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Old 01-11-22, 11:51 PM
  #34  
verktyg 
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Bikes: Current favorites: 1988 Peugeot Birraritz, 1984 Gitane Super Corsa, 1981 Bianchi Campione Del Mondo, 1992 Paramount OS, 1990 Bianchi Mondiale, 1988 Colnago Technos, 1985 RalieghUSA Team Pro, 1973 Holdsworth

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Cracked Stem????

Originally Posted by smontanaro View Post
Is there something super special about the stem, like, it was made of unobtainium? If not, why not just source a replacement?
EDITORIAL: It never ceases to amaze me how many C&V fans will spend thousands of dollars on a classic bike and CHEAP OUT on a critical item like a stem that can be replaced for $50-$75.... SMH

Originally Posted by obuckler View Post
This comment showed up on velobase in 2014 by an “s barber” : “These stems are sometimes found with a crack in the aluminum where the conical splines of the nut wedged into the alloy. These cracks are typically non-critical.” There’s an unrelated comment above that by a wolfram verktyg… there is a user here named Verktyg also! Probably same?
Yes, verktyg tis I but I would NEVER make a comment like that!

Think of your head as a cantaloupe or maybe a small watermelon or honeydew (honey-do)... Back in the 70's I knew some Docs doing their residencies at several local hospitals. They described making morning rounds in the the neurology wards as "watering the vegetables"! Sad...



Originally Posted by randyjawa View Post
I would not trust that stem for a single ride. If it fails, utterly, and it will, your handlebar will become darn near useless. Get rid of the stem and get a new another one - they are not that expensive!
Please refer to my first response above.

Originally Posted by TPL View Post
Just for fun ....why not put the phone number of the nearest maxillofacial surgeon on your speed dial ?
SAD but very true...

Originally Posted by bulgie View Post
When I was young and immortal (and poor), I often rode parts with known cracks, and I definitely would have ridden that stem. I'm with scarlson and rhm , the crack is unlikely to fail catastrophically. But I've turned into a scaredy-cat since I got old and breakable. Knowing it's there would bum me out on high-speed downhills.

Here's a TTT that failed on me when the bike fell over:




Totally different location than OP's crack though. Mark B
Back in the early 70's when we were young and dumb and everything was trial and error because there was no one around to teach us any better, we (all the local shops) frequently used undersized alloy bars with Cinelli and 3TTT stems.

They were much prettier than the ugly cast aluminum "death stems". Although they were hard to find we could get those forged stems with 22.0mm quills for French and some other European bikes that used metric tubes.

Back then, Cinelli and 3TTT bars were also hard to get plus they were super expensive so we clamped the beautiful Italian forged stems down on 25mm alloy French bars. DOH! After cracking or breaking the clamps on 2-3 stems during assembly, we learned better - the hard way.

Back in 1975 I mounted a Milremo badged internally reinforced 25mm Philippe Professional bar in this 26.4mm Cinelli stem. I used it for over 35 years on at least 3 different bikes that I put a lot of miles on.




One day I realized that the 38cm wide bars were way too narrow for me. When I spread the bar clamp to remove the old bars, the front of it went flying across my workbench with a musical ping!

This break is in a different area but it brings up a point. I suspect that many cracked or broken bar clamps can be traced back to clamping down on undersized bars. Unlike steel which can be repeatedly deformed, aluminum has a much lower capacity for repeated bending before it fails.

Someone gave me this 3TTT stem. On closer examination I saw the cracks in the clamp... Into the junk box!





Here's a Philippe stem with a similar crack:



It appears that some of these cracks may be due to flaws in the forgings but who knows.

I'm always cautious about buying used stems, especially if the clamp needs to be spread. You never know the history of any bike component, especially something as critical as a stem!

verktyg
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Last edited by verktyg; 01-11-22 at 11:59 PM.
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