Cranksets: Alloy or Carbon? - settle the score

[GuyGadois]

My riding buddy is an admitted retro grouch. In his words, “I just prefer metal”. He is looking for a new crank and said he prefers alloy cranksets partly because he has had two carbon cranks sets have the pedal insert loosen (they were FSA, how did you guess). I also love riding metal tubes but really prefer carbon cranks. We both still road race, although just slower and less often.

Are there many out there that have a strong preference to either material for road riding cranks? Have I just drank the kool-aid on carbon cranks or does my retro grouch buddy need to update his bias? We need this settled. :bike:

Sincerely,

Guy Gadois and Bob Loblaw

[AngryScientist]

The only pedal inserts I have heard to fail with any alarming frequency are FSA. I would avoid those cranks at pretty much any cost.

To me; a road racing bike should have carbon components.

A gravel bike should have alloy

A retro grouch bike should have polished alloy

[eBAUMANN]

In use, can't tell a difference really. Especially with high end Shimano alloy cranks.

There is little to no price difference these days so I typically go carbon to save a few grams.

[rheosibal]

What groupset does your retro-grouch friend currently have?

[Mark McM]

It depends. On my MTB, I strongly prefer metal cranks, because they tolerate being bashed against rocks better. On the road, I have a slight preference for metal cranks, because my shoe/ankle tends to rub the side of the cranks, and metal tends to hold up to the abrasion better (on one set of metal cranks, I even wore a groove into the crank where a steel shoe buckle rubbed against it).

On my crit. racing bike I have carbon cranks, because, well, they just aesthetically matched the rest of the bike better. Although I'm not sure how I'd feel about continuing to use them in case there was crash where the pedal got slammed against the ground with a lot of force.

[skiezo]

Years ago I had a Zipp crank insert pull right out of the crank arm. I am pretty sure that was one of the first crankset the Zipp came out with. Thy did warranty the crank but my trust was never there after that mishap.
For an alloy CS I kinda like the looks of the rotor cranks. I may give a set of these a try on my next build which will be in a month or so.

[Kontact]

CF just doesn't appear to be the ideal material for a crank, otherwise Dura Ace would probably have graduated to it by now.

If you can make a part out of cheaper, more durable material at the same weight, why would you use anything else?

Aesthetics.

[eBAUMANN]

CF just doesn't appear to be the ideal material for a crank, otherwise Dura Ace would probably have graduated to it by now.

If you can make a part out of cheaper, more durable material at the same weight, why would you use anything else?

Aesthetics.

What exactly makes carbon less durable than aluminum?
I have pounded the ever loving crap out of both materials on and off-road and guess what? they both work great!
That said, ive never seen a crank crank snap in half mid-arm (and we've all seen that with alloy).

I would also argue that there isnt really much of an aesthetic difference between a carbon crank and a black alloy crank.

A cheap alloy crank is a boat anchor.
A cheap carbon crank is still lighter than almost every expensive alloy crank, and probably just as stiff.

[R3awak3n]

Both are fine. I love my carbon campy cranks but also really liked my hollowgrams.

[ergott]

CF just doesn't appear to be the ideal material for a crank, otherwise Dura Ace would probably have graduated to it by now.

If you can make a part out of cheaper, more durable material at the same weight, why would you use anything else?

Aesthetics.

Plenty of modern Dura Ace/Ultegra cranks fail. Check google.

[Kontact]

What exactly makes carbon less durable than aluminum?
I have pounded the ever loving crap out of both materials on and off-road and guess what? they both work great!
That said, ive never seen a crank crank snap in half mid-arm (and we've all seen that with alloy).

I would also argue that there isnt really much of an aesthetic difference between a carbon crank and a black alloy crank.

A cheap alloy crank is a boat anchor.
A cheap carbon crank is still lighter than almost every expensive alloy crank, and probably just as stiff.

Carbon fiber is less impact resistant. I'm not talking about structural failure from normal use, but all the other stuff that happens to bicycle parts.


I'm not aware of any "cheap" carbon fiber cranks.


And there might be little different in looks between black alloy and carbon, but aesthetics are just as much knowing what something is. Cubic zirconium, etc.

[.RJ]

carbon cranks still have an aluminum core...

[ergott]

Carbon fiber is less impact resistant.

