Because it's easier to mount it inside the triangle and actually adjust it because the bolts come in from the bottom. And the threads are in the caliper, so less work for the frame manufacturer again.
Likely. (Properly) changing a Vivid's travel is no trivial task, it's doubtful unless it's been through a shop. Anyway, go to MTBR for susp tech support.
Likely.
(Properly) changing a Vivid's travel is no trivial task, it's doubtful unless it's been through a shop.
Hi! This is my first post on this thread, but I have been reading for 2 years now. I talked with Sam pilgrim and a few other...
Hi! This is my first post on this thread, but I have been reading for 2 years now.
I talked with Sam pilgrim and a few other canyon guys at Tennessee Nationals, and also got to swing a leg over the Production New canyon sender. Supposedly the bike was supposed to release April 12 (that’s what Sam said, he also verified that it was the production version he was riding) so there’s a chance maybe it is releasing this month still? His bike had a baby blue color with white canyon letters. The (production?) bike also was equipped with the KIS system. looked identical to the proto. You could see Sam riding it in his Tennessee race vlog from a few weeks ago.
Take this information lightly since I have essentially no proof of this conversation with me and Sam lol, but he seems like a down to earth guy and I doubt he would just lie out of his ass. Unsure if this info has been covered or not.
Because it's easier to mount it inside the triangle and actually adjust it because the bolts come in from the bottom. And the threads are in...
Because it's easier to mount it inside the triangle and actually adjust it because the bolts come in from the bottom. And the threads are in the caliper, so less work for the frame manufacturer again.
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a compressive load up the length of the stay, vastly increasing load carrying capacity of the mount as a system, which in turn can result in thinner tubing, shaving weight and providing better ride feel for some. That same built in torque takeout can result in a quieter brake system. Maybe moot in MTB whirled, but a valid design concern on the roadie front. Additionally, should one go hamfisted on securing the caliper and roach a thread the frame isn't toast. Get a new caliper, bleed, and go on your way. I don't think it's perfect (it can def use more side-to-side adjustment to me), but there's a lot to appreciate about the design. Hayes was right on the old 22mm mounts.
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a...
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a compressive load up the length of the stay, vastly increasing load carrying capacity of the mount as a system, which in turn can result in thinner tubing, shaving weight and providing better ride feel for some. That same built in torque takeout can result in a quieter brake system. Maybe moot in MTB whirled, but a valid design concern on the roadie front. Additionally, should one go hamfisted on securing the caliper and roach a thread the frame isn't toast. Get a new caliper, bleed, and go on your way. I don't think it's perfect (it can def use more side-to-side adjustment to me), but there's a lot to appreciate about the design. Hayes was right on the old 22mm mounts.
I am old enough to have worked at a bicycle factory that manufactured bikes with the hayes 22mm mount, and old enough to have competed in stock trials, slalom and XC with a 22mm post mount.
Afaik, every bike we manufactured with the 22mm mounts cracked at the chainstay, where the boss was mitered and welded in, and most of the Treks and Fishers I saw in the ds/street/huck meat space cracked too. The only way to do this solution well offroad is to make a very long NDS drop chunk that integrates the brake mount into it.
Sram’s concentric brake mount patent is a much better solution to mounting on the chainstays, imo.
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a...
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a compressive load up the length of the stay, vastly increasing load carrying capacity of the mount as a system, which in turn can result in thinner tubing, shaving weight and providing better ride feel for some. That same built in torque takeout can result in a quieter brake system. Maybe moot in MTB whirled, but a valid design concern on the roadie front. Additionally, should one go hamfisted on securing the caliper and roach a thread the frame isn't toast. Get a new caliper, bleed, and go on your way. I don't think it's perfect (it can def use more side-to-side adjustment to me), but there's a lot to appreciate about the design. Hayes was right on the old 22mm mounts.
I am old enough to have worked at a bicycle factory that manufactured bikes with the hayes 22mm mount, and old enough to have competed in...
I am old enough to have worked at a bicycle factory that manufactured bikes with the hayes 22mm mount, and old enough to have competed in stock trials, slalom and XC with a 22mm post mount.
