Racework Carbon Cranks

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taladjidi
Posts: 13
Joined: Sun Aug 16, 2020 11:16 pm
Location: Paris, France

by taladjidi

Hi, as promised, here are some pictures : the crack is a hairline crack (not that visible on the picture but protrudes 1mm or so from the surface) that goes from the innermost bolt all across the top of the crank.
I'll still try to ride them to my commute to work tomorrow morning (20k round trip) and see if anything moves. I'm waiting on the seller's reply following these pictures.
(PS : Please don't mind the dirty bike, we had a lot of rain in the last months in the Paris area ...)
signal-2023-05-23-204346_005.jpeg
signal-2023-05-23-204346_003.jpeg
signal-2023-05-23-204346_002.jpeg
signal-2023-05-23-204346_004.jpeg

by Weenie


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MagicShite
Posts: 425
Joined: Sun Jun 26, 2016 3:33 pm

by MagicShite

taladjidi wrote:
Mon May 22, 2023 9:54 am
Hi all, I took the bait and bought one of these in order to swap my PM to a Sigeyi axo. The non-drive side crank arm cracked as I was tightening the two pinch bolts. Since there was no torque info I started at 8 N.m (I took for reference that Shimano cranks have a 12 to 14 N.m rating). I stopped as soon as I heard suspicious noises but the damage was done ... Guesstimating, I'd say that I was around 5 N.m given how easy the bolts turned.
I'll upload some pictures tonight. I'll try to contact the seller to get a replacement arm, if this fails I'll try to find a 3 bolt SRAM Red GXP crankset.
I would really be interested if someone has any experience with it and what torque they used, else I guess I'll just be the Guinea pig for the community :D
if these are the neutron copies, IIRC the ratings are 6-7nm for the bolts.

StiffWeenies
Posts: 613
Joined: Sun Feb 28, 2021 3:39 pm

by StiffWeenies

MagicShite wrote:
Wed May 24, 2023 3:49 am
taladjidi wrote:
Mon May 22, 2023 9:54 am
Hi all, I took the bait and bought one of these in order to swap my PM to a Sigeyi axo. The non-drive side crank arm cracked as I was tightening the two pinch bolts. Since there was no torque info I started at 8 N.m (I took for reference that Shimano cranks have a 12 to 14 N.m rating). I stopped as soon as I heard suspicious noises but the damage was done ... Guesstimating, I'd say that I was around 5 N.m given how easy the bolts turned.
I'll upload some pictures tonight. I'll try to contact the seller to get a replacement arm, if this fails I'll try to find a 3 bolt SRAM Red GXP crankset.
I would really be interested if someone has any experience with it and what torque they used, else I guess I'll just be the Guinea pig for the community :D
if these are the neutron copies, IIRC the ratings are 6-7nm for the bolts.
I think the OEM for Neutron/Onirii is Jiankun? those cranks and this Racework are not safe to ride...

taladjidi
Posts: 13
Joined: Sun Aug 16, 2020 11:16 pm
Location: Paris, France

by taladjidi

MagicShite wrote:
Wed May 24, 2023 3:49 am
taladjidi wrote:
Mon May 22, 2023 9:54 am
Hi all, I took the bait and bought one of these in order to swap my PM to a Sigeyi axo. The non-drive side crank arm cracked as I was tightening the two pinch bolts. Since there was no torque info I started at 8 N.m (I took for reference that Shimano cranks have a 12 to 14 N.m rating). I stopped as soon as I heard suspicious noises but the damage was done ... Guesstimating, I'd say that I was around 5 N.m given how easy the bolts turned.
I'll upload some pictures tonight. I'll try to contact the seller to get a replacement arm, if this fails I'll try to find a 3 bolt SRAM Red GXP crankset.
I would really be interested if someone has any experience with it and what torque they used, else I guess I'll just be the Guinea pig for the community :D
if these are the neutron copies, IIRC the ratings are 6-7nm for the bolts.
Thanks for the heads up. For now it survived the 10k commute to work. I'm kind of sure it will fail at some point, but I got quick replies from the seller and I think I should be able to get a replacement arm.
Let's say I'm betting that it will not fail within the time frame :twisted:

iamraymond
Posts: 624
Joined: Wed Jun 28, 2017 8:59 am

by iamraymond

Another ww tried these cranks and had the same issue with the left arm cracking.
gurk700 wrote:
Sun May 21, 2023 12:41 am

Weeeeelp. I love some chinese products but this is not it.
Left crank started creaking like insane. Louder than any BB I've heard creak. But this was definitely the crank creaking (I'd stop pedaling with left and the creak would stop). I came home. Sure enough, the crank was split through where the pinch bolts are. I didn't overtorque it at all either.