That's just not true. It's all about how you design with any material.

https://www.youtube.com/watch?v=VfjjiHGuHoc

https://youtu.be/w5eMMf11uhM?t=5m0s

[eBAUMANN]

Carbon fiber is less impact resistant. I'm not talking about structural failure from normal use, but all the other stuff that happens to bicycle parts.


I'm not aware of any "cheap" carbon fiber cranks.


And there might be little different in looks between black alloy and carbon, but aesthetics are just as much knowing what something is. Cubic zirconium, etc.

Carbon fiber is extremely durable when applied/designed correctly. (See above post)

Cheap carbon cranks? Look anywhere. You can easily get a set for under $100, all day every day. I have several for sale right now, as a matter of fact.

Aesthetics, by definition, are visual ONLY.
You cannot layer you own knowledge of something on top of its ACTUAL aesthetic presentation and call it an aesthetic difference...its not, its your personal subjective perception of that thing at that point.

[Kontact]

That's just not true. It's all about how you design with any material.


I'm not making a big deal about this as a CF vs aluminum thing in general, but there is no doubt that if you smack the very directional side of a CF object with a sharp edge it does more damage to the structural strength of that object than a similarly stiff/strong object made of aluminum. For a bike frame we live with that because carbon both rides nicer and is lighter in the long spans of a frame or fork. But small objects requiring more mechanical attachment points plays against carbon's strengths since those holes can't always be aligned perfectly with the directional fibers.

Carbon fiber is extremely durable when applied/designed correctly. (See above post)

Cheap carbon cranks? Look anywhere. You can easily get a set for under $100, all day every day. I have several for sale right now, as a matter of fact.

Aesthetics, by definition, are visual ONLY.
You cannot layer you own knowledge of something on top of its ACTUAL aesthetic presentation and call it an aesthetic difference...its not, its your personal subjective perception of that thing at that point.

A cheap alloy crank is $30.

If the appreciation of beauty is only visual, then excuse my misuse of "aesthetic". But carbon fiber doesn't look like shiny black anodizing.



I don't think this is an important debate. I wouldn't choose carbon cranks mainly because the clear coats always seem to get screwed up out of proportion to the wear. I'm just saying that both materials work, and one has certain practical advantages. But when you're equipping an $8000 bike, practicality is not very important.

[EDS]

The only pedal inserts I have heard to fail with any alarming frequency are FSA. I would avoid those cranks at pretty much any cost.

To me; a road racing bike should have carbon components.

A gravel bike should have alloy

A retro grouch bike should have polished alloy

Not sure the guys road racing on shimano would agree!

[FlashUNC]

Carbon. If you're hitting the crank on a road bike with any regularity you're doing it wrong.

[ergott]

Kontact, you made a statement that carbon was less impact resistant and I not only disagreed with you, I gave you proof. Your tangent reply has nothing to do with what I posted.

Also, using Shimano as a standard and reason carbon isn't good enough for cranks ignores the fact that their current 2 piece forged cranks can and have failed. Again, it's about the design of the material not the material. Look at Campagnolo and Sram. They have both had durable carbon cranks out on the market for many years now.

Sent from my SM-G950U using Tapatalk

[CSKeller]

No issues with the carbon Look Zed2 crank on my 695. Solid, light, strong, reliable and great looking.

Have Campy Chorus and Super Record carbon cranks on my other 2 rides...same thing, light, strong reliable and gorgeous!

I'll be putting an alloy Campy Record crank on my lugged steel bike because it is solid, strong, reasonably light is gorgeous and just looks right.

Imho, Shimano cranks may work well but have never looked good at all. Ymmv

Sent from my Pixel 2 XL using Tapatalk

[cmbicycles]

I think he has already decided the score is settled, no?

https://forums.thepaceline.net/showthread.php?t=219185

[Kontact]

Kontact, you made a statement that carbon was less impact resistant and I not only disagreed with you, I gave you proof. Your tangent reply has nothing to do with what I posted.

Also, using Shimano as a standard and reason carbon isn't good enough for cranks ignores the fact that their current 2 piece forged cranks can and have failed. Again, it's about the design of the material not the material. Look at Campagnolo and Sram. They have both had durable carbon cranks out on the market for many years now.

Sent from my SM-G950U using Tapatalk

I didn't realize youtube videos proved things.

