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OOOOOOOh Gee Are Eee
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Yeah, but the claim that aluminum cranks NEVER give you problems is just as ridiculous as saying Race Face Next SL is durable. Plenty of people have pulled pedals out of aluminum cranks, bent cranks, had interface problems, etc.

IME, Race Face carbon cranks should not be used as an example of CF cranks. They have been systemically bad, while SRAM has managed to make a durable product IME. I've broken 3 sets of the RF and the SRAM stuff has held up amazing. This appears to be due to SRAM using a metal skeleton inside the crank, rather than pedal/axle inserts bonded blindly into carbon fiber with the RF stuff.

Hollow shimano cranks are generally a good value, but they keep changing their chainring mounting standards basically every year or so. There are other metal cranksets that are a good value. If you learn/research a bit about aluminum alloys, you'll see there is a difference between some of the lower end and higher end aluminum stuff.
No disagreement from me.

I mentioned above I love my SRAM carbon cranks and have never had an issue with them. That's also why I asked the above poster who had carbon cranks fail what brand they were.
 

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Just get eeWings and never think about getting cranks again. They're only a little more than twice the cost of carbon cranks and will be better in every way. And they should last you the rest of your life.
 

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Discussion Starter · #23 ·
Just get eeWings and never think about getting cranks again. They're only a little more than twice the cost of carbon cranks and will be better in every way. And they should last you the rest of your life.
I'm gonna try a $2 scratch-off today. If I win big, I'll consider them. 😅
 

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I'm gonna try a $2 scratch-off today. If I win big, I'll consider them. 😅
Overally I think the performance gain is relatively minor when talking about different types of cranks. I feel like the best value is probably GX cranks or similar. I've ran them for years and they are bombproof. No doubt eeWings are expensive and probably a waste of money in relation to the performance gain over aluminum cranks. If you're considering spending $4-500 on carbon cranks I think it's worth waiting and saving for eeWings.
 

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Discussion Starter · #25 ·
What do people think about the Truvativ Descendant Carbon Eagle Dub crankset for $260? I know the weight savings aren't there. Any tangible differences for the minor price increase over the Dub 7k's? Is carbon that cheap is even worth it?
 

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Formerly of Kent
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My Hollowgram SiSL2s are lighter than most carbon cranks, stiffer than most, and far more durable.


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What do people think about the Truvativ Descendant Carbon Eagle Dub crankset for $260? I know the weight savings aren't there. Any tangible differences for the minor price increase over the Dub 7k's? Is carbon that cheap is even worth it?
I don't see the point of going carbon unless there is substantial weight savings. Aluminum will be more durable. The difference in stiffness will be negligible.
 

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We swapped the aluminum SRAM NX cranks on my wife's bike to CF Truvativ Stylos (which I also have on my bike). I would estimate that shaved almost 1/4 lb off of her bike. Is it "worth it"? That's a matter of opinion with no right answer.

I snapped an aluminum Shimano LX crank arm in half on my commuter while sprinting away from a stoplight a few years back. It was an old crank and probably had a stress riser (nick) in the metal from years of use. But, everything can break.
 

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Curious now because I had a pair fail too. Which brand of cranks?
Race Face cranks failed twice. SRAM failed on me as well. It seems to be the crank-bolt area that fails on ALL carbon cranks. They don't fail for people who don't ride enough for the 'need' to change chain rings often. But for those who habitually change out the rings two or 3 times per season....like me...they fail. It doesn't matter if you use a torque wrench set to the recommended torque. They just fail eventually....leaving you with a set of pristine crank arms that are no good because of the mounting area failure. People who don't pull their crank arms often will likely get a lot longer life span out of the carbon arm set. But if you pull the cranks often....they will fail quite soon, though, I do suppose that if you are under 130 pounds body weight, it might make them last a bit longer. But anyone who is 150pounds or higher....forget about it. Aluminum are the way to go. They simply do---not---fail...regardless of how often you might need to pull the crank arms.
 

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OOOOOOOh Gee Are Eee
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Race Face cranks failed twice. SRAM failed on me as well. It seems to be the crank-bolt area that fails on ALL carbon cranks. They don't fail for people who don't ride enough for the 'need' to change chain rings often. But for those who habitually change out the rings two or 3 times per season....like me...they fail. It doesn't matter if you use a torque wrench set to the recommended torque. They just fail eventually....leaving you with a set of pristine crank arms that are no good because of the mounting area failure. People who don't pull their crank arms often will likely get a lot longer life span out of the carbon arm set. But if you pull the cranks often....they will fail quite soon, though, I do suppose that if you are under 130 pounds body weight, it might make them last a bit longer. But anyone who is 150pounds or higher....forget about it. Aluminum are the way to go. They simply do---not---fail...regardless of how often you might need to pull the crank arms.
I weigh 215 pounds and when I'm in peak shape I struggle my way down to 190.

I have thousands of miles on my SRAM X0s and they are still solid. Though I don't pull my cranks unless the bottom bracket is failing. Why would you?

The RaceFace Next SL cranks are apparently pretty notorious for being bad though so no surprises there.

I have trouble drawing conclusions about carbon when one of the cranksets I bought is a known lemon and the other reliable.
 

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Oh, So Interesting!
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A few thoughts...