Afaik, every bike we manufactured with the 22mm mounts cracked at the chainstay, where the boss was mitered and welded in, and most of the Treks and Fishers I saw in the ds/street/huck meat space cracked too. The only way to do this solution well offroad is to make a very long NDS drop chunk that integrates the brake mount into it.
Sram’s concentric brake mount patent is a much better solution to mounting on the chainstays, imo.
Color me cautiously optimistic about the concentric pivot. But real interesting about your experience with the 22s. Granted, most of the bikes back in our early days weight was a huge focus, but I can honestly say I haven't seen any of the old Trek/Fishers show up busted at the stay. Granted, there weren't a lotta street and trials riders around my parts, and the Trek fam of bicycles all had the mount cast into the dropout, not a separate piece.
Color me cautiously optimistic about the concentric pivot. But real interesting about your experience with the 22s. Granted, most of the bikes back in our early...
Color me cautiously optimistic about the concentric pivot. But real interesting about your experience with the 22s. Granted, most of the bikes back in our early days weight was a huge focus, but I can honestly say I haven't seen any of the old Trek/Fishers show up busted at the stay. Granted, there weren't a lotta street and trials riders around my parts, and the Trek fam of bicycles all had the mount cast into the dropout, not a separate piece.
I forgot to mention broken I.F.’s and Schwinn’s with 22mm post mount, too! If you weren’t working in a factory or in the pits at every Norba National and Freestyle mtb event 20+ years ago, I could see missing the failures.
A consistent thing with most failed chainstays was that they… weren’t butted or formed with the disc mount in mind.
Color me cautiously optimistic about the concentric pivot. But real interesting about your experience with the 22s. Granted, most of the bikes back in our early...
Color me cautiously optimistic about the concentric pivot. But real interesting about your experience with the 22s. Granted, most of the bikes back in our early days weight was a huge focus, but I can honestly say I haven't seen any of the old Trek/Fishers show up busted at the stay. Granted, there weren't a lotta street and trials riders around my parts, and the Trek fam of bicycles all had the mount cast into the dropout, not a separate piece.
I forgot to mention broken I.F.’s and Schwinn’s with 22mm post mount, too! If you weren’t working in a factory or in the pits at every...
I forgot to mention broken I.F.’s and Schwinn’s with 22mm post mount, too! If you weren’t working in a factory or in the pits at every Norba National and Freestyle mtb event 20+ years ago, I could see missing the failures.
A consistent thing with most failed chainstays was that they… weren’t butted or formed with the disc mount in mind.
Hahahaha! Then we might be able to say the mount itself wasn't necessarily the issue. One can only hope that any MTB co adopting FM has enough historical knowledge to spec appropriate chainstays! TBF, there were quite a number of bikes with IS mount related failures in the same timeframe. Those I did see. The OG Surly Instigator was a classic case around these parts.
Flat mount in steel MTB is a recipe for disaster. There is very little chainstay remaining once you miter out space for the mount. It was designed for carbon with zero consideration for steel.
please don't respond about geo to this (or even respond at all), but just FYI, you can easily compare bikes and their geo in our product guide. here's a quick one i put together between a dreadnaught, firebird and sb165 - new bikes are being added all the time.
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a...
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a compressive load up the length of the stay, vastly increasing load carrying capacity of the mount as a system, which in turn can result in thinner tubing, shaving weight and providing better ride feel for some. That same built in torque takeout can result in a quieter brake system. Maybe moot in MTB whirled, but a valid design concern on the roadie front. Additionally, should one go hamfisted on securing the caliper and roach a thread the frame isn't toast. Get a new caliper, bleed, and go on your way. I don't think it's perfect (it can def use more side-to-side adjustment to me), but there's a lot to appreciate about the design. Hayes was right on the old 22mm mounts.
Despite this, the preferred answer is I.S. mounting.
please don't respond about geo to this (or even respond at all), but just FYI, you can easily compare bikes and their geo in our product...
please don't respond about geo to this (or even respond at all), but just FYI, you can easily compare bikes and their geo in our product guide. here's a quick one i put together between a dreadnaught, firebird and sb165 - new bikes are being added all the time.