The fracture toughness of aluminum is 22-35 MPa√m
The fracture toughness of carbon fiber is 6.1-88 MPa√m

The low end of the scale comes from fiber alignment.

http://www-mdp.eng.cam.ac.uk/web/library/enginfo/cueddatabooks/materials.pdf

[ergott]

I didn't realize youtube videos proved things.

The fracture toughness of aluminum is 22-35 MPa√m
The fracture toughness of carbon fiber is 6.1-88 MPa√m

The low end of the scale comes from fiber alignment.

http://www-mdp.eng.cam.ac.uk/web/library/enginfo/cueddatabooks/materials.pdf

CAN BE DESIGNED!!!!!!!! You conveniently left out that part. You will never be able to show me similar footage of an aluminium rim or frame surviving that.

[mcteague]

The right pedal insert came loose on my Campagnolo Chorus carbon crank after about 8 years or so. I was pretty disappointed but I still replaced it with a newer version of the same crank. Previously, the only crank failure I ever had was on an old Avocet one that snapped off at the pedal hole.

Tim

[chiasticon]

both materials are fine. just don't buy FSA and you should be alright.

[pdonk]

I had a zipp carbon crank break about an inch above the pedal while climbing up a hill, glad it did not happen descending. I stopped about a mile before it happened because I thought a pedal spindle was bent but couldn't see any problems then it let loose when I stood up. Don't think I'll get another carbon crank.

For aluminum cranks, I have had the taper of the crank expand over time on a set of cook bros (know to do this) and with shimano had a pedal seize in - neither were dangerous or caused me to fall and were likely caused by youthful exuberance and not being that mechanically knowledgeable.

[saab2000]

I had a zipp carbon crank break about an inch above the pedal while climbing up a hill, glad it did not happen descending. I stopped about a mile before it happened because I thought a pedal spindle was bent but couldn't see any problems then it let loose when I stood up. Don't think I'll get another carbon crank.

For aluminum cranks, I have had the taper of the crank expand over time on a set of cook bros (know to do this) and with shimano had a pedal seize in - neither were dangerous or caused me to fall and were likely caused by youthful exuberance and not being that mechanically knowledgeable.

That looks a lot like a metal crank with a carbon aesthetic cover.

I own Shimano aluminum cranks and Campagnolo carbon cranks. I'd happily buy either again. No issues with either one.

There's really no score to settle. And as for polished aluminum on retrogrouch bikes? :rolleyes: I love when someone builds up a bike built last week with polished aluminum. Nobody is fooled. It's not 1987 anymore.

[jumphigher]

I agree that theý're both good materials for cranksets. No score to settle, I like them both.

[cmbicycles]

I didn't realize youtube videos proved things.

The fracture toughness of aluminum is 22-35 MPa√m
The fracture toughness of carbon fiber is 6.1-88 MPa√m

The low end of the scale comes from fiber alignment.

http://www-mdp.eng.cam.ac.uk/web/library/enginfo/cueddatabooks/materials.pdf

Outside my scope of practice, but it appears this data is from 2003, so its likely there have been some advances in the last 15 years on both sides. Still, and maybe I'm reading this wrong, doesn't this show that carbon fiber can be significantly stronger than aluminum? It also shows it can be weaker, but I would doubt much of that range of material is used in structural applications.

[SpokeValley]

Both are fine. I love my carbon campy cranks but also really liked my hollowgrams.

Agreed. I haven't had any problems with either one. My go fast bike has carbon, gravel: alloy.

[batman1425]

Outside my scope of practice, but it appears this data is from 2003, so its likely there have been some advances in the last 15 years on both sides. Still, and maybe I'm reading this wrong, doesn't this show that carbon fiber can be significantly stronger than aluminum? It also shows it can be weaker, but I would doubt much of that range of material is used in structural applications.

I think this is the point Ergott is raising, it is about design and it's adaptation to the material being used. The intrinsic properties of the material guide the design constraints, but just because x-plies of laminated cured CF is or is not as strong in a particular direction or impact resistant as a similar mass or shape of aluminum does not mean that either is any more or less appropriate for the application. Its about if the design is appropriate for the material used.

There are plenty of impact heavy applications where carbon fiber used preferentially over other materials, and with great success. In rowing, oars and hulls have been made from carbon for decades and they are tough - particularly oars. The shafts take a beating day in and day out, particularly in novice hands, and it is rare that you see one break. F1 cars are essentially completely made of carbon fiber. Same for many super cars with carbon tub chassis. Clearly there are advantages if engineered properly.

