I always imagine the benchmark to be the one that all others aspire to be like?
My definition of a benchmark is simply something against which others are evaluated. It doesn't need to subject to bias. And the resources for the crankset development were neither my own nor from an investor. I'm just a poor guy who loves riding and found myself in a unique position to design some cool stuff. Let's not go off topic and stick to stems and stiffness.
What about actual (absolute) stiffness if that is ones priority?
Good point. Being so light, this stem probably won't have stiffness levels such as those purposely built for it, nor was it intended to. Thankfully, my stem design isn't a wet noodle, as light as it is. If it was, I'd be ashamed to showcase it.
It's hard to quantify what constitutes ‘feeling stiff’ though. To some, a certain stem is stiff enough, and to others it's not, depending entirely on the perception of the individual. My benchmarks were Thomson for stiffness, Syntace for durability and Extralite for weight. All make excellent products. Though "feel" may be a good indicator to some, sensitivity differs from person to person and can be unreliable.
For example, although I calculated the absolute values of my own stem design under certain load cases, and only know the approximate stiffness of certain stems compared to another. Fortunately, I've ridden/worked with various stem brands/models with the same bars and in similar lengths. From Pro to Ritchey, 3T, Syntace, Deda, Ringlé, Specialized, USE, Zipp to no-name el-cheapo, also in various materials.
My ideal method of comparison would be a standardized test to measure deflection, isolating a stem from fork and handlebar. Hopefully, it won't be long before I'm able to generate some numbers, though in my view such a test is best done by a 3rd party to prevent favoritism. I'm seeking a party with whom to do this without getting charged excessively.
The difference is not something minuscule that you just barely sense, it's a whole different bike alltogether.
I'm not saying heavier is better, but it's hard to believe claims of something that is just extremely light also being super stiff. Sure in a stiffness to weight ratio comparison, but as I said. That really doesn't say much about actual stiffness... Something 1/4 of the weight at twice the stiffness (to weight) is still only half as stiff.
Indeed, notwithstanding the hypothetical nature of this argumentation.
I find STW values somewhat misleading, since a difference in mass isn't something particularly noticeable. I prefer to avoid relative terms like strength of stiffness-to-weight, however exciting they may sound to some. Most ‘scale-weenies’ don't realize that strength doesn't necessarily correlate to either weight or stiffness and STW is merely the outcome of a division of mass by a given force or deflection coefficient. It needlessly complicates.
Conclusion: how stiff a design ends up at is all in the combination of a given material, processing and fabrication, design (engineering) and finish. That's what makes industrial design and mechanical engineering so exciting, and there are so many variables that, as you indicated, no two bikes will feel the same, even when they look identical.
User Name wrote:
but I've been told before I don't belong here.
I also replace ti bolts with steel ones.
You're welcome here. I don't see why you wouldn't belong in this discussion. I found many titanium bolts to be inadequate for stems. I've had some stems that had 'em and experienced no issues with them, but I've become more careful when it comes to putting a product onto the market. I wanna rule everything out that can go wrong as much as possible. For production stems, I contemplated going with steel, since I've had some issues with prototype bolts. These weren't due to a faulty design, might I add, but rather the handiwork of poor craftsmanship from machinists.
I found a solution in a novel process that forms/forges the Wert 6Al/4V titanium bolts in a single operation, thread, head and everything. These bolts have been tested significantly stronger than steel or other titanium equivalents. When you make stems this light available to the public, you don't want to leave things to chance.
Good luck with your products. As a 6'5"/85kg rider I feel the Calnago feeling about super light parts, in particular stems. The lightest stem I used is the new Superlegerra, claimed at 100g, weighted at 120g for a 120mm...
Thanks, I appreciate your well-wishes. Though I'm only 6'0"/1m83 and around 70kg/155lbs, I can empathize with bigger and heavier riders.
For many years, I swore by my trusted Syntace Megaforce 260, a hefty and outdated model. I've worked with Deda stems and once tried a Newton 31.7 myself, but it didn't inspire the confidence I hoped for. Given my experience, a Superleggero simply wouldn't be my choice.
My view on this Deda model is that they made a lighter stem by omitting material but not actually improving overall ride characteristics. For what I expect a stem to do, I find the Superleggero rather lacking. I'm not saying it's a bad stem, since I think Deda made a decent effort that will please plenty of riders, plus there are lesser stems out there. Having worked with and on stems gave me the experience reflected in my design. I wouldn't mind to see the Superleggero included in a comparison test though.
Here are some of my personal views on stem stiffness. I differentiate between 2 types:
1) Torsional deflection, noticed when as pulling on one side of the bars and pushing on the other, and
2) Vertical movement, when pushing down on both sides, for example when riding over a bump or a hole
The biggest contributor to stem strength and stiffness I found to be the cross-section of the area between bars and fork. Both wall thickness and profile are important contributing factors. Strength comes from how a load is transferred through a structure and can be calculated through a load path. Smooth transitions between shapes allow surface stresses to diffuse as forces are exerted onto a structure.
The clamp areas around bars and fork are where many brands put more material in comparison to my design, so my stem has relatively more material in its barrel than the clamp areas. On my stem, due to a larger barrel, less material is needed for the clamp areas. Therefore, much weight is eliminated simply by changing one parameter, which simultaneously positively contributes to its rigidity. Part of the weight save equation is due to my proprietary bolt design. Lastly, stem length has a significant influence on stiffness.
When riding on cobbles or over rough terrain, you don't want your hands to be shaken off the bars or hoods. Though this is more the area of transmitted vibration/resonation. With my stem design, I chose a certain stiffness range as an absolute value at a reasonable weight of what 'feels' acceptable on a bike, while taking aesthetics into account.