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a...
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a compressive load up the length of the stay, vastly increasing load carrying capacity of the mount as a system, which in turn can result in thinner tubing, shaving weight and providing better ride feel for some. That same built in torque takeout can result in a quieter brake system. Maybe moot in MTB whirled, but a valid design concern on the roadie front. Additionally, should one go hamfisted on securing the caliper and roach a thread the frame isn't toast. Get a new caliper, bleed, and go on your way. I don't think it's perfect (it can def use more side-to-side adjustment to me), but there's a lot to appreciate about the design. Hayes was right on the old 22mm mounts.
Despite this, the preferred answer is I.S. mounting.
Yes. We had a standard that did not require threads to be cut into either frames *or* the calipers themselves. Roach a thread and you don't need to repair a frame, replace a caliper, or bleed your brake line -- just replace a cheap aluminum adapter.
And don't get me started on how many slightly different lengths of flat-mount brake bolts are out there because every different chainstay depth requires a different bolt.
Flat-mount brakes: brought to you by the same minds that think thru-headset cable/hose routing is a perfectly fine idea.
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a...
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a compressive load up the length of the stay, vastly increasing load carrying capacity of the mount as a system, which in turn can result in thinner tubing, shaving weight and providing better ride feel for some. That same built in torque takeout can result in a quieter brake system. Maybe moot in MTB whirled, but a valid design concern on the roadie front. Additionally, should one go hamfisted on securing the caliper and roach a thread the frame isn't toast. Get a new caliper, bleed, and go on your way. I don't think it's perfect (it can def use more side-to-side adjustment to me), but there's a lot to appreciate about the design. Hayes was right on the old 22mm mounts.
Despite this, the preferred answer is I.S. mounting.
We are free to disagree on this matter. I think post mount with its manufacturing dimensional requirements makes for a more robust mount. I ain't judging your opinion, just disagreeing.
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a...
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a compressive load up the length of the stay, vastly increasing load carrying capacity of the mount as a system, which in turn can result in thinner tubing, shaving weight and providing better ride feel for some. That same built in torque takeout can result in a quieter brake system. Maybe moot in MTB whirled, but a valid design concern on the roadie front. Additionally, should one go hamfisted on securing the caliper and roach a thread the frame isn't toast. Get a new caliper, bleed, and go on your way. I don't think it's perfect (it can def use more side-to-side adjustment to me), but there's a lot to appreciate about the design. Hayes was right on the old 22mm mounts.
Yes. We had a standard that did not require threads to be cut into either frames *or* the calipers themselves. Roach a thread and you don't...
Yes. We had a standard that did not require threads to be cut into either frames *or* the calipers themselves. Roach a thread and you don't need to repair a frame, replace a caliper, or bleed your brake line -- just replace a cheap aluminum adapter.
And don't get me started on how many slightly different lengths of flat-mount brake bolts are out there because every different chainstay depth requires a different bolt.
Flat-mount brakes: brought to you by the same minds that think thru-headset cable/hose routing is a perfectly fine idea.
Hear you on the flat mount dimensional front. The variability there is rather nuts, but by the same token so is the number of adapters necessary for PM or IS mounts. I like the idea of what flat mount can bring to the table for the reasons I listed prev, however the variability between manufacturers and where they chose to set their origins for the design center is much to be desired.
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a...
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a compressive load up the length of the stay, vastly increasing load carrying capacity of the mount as a system, which in turn can result in thinner tubing, shaving weight and providing better ride feel for some. That same built in torque takeout can result in a quieter brake system. Maybe moot in MTB whirled, but a valid design concern on the roadie front. Additionally, should one go hamfisted on securing the caliper and roach a thread the frame isn't toast. Get a new caliper, bleed, and go on your way. I don't think it's perfect (it can def use more side-to-side adjustment to me), but there's a lot to appreciate about the design. Hayes was right on the old 22mm mounts.