Both materials can be engineered to perform safely within the envelope of regular and reasonable use and both can (and do fail) if used outside of that range. But to claim that one is superior to another based solely on the material of construction ignores the engineering that has been done to use that material appropriately and is a quite short sighted view.

[loxx0050]

I have no real preference either and have a set of either one on my bikes. Alloy ones (Rotor 3D+ currently) and a SRAM Force 22 carbon arms. I really can't tell the difference in feel between either one. Actually I am more partial to Rotor cranks which are pretty much all alloy.

Yes, there is always the risk of the threaded insert in carbon arms eventually failing but the same could be said for the pedal threads in an aluminum crank since it is pretty soft stuff compared to the steel pedal spindles. At my workplace we have a machine shop dealing in aluminum whenever we can (easier to machine than stainless steel which what we use for strength or high temp applications) and use helicoil inserts for the threaded holes in aluminum (since most bolts are steel and you really don't want to use aluminum bolts for our applications).

An interesting thing to watch is this video on fatigue testing to failure of carbon vs alloy handlebars.

https://www.youtube.com/watch?v=0stL5Q9b_oo

[semdoug]

I have no preference either way. I own bikes with both, Record and 7700, and have never told myself to replace either one do to "need" or preference.

I must admit the polished Potenza crank arms on that one NAHBS bike really popped. Does that make me a retro grouch?

[berserk87]

In my experience this is a non-issue. I've ridden all levels of Shimano and Campy alloy cranks, and carbon cranks from FSA (several) and Zipp.

The only cranks that I broke were the Zipp cranks. I got them used at a swap meet and there was no harm done (to me) as the breakage was a crack that formed around the threaded hole.

I couldn't perceive any difference between the alloy cranks and the carbon cranks in terms of performance.

[pasadena]

SRAM Red carbon just because it's a lot lighter than Dura Ace
No problems and I really like the looks.

Didn't Shimano make a full carbon Dura Ace crankset? I seem to remember maybe the 7800-7900 vintage, there was a rare one?

I like Shimano because of the high quality bottom brackets and precision engineering on the chainrings.
It's more about the performance at the end of the day. I sacrificed a bit of that for the weight.

[tommyrod74]

I've never once seen any reason to seek out a carbon crankset.

I purposely avoid them for XC because, well, rock strikes happen and even without impact I see carbon XC cranks looking far worse than their age due to clearcoat rubbing.

I've not avoided them on road bikes but, as nice as Dura-Ace/Ultegra are, especially for the price, I've never bothered.

I've always seen them like I view carbon stems - best case scenario, they match the other carbon stuff and are no worse than aluminum versions; worst case, you lose your teeth. Just seems like an application where aluminum makes more sense, I'd rather spend money elsewhere.

[mt2u77]

Just trying to come up with a theoretical benefit of one over the other here-- carbon cranks necessarily add another dissimilar junction subject to galvanic corrosion. In practice, I've never had a problem and suspect it's a non-issue with a modicum of maintenance and proper assembly.

[choke]

For me it's always silver alloy. I purchased one bike that had a carbon Chorus crank and promptly replaced it.

[pdmtong]

I put some of these on my mtb cranks and the rock strike issue is a non-issue
https://www.amazon.com/dp/B007YH7P3W/ref=cm_sw_su_dp

https://images-na.ssl-images-amazon.com/images/I/71M9svmUg8L._SL1500_.jpg

[fishbolish]

i've had a Time carbon crankset spider move/become unbonded from the bonded bb axle( enough to feel my cadence change between both legs) ,which was replaced by an easton carbon crankset which did the same thing within a year....both companies distanced themselves from that product..aka SOL

replaced it with a rotor & had many trouble free miles

gonna give a campy carbon 11 speed a try on the bike i'm putting together this spring

[Red Tornado]

I use aluminum on my dirt bikes, and have both carbon & aluminum on road bikes. The well known manufacturers all make good product in both materials. The OP's buddy should get the best combination of looks/affordability/compatibility.

FWIW I have a set of carbon FSA cranks purchased in 2004. Been on 2 road bikes & now with just 1 chainring on a SS road bike. Tons of miles on them, original pedal inserts still intact. Know several guys that bought the same cranks around the same time & all going strong.

[berserk87]

Didn't Shimano make a full carbon Dura Ace crankset? I seem to remember maybe the 7800-7900 vintage, there was a rare one?


