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Modolo Professional stem failures > Help me get this straight

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Modolo Professional stem failures > Help me get this straight

Old 04-25-17, 12:29 PM
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billytwosheds 
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Modolo Professional stem failures > Help me get this straight

Over in the C&V appraisals, it was mentioned that a stem on one of the bikes was one of the infamous failing Modolo stems from the late 80's / early 90's.

It just so happens that I have a similar stem going on a build right now...

So after some Internet research, I'm nailing down the details of which stem(s) were risky (if not all of the Modolo's of this period).

John Allen wrote up a whole article on why this design fails:

Hazardous bicycle handlebar stems

Here's a pic of a failed Modolo stem from his article:



A note on the Velobase page for Modolo Flash suggests that only a few stems in the line were recalled:

VeloBase.com - Component: Modolo Flash

The Professional was recalled, not the Flash. The design was changed to have less of a V underneath and put more material around the weak point of the countersunk bolt underneath. The photo is of a beefier model. John Allen has a photo of the breaky model on his site.
And then this recall notice (1990) suggests there were reinforced replacement stems that can be identified:



So assuming the stem I have is one of the recalled models, I'll just be taking it off.

But if it's a reinforced/replacement model, am I taking an unnecessary risk by using it?

FWIW no aero bars are in use (which were noted as a common stress-increasing issue for these stems in particular.

TIA
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Old 04-25-17, 12:41 PM
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Not sure if it has something to do with the failures, but I noticed that unlike most other similar aero style stems from the mid 80's, the Modolos had the upended seam at the clamp on the top of the stem, while the others had it at the bottom. Their design is a bit counterintuitive and frankly, not so attractive, but maybe they did such so as not to end up copying other manufacturer's aero stem designs.
Doing such takes a lot of material off from both top and bottom of the clamp area of the stem which I think could have caused the failures. Seems like Modolos fix was just to add more material at the bottom of the stem where the bolt goes through. I guess the fix worked, but resulted in a heavier stem design.

Last edited by Chombi1; 04-25-17 at 02:25 PM.
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Old 04-25-17, 02:18 PM
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Originally Posted by Chombi1 View Post
Seems like Modolos fix was just to add more material at the boll Tom of the stem where the bolt goes through. I guess the fix worked, but resulted in a heavier stem design.
Yeah, that sounds about right.

Turns out mine is the weaker original version, and I eyeballed a hairline crack on one side of the clamp after closer inspection. The bike was put on hold after failing to get Sheldon's alternative cable routing working on a 10spd shifter / 9spd cassette, but maybe it's better I didn't ride it after all!

Yikes.
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Old 04-25-17, 05:40 PM
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I may have a Speedy with the narrower stem. Closer inspection with magnifying glass required.
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Old 04-25-17, 06:26 PM
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My two cents...
I've been using a 130mm X-Eras stem for over 20 years with no symptoms such as creaking or stress fractures. The X-Eras is one of the good stems.
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Old 04-26-17, 05:48 AM
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I recently acquired a Modolo stem in a parts box that came with the Ochsner I bought for my daughter. The stem I have is pictured below and I believe the one on Liz's bike looks the same, but she's away at school. All this has me thinking that the one I have may be the recalled stem, although it doesn't look like it from the 1st post. I especially don't want her's to be a potential safety issue....I'll get her to send me a photo when she can.

Does this look like a problem stem ?

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Old 04-26-17, 09:25 AM
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If there is a flat strip running along the bottom of the stem extension, it would be the recalled stem. If it is smooth and rounded from side to side, then you have the improved/safe stem.

Last edited by Chombi1; 04-26-17 at 04:47 PM.
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Old 04-26-17, 11:34 AM
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The one of the left is a recall stem. Notice how thin the edges leading up to the counterbore are?
The stem on the right has more metal surrounding the counterbore, thus safe(r).

Modolo stem comparison.jpg
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Old 04-26-17, 11:51 AM
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Originally Posted by Deal4Fuji View Post
Does this look like a problem stem ?
This looks like a newer or replacement stem -- it's pretty rounded and doesn't have the harder edges of the recalled version.
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Old 04-26-17, 02:59 PM
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Originally Posted by billytwosheds View Post
This looks like a newer or replacement stem -- it's pretty rounded and doesn't have the harder edges of the recalled version.
Originally Posted by tyler_fred View Post
The one of the left is a recall stem. Notice how thin the edges leading up to the counterbore are?
The stem on the right has more metal surrounding the counterbore, thus safe(r).
Thanks guys - I may be back when I can get a photo of my daughter's, if I can't tell from the info you gave me
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Old 04-26-17, 03:58 PM
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Originally Posted by billytwosheds View Post
Yeah, that sounds about right.

Turns out mine is the weaker original version, and I eyeballed a hairline crack on one side of the clamp after closer inspection. The bike was put on hold after failing to get Sheldon's alternative cable routing working on a 10spd shifter / 9spd cassette, but maybe it's better I didn't ride it after all!

Yikes.
Wow, that was close. Sounds like it would've definitely failed, could've been a major crash.
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Old 04-26-17, 09:57 PM
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My thoughts indeed, @exmechanic89.

Here's the stem I just removed from the build:



Note the hard edges, pretty sure it's a bad one.



And the crack is visible here:



Either way, I'm glad it's not on a bike. It'd be fine on a trainer. Oh well.
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Old 04-27-17, 09:08 AM
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Originally Posted by billytwosheds View Post
My thoughts indeed, @exmechanic89.

Here's the stem I just removed from the build:



Note the hard edges, pretty sure it's a bad one.



And the crack is visible here:



Either way, I'm glad it's not on a bike. It'd be fine on a trainer. Oh well.

Holy ****. Thank you for this thread! Hopefully lots of people here will see this and be informed about the problem.
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Old 04-27-17, 09:25 PM
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@tuna , check your Quantum
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Old 04-27-17, 09:38 PM
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I continued to ride mine (1987) until a year or two ago, completely ignorant of the recall until then. It provided the main motivation to update my component set (and I used a Nitto stem and bars -- less authentic, I guess, but hopefully less potentially harmful).
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Old 04-30-17, 08:19 PM
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Originally Posted by fleslider View Post
@tuna , check your Quantum
Thanks @fleslider

I will take a look at mine, it is about that age.

I might have to get a vintage Cinelli bar/stem for that bike.
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