Carbon vs aluminum

[Orangie]

What do you think the outcome would have been if this were carbon ??

 

[Bomble]

Bounced off, hopefully ?

 

[Orangie]

Shattered my guess.

 

[NULevo]

Try this, I like the bit at around 5 .00....

 

[Jdog]

I’ve seen many videos of carbon being “tested” at a factory yet no breakages but in the real world I’ve personally witnessed and experienced carbon frames and bars disintegrate.

I’m firmly team alloy!

 

[Fivetones]

It’s an interesting topic this. I prefer the failure modes of alloy over carbon (I ride alloy) but I’m not sure one can generalise about each as each manufacturer has different design criteria for their frames.

A cheap carbon frame might not have as good a layup as a more expensive one. To me I’d be satisfied Santa Cruz gets this right but their frames are anything but cheap

 

[NULevo]

It’s an interesting topic this. I prefer the failure modes of alloy over carbon (I ride alloy) but I’m not sure one can generalise about each as each manufacturer has different design criteria for their frames.

A cheap carbon frame might not have as good a layup as a more expensive one. To me I’d be satisfied Santa Cruz gets this right but their frames are anything but cheap

I agree and hope my carbon Levo is up to that standard!

 

[Orangie]

My frame had a dent big enough to hit the battery. Ball peen hammer pushed it right out. Not an option with carbon. But I was lucky to have access to the back side. Usually not the case. Would just have to live with a dent normally

 

[Kodo28]

Check below video, concerning carbon vs aluminium

 

[HORSPWR]

My frame had a dent big enough to hit the battery. Ball peen hammer pushed it right out. Not an option with carbon. But I was lucky to have access to the back side. Usually not the case. Would just have to live with a dent normally

That's why I always use this on my new bikes!
Transparent / Clear Anti Chip Tape - 48mm x 5M

 

[Orangie]

I have that. Wasn’t any help for this

 

[Gary]

Check below video, concerning carbon vs aluminium

What did the German guys say?

"All bicycle frames will break if you swing steel bars at their downtubes"?

No shit German guys, congratulations on stretching out your video to half an hour.

 

[Fivetones]

? Agreed!

What the hell is that test meant to simulate? Two click hunters driving traffic to their channel? The Santa Cruz guys at least has some level of logic to the test even if one of the tests was the ‘dipstick leaving $10000 bike on roof rack and driving into their garage’.

Carbon and alu have different failure modes but not all alu or carbon frames are made the same. You can only make decisions based on specific models or generalise and make a decision about failure mode you might prefer. (I don’t draw this specifically from cycling btw, part of my work is computer modelling and imaging of advanced materials for automotive/aerospace).

 

[Kodo28]

Read at least initial question of this thread so you would maybe understand the meaning of that video .
Based on the initial question, the video shows that carbon can handle small impact without major damage on frame which same impact could lead to a small dent on alu.

 

[Jdog]

Check below video, concerning carbon vs aluminium

Honestly one of the worst and most pointless tests I've ever watched! Absolutely no science applied at all, the alloy frame is secured and appears to be hit harder while the carbon one is loose and dodges some hits by not being secure and to top it off its in German.

0/10

 

[Beekeeper]

With the new Cubes, any EMTB with travel more than 120mm seems only available in a carbon frame option. I find this a bit puzzling why there is no aluminium option for the 140 and 160 travel bikes

 

[OldGoatMTB]

That's why I always use this on my new bikes!
Transparent / Clear Anti Chip Tape - 48mm x 5M

Do you put it all over your car fenders, too, so that if you’re in an accident you won’t have to take it into the auto repair shop?

 

[lcarron]

For my powerfly it was a no brainer. Because the powerfly 9.7 has a longer suspension and of course a carbon frame compare to the pwr 7.
You can’t beat they for $500. On the other hand the paint on the carbon frame is not as good as on the aluminum because the paint flakes easily.
You will have to put a invisible frame protection.

 

[GrandPaBrogan]

Look up “Stress-Risers” for both materials.