I think they did. I remember seeing them for sale here and there.

[eBAUMANN]

I've always seen them like I view carbon stems - best case scenario, they match the other carbon stuff and are no worse than aluminum versions; worst case, you lose your teeth. Just seems like an application where aluminum makes more sense, I'd rather spend money elsewhere.

ive seen far more alloy stems crack/break than carbon.
in fact, i dont think ive ever seen a carbon stem fail...im sure its happened, ive just never seen it.
meanwhile, i think probably anyone here who has used thomson stems long enough has seen one (or more) develop cracks either in the faceplate or steerer clamp.

[kramnnim]

FSA sucks

Also, delaminated Shimano 9000 crank arms are not that uncommon...

[saab2000]

FSA sucks

Also, delaminated Shimano 9000 crank arms are not that uncommon...

What can delaminate? They're aluminum. My 9000 cranks have been flawless.

Are you able to provide evidence of delaminated Shimano 9000 cranksets?

[simonov]

What can delaminate? They're aluminum. My 9000 cranks have been flawless.

Are you able to provide evidence of delaminated Shimano 9000 cranksets?

Some fun ones here: https://www.instagram.com/thanksshimano/

[tommyrod74]

ive seen far more alloy stems crack/break than carbon.
in fact, i dont think ive ever seen a carbon stem fail...im sure its happened, ive just never seen it.
meanwhile, i think probably anyone here who has used thomson stems long enough has seen one (or more) develop cracks either in the faceplate or steerer clamp.

There are far, far fewer carbon stems on the market than aluminum ones, so that doesn't surprise me. Thomson is the only modern stem of any type I've seen to crack with any regularity (and one of the few remaining CNC machined billet stems, non-forged). Carbon stems seem like a dead-end at this point in the evolution of that part, as very few companies bother.

My point was not so much likely breakage, more that with stems there appears to be zero advantage to carbon as carbon stems can't really be any lighter that aluminum ones (and are often heavier) without being too fragile, in a place I least want to be concerned with fragility.

I feel the same about carbon cranks - though less so about fragility (except cosmetic), and more so about cost vs. performance.

[oldpotatoe]

CF just doesn't appear to be the ideal material for a crank, otherwise Dura Ace would probably have graduated to it by now.

If you can make a part out of cheaper, more durable material at the same weight, why would you use anything else?

Aesthetics.

shimano has had premier alloy manufacturing for a long time. Like many things 'shimano', they don't respond to market 'trends' like Campag or sram do. They just see no reason to do certain things..like CF cranks and BB30/PFBB30 type cranks.

[pdonk]

That looks a lot like a metal crank with a carbon aesthetic cover.



They were a set of zipp 300s. As per Zipps description:

With a strength 3x more than traditional methods, the ZIPP 300 cranks can use two intricately forged and machined aluminum slugs only where they are needed and does not require an internal aluminum spine to hold the crank together.

It appears as though there is a polystyrene core and that they they broke where the aluminum and polystyrene met. considering when they broke they were 12 years old and probably had 35000 km on them, not a bad life expectancy for a weight weenie part.

[kramnnim]

What can delaminate? They're aluminum. My 9000 cranks have been flawless.

Are you able to provide evidence of delaminated Shimano 9000 cranksets?

They're 2 pieces bonded together.

I've seen failed 9000 arms on FB but can't find them now. Here's a thread full of 6800, similar construction and failure as the 9000 I've seen. http://www.bikeradar.com/forums/viewtopic.php?f=40004&t=13064693

Edit: this may work? https://scontent-iad3-1.xx.fbcdn.net/v/t1.0-9/19145872_1749901201691438_3403323583303917844_n.jp g?oh=9bdc4e4fb453ce46f692427bc6ddff73&oe=5B42352E

[bobswire]

Why do we even start these he said she said which is better CF/Steel/Alu/Tia threads. As though it will settle the question once and for all. They are all good materials in the application of bicycles and components. :bike: :( :bike: :( :bike: :( :bike:

[Rada]

Plenty of modern Dura Ace/Ultegra cranks fail. Check google.

Plenty of modern Campagnolo cranks fail. Check Google.

[jtbadge]

Why do we even start these he said she said which is better CF/Steel/Alu/Tia threads. As though it will settle the question once and for all. They are all good materials in the application of bicycles and components. :bike: :( :bike: :( :bike: :( :bike:

Yeah, this is more tedious than every thread on the "STEEL IS REAL !!! - Classic Vintage Road Bikes" Facebook group.