I'll stick to Praxis cranks for cheap light options.

otnemem
Posts: 398
Joined: Fri Jun 28, 2019 7:55 am

by otnemem

Judging from where it cracked it seems clear to me that they are structurally deficient. Can't help but picture a catastrophic failure while grinding up a steep climb out of the saddle and smashing my balls.
Run, don't walk.

TidyDinosaur
Posts: 75
Joined: Thu Sep 29, 2022 6:48 pm
Location: Central EU

by TidyDinosaur

Someone on chinertown.com had the same experience... You could have spared yourself the troubles :)

MagicShite
Posts: 425
Joined: Sun Jun 26, 2016 3:33 pm

by MagicShite

StiffWeenies wrote:
Wed May 24, 2023 4:06 am
MagicShite wrote:
Wed May 24, 2023 3:49 am
taladjidi wrote:
Mon May 22, 2023 9:54 am
Hi all, I took the bait and bought one of these in order to swap my PM to a Sigeyi axo. The non-drive side crank arm cracked as I was tightening the two pinch bolts. Since there was no torque info I started at 8 N.m (I took for reference that Shimano cranks have a 12 to 14 N.m rating). I stopped as soon as I heard suspicious noises but the damage was done ... Guesstimating, I'd say that I was around 5 N.m given how easy the bolts turned.
I'll upload some pictures tonight. I'll try to contact the seller to get a replacement arm, if this fails I'll try to find a 3 bolt SRAM Red GXP crankset.
I would really be interested if someone has any experience with it and what torque they used, else I guess I'll just be the Guinea pig for the community :D
if these are the neutron copies, IIRC the ratings are 6-7nm for the bolts.
I think the OEM for Neutron/Onirii is Jiankun? those cranks and this Racework are not safe to ride...

pinchbolt system with carbon cranks is a disaster.

Should have just went for a bolt to spline interface.

gurk700
Posts: 956
Joined: Fri Jan 20, 2017 7:40 pm

by gurk700

MagicShite wrote:
Wed May 24, 2023 2:59 pm
StiffWeenies wrote:
Wed May 24, 2023 4:06 am
MagicShite wrote:
Wed May 24, 2023 3:49 am
taladjidi wrote:
Mon May 22, 2023 9:54 am
Hi all, I took the bait and bought one of these in order to swap my PM to a Sigeyi axo. The non-drive side crank arm cracked as I was tightening the two pinch bolts. Since there was no torque info I started at 8 N.m (I took for reference that Shimano cranks have a 12 to 14 N.m rating). I stopped as soon as I heard suspicious noises but the damage was done ... Guesstimating, I'd say that I was around 5 N.m given how easy the bolts turned.
I'll upload some pictures tonight. I'll try to contact the seller to get a replacement arm, if this fails I'll try to find a 3 bolt SRAM Red GXP crankset.
I would really be interested if someone has any experience with it and what torque they used, else I guess I'll just be the Guinea pig for the community :D
if these are the neutron copies, IIRC the ratings are 6-7nm for the bolts.
I think the OEM for Neutron/Onirii is Jiankun? those cranks and this Racework are not safe to ride...

pinchbolt system with carbon cranks is a disaster.