Think of them as the perforated holes on postage stamps (some might remember what those are), or a thin nick on a party balloon or inflated latex bladder, or scoring on a ceramic tile, a stone chip on a car windscreen, or a sharp crease on a piece of paper, etc.

For carbon fibre, gouges and sharp scratches are potential hot spots for catastrophic failure. The closest thing that carbon composite construction resembles is Wood - fibres bound tightly together by resin. However, carbon fibres are much stronger, and the direction of the fibre weave can be engineered specifically - unlike wood (or bamboo) whose fibres are uni-directional. However, they both make a similar sudden 'snap' sound should they fail. A blunt impact may cause a carbon composite tube to absorb the energy and bounce back without a dent. However, simply dropping the bike against a sharp rock (or concrete curb) can easily gouge and scratch the outer fibres. It'll look fine, but now you've got a stress-riser... a ticking timer. It might be fine for many years, but if a specific loading occurs - then it could fail suddenly without warning. A visiting pro-MTB rider got her carbon handlebars scratched during bike transport. Her mechanic and I couldn't tell if the nick got past the clear coat or not... so she elected to replace it straight away. That's just the way it is with carbon. It's strength is uncompromised as long as all the fibres remain contiguous.

Bad news for aluminium thin tubing (especially for double or triple butted), is a substantial pushed-in dent or a ding - but primarily vulnerable on sections that are subjected to compression (or the compression side of an applied bending load). An empty aluminium can might support your weight, but if you put a dent on its side, it won't. However, thicker tubing is largely unaffected by small dents, gouges or scratches... and not all dimples weaken thin-metal shapes. Aluminium bike frames are usually either 6000 or 7000 series aircraft alloys. These frames are welded and formed when the aluminium is in a ZERO state. After welds have been annealed, distortions re-aligned, and machining completed - it is then heat treated for final strength and stiffness. Unlike more malleable steel frames, any acute bending that occurs AFTER the heat treatment will also create a stress-riser in aluminium. Hammering a small dent might be OK but generally bending back a frame member might be fine for a commuter bike, but irresponsible for a pro DH race bike. This is also the reason why welding a crack on an aluminium frame never works - as more cracks just reappear next to the new malefic weld bead. The overall integrity of the heat-treatment of aluminium frame will also start degrading over time depending on the metallurgy. I've been told it's 30-40 years for 6061-T6 according to a Chinese manufacturer, but I had no way of fact checking that... seeing as the bike will be well and truely obsolete by then. Or, you could strip the paint and get it heat treated again indefinitely, but no one will bother to do that.

CARBON vs ALUMINIUM... they are both susceptible to failure yes, but they fail like chalk and cheese. Removed from its intended application, one cannot really say that one material is better or worse than the other. Environmental recycling on the other hand, is a different story.

 

[urastus]

For me, aluminium is easy to live with; it just isn't any trouble. It's about a 500gm hit in weight. It doesn't need other materials for joints or threads. For ebikes it is a much better for heat transfer. The only damaged frames I've seen on trail, were cracks, fractures, holes in cf frames. Never from casing a jump, stuff like falling on rock; once a bike leaning against a tree fell onto a rock and cracked the down tube. One not so long ago was a failure in the head tube of a high end specialized - just out of warranty. Apparently it wasn't from any impact; the dude was told by a high end boat builder / engineer that he could repair it but he wouldn't use it mountain biking. Specialized told him it couldn't be repaired. Maybe it's luck - aren't all cf frames hand made like the old days of fibre glassing? For sure though, if I was offered a really good deal, I'd probably take a cf bike; generally aluminium is a fair bit cheaper too. I am an inverted snob - generally function over form.

 

[R120]

With the new Cubes, any EMTB with travel more than 120mm seems only available in a carbon frame option. I find this a bit puzzling why there is no aluminium option for the 140 and 160 travel bikes

I think this is because the Cubes are already heavy despite being carbon, they are heavier than a lot of alloy bikes, so for the reason that its going to a both be cheaper to use one material through the range, and also to try and minimise weight.