SRAM GX Eagle cranks are $130 including a chainring. Weight is given with the ring. XO1 is sold w/o and weight is given w/o ring to make the difference seem larger. The difference is about 1/4 lb IRL vs carbon or eewings.

eewings look like the best solution but the price is wtf and carbon is unreliable, IME.

I think carbon cranks are more reliable when used with shorter clipless pedals. Flats or clips w/ big platforms will put far more torque on the pedal threads when the end of the pedal hits a rock.

Handlebars are the best use of carbon on a mtb because they damp vibration better than Al and don't fatigue. Same with the frame, but more tradeoffs.

For the vast majority of buyers, spending more than $130 on GX Al cranks seems like a waste of money. It's hard to argue carbon is as reliable and Ti is unreasonably priced.

I spent $135 on an AB PVD coated oval front chainring though, $5 more than the crankset, in hopes it'll last much longer than a std ring. I actually wanted to buy eewings, but just can't justify it. I don't think they are functionally better than GX Al.
 

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Trail Ninja
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Shimano XT far stiffer than SRAM XO carbon. 102 N of force for each mm of flex/deflection vs 78 N.

Stiffness-to-weight is another story though. Between cranks of similar weight, cranks with large hollow sections were stiffer. Lightning/SWorks has some of the best stiffness-to-weight. Heavier cranks are generally stiffer.

Upgrade worthiness here more dependent on riding style. If you prefer to plow and cruise with stability, comfort, smoothness, steady-turtle-like pacing, etc. over being active with agility, playfulness, thrills, rapid-accelerating-rabbit-like pacing, etc. then it's generally a waste to spend money on lightweight cranks. Carbon is generally a compromise people make for the sake of lowering weight.
 

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Elitest thrill junkie
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Shimano XT far stiffer than SRAM XO carbon. 102 N of force for each mm of flex/deflection vs 78 N.
I have to wonder here, is that the 30mm SRAM spindle? By the picture, it doesn't look like it. It looks like the 24mm.
 

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Trail Ninja
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My Hollowgram SiSL2s are lighter than most carbon cranks, stiffer than most, and far more durable.
Longevity is suspect though, due to the nature of bonding of clam-shell style designs. They got to create a lot of surface area for the bond, especially in high-stress areas, without creating additional stress risers.

It's also difficult to insulate the bond from exposure to the environment and other real-world hazards that can weaken the bond (heat/cold, humidity, salt, solvents, oil).
 

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Disgruntled Peccary
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I have to wonder here, is that the 30mm SRAM spindle? By the picture, it doesn't look like it. It looks like the 24mm.
I'm not sure how much that'll matter. After all, tubes generally don't deform (twist) with torque (with the exception of the suspension component known as a torque-tube, ie.. specifically designed to do so)..

I remain dubious of the claim that a larger through tube is better for the meager amount of torque we actually generate at the crank.
 

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Longevity is suspect though, due to the nature of bonding of clam-shell style designs. They got to create a lot of surface area for the bond, especially in high-stress areas, without creating additional stress risers.

It's also difficult to insulate the bond from exposure to the environment and other real-world hazards that can weaken the bond (heat/cold, humidity, salt, solvents, oil).
They've lasted a hell of a lot longer than RF SL pedal inserts ;)
 

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I have Next SL cranks on 3 bikes. The cranksets have all been great and long lasting. Their bearings are worthless so I use other brands for that.
 

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I think your question should better be : What is the benefit of Aluminum over Carbon. The answer is : Aluminum cranks NEVER give you problems, and, are nearly just as light. Every single pair of carbon cranks I tried on my MTB failed in less than a single season. After the 3rd pair I went back to Aluminum and have never looked back. Aluminum cranks simply work, never fail, and never produce issues....and...are cheaper.
I’ve bent more aluminum cranks than I care to think about, from SRAM, Raceface and Shimano. My old 11 speed x01 cranks were sold at 5 years old and thousands of miles with no problems other than those junk pf30 gxp bearings. My new 12 speed x01 cranks have been great so far, but it’s early days still. It’s also nice that they are now $350 so a little more palatable pricing than before.
 

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I have Next SL cranks on 3 bikes. The cranksets have all been great and long lasting. Their bearings are worthless so I use other brands for that.
I remember when we heard the issue was solved with the G4's, then it wasn't.
Just maybe they got it right this time? No worth the risk to me for no gain. There's a reason carbon frames have been getting heavier.

Just a refresher since a sample size of 3 is meaningless.

A single shop warranty box:
1924761
 

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Trail Ninja
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I'm not sure how much that'll matter. After all, tubes generally don't deform (twist) with torque (with the exception of the suspension component known as a torque-tube, ie.. specifically designed to do so)..

I remain dubious of the claim that a larger through tube is better for the meager amount of torque we actually generate at the crank.
The assumption that flex is energy loss is also misguided. Flex is a form of stored energy. Metals have an elastic range where they return to their original shape. It's more a matter of it being returned in a useful manner or not. Twist just gets returned at the dead part of the stroke, which is a good thing IMO.

That said, 7075-T6 has ~1/3 the stiffness, strength, and weight of 4130. It's a more efficient use of mass to increase the diameter of the spindle to make up for the difference in stiffness, rather than increasing wall thickness. Making a 4130 spindle lighter will make it more prone to buckling.

There are stiffness losses from the narrower-spaced bearings. Larger bearings have more drag. Easier to machine aluminum.
 
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