Should have just went for a bolt to spline interface.
FWIW I think it's ok when done right and Carbonworks had the right approach, just horrible execution.
Pinchbolt on carbon is what hundreds of stem / fork combo are doing and fine for the most part, granted it's couple nm's less in that application..

but yeah best avoid carbonworks from my experience.

gurk700
Posts: 956
Joined: Fri Jan 20, 2017 7:40 pm

by gurk700

taladjidi wrote:
Tue May 23, 2023 8:23 pm
Hi, as promised, here are some pictures : the crack is a hairline crack (not that visible on the picture but protrudes 1mm or so from the surface) that goes from the innermost bolt all across the top of the crank.
I'll still try to ride them to my commute to work tomorrow morning (20k round trip) and see if anything moves. I'm waiting on the seller's reply following these pictures.
(PS : Please don't mind the dirty bike, we had a lot of rain in the last months in the Paris area ...)
signal-2023-05-23-204346_005.jpeg
signal-2023-05-23-204346_003.jpeg
signal-2023-05-23-204346_002.jpeg
signal-2023-05-23-204346_004.jpeg
Yep. This is EXACTLY what happened to mine.

taladjidi
Posts: 13
Joined: Sun Aug 16, 2020 11:16 pm
Location: Paris, France

by taladjidi

gurk700 wrote:
Thu May 25, 2023 5:11 am
FWIW I think it's ok when done right and Carbonworks had the right approach, just horrible execution.
Pinchbolt on carbon is what hundreds of stem / fork combo are doing and fine for the most part, granted it's couple nm's less in that application..

but yeah best avoid carbonworks from my experience.
"Live and learn" as they say ... That was my thinking when going for them, all of my other carbon parts that have a similar interface had 0 issues. I definitely should have checked out Chinertown, I don't know why I did not think about it :noidea:

motty
Posts: 10
Joined: Wed Aug 30, 2023 8:51 pm

by motty

Looks like they've redesigned it so there's no pinch bolt now?

Have to say I'm tempted even though the risk still seems high.

https://a.aliexpress.com/_mPLuxKq

toxin
Posts: 496
Joined: Tue Apr 18, 2023 5:56 pm

by toxin

It's still a 24 mm alu spindle and not all that light either...

wickedsixx
Posts: 5
Joined: Sat Oct 23, 2021 7:50 am

by wickedsixx

A quick input for anyone looking to buy this crank in its updated/ revised design. The axle length is rather short so it will NOT fit a BB86 shell if you run a BB with "lips" that protrude a lot such as the Gineya which has about 3mm of lip on both sides. My bet is you might have to go one-piece such as BB Infinite with this one. A BB with 1,5mm on each side might be the limit for this crank if you want to tighten it to the recommended torque.

Also tried it on a T47 frame with very minimal BB lips from BB Infinite, I managed to tighten it to about max 12nm (suggested 35-40nm). I'd say its a design flaw, the axle should be atleast 1-2mm wider to be viable in my opinion.

TidyDinosaur
Posts: 75
Joined: Thu Sep 29, 2022 6:48 pm
Location: Central EU

by TidyDinosaur

wickedsixx wrote:
Fri Jan 19, 2024 12:18 pm
A quick input for anyone looking to buy this crank in its updated/ revised design. The axle length is rather short so it will NOT fit a BB86 shell if you run a BB with "lips" that protrude a lot such as the Gineya which has about 3mm of lip on both sides. My bet is you might have to go one-piece such as BB Infinite with this one. A BB with 1,5mm on each side might be the limit for this crank if you want to tighten it to the recommended torque.

Also tried it on a T47 frame with very minimal BB lips from BB Infinite, I managed to tighten it to about max 12nm (suggested 35-40nm). I'd say its a design flaw, the axle should be atleast 1-2mm wider to be viable in my opinion.
Yes, that is correct. I bought 2 of these. Tried installing the first one on my gravel bike with a cheap Aliexpress BSA BB and the bearing seized after just a little bit of torque on the bolt. Spend an hour trying to figure out what I was doing wrong...
I had a shimano BB lying around and decided to install that and see what happened. And now everything fitted (but with only about 0,5mm to spare). It seems the 7mm bearings on most BSA BB's are too wide for this crankset and the shimano BB uses 6mm bearings so is a little narrower.
After that I installed the other crank on my commuter that has an older Shimano BSA MTB BB and no problem there...

So yes, the crank is faulty in my opinion and the axle is too short.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

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