We are free to disagree on this matter. I think post mount with its manufacturing dimensional requirements makes for a more robust mount. I ain't judging...
We are free to disagree on this matter. I think post mount with its manufacturing dimensional requirements makes for a more robust mount. I ain't judging your opinion, just disagreeing.
Is anybody on a steel frame really concerned IS isn't sufficiently robust?
also,
"please don't even respond at all" is an excellent, if somewhat abridged, quote.
please don't respond about geo to this (or even respond at all), but just FYI, you can easily compare bikes and their geo in our product...
please don't respond about geo to this (or even respond at all), but just FYI, you can easily compare bikes and their geo in our product guide. here's a quick one i put together between a dreadnaught, firebird and sb165 - new bikes are being added all the time.
This is cool, and something I’d like to see with it is what the “median” bike is though the years. What’s that crabbiest crab bike geometry, and how far off that median geo is a selected bike?
Yes. We had a standard that did not require threads to be cut into either frames *or* the calipers themselves. Roach a thread and you don't...
Yes. We had a standard that did not require threads to be cut into either frames *or* the calipers themselves. Roach a thread and you don't need to repair a frame, replace a caliper, or bleed your brake line -- just replace a cheap aluminum adapter.
And don't get me started on how many slightly different lengths of flat-mount brake bolts are out there because every different chainstay depth requires a different bolt.
Flat-mount brakes: brought to you by the same minds that think thru-headset cable/hose routing is a perfectly fine idea.
Hear you on the flat mount dimensional front. The variability there is rather nuts, but by the same token so is the number of adapters necessary...
Hear you on the flat mount dimensional front. The variability there is rather nuts, but by the same token so is the number of adapters necessary for PM or IS mounts. I like the idea of what flat mount can bring to the table for the reasons I listed prev, however the variability between manufacturers and where they chose to set their origins for the design center is much to be desired.
Counterpoint: flat mount brakes also require adapters for different rotor sizes, except for the default 140 or 160 mm (depending on frame manufacturer).
For the record, I do not know enough about engineering & frame design to question any of what you said about more efficient loading of the frame/tubing. I assume you're correct in that regard. It's plausible that there are engineering gains achieved by relocating the caliper. But from an end user or mechanic perspective, it's a pain in the ass.
I do wonder if the bolt spacing pattern limits the achievable size/power of calipers. AFAIK only Hope has made a 4-piston flat-mount caliper so far.
We are free to disagree on this matter. I think post mount with its manufacturing dimensional requirements makes for a more robust mount. I ain't judging...
We are free to disagree on this matter. I think post mount with its manufacturing dimensional requirements makes for a more robust mount. I ain't judging your opinion, just disagreeing.
Is anybody on a steel frame really concerned IS isn't sufficiently robust?
also,
"please don't even respond at all" is an excellent, if somewhat abridged, quote.
Not sure what's meant by that last bit, but no matter.
When I say robust mount, I mean in light of taking cross sectional load off the mount screws as well as creating a stiffer interface between the caliper and the frame, which post mount does. Brake force is applied directly to the mount, not through the screws. Some IS mounts are flexy buggers, which results in noise and worse case, vibration. Post Mount pretty much does away with that. Like all things, end game is about tradeoffs. IS is easier to manufacture, PM creates a better interface.
I said it before, I'll say it again. That new UNNO is head and shoulders above any other ebike option right now. Long travel, burly build, still light weight, incredible aesthetics, next gen motor. Price isn't insane either, at least compared to the competition.
How how unfair is it, Cesar is not only a fast rider, hes better looking than all of us and living the dream of being a bike and moto engineer.
Not sure what's meant by that last bit, but no matter. When I say robust mount, I mean in light of taking cross sectional load off the...
Not sure what's meant by that last bit, but no matter.
When I say robust mount, I mean in light of taking cross sectional load off the mount screws as well as creating a stiffer interface between the caliper and the frame, which post mount does. Brake force is applied directly to the mount, not through the screws. Some IS mounts are flexy buggers, which results in noise and worse case, vibration. Post Mount pretty much does away with that. Like all things, end game is about tradeoffs. IS is easier to manufacture, PM creates a better interface.
