Cheap Chinese Crankset ⚠️ Is failure inevitable?

2 years ago, I got a lightweight crankset from AliExpress. How is it holding up, and will aluminium fatigue lead to failure…?

SIROKO CLOTHING LINK:

I have been using my cheap aluminium crankset from AliExpress nearly every day for the last 2 years. It is branded CVR and produced by a company called Zrace, but Sensah have also provided them with their Empire groupset. The crankset is nice and stiff, rides nicely, shifts well, looks good, and only weighs 711g. So what’s the catch?

Well, it’s a Shimano hollowtech compatible crankset, so the axle spindle is 24mm in diameter. To my knowledge Shimano only ever use steel for their axle spindles. The potential issue with my cheap crankset, is that the axle is made of aluminium.

One difference that steel has compared to aluminium, is that after repeated loads, aluminium will fatigue, whereas steel has an indefinite fatigue life.What does this mean for my crank, how much longer will it last, what are the risks, and should you be concerned? Let’s find out!

New Siroko Film:

New Senicx Crankset:

Timestamps:
00:00 – Start
00:30 – Sponsor segment
01:08 – Intro
02:18 – Crank arms & chainrings
05:52 – Aluminium axle
08:15 – Broken axle examples
09:18 – Steel bearings vs aluminium axle
10:01 – Final thoughts & advice
10:35 – SRAM DUB axles

Intro roll:

Music:
Fresh Healthy Perspectives
The Process
Still Not Rite
Take Me Down to The Fashion Show
Waves of August

About Trace Velo:
I love cycling, and I love getting pro cycling kit for less. If it’s cheap, from China, and made of carbon fibre, I’m interested!

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Email:

Please note:
With the exception of Siroko and Senicx, all other products demonstrated in this video have been purchased by me, and I have no affiliation to any of the sellers or vendors shown.

In addition, I am not a professionally trained bike mechanic. There can be risks associated with using products that are unbranded, untested, or come from sources where the provenance is unknown. Please talk to a qualified bike mechanic if you are in any doubt.

In essence, be careful, do your research, and cycle safe!!!

[TraceVelo]

So after perusing the comments section, a few engineers, including Hambini and PeakTorque, mentioned that the broken axles I demonstrated could be due to a shear failure (due to torsional overload), potentially amplified by internal defects within the aluminium. This theory could well hold up, as the broken axles were not particularly old, so aluminium fatigue is unlikely to be the only suspect, and the QC on some of these cheaper parts is definitely a little questionable. Anyway, appreciate all the comments on this one, every day is a school day folks!

[Jayneflakes]

That is dedication to your viewers, risking a broken axle, torn open flesh, a horrific road accident, being fed on by zombies and the calamitous end of the world, just to prove that Aluminium is fine for a crank axle! Good work as always, keep it up because your videos are always lovely and fun. 😁

[Medievalfan]

Engineer here: Those machining marks in the middlesection kind of worried me back in the originial video about that crankset and now my worries are proven right by the mode of failure shown. The rough machining results in troughs and spikes in the surface, similar to a threaded rod, just not that deep. But it is apparantly enough to cause stress spikes in those throughs that go right around the part. Just a recipe for cracks forming and finally failure in the part. Hence shimano HTII axles are smoothed in the middlepart. If they maybe sandblasted the surface or went over it with a finer feed rate at the machine those axles would be way more reliable. Also the axles shown for SRAM are smooth and plated all around.

[Hambini]

Those failures don't look like metal fatigue they look like torsional overload or shear overload.

[kris]

Shimano HAS used aluminum axle!
12 years on my Shimano DEORE LX crankset, and those are still running!
The stiffest cranks that I ever used! Excellent cranks! Greetings from Croatia 😊

[danielbum]

I remember you promising to report back on the aluminium spindle's durability back then. Top lad!

