When the Spanish fairy tale shattered — Lab test: the stiffness of the stems

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kiritozhang
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by kiritozhang

integration wrote:
Fri Feb 05, 2021 3:13 am
Thanks for doing the review on these stems the results are very insightful. If the goal is testing for stiffness would you consider testing some of the alleged "super stiff" stems? Like the Pro Carbon Sprint, the new Pro Vibe carbon, Zipp SL Sprint, S-Works Venge, etc. See if those manufacturer's claims address really what they say. Would be interesting to see how they actually stack up to the ones you've already tested.
If you are not a tank or an elephant, these stems will hardly have any physical variables in actual use. Therefore, there is no need for testing.
I even use these stems as alloy fixtures for other tests.

DHG01
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by DHG01

AMGRoadster wrote:
Fri Feb 05, 2021 2:45 am
Thanks for posting the results of your test. That said your tests add a simple data point to the decision factor and one that is not applicable to 99+% of riders. What is the mean time between failure? What is the impact of fatigue? What is the reliability of the product? What is the support from the manufacturer or distributor?

I take this position from a very personal position. The only catastrophic failure I have ever had with a bike part. Is a highly rated stem on this board as it is very lightweight. However it quickly failed due to fatigue and could not survive the rigors of real life.

What stem am I referencing That would be the Uno.

Yikes! I had it in my radar now that they have a version with no logos. Was that road cycling?

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mortirolo
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by mortirolo

Mcfk, tune Geiles Teil 4.0, Extralite...
https://blog.fairwheelbikes.com/reviews ... em-review/
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garbageman
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by garbageman

That's one porky Zipp Service Course SL used in the test - I have a 110mm/-6 and it weighs 136g and a 90mm/-17 that's a couple grams lighter - both in the "Beyond Black" finish. I wonder if they are less stiff as well as lighter.

OnTheRivet
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by OnTheRivet

AMGRoadster wrote:
Fri Feb 05, 2021 2:45 am
Thanks for posting the results of your test. That said your tests add a simple data point to the decision factor and one that is not applicable to 99+% of riders. What is the mean time between failure? What is the impact of fatigue? What is the reliability of the product? What is the support from the manufacturer or distributor?

I take this position from a very personal position. The only catastrophic failure I have ever had with a bike part. Is a highly rated stem on this board as it is very lightweight. However it quickly failed due to fatigue and could not survive the rigors of real life.

What stem am I referencing That would be the Uno.
I would like to see a picture of this. As a near net shape forged part failure would generally be from an inclusion as opposed to any real design flaw. I know a company like Kalloy (Make the uno) are a huge OE supplier and do large amounts of fatugue testing. They also have one of the most advanced forging factories in the world.

FlatlandClimber
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by FlatlandClimber

For my Specialized ÆTHOS, I have ordered a Darimo IX4 Stem (120mm, -12) and put it on my bike and was pretty shocked by how fragile it appeared. Even at very low tourque, it creaked quite a lot. When I had everything assembled, I did some load testing, rather non scientific. Putting body weight on the handlebars, hard sprints out of the saddle etc.
While I usually like Darimo products (the Loop T1 Seatpost for Tarmac I had was magnificent), this one is a no-no for me. It feels so weak and bouncy, that I wouldn't want to do a fast downhill or a hard sprint in a race on it.
I returned it and got the Extralite one instead, same length, same angle. It is 11g heavier and as stiff as it gets. Night and day. I will just cut my finger nails more frequently to make up for the extra weight and but ride with confidence.
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ChiZ01
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by ChiZ01

looking at those weights while looking at my redshift stem haha

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wheelsONfire
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by wheelsONfire

FlatlandClimber wrote:
Wed Feb 10, 2021 4:26 pm
For my Specialized ÆTHOS, I have ordered a Darimo IX4 Stem (120mm, -12) and put it on my bike and was pretty shocked by how fragile it appeared. Even at very low tourque, it creaked quite a lot. When I had everything assembled, I did some load testing, rather non scientific. Putting body weight on the handlebars, hard sprints out of the saddle etc.
While I usually like Darimo products (the Loop T1 Seatpost for Tarmac I had was magnificent), this one is a no-no for me. It feels so weak and bouncy, that I wouldn't want to do a fast downhill or a hard sprint in a race on it.
I returned it and got the Extralite one instead, same length, same angle. It is 11g heavier and as stiff as it gets. Night and day. I will just cut my finger nails more frequently to make up for the extra weight and but ride with confidence.
Wow, good to know. I don't think Extralite holds stiffness, Darimo even worse, would be a no no for me to.
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Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.

