Carbon fibre crankset

Anyone using carbon fibre crankset? Reading about them recently the claim is they are more efficient on XC bikes as they flex less and offer better power transfer. Worth it the cost, or weight saving snake oil?

Marginal gains. Youll pay a LOT more for something only slightly better than Shimano SLX.

I’ve no qualms about strength, but the issues I see frequently (admittedly mostly from RF) with debonding inserts is enough to make me think SLX/XT are probably far better options for minimal weight/flex advantages (and I almost certainly wouldn’t notice the flex at my weight and power)

Having been one of the many owners of RaceFace sixc carbon cranks, I’m unlikely to trust carbon cranks again in a hurry.

My personal rule for RF is nothing with moving parts (ask their bottom bracket owners and my atlas pedals were shite) and nothing where two materials meet (like their cranks)

Their turbine alloy cranks, stems, bars etc are fine.

The extra 300 quid or so for a set of RF ERAs over Aeffects is pretty hard to justify for MTB, especially given the knocks I can see on my cranks. I’d fit carbon cranks if i was going for a weight saving build but i’d spend the money in quite a few other places first.

On the road/cross/gravel side- been running a set of force carbon cranks I got off here second hand maybe five years ago. They saved a useful bit of weight, have been no fuss to live with and I figure the likelihood of giving them a proper clout is reduced away from MTB. Would go carbon again if they hit the right specs

Only ever had one pair that came with a bike and they were some SRAM. Had no issues what ever with them. I wouldn’t even touch RF alloy cranks never mind the carbon versions.

^ only carbon cranks I had were SRAM which came on a bike and were battered on rocks, etc, .. for several years with no problems at all.

Can’t comments on gains.

I have a SRAM Eagle X01 crankset on my bike and I don’t notice any difference in flex or power transfer compared to a standard aluminium crankset. They’ve been totally bombproof but I don’ t think there’s any advantage other than them being 100 grammes lighter than the stock alu GX crankset that came with the bike.

If you want some really light, really strong, tarty (and exceptionally expensive) cranks then Cane Creek eeWings are the way to go. And I would second staying away from Race Face carbon cranks.

I’ve SRAM Force 1 on my gravel bike, done +5k miles, 50/50 offroad – no issues whatsoever.

Also had a set of SRAM’s on an older bike, carbon Camber Evo, the bike was bought s/h and then I did 3k miles in the Tweed Valley (so think wet & rocky) – frame went baggy at various pivot points plus ovalised the top headset seat, cranks were perfect (but press fit, so not used since).

I wouldn’t buy a set aftermarket, but happy to buy a bike with them.

I’ve got carbon Sram X1 GXP cranks on one mtb and carbon Truvativ Descendant on the other (I think essentially a GX carbon crank with a different badge). The X1’s especially have seen a lot of hammer and so far so good. They look a bit bashed up but still ok.

They’ve seen some general riding locally, Dyfi bike park and off piste, Bike Park Wales, Antur Stiniog, Snowdon etc – plenty of rocks bashed off them.

I went for the X1 as I got them cheaply for £150. The descendants I was trying to make a hardtail build with a heavy ish steel frame a bit lighter – hence carbon. Plus overall I like sram chainrings the best for retention and durability.

I’ve had a set of FSA carbon cranks for years and they’ve been regularly hoofed into rocks and covered in moorland filth with no issues.Don’t notice any difference over alloy

I only bought them because the choice of cranks with a BB30 bottom bracket is limited and they were cheap(ish) on CRC at the time. Weight gains are irrelevent when you’re as keen on pies as I am

SRAM X01 on the DH Session… they do what they’re supposed to and work fine. They’ve had a hard life for sure.

In terms of the flex/ power transfer thing, pure snake oil.

Even if you have exceptionally flexy cranks, like some titanium ones from the late 90s say, the power loss from flex will be returned at the end of the power stroke.

If it’s a long day out, then flexy contact points mean less fatigue and potentially going faster for longer.

Only real reason for carbon cranks is weight weeny gainz.  They’re not even particularly blingy, you need eeWings for that.

Set of Truativ Descendant on the Enduro (came on the bike, I wouldn’t buy carbon cranks). Have lasted the lifetime of the bike so far, bashed up now and look bad, but holding up well enough. Wouldn’t judge them any different in use to the alloy GX on my other bike.

I’ve had carbon cranks on my road bike for about 15 years with zero issues.

Are they functionally better than shimano 105, probably not meaningfully, but they look cool.

They are (or were, obviously everything moves on) lighter than aluminum cranks.

They are at least as stiff as HT2 cranks which is the benchmark. Like most bike components I think there’s a a threshold beyond which it doesn’t matter. I’ve got some alloy RF Deus cranks which are objectively “not stiff”.  I don’t think it matters so much to power output, it just feels a bit softer and the trail buzzes less with them.

I suspect in terms of bang for your buck upgraders it’s probably worse value than chain wax and silly jockey wheels. And way behind a fresh Vs worn drivetrain and way way behind tyre choice. Even the weight saving (and stiffness to a similar extent) is probably better with a £300 pair of shoes than a £300 chain set.

Sram X01 carbon cranks on my Chisel hardtail. Previously they have been on a Vitus Sommet, a Norco Optic and a Rocky Mountain Altitude. Still going strong.

Sram T-Type X01 cranks on my Raaw Madonna. Not that old, but have total faith in them.

No reason not to trust carbon cranks from an established manufacturer.

Onzadog
Having been one of the many owners of RaceFace sixc carbon cranks, I’m unlikely to trust carbon cranks again in a hurry.

My personal rule for RF is nothing with moving parts (ask their bottom bracket owners and my atlas pedals were shite) and nothing where two materials meet (like their cranks)

I remember doing a bit of a poll on here, and of the folks who replied that had owned RaceFace carbon cranks, something like 95% of the cranks people had owned had broken. 3 sets for me.