[benb]

I'd probably trust Campy if I had a Campy bike but I often have a hard time believing many companies are putting more engineering into the design of their components than Shimano. If Shimano has worked on Carbon and not really seen a reason to move to it for cranks, and I know and love the Shimano cranks it's easy for me to stick with them. That's the guiding factor for me when someone says "Carbon can be stronger if it's designed properly" Yes it can, but who is designing it?

I know people in person who have broken Shimano alloy cranks from fatigue over long periods of time. (e.x. 300+ watt FTP riders who ride 8-10k miles per year on one bike in all weather for 10+ years). But then there are probably 100 DA/Ultegra cranksets out on the road for every 1 of a lot of the boutique cranks out there that use Carbon, so your chances of seeing a failure are way higher even if they actually fail at a lower rate. Even Campy seems to have mostly been dropped from OEM.

I'm really skeptical of the engineering at a lot of the smaller bike companies. I think a lot them might just have more marketing engineering than actual engineers.. certainly some of them have 0 degreed engineers on full time staff. Bikes are simple enough that trial and error can work and real/serious engineering is not always necessary and can be overly expensive but on some of these fancier/lighter carbon products it makes a difference. Shimano and Campy are big enough to amortize the cost of real engineering across the 10s/100s of thousands of units they ship, some of the others maybe not.

I don't really want to throw companies under the bus but I've personally run into some places that I found out didn't actually have any engineers at all despite marketing. It definitely seems too expensive at small volumes.

FWIW I am one of those people who scared the sh*t out of myself when my Thomson stem cracked so it's not like I think aluminum is automatically safer.

[rain dogs]

I'd probably trust Campy if I had a Campy bike but I often have a hard time believing many companies are putting more engineering into the design of their components than Shimano....

I'm really skeptical of the engineering at a lot of the smaller bike companies. I think a lot them might just have more marketing engineering than actual engineers..

Do you know that Campagnolo has a long history of making components for the Italian military, Lamborghini and many other racing companies? Sure, that was alloy, but their carbon production is equally seen as being some of the most sophisticated in the world. It's part of the reason why Stages took so long with a Campy arm. Stages said that the crank construction was so complex it was difficult to apply the process they used with all the other cranks on Campagnolo's.

It's not mario and luigi just randomly resining things together over a pizza.

Re: the alu vs carbon. The right answer is the best engineered crank arm... that so vastly takes priority over the material that the rest of the conversation is just noise. Dura Ace cranks though are pretty modest, middle of the pack, to what is being produced well out there.

[Mark McM]

Do you know that Campagnolo has a long history of making components for the Italian military, Lamborghini and many other racing companies?

Does Campagnolo design the components for the military, Lamborghini, and other racing companies, or do they just manufacture them?

As an engineer that has worked for companies that design products, we have worked with many fabrication houses. Most are very good at producing products to the drawings and specs. we provide, but that doesn't guarantee that they will function well. If we provide a faulty design to the fabricators, they will produce a high precision, but ultimately faulty, product.

Campagnolo's foray into the MTB realm a few years ago shows that they can produce well manufactured precision components, that just aren't designed to perform well.

[batman1425]

If Shimano has worked on Carbon and not really seen a reason to move to it for cranks, and I know and love the Shimano cranks it's easy for me to stick with them. That's the guiding factor for me when someone says "Carbon can be stronger if it's designed properly" Yes it can, but who is designing it?

Another factor to this is the intellectual, experiential, an manufacturing investment a company like Shimano has put into the aluminum manufacturing and that matters a lot in this case.

They were (and still are) the industry leaders in aluminum manufacturing. They have a lot of time and money invested in that pipe line, and are very good at what they do. Can you make a similarly reliable and functional product out of CF, sure, and other companies which don't have Shimano's aluminum capabilities are. I think Shimano did the math and said - sure we can make product that performs to our standards out of CF, but doing so would require a huge time and materials investment, and what we do currently is market comparable to any CF option out there. For Shimano to go to CF, devalues the investment they have put into the aluminum front. Unless sales drop because people want CF cranks, or competitor CF cranks become so much better than what Shimano can make from metal and their projected losses outweigh the cost of re-engineering and scale manufacturing in CF, there's no reason for them to invest that money.

