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Why slammed stems?

Old 04-13-19, 08:07 PM
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Sheldon Brown says there can be problems with butted steerers and slammed stems:

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Old 04-13-19, 08:41 PM
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Originally Posted by Chombi1 View Post

My stems are quite low, but never slammed. All from getting used to laid out, flat back position riding I developed, emulating (at least, tried to.....) the Guimard's Gitane pro team in the 80's
I've been always surprised though, that even at this low stem position, how I'm not that far from the minimum insertion line with most of my stems...
This is a nice example of a reasonable slopping top tine. A good rule of thumb is the rider should be comfortable in both the drop and upright position with a vertical or lightly sloping top line the line between the seat clamp and the center of stem with about a fist on the seat. post and 2 fingers on the stem. If its a lot different chances are the bike is too small or too big.
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Old 04-13-19, 09:41 PM
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Depending on how you do it, slammed (threadless) stems can looks pretty sweet. Comfortable or not, it's like concept cars--exaggerated proportions in search of the visual 'thrust' that the person or designer is going for. I don't find a slammed quill stem to be attractive as the quill stem form factor is to make a "7" and not a single line. Low-set quills are fine, and all of us have a height range that brings about our idea of an ideal "rise-to-run" proportion. This generally gets trickier with tall and short frames, for various reasons.

In the case of my '15 CAAD10 Black, Inc. Disc, the steerer was already cut super low. The saddle to bar drop is the most extreme of my fleet, but hey, horizontal emphasis = speedy looking. I have tan wall 28mm tires (same size as these Schwalbs) on this now, and normally I'm not one for the murdered out look (lol, as I have three bikes with largely this aesthetic, well, they're at least not all matte black everything--that's lame), but man, this thing looks hot.

Stem conversion, with only a 'slammed' look being visually acceptable given the bike's race geometry and purpose. Also hot.

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Old 04-14-19, 12:22 PM
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Depending on the rider's physical proportions, mass distribution and intended pedaling intensity, the positioning of the saddle and handlebar relative to the bb can be all over the place.

Shorter, more-intense rides with very-fit riders favor a body mass center that is further ahead of the bottom bracket, the better to resist pedaling forces which apply rearward rotation torque about the bb to the rider's body.

And such forward positioning of the rider over the bb will move the rider's hands both forward and downward along a circle centered around the bb.

So, for better mass-balance over the bb while pedaling hard, a lower and longer stem becomes appropriate as the saddle also moves forward.
Endurance bikes favor a more-rearward body mass positioning over the bb as appropriate to a lower level of pedaling force.
So with that, a taller headtube allows the handlebar position to follow the concentric circle about the bb upward and rearward as the saddle moves rearward.

A bigger frame can tend to force the issue toward a forward body positioning, as the rider tries to achieve a better mass positioning over the bb so as to prevent the steering from feeling too flighty if it's a race bike with aggressive steering geometry.
Using a shorter stem not only quickens the steering, but also puts the front tire further ahead of the rider's body and closer to a leading rider's rear wheel, so drafting efficiency is compromised.

This one is a good visual example of my trying to fit on a bike with a bit too much toptube length for all but very intense levels of pedaling effort relative to my age. Thus descending comfort and control are likely compromised, as is comfort on longer rides. Still not a bad bike for 2-3-hour rides however, and I'll perhaps try a shorter stem one of these days if I don't sell it first.

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Old 04-14-19, 07:41 PM
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From Sheldon Brown: "

Why The Seven?

The "7" shaped handlebar stem gets its shape from a historical accident. The style in the old days was to ride rather tall frames by our standards, and the older handlebar shapes had less drop than modern designs. (When the transition from the "highwheeler" to the "safety" bike occurred, the idea of being able to stand over the frame did not occur immediately. Cyclists were in the habit of having to mount and dismount on the fly.) The stem would usually be inserted so that only an inch or less stuck out of the headset. The "7" shape allowed the lowest possible handlebar placement with as much forward reach as was wanted.

Nowadays, most cyclists set their stems all the way up (at the "minimum insertion" mark). With the smaller frame sizes used now, the "7" shaped stem is an atavism, a stylistic holdover from an obsolete technology. An extended "7" stem is two sides of a triangle. A stem that follows the diagonal, directly from just above the headset to the handlebar clamp makes more sense geometrically. Such a stem would be as strong as a similarly made "7" stem, but substantially lighter. It would also be more crash-worthy. Modern Allen-bolt stems are certainly safer than the old style that had a protruding hex head and a sharp rear corner, but the shape is still a threat to the rider's groin in a collision.

There is a trend to use "mountain-bike type" stems on road bikes, and it really makes a lot of sense. All that the "7" stem has going for it is tradition."
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Old 04-15-19, 12:39 AM
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^^^ And the fact that it looks nice! Haha.

Actually, amusingly the recent trend of aero bikes has an integrated stem that can either lie close to flush with the TT in extreme situations or can have a number of stem-matching aero spacers (up to 7cm or so!). Guess what shape that stem-and-spacer combo makes??? A seven! Nothing is new, and the new '7' looks considerably worse. Proportions proportions proportions!

Current generation Giant Propel. Yikes. [and yes, I've seen a Propel Advanced Disc in orange/black in person and there is a lot to like looks wise, but that stem better be super low with no spacers otherwise, it still looks bad in real life...]

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Old 04-15-19, 02:15 AM
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Originally Posted by jade408 View Post
D: why is this a trend for regular people
It's not.
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Old 04-15-19, 02:58 AM
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This thread needs a Tecnomic stem for balance.

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Old 04-15-19, 05:13 PM
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LOL, thanks Andy. Two fistfuls of stem, nice...
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Old 04-15-19, 06:10 PM
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I saw a post, recently that theorized that other than style or looking like a pro rider bike, stems are slammed because fewer riders use the drops....and slamming a stem effectively puts the top of the bars where the drops would be on an unslammed stem.

again a theory, not mine, but it makes sense to me
Looking for Torpado Superlight 58cm
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Old 04-15-19, 07:03 PM
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Slammed stems = Popped collars.
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