Similar rule for me with Raceface – don’t buy a RaceFace product with a bearing in it, don’t buy a RaceFace product with carbon in it.

SixCs on my Starling for the last 8 years (and they were 2nd hand when I got them) but I’m not going to comment further as I’m off to Morzine on Friday and don’t want to jinx anything.

A few years ago I got a Truvativ Stylo carbon crankset for an old bike on a mad cheap deal second hand. The difference was actually quite noticeable…but I was also upgrading from a SRAM SX with a square taper-like BB. Was probably the half kilo of weight that I noticed more than anything…and I wouldn’t pay full price.

As the one who always counters the above, I have some RF Next SL Carbon cranks which are now maybe 6 or 7 years old. They are still absolutely fine. Taken some knocks, but no issues. Maybe I’m lucky? I’m fairly light, mainly ride xc down south, no big jumps and hard landings etc. etc.

Edit Got them in Feb 2015 and have ridden circa 5,000 miles on them

A friend who takes care of his bike and is very much a wheels on the ground guy, snapped a set of sram cranks. Not for me.

Yeah, cos I’ve always felt like Mr Soft with those wibbly wobbly aluminium cranks lol

I’ve got carbon Praxis Works cranks on my Tripster now, the one big advantage over the previous Shimano cranks is that they haven’t peeled apart yet.

Cranks are one of those things where there’s almost no reason to buy anything other than the Shimano option that best fits your budget.

There are lighter options than XTR, but not many, and if you throw cost and the robustness of the 24mm BBs into the mix, then its very difficult to justify anything else. (30mm axle in a BSA BB = no sealing tube between the cups = water ingress)

(I’d have EE Wings if I could justify the extra cost, as they’re the only thing significantly lighter but equally bombproof, but even at mates rates, its “point and laugh” pricing.)

The other thing to consider is if your heels rub the cranks when you pedal. Mine do and all my cranks look hideous as a result. Helitape lasts a couple of hours if its wet/gritty and something as relatively soft as carbon, I’d be worried about wearing enough to cause structural issues.

SpeederFull
SixCs on my Starling for the last 8 years (and they were 2nd hand when I got them) but I’m not going to comment further as I’m off to Morzine on Friday and don’t want to jinx anything.

You’re probably out of the woods as far a manufacturing defects go at that point :)

They tended to break early – just lots of them where the pedals insert wasn’t mated to the carbon properly, I think.  I got about two hours XC riding out of my first set of SixCs

For sure, eeWings if you win the lottery, but I’d still hide the receipt from the wife. ?

+1 for SRAM carbon cranks. I’ve had several sets over the years with zero issues.

-3 for anything drivetrain related from Raceface.

I’ve got eeWings on my MTB, and other than the fact they look really REALLY cool, there are very few gains to be felt over the XT set they replaced. Maybe a hair stiffer on the first few pedal strokes of the first ride, but otherwise haven’t noticed any difference when riding.

Got some 11YO XX1s on my gravel/commuter, that had 7 years of been battered (and they look it) on the MTB prior to fitting.

Also had some carbon ones made for a pinion gearbox that then went into production, lots lighter than the forged Alu OEM ones, but not really noticeably any stiffer.

Buy EEWings/Ti cos it looks cool, it’s a bit stiffer, but not a lot.

After going through 2 sets of RF Next SL and 2 sets of Next R, I wouldn’t buy carbon again. I ended up with Turbines which are now 6 years old and still going strong.

EE Wings if I had loads of cash but I don’t. They’re gorgeous.

I’m one of the 5% whose RF Next cranks are fine, after nearly 8 years on my Jeffsy. They don’t feel a lot different to aluminium, but they were part of an extremely blingy spec on the first year’s bikes.

Like everyone else with Next SLs I broke a set, got another set on warranty then broke them too. Not even the same failure each time. But that’s not carbon, it’s Raceface having no idea what they were doing. The new ones seem to be better, you can learn a lot by doing it completely wrong 5 or 6 times in a row.

I had some old truvativ ones that were great, very heavily used- eventually I retired them because I’d worn a decent way through the carbon! But they still worked just fine. And the modern SRAM ones seem really good. But SRAM cranks are basically just a trick to hook you on a lifetime addiction to their piss poor bottom brackets. If you could get a SRAM crank on a 24mm HT2 spindle that’s what’d be on my bike.

Don’t think I’ll ever put carbon cranks on my bike, seen and heard of far too many failing, I’ve stuck with XT from 9sp through to 12sp, only Middleburns made me stray for a few years but I’ve remained a devout XT user and fan of HT2 24mm BBs but there’s a distinct lack of sexy cranks for them, every time something new and exciting comes out it’s 30mm or stupid bloody dub.

I’ve got some SRAM ones on my enduro bike that have been faultless for six years, but BLOODY HELL, THE TORQUE??? Getting them off to change the bb was a two-person swearathon. Nice cranks, but prefer the XTs on my other bikes for price and serviceability.

I haven’t ever had carbon cranks but I am thoroughly impressed how well Race Face warranty worked with numerous breakages my mate had with his NextSL and SixCs.
Sure there were some issues with delivery times as stuff was sent overseas but I believe they always delivered. I might be tempted to buy some if they made them with 24mm axle but I would be sure to keep spare cranks ready in the shed.

Whilst I’d be VERY shy about buying carbon cranks for mtb, you’ve got to note that Shimano hasn’t exactly covered itself in glory as far as Aluminium cranks in recent years. A total FlusterCluck in fact, and dodging recalls in Europe where the regulators are spineless.

I changed some Sram GX cranks to XX1. Don’t notice any extra stiffness, but they are quite a bit lighter. Look nice too.