[Angel_EU]

Luke maybe you won't read that but i want to let you know i'm an avid (and subscribed!) viewer from Spain that really enjoys your vids. I value inmensely your honesty and dedication to this sector of cheap bike stuff. I own a cheap mtb kinda converted for road use but i plan to build myself a proper disc brake road bike this year using a frame and parts reviewed in your videos. Just wanted to let you know you have active viewers from all around the world that find tremendous value in your work. Take care mate, and keep doing this forever please :D

[two-eyedRoy]

Great vid as usual Luke! :)

I can see the failure point in your crank spindle.
11:34 - 11:36 as it rotates through the light you can see a hairline crack including a couple of pits in keypad 8 (break the screen into 9 [3 rows, 3 columns, 8 is the bottom middle square]).
Can't say when it'll go, but when it does I'd put money on that area being it.
I doubt changing the machining (from that fast rough cut that's almost a thread to something smoother that takes longer) would make any difference as that hairline looks to have been present during machining (evidence being the little facets either side of the crack that glint in the light)
That does also imply the the bar stock was not forged and possibly not extruded either (could be wrong on the latter, not entirely sure).

Like the '80s Castrol ad. 'Oils ain't Oils', metals are no different. AL 7075 cast is rather inferior (crystaline structure) to extruded 7075 (crystaline structure uniformity) and then forged 7075 is slightly better again (crystaline structure uniformity under compression). Those three states are also increasing in cost to purchase.

A note on advertising jargon: A 'billet' is just a single piece or chunk of material. It doesn't define any level of quality.
A billet of junk material, is still junk.
It's a fad term from the car wheel industry that since got picked up by motorsports and now any manufacturer wanting to hype up a product now faps into their own face about billet this/that in their advertising.
The term/phrase you want to read/hear is 'Billet Forging', because the Forging gives the material it's best structural properties.

[godlike]

I was wondering when you would make an update on this crankset and it finally came! This is why I always consult your channel in regards to these chinese parts. I have the same crankset and it feels so great to ride! The bottom bracket was kinda iffy tho so I got that replaced quickly but seeing how much punishment yours was able to take just gives me peace of mind that I'll be able to ride my bike without worrying about my crankset. Awesome stuff as always Luke!

[dickenscider]

Cant wait for the fully carbon brake caliper video. Been in my shopping cart for a few weeks now.

[mbrennen]

Great to see a follow up review long term. Really enjoying the videos.

[markk]

great video. Thanks. I just checked all of my chinese cranksets. I’m glad to report that SMLLOW, iXF and Claw cranksets have steel axles.

[grantnyenes]

Great video, interesting to see a crank failure from trace and a Dura ace crank failure vid by Hambini on the same day! It seems the cheap ones no worse than the most expensive…

[MrLambik]

@TraceVelo : Smoother surface will increase the resistance towards fatique. The 'lines' of milling will increase the chance of tear or rupture. Smoothing it with sanding paper will increase the durability in regard of fatique. The initiation of the cracks are on the surface, smoothing it will decrease that initiation of a crack.

[simplyxuan]

Hi Luke! Just wanna share my experience here on this exact crankset too!

I had 2 of this exact cranks in 165mm. Both had the same problems where the GXP mounting surface on the crank is slanted/offset, such that my chainring doesn't spin in a straight-line. It cause my chain to rub both sides of my FD even in 50-11 gear.

For the #1 purchase, I told the seller about the issue where my chainring doesn't spin straight. The seller kindly told me that the chainrings are CNC-ed to a good tolerance, and it must be the cranks that have issue.
With little questions asked, the seller sent me a new crank, and the problem is solved.

For my #2 purchase, the slant/offset seems even worse. Worse part is no reply from seller yet.

So kinda hit or miss

[vazione]

I love these update videos on parts from China, keep up the great work Luke! You’re my favorite bike content creator. 👍🏼

[tomermahlis]

I am glad ur been transparent with all the products you review

[ramrodk]

great Video, you really improved your Video quality! Perfect Mix of Entertainment und Science

[Kacavida]

Hi there.
5:30 Your right knee reaches more under the handlebar then you left, from top view, as if you have 175 mm crank on you right and 170mm crank on you left.
8:20 Fotage reveals cranks break toward the non-drive side sugesting the load was applyed on the left crank uppon breaking.
To hinder axle break, try applying a pull on the drive side while applying pressure on the left crank.
That is, help your left crank spread the load buy pulling simultaneously on the right crank, ballance the load with opposite load.

[auto]

I worked at a bikeshop in highschool. There was a old man who rode his bike 365 days everywhere and its a was a old alu raleigh frame for commuting and he told us that when he was making a turn down a hill he felt the crankset area loose and he couldnt transfer power. As it turns out the frame gave at the bb area due to fatigue and only the top welds where holding it. Nothing bad happened since he has braked already. That was a cool experience.