PrettyA
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by PrettyA

Amazing testing kiritozhang
Quick qs, are you related to EXS cycling as I saw you guys posting a picture on insta for the stem testing 2 weeks ago.
If you are, when will the lightweight integrated bar be out?

Jan
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by Jan

Images not found. Can you fix this, kiritozhang?

happydogww
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by happydogww

The original article can be found here https://cyclingcollege.com/index.php/20 ... the-stems/

The images are from facebook and have expired so they dont work anymore.

Thank you kiritozhang & alanyu for the hard work

Johnny Rad
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by Johnny Rad

Thx for the link to the stem test.

Yes, thx for the work indeed.
happydogww wrote:
Wed May 05, 2021 4:16 pm
The original article can be found here https://cyclingcollege.com/index.php/20 ... the-stems/

The images are from facebook and have expired so they dont work anymore.

Thank you kiritozhang & alanyu for the hard work

InoxEPS
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by InoxEPS

FlatlandClimber wrote:
Wed Feb 10, 2021 4:26 pm
For my Specialized ÆTHOS, I have ordered a Darimo IX4 Stem (120mm, -12) and put it on my bike and was pretty shocked by how fragile it appeared. Even at very low tourque, it creaked quite a lot. When I had everything assembled, I did some load testing, rather non scientific. Putting body weight on the handlebars, hard sprints out of the saddle etc.
While I usually like Darimo products (the Loop T1 Seatpost for Tarmac I had was magnificent), this one is a no-no for me. It feels so weak and bouncy, that I wouldn't want to do a fast downhill or a hard sprint in a race on it.
I returned it and got the Extralite one instead, same length, same angle. It is 11g heavier and as stiff as it gets. Night and day. I will just cut my finger nails more frequently to make up for the extra weight and but ride with confidence.
I totally agree with you.

Angui
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Joined: Thu Jun 25, 2020 10:12 pm

by Angui

kiritozhang wrote:
Fri Feb 05, 2021 3:17 am
DHG01 wrote:
Thu Feb 04, 2021 6:21 pm
As expected, Uno is a solid /balanced choice.
Including Extralite and Darimo with stems that weigh twice as much seems a bit pointless; not sure consumers choose between those extremes. On the other hand, it is useful providing a spectrum across different products.

Extralite performs very well; stiffer than Darimo being 2 cm longer.

I had a pretty light stem from Lyte; it wasn't stiff enough for gravel and I had to take it off. I now have it on a road bike, and it's absolutely fine (no issues in comparison with Enve, Ritchey Classic, etc I have in other bikes). I wonder where that threshold is in those stems.

Finally, I don't really like it when a someone generalizes and says "....wouldn't trust x from China". So you can imagine what I think about the thread title. On top of that, OP seems to be holding some form of grudge with Darimo. They push all the limits to achieve light and safe products. They will customize and adapt to specific needs. Not a product I like, but criticism here seems a bit harsh.

Anyway, interesting review.
DARIMO's handlebars and seatposts are made to the extreme, and I can see their style. But they compromised on the stem. This makes me feel puzzled and unhappy.
Hi Kiritozhang
what in your view is the minimum torsional stiffness that a stem should present and how do you calculate that please?
Yes Darimo is lowest at 288N/mm but... and so what? Isn't 288N a pretty strong force to exert for an individual, and then that would be per mm while of course no individual concentrates their force that much?
I may misunderstand of course, basically am interested to understand what "good enough" is in the real world?
thank you!

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neeb
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by neeb

I agree. Stiffness in a stem (just as in a frame) is not something to be maximised as much as possible, it will have an optimal value depending on the user and the use.

For me the Darimo stem and bar combination has the perfect balance of stiffness and compliance, I love it. Stiffer would just be harsher. But I'm light and not a sprinter. Doubtless it would be less ideal for Peter Sagan...

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