As someone with a front seat on brake mount designs/development for a number of years, there are pros and cons to each mounting method depending on the material and frame design, and the intended customer. Often the intended customer preference outweighs the best possible engineered solution. Shear force loading the caliper bolts is a non-issue in most cycling applications. For a steel frame, the complexity and cost of using either a post mount or direct mount design might go against the simplicity and cost reduction goals of that project. Those customers might prefer something simple, inexpensive, and easy to use. Post or direct mount forgings are also subject to failure at the weld from design or fabrication errors. TLDR; you can't apply a blanket solution for all applications.
Back to rumours; I look forward to evolving brake designs that Sram's direct mount design will create.
How many? Cause honestly if it's a handful, they need to rethink that whole flex stay decision and start handing out updated ones with bearing pivots.
Peak bending moment occurs at the axle end of the seat stay. This snapping is unrelated to the flex stay if it's happening at the linkage end. Looks like it's a compression failure in the tube that wouldn't be fixed by adding.the bearing.
Also given the brake mount location the actual angle change on the flex stay is negligible and the 6 bar description is more academic then actually measurable. That said I've not modelled the kinematic myself.
That rear brake mount can go fuck itself though.
Really, why would you use road mount on a mountain bike? I know there are adapters but PM is honestly the best mount there is...
Because it's easier to mount it inside the triangle and actually adjust it because the bolts come in from the bottom. And the threads are in the caliper, so less work for the frame manufacturer again.
I’m a big proponent that steel hardtails should always have adjustable dropouts also so they can be run single speed.
Your bias is showin' there, bub!
Don’t remember hearing or seeing anything about the Strive. It was a Downhill event so…
And more. Inside the triangle flat mount decouples shear forces across the chain and seat stays. Changes the cross-sectional shear on the seat stay into a compressive load up the length of the stay, vastly increasing load carrying capacity of the mount as a system, which in turn can result in thinner tubing, shaving weight and providing better ride feel for some. That same built in torque takeout can result in a quieter brake system. Maybe moot in MTB whirled, but a valid design concern on the roadie front. Additionally, should one go hamfisted on securing the caliper and roach a thread the frame isn't toast. Get a new caliper, bleed, and go on your way. I don't think it's perfect (it can def use more side-to-side adjustment to me), but there's a lot to appreciate about the design. Hayes was right on the old 22mm mounts.
I am old enough to have worked at a bicycle factory that manufactured bikes with the hayes 22mm mount, and old enough to have competed in stock trials, slalom and XC with a 22mm post mount.
Afaik, every bike we manufactured with the 22mm mounts cracked at the chainstay, where the boss was mitered and welded in, and most of the Treks and Fishers I saw in the ds/street/huck meat space cracked too. The only way to do this solution well offroad is to make a very long NDS drop chunk that integrates the brake mount into it.
Sram’s concentric brake mount patent is a much better solution to mounting on the chainstays, imo.
Color me cautiously optimistic about the concentric pivot. But real interesting about your experience with the 22s. Granted, most of the bikes back in our early days weight was a huge focus, but I can honestly say I haven't seen any of the old Trek/Fishers show up busted at the stay. Granted, there weren't a lotta street and trials riders around my parts, and the Trek fam of bicycles all had the mount cast into the dropout, not a separate piece.
I forgot to mention broken I.F.’s and Schwinn’s with 22mm post mount, too! If you weren’t working in a factory or in the pits at every Norba National and Freestyle mtb event 20+ years ago, I could see missing the failures.
A consistent thing with most failed chainstays was that they… weren’t butted or formed with the disc mount in mind.
Hahahaha! Then we might be able to say the mount itself wasn't necessarily the issue. One can only hope that any MTB co adopting FM has enough historical knowledge to spec appropriate chainstays! TBF, there were quite a number of bikes with IS mount related failures in the same timeframe. Those I did see. The OG Surly Instigator was a classic case around these parts.