All that said - this isn't to say that one is dramatically better than the other, because if that were the case, there WOULD be pressure for big companies to adopt similar material standards. Shimano sticking to alloy, IMO, suggests that the differences slim and they can still make good stuff using the materials and processes that they know best. Going the other way, the reason that Sram and Campy have adopted CF is IMO because the cost of entry to produce an alloy crank on par with Shimano. Way to expensive to get to where shimano is at with alloy - so make a similar product with CF.

[tommyrod74]

Way to expensive to get to where shimano is at with alloy - so make a similar product with CF.

This was always my impression as well. The machinery to produce the hollowtech cranksets is likely prohibitively expensive for competitors to emulate - and, similarly, means that SHimano is unlikely to abandon the technique without compelling reasons.

[benb]

I didn't mean to imply I wouldn't trust Campagnolo components. They're obviously one of the big giants like Shimano.

You could definitely say Shimano's investment in Hollow forging and the like could cause them to want to rest on their laurels rather than innovating on new carbon stuff.

But at the same time every time some magazine or website (usually German?) tests these things none of the Carbon cranks seem to equal the Shimano stuff across the board in all the different variables.

[macaroon]

There's alot of nonsense on this thread. What're these special Shimano manufacturing techniques that no one else knows how to do?

Looking at the test below, carbon cranks appear to be better by a country mile http://blog.fairwheelbikes.com/reviews-and-testing/road-bike-crank-testing/

Obviously they cost a fortune, and SRAM and Campag don't have a clue how to make them properly as they're way behind THM. Or they build them conservatively, or they don't think they're worth any other refinement.

Carbon is king when it comes to bicycle components. It's been mentioned already, but stems are probably the only part that aren't worth bothering with in carbon.

But personally, I'm happy with my alloy cranks.

[tommyrod74]

There's alot of nonsense on this thread. What're these special Shimano manufacturing techniques that no one else knows how to do?

Looking at the test below, carbon cranks appear to be better by a country mile http://blog.fairwheelbikes.com/reviews-and-testing/road-bike-crank-testing/

Obviously they cost a fortune, and SRAM and Campag don't have a clue how to make them properly as they're way behind THM. Or they build them conservatively, or they don't think they're worth any other refinement.

Carbon is king when it comes to bicycle components. It's been mentioned already, but stems are probably the only part that aren't worth bothering with in carbon.

But personally, I'm happy with my alloy cranks.

It's not so much that others don't know how to do advanced alloy cranks (though that may be true to an extent), it's that it takes a huge company to make the capital investment in the tooling to forge the parts.

I have yet to see a carbon crank that makes me think I need it over my Dura-Ace or XTR.

[pdmtong]

I'd probably trust Campy if I had a Campy bike but I often have a hard time believing many companies are putting more engineering into the design of their components than Shimano. If Shimano has worked on Carbon and not really seen a reason to move to it for cranks, and I know and love the Shimano cranks it's easy for me to stick with them. That's the guiding factor for me when someone says "Carbon can be stronger if it's designed properly" Yes it can, but who is designing it?

I know people in person who have broken Shimano alloy cranks from fatigue over long periods of time. (e.x. 300+ watt FTP riders who ride 8-10k miles per year on one bike in all weather for 10+ years). But then there are probably 100 DA/Ultegra cranksets out on the road for every 1 of a lot of the boutique cranks out there that use Carbon, so your chances of seeing a failure are way higher even if they actually fail at a lower rate. Even Campy seems to have mostly been dropped from OEM.

I'm really skeptical of the engineering at a lot of the smaller bike companies. I think a lot them might just have more marketing engineering than actual engineers.. certainly some of them have 0 degreed engineers on full time staff. Bikes are simple enough that trial and error can work and real/serious engineering is not always necessary and can be overly expensive but on some of these fancier/lighter carbon products it makes a difference. Shimano and Campy are big enough to amortize the cost of real engineering across the 10s/100s of thousands of units they ship, some of the others maybe not.

I don't really want to throw companies under the bus but I've personally run into some places that I found out didn't actually have any engineers at all despite marketing. It definitely seems too expensive at small volumes.

FWIW I am one of those people who scared the sh*t out of myself when my Thomson stem cracked so it's not like I think aluminum is automatically safer.

shimano metallurgy is remarkable, unbelievable, consistently mind-blowing.
If I was all in on shimano I could care less if they did a carbon crank or not.

