Bike Anti-Porn - When Things Go Wrong

Yes, Cinelli is an exception!

Yes, Cinelli is MOSTLY an exception!

Ti stems are stupid, they always look clunky

It's probably about time somebody one-ups the Grammo with something in 3D-printed Ti, innit.

Considering that if you make a stem in carbon, it's just what they call black aluminium - because it has to be strong in every direction, the strength to weight is hardly better than forged ally...

The Grammo seemed to offer a miraculous combination of high performance and light weight when introduced because it was hollow, and competing against solid stems. With metal stems, you tend to run out of stiffness before you run out of strength. Since torsional stiffness in the extension is where your trouble is, it's hard to do better than a round tube. Outside of weight-weenie contests, there's little to be gained by making a stem more expensive than a net-shape forged 7000-series aluminium alloy job, because those can already be done stiff and strong enough at just over 100g for a 100mm stem. Using either exotic alloys or additive manufacturing isn't going to get you 30g off that. The 3D printed stems currently available (Mythos, Nex-Gen, Bastion) show no benefit over much cheaper forged aluminium alloy models. At the high end, everything is heading in the direction of integrated bar-stem construction for the aeros.

it's hard to do better than a round tube

Well yeah, that seems intuitively correct for sure.

But there'd certainly be some subtlety in a completely optimised shape, given you're joining two orthogonal tubes, and each end has clamps on it with chunky bits for bolts to thread into... But it probably only amounts to a handful of grams anyway.

The price of that Bastion stem! Sheesh

there'd certainly be some subtlety in a completely optimised shape

There might be tiny gains at the ends which can be realised by additive manufacture which are impossible with forging plus a 5-axis closed loop CNC second operation, but as you say, even the most ardent weight weenie has other places to look before getting to $200/g savings on the stem, and sprinters looking for maximum stiffness can use 200g stems and still make the UCI minimumffor total machine weight.

Spa Cycles seem a good option right now £65

https://www.spacycles.co.uk/m9b0s88p3902/SPA-CYCLES-Titanium-Stem

I got one of those on my steamroller. Really nice but the supplied screws seemed dangerously short to me so I replaced them.

Hm, is that weld meant to have a hole in it?

It's just the end of the weld. Pretty normal

It's just the end of the weld

I assume he's talking about the egregious gap between the start and the end, not the cute little dimple in the end.

the end of the weld

I feel fine.

^ underrated post

And that's the one they took a photo of...

O_o

To my eye, there's no gap. The end of the weld overlaps the start.

.

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Mine often are. Half the forum has me on ignore.

Cant really see the bikes? Or is it enough that one of them is a colnago?

I'm guessing it's that helmet

Yep that's what i'm guessing too, unless it's the bar tape on the Colnago's!

The helmet is nice

Strong Barry the Cat vibes

https://www.cookdandbombd.co.uk/forums/index.php?topic=31043.570

XC elbows on a road bike?

Apparently a work in progress, maybe the next step is launch into the sea.. 🤞

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