather spend closer to $1000. This may sound shallow but how the bike looks (to me) is as important as the components. An ugly paint job or frame will turn me away quick. So yes the bling factor isn't a bad thing but I wouldn't spend $500 more for just bling.


There is nothing wrong with bling factor, as long you know it is one of the reasons.

Frankly, since most people do not ride hardtails, a carbon HT will impress.


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## smilinsteve (Jul 21, 2009)

I hear carbon, although stiff, has good vibration dampening and shock absorption characteristics and is more comfortable than aluminum. Based on my carbon handlebars, I believe it.


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## CupOfJava (Dec 1, 2008)

rockyrunner99 said:


> If it were me I would stick with the aluminum, and probably go with the 29er. Forgive me if I am wrong, but it doesn't sound like you are competitive biker, you just do it for the fun and exercise, right. I am not familiar with carbon bike frames, but I would imagine that even though it is strong in the shape of the frame. *If you were to have a crash and the frame hit a rock, wouldn't it crack or puncture the frame easier. How much is a repair on a carbon frame over an aluminum? How does the warranty on the frames compare?*


As far as I know carbon fiber has much longer fatigue life than Aluminum. As aluminum flexes it gets weaker over time. Think about a bending a piece of metal back and forth until it finally breaks. Where as compared to aluminum, carbon fiber has a near infinite fatigue life because of its elasticity. It is able to flex and then reform back to its original shape without getting weaker. This elasticity is what makes carbon a softer ride than aluminum. One downside to that is that carbon fiber will snap as opposed to continue to bend out of shape if too much force is applied to it. This means carbon fiber is a brittle material. But that doesn't me that it's weak. I have crashed my carbon Monkeylite SL handlebars into a tree at full speed going downhill and aside from a few scratches they were perfectly fine. It would take a lot to break a carbon frame. At the thickest part of the frame (the head tube bottom bracket) it would be nearly impossible to break carbon while riding where as it would still be possible to crack and aluminum frame at those points. The weakness of carbon is at the points where the carbon is the thinnest like the top tube and down tube.


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## CHUM (Aug 30, 2004)

carbon feels MUCH better than aluminim...er..alimun....agh....aluminum.....

and is strong as hell.......


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## CaveGiant (Aug 21, 2007)

Carbon Fibre vs Aluminium is not a huge difference. Both materials can be modified to ride in different ways.

The big change here is between 26" vs 29".

The difference is huge, especially if you are taller than average.

Search on the 29er forum, they will explain the differences.

To summarise, wheels have the attack angle of a slacker frame without the disadvantages.

It rides like a longer travel frame without the disadvantages.
Wheels have more momentum so roll through harder stuff.

Main advantage for me is I have never rode a bike that fits me until I rode a 29er.

The trade off is smoother acceleration/deceleration due to increased inertia of wheels.
This means the bike is less 'jerky', sometimes i miss this, I however do not miss falling off the back or front of my bike as it changed speed too fast.

I was a crap rider before I went 29", I occasionally get an audience when tackling advanced rock gardens now. Trust me when random walkers stop to watch you ride, it feels awesome.

If you live in the North of the UK you can borrow my ride, not a HT but might convince you of what you are paying for.

29er is the way forwards for short travel/HT.
There is an argument either way for longer travel as the advantages are less pronounced.


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## CaveGiant (Aug 21, 2007)

Aluminium,

Aluminum is believed to be a typo. The first guy to make Aluminium commercially viable registered the 'invention' as aluminium. However when marketing the product the adverts said Aluminum. 

Typo/brand name of his product - either way, it is aluminium.


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## yurtinus (Jun 9, 2009)

CaveGiant said:


> Aluminium.


Go back to the Britains, weirdo!!

I kid, I kid 

Serious question on the Carbons though-- historically I've read there has been greater risk of them delaminating from smaller impacts making them more susceptible to rocks kicked up by the tires than aluminum. Have the newer designs and epoxies resolved it? Was it ever even an issue? Am I just talking out of my @$$?