BUT

I have campagnolo on the road bikes.

[m_sasso]

If what the biggest, baddest and fastest use is any indication of what material is best?

At the recent UCI Track Cycling World Championships in the 1km gauge of strength and speed the majority of the 8 finalists were still using metal cranksets including the winner Jeffery Hoogland @ 59.459/km.

[AngryScientist]

sometimes though, it's just got to be alloy.

https://1.bp.blogspot.com/-22dWnbb5ogg/Wmz82BBmWBI/AAAAAAAAC9s/l76DkNpujAc6jiJiR-WV70RwzCbv7EgTQCLcBGAs/s1200/IMG_1980.JPG

[AngryScientist]

other times - it's just got to be carbon.

https://2.bp.blogspot.com/-KL94nT9nfMg/WBX5agj9WjI/AAAAAAAACoY/qInUVn3xdPMuI9jjlxQhEJ8Cf_Yn0X_twCLcB/s1200/IMG_1080.JPG

[benb]

Those linked tests were pretty interesting.

They mentioned if you cared about Shift Quality the D/A cranks were best, and also that the D/A cranks would have been the stiffest, and moved way up the rankings, if Shimano started shipping them with a 30mm axle option.

That would certainly be nice since then we wouldn't need all the adapters and such.

The 300g difference between the D/A and the lightest carbon cranks in the test is certainly significant.

[tommyrod74]

Those linked tests were pretty interesting.

They mentioned if you cared about Shift Quality the D/A cranks were best, and also that the D/A cranks would have been the stiffest, and moved way up the rankings, if Shimano started shipping them with a 30mm axle option.

That would certainly be nice since then we wouldn't need all the adapters and such.

The 300g difference between the D/A and the lightest carbon cranks in the test is certainly significant.

It would be nice if and only if 30mm shells were all threaded - or it became feasible to run a (theoretical) 30mm spindle Shimano crank in a standard BSA shell frame with bearings that lasted more than 10 minutes.

I will not go back to a press fit or BB30 BB system by choice ever again.

[Rada]

Those linked tests were pretty interesting.

They mentioned if you cared about Shift Quality the D/A cranks were best, and also that the D/A cranks would have been the stiffest, and moved way up the rankings, if Shimano started shipping them with a 30mm axle option.

That would certainly be nice since then we wouldn't need all the adapters and such.

The 300g difference between the D/A and the lightest carbon cranks in the test is certainly significant.

My math must be off, but where are you getting 300g?

[benb]

My math must be off, but where are you getting 300g?

No you're right, it's 200g. One of the Clavicula's is 494g, and it's non drive side crank is slightly stiffer than the D/A one.

Of course it is over 2X as expensive too, so it probably fails any grams/$ tests but 200g still seems like a fairly significant # I guess.

I couldn't see the whole chart on my phone last night as that site has a brain dead mobile design... the D/A crankset on the drive side is still the stiffest one in the test. It's totally let down by the 24mm tube apparently.

[tommyrod74]

No you're right, it's 200g. One of the Clavicula's is 494g, and it's non drive side crank is slightly stiffer than the D/A one.

Of course it is over 2X as expensive too, so it probably fails any grams/$ tests but 200g still seems like a fairly significant # I guess.

I couldn't see the whole chart on my phone last night as that site has a brain dead mobile design... the D/A crankset on the drive side is still the stiffest one in the test. It's totally let down by the 24mm tube apparently.

This illustrates my line of thinking here - I could, for that additional cost, drop 200 grams via lighter wheels/tires and see a far better translation to improved speed. My bike's already very light, so...

[benb]

All academic for me, Dura Ace is usually too rich for me too, I have Ultegra on my most expensive bike.

And right now I'm trying to lose something like 4000g from me and that's free.

I have one bike that is between 16.5-17lbs, not really interested in losing weight by spending money, and right now since the weather is sloppy I'm riding my All City Space Horse with 105, Fenders, and the original stock wheelset, it's probably 26lbs in current form, and that's with almost everything upgraded except the wheels, although obviously only to modest levels.

I am also pretty intolerant of poor shifting... the article mentioned the Shimano crankset having the best shifting. The degradation in front shifting with SRAM (mechanical) for me is enough to be annoying. So I wouldn't be real interested in a $1000+ crankset to save a few hundred grams if it degraded shifting.