Apologies if I get this wrong. It's been a while since I wrapped my head around degrees of freedom.
First, I didn't really want to leave the impression that this was a big problem in the review, just that it was different.
Next, I must say that I don't think I've ever really struggled with a single faceplate system on a stem. I certainly have never damaged a bar with one. I cracked a Thomson faceplate once, but that was probably my fault.
What's a bit strange about the Burgtec system is that if you look at most stems, the top and bottom bolts run parallel to one another. This allows for one axis of movement for your faceplate (in and out, parallel to the bolts). There are probably exceptions to this rule, but the Burgtec seems particularly extreme.
If you look at the Burgtec system, the bolts are at a fairly substantial angle to one another. In essence, there is really only one position for your faceplate to be in, and it only allows for very limited amounts of movement from that position. In that sense, it feels "over-constrained". There's no free axis of movement with the bolts in place. I guess there are two ways of looking at this:
\- One, the faceplate is going to naturally go to the right position because that's the only one where it sits comfortably
\- Two, if you don't get it all lined up perfectly, (or if the tolerances are off) there's a chance you're putting some weird loading into something
Again, it's not a huge deal, it's just not what I'm used to dealing with. Once you have it all lined up, it's fine. In my mind, it seems a bit easier to just have one part to worry about, and not two. And if you are going to have two, it seems a bit easier to have something like the Renthal system where you have no gap on the bottom and a gap on the top.
A mechanical designer could probably tear everything that I've said here to shreds, but there is (probably) no arguing that what they've done here is different than what most do. It felt worth a comment.
July 7, 2021, 4:08 p.m. - Dave Tolnai
Apologies if I get this wrong. It's been a while since I wrapped my head around degrees of freedom. First, I didn't really want to leave the impression that this was a big problem in the review, just that it was different. Next, I must say that I don't think I've ever really struggled with a single faceplate system on a stem. I certainly have never damaged a bar with one. I cracked a Thomson faceplate once, but that was probably my fault. What's a bit strange about the Burgtec system is that if you look at most stems, the top and bottom bolts run parallel to one another. This allows for one axis of movement for your faceplate (in and out, parallel to the bolts). There are probably exceptions to this rule, but the Burgtec seems particularly extreme. If you look at the Burgtec system, the bolts are at a fairly substantial angle to one another. In essence, there is really only one position for your faceplate to be in, and it only allows for very limited amounts of movement from that position. In that sense, it feels "over-constrained". There's no free axis of movement with the bolts in place. I guess there are two ways of looking at this: \- One, the faceplate is going to naturally go to the right position because that's the only one where it sits comfortably \- Two, if you don't get it all lined up perfectly, (or if the tolerances are off) there's a chance you're putting some weird loading into something Again, it's not a huge deal, it's just not what I'm used to dealing with. Once you have it all lined up, it's fine. In my mind, it seems a bit easier to just have one part to worry about, and not two. And if you are going to have two, it seems a bit easier to have something like the Renthal system where you have no gap on the bottom and a gap on the top. A mechanical designer could probably tear everything that I've said here to shreds, but there is (probably) no arguing that what they've done here is different than what most do. It felt worth a comment.