Carbon v Alu pros and cons

[Generaal Gert]

Gert, Giant frames are guaranteed for life - as long as you are the original purchaser. Just take it back to your supplier. [emoji106]

Did just that... But hoping I can upgrade to a carbon a pay in the difference... [emoji16]

[rouxtjie]

Broke my Giant Anthem x1 Alu frame over the weekend, also now considering a carbon frame... will be following this.

Carbon also fails....catastrophically so. If your main need "strength", steel might be a better fit

[Generaal Gert]

Carbon also fails....catastrophically so. If your main need "strength", steel might be a better fit

That's true... But as I'll need to stay with Giant I will need to choose between alu and carbon.

 

Sorry for high jacking the thread...

[pista]

Nothing wrong with a good Allu frame like the Cannondale CAAD10.

 

Many manufacturers claim super light weights for their carbon frames.Once you add the paint,bb shell and d-hanger then they very similar in weight.

[rouxtjie]

That's true... But as I'll need to stay with Giant I will need to choose between alu and carbon.

 

Sorry for high jacking the thread...

Ah I see, ja the carbon's are nice... 

[GoLefty!!]

the only measurable advantage carbon has over aluminium is rigidity.

 

Othere than that, it makes no difference. An Aluminium PYGA rides better than 10 other carbon mtb's.

A al Anthem is marginallyless stiff at the head tube than the Advanced version.

 

When I switched from Al Rush to Carbon Rush to Carbon Scalpel there was a noticeable difference in headtube stiffness not because of material change but because the carbon bikes head tube to top and down tube jnctions are absolutely massive compared to the AL versions.

 

design design design.

[sawystertrance]

the only measurable advantage carbon has over aluminium is rigidity.

 

Othere than that, it makes no difference. An Aluminium PYGA rides better than 10 other carbon mtb's.

A al Anthem is marginallyless stiff at the head tube than the Advanced version.

 

When I switched from Al Rush to Carbon Rush to Carbon Scalpel there was a noticeable difference in headtube stiffness not because of material change but because the carbon bikes head tube to top and down tube jnctions are absolutely massive compared to the AL versions.

 

design design design.

Now I'm properly confused. Some guys (like nasmo, Huez and Dirkitect) say that carbon flexes and is more comfortable but you think it is stiffer. Is there some way that both opinions can be true under different interpretations or conditions?

[rouxtjie]

Now I'm properly confused. Some guys (like nasmo, Huez and Dirkitect) say that carbon flexes and is more comfortable but you think it is stiffer. Is there some way that both opinions can be true under different interpretations or conditions?

Compliance <> flex

 

Carbon's design / layup makes it bend ever so slightly, but in a direction that makes the ride comfortable and without you losing power.

[nazmo]

sawystertrance, thats the point of carbon. They can design it to flex in certain areas and be super stiff in others. You want stiffness where your power transfer happens, bottom bracket and bottom tube, you might want flex towards your seat post, or top tube.

 

Also, when I mean flex, Im referring more to the ability to absorb shock. They do this with different layering of different carbon. So you get more flexibility in how to design the geometry with less of a weight penalty.

 

my giant has a ridiculously wide bottom tube, so wide that it actually tapers to the one side just to fit the bottom bracket. That sort of design would be tricky to do with alu, and might give a weight penalty

[sawystertrance]

Thanks rouxtjie and nazmo,

 

That makes perfect sense and is something I missed. Altogether it means my mate will have to do as much test riding as he can since the flex/stiffness will surely change between brands and models.

Thanks to all for the input

[GoLefty!!]

the other thing to consider is that carbon has very poor impact resistance. Aluminium handles rock strikes and tumbles a lot better than carbon. Fortunately Carbon is layed up in such a way that should resist most accidents it unfortunately cannot handle big impacts to the down tube which is most exposed.

[rouxtjie]

Thanks rouxtjie and nazmo,

 

That makes perfect sense and is something I missed. Altogether it means my mate will have to do as much test riding as he can since the flex/stiffness will surely change between brands and models.

Thanks to all for the input

Yea deffos, design is everything....after aero of course 

[Butterbean]

It's pointless.

 

If it's a dual sus, go for Alu. The flex and forgiveness in carbon is made redundant by the rear shock.

 

Carbon is strong in so many ways, but particularly weak when it comes to impacts. Alu is better at this.

 

Alu will be close in weight, less to worry about when it comes to crashes, very stiff and strong, and your rear shock will smooth out the bumps.

 

Plus, unless you're a super top pro, I don't see how you might take advantage, never mind even notice the difference of the tiny gains of carbon.

 

Just my 2c.

[GoLefty!!]

sawystertrance, thats the point of carbon. They can design it to flex in certain areas and be super stiff in others. You want stiffness where your power transfer happens, bottom bracket and bottom tube, you might want flex towards your seat post, or top tube.

 

Also, when I mean flex, Im referring more to the ability to absorb shock. They do this with different layering of different carbon. So you get more flexibility in how to design the geometry with less of a weight penalty.

 

my giant has a ridiculously wide bottom tube, so wide that it actually tapers to the one side just to fit the bottom bracket. That sort of design would be tricky to do with alu, and might give a weight penalty

 

 

You right but also not absolutely correct.

 

Aluminium can also be designed to flex and last a long time. Next time you take a flight make sure you book a window seat and watch the wings for the next few hours.

 

When aluminium was the material of choice (like 1990 through to 2002) there were bikes that were super stiff yet compliant in the right directions. Cannondale were leaders in this are since they had no historical attachment to smaller diameter tubes.

Once over size tubes became the norm there was greater strides in marrying bb stiffness to vertical compliance. Principia REX and Cannondale CAAD frames were probably leaders in this area.

 

so it still comes back to design

[MoreTrails]

 

[Bizkit031]

Carbon = Light, stiff, sexy, can be formed into any shape, some compliance but fails catastrophically and isnt cheap 

Alu = Light enough, stiff enough, cheap, can be molded into crazy tube shapes but not sexy, unforgiving ito compliance and cannot be repaired easily

Steel = Strong, retro, very compliant, can be repaired if needs be but not cheap, is heavy and cannot be formed into special tubes.

Ti = Light, compliant, strong but not cheap and needs special skills ito welding and tubes can't be formed into any form.

 

Pick your poison

I beg to differ with you on Alu cannot be repaired,it can be repaired seen it done before.