 

[Bomble]

For me, aluminium is easy to live with; it just isn't any trouble. It's about a 500gm hit in weight. It doesn't need other materials for joints or threads. For ebikes it is a much better for heat transfer. The only damaged frames I've seen on trail, were cracks, fractures, holes in cf frames. Never from casing a jump, stuff like falling on rock; once a bike leaning against a tree fell onto a rock and cracked the down tube. One not so long ago was a failure in the head tube of a high end specialized - just out of warranty. Apparently it wasn't from any impact; the dude was told by a high end boat builder / engineer that he could repair it but he wouldn't use it mountain biking. Specialized told him it couldn't be repaired. Maybe it's luck - aren't all cf frames hand made like the old days of fibre glassing? For sure though, if I was offered a really good deal, I'd probably take a cf bike; generally aluminium is a fair bit cheaper too. I am an inverted snob - generally function over form.

Think I read it’s a 2kg difference on the Rail.

 

[urastus]

Think I read it’s a 2kg difference on the Rail.

That's a big difference. For the e160 and the e160 Limited (the aluminium model) it's 500gm. I think 500gm is also an oft quoted generic weight difference between cf and aluminium. Even 500gms is considered the high end of difference that should cover most bikes. 1lb for mtb, .5lb for road. Maybe there is something else going on with the different rails? I remember good acoustic full suspension bike frames were less than 2kg total weight, especially the scotts.

I have to confess, I've never owned a cf bike. I've done some research recently because of this question - it seems cf has come a long way, and should by all means be stronger and last longer - aluminium suffers from fatigue. Then I remind myself of the damaged bikes I've seen, all in the last few years and as recently as two months ago! Maybe it's just because most bikes I see on the trails now are cf? Any way, next bike I research for buying cf will be in the mix. That probably means it's for my partner - she's next

 

[dobbyhasfriends]

I just prefer alloy regardless of 'breakability' it just doesnt feel as harsh

 

[Gazzaaitken]

I've been riding carbon bikes from 2011, and never had an issue with any of them.
I've had plenty of off's, taken them to spain etc with no issues. I wouldn't hesitate to buying one.

 

[steve_sordy]

My Focus Jam2 weighed 1kg less CF vs the alloy version.

The reduced weight was important to me because I have a back problem and it is less weight to heave about on and off the tow bar rack, workstand, over gates etc.

 

[OldGoatMTB]

I just prefer alloy regardless of 'breakability' it just doesnt feel as harsh

I never understand about bikes feeling 'harsh' nowadays, what with fat tires, shocks front and back, etc.

 

[Pdoz]

if one of the tests was the ‘dipstick leaving $10000 bike on roof rack and driving into their garage’.

Would you like to come have that conversation with my wife?

 

[dobbyhasfriends]

I never understand about bikes feeling 'harsh' nowadays, what with fat tires, shocks front and back, etc.

yea possibly 'harsh' is the wrong word.. possibly 'less compliant' or 'less bendy'
I dunno but I do know that i had a carbon Levo until 2 weeks ago and now I have an ally Levo and there is certainly a difference and I personally prefer the ally

 

[GrandPaBrogan]

I never understand about bikes feeling 'harsh' nowadays, what with fat tires, shocks front and back, etc.

May have something to do with the new low-rise handlebar trend with 35mm stem clamp diameter. I don't mix with racing circles any more but back then, I've never heard of the old 31.8mm handlebars breaking at the stem interface (maybe they do as of late, I don't know). After a 10+ years hiatus I was surprised that this standard has been upgraded. I've since heard of handlebar manufacturers re-engineering their 35mm bar designs (both carbon and alloy) to add more flex - and feel more like the old 31.8mm bars. Go figure??

Anyway, when I got my brand new Giant Trance e+Pro last year, the low rise 35mm bar was stiff as lead pipe. But the low bar position bothered me the most, so when I replaced the bars with a 40mm rise (inherently flexier because it has more bends), I also got a 31.8mm bar with matching stem. I'm not saying it's right for everyone... but it's much nicer to me.