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## quietcornerrider (Jun 6, 2009)

Carbon - Stiffer material, but yields a softer more impact absorbing ride, infinite fatigue resistance, lighter (most of the time), tough as nails, more expensive, CAN be repaired, but it is not advised in the slightest.

Aluminum - Light, strong, easy to repair compared to carbon, tough as nails, less expensive, stiff but doesn't soak up vibration like carbon, fatigues faster than carbon, but we're talking years here.

Personally, I think if they found a way to ACTUALLY repair carbon fiber, and not just patch and hope for the best, this would be THE frame material to make bikes out of. 

Actually, there is NO reason any and all road bikes should be made from anything other than carbon.

Mountain bikes see WAY more abuse, and the repair issue is a concern, since they CAN crack/break if they receive a hard enough hit. But that's why you see a TON of XC carbon bikes and not a lot of downhill or freeride bikes. They exist, but their numbers are minuscule compared to XC bikes.

Plus, it sounds like you are a recreational rider, not doing a ton of ground pounding.

I say carbon.


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## trailville (Jul 24, 2006)

I say go for the carbon 26er if you can afford it. But I may be biased since I've been riding one for almost 15 years. Aluminumumuinimyn is fine, but there' something special about riding a light carbon hardtail. 
29er? Bah Humbug.


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## CaveGiant (Aug 21, 2007)

I like the way everyone else is talking about carbon vs Al; wheras I am talking 29 vs 26.

Come over to the dark side, go 29er.


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## tjkm (Jun 9, 2007)

I went with an aluminum 29er HT and am very happy with it. More efficient climber now than I was on my 26" FS bike. I blast up hills that I used to get half way up and blow up on before.


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## RacerLex (Jan 20, 2010)

Thanks for the responses. I went to a local shop was able to ride both the carbon and expert 26" Zaskar. I was surprised that the carbon was only about a 1 lbs lighter than the aluminum model, thought the difference would have been several lbs more. Without taking the bikes offroad I couldn't say the difference between aluminum and carbon was worth the price in this case. At the same time I tested a Zaskar 29" (not the Pro) which road much different than the 26" as everyone knows.

I don't have enough seat time to make a decision on exactly which bike I"m going with, waiting for the 2010 inventory to show up. But I've been doing quite a bit of reading and after riding 26" hard tail for a decade I'm ready to try out a 29r. :thumbsup: 

Here's my list of 2010 29r's to test. If you'll notice I'm all over the place ride now, not sure if I want SS, rigid fork, though I doubt I'd spend more than $700 on a bike without gears). I'm also considering lightly used bikes.

1. GT: Zaskar 9r Pro, Peace 9r
2. Redline: Everything (D660, D600, D440, Monocog 29er + Flight)
3. Specialized Stumpjumper Comp 29, Rockhopper SL Comp 29
4. Haro Mary SS (2009). The 2010 Haro frame doesn't look so great to me.

Gary Fisher: I was considering GF but I was told the G2 geometry uses a custom offset front fork. Is that true? So if I'm looking at changing forks in the future I couldn't buy an off the shelf fork without messing up the offset?

Anyhow that's my 29r list, let me know if there's a "must add"! Thanks!


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## smilinsteve (Jul 21, 2009)

RacerLex said:


> I was surprised that the carbon was only about a 1 lbs lighter than the aluminum model, thought the difference would have been several lbs more.


Well, if they had the same parts the only wieght difference would be in the frame. If an aluminum frame typically weighs 4 pounds, it is hard to knock "several pounds" off it.


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## RacerLex (Jan 20, 2010)

smilinsteve said:


> Well, if they had the same parts the only wieght difference would be in the frame. If an aluminum frame typically weighs 4 pounds, it is hard to knock "several pounds" off it.


That's why my post is in the beginner's corner!


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