Flat mount in steel MTB is a recipe for disaster. There is very little chainstay remaining once you miter out space for the mount. It was designed for carbon with zero consideration for steel.
please don't respond about geo to this (or even respond at all), but just FYI, you can easily compare bikes and their geo in our product guide. here's a quick one i put together between a dreadnaught, firebird and sb165 - new bikes are being added all the time.
https://www.vitalmtb.com/product/compare/64471,64876,50471?sizes%5B%5D=50471%2C140291&sizes%5B%5D=64471%2C268071&sizes%5B%5D=64876%2C269856
Despite this, the preferred answer is I.S. mounting.
yeah, nah. bikeinsights is much better for these typ of comparisons.
Yes. We had a standard that did not require threads to be cut into either frames *or* the calipers themselves. Roach a thread and you don't need to repair a frame, replace a caliper, or bleed your brake line -- just replace a cheap aluminum adapter.
And don't get me started on how many slightly different lengths of flat-mount brake bolts are out there because every different chainstay depth requires a different bolt.
Flat-mount brakes: brought to you by the same minds that think thru-headset cable/hose routing is a perfectly fine idea.
We are free to disagree on this matter. I think post mount with its manufacturing dimensional requirements makes for a more robust mount. I ain't judging your opinion, just disagreeing.
Hear you on the flat mount dimensional front. The variability there is rather nuts, but by the same token so is the number of adapters necessary for PM or IS mounts. I like the idea of what flat mount can bring to the table for the reasons I listed prev, however the variability between manufacturers and where they chose to set their origins for the design center is much to be desired.
Is anybody on a steel frame really concerned IS isn't sufficiently robust?
also,
"please don't even respond at all" is an excellent, if somewhat abridged, quote.
This is cool, and something I’d like to see with it is what the “median” bike is though the years. What’s that crabbiest crab bike geometry, and how far off that median geo is a selected bike?
Counterpoint: flat mount brakes also require adapters for different rotor sizes, except for the default 140 or 160 mm (depending on frame manufacturer).
For the record, I do not know enough about engineering & frame design to question any of what you said about more efficient loading of the frame/tubing. I assume you're correct in that regard. It's plausible that there are engineering gains achieved by relocating the caliper. But from an end user or mechanic perspective, it's a pain in the ass.
I do wonder if the bolt spacing pattern limits the achievable size/power of calipers. AFAIK only Hope has made a 4-piston flat-mount caliper so far.
You were probably eagerly waiting for another company to step up and enter the pedal/stem/bar market, here you go (some sarcasm detected): https://www.vitalmtb.com/news/press-release/leatt-enters-components-category-pedals-stems-grips-and-handlebars.
Not sure what's meant by that last bit, but no matter.
When I say robust mount, I mean in light of taking cross sectional load off the mount screws as well as creating a stiffer interface between the caliper and the frame, which post mount does. Brake force is applied directly to the mount, not through the screws. Some IS mounts are flexy buggers, which results in noise and worse case, vibration. Post Mount pretty much does away with that. Like all things, end game is about tradeoffs. IS is easier to manufacture, PM creates a better interface.
I hope they're not quoting me and that I'm not in trouble 😅 I sincerely apologise for my part in starting that discussion.
I said it before, I'll say it again. That new UNNO is head and shoulders above any other ebike option right now. Long travel, burly build, still light weight, incredible aesthetics, next gen motor. Price isn't insane either, at least compared to the competition.
How how unfair is it, Cesar is not only a fast rider, hes better looking than all of us and living the dream of being a bike and moto engineer.
https://www.youtube.com/watch?v=DAd4hRvaLrc
bernard walks through his pivot phoenix (raw and 17 q's to follow this week too)
on how many frames is he by now? i have seen so many snapped rear ends before on such a new model on social media
As someone with a front seat on brake mount designs/development for a number of years, there are pros and cons to each mounting method depending on the material and frame design, and the intended customer. Often the intended customer preference outweighs the best possible engineered solution. Shear force loading the caliper bolts is a non-issue in most cycling applications. For a steel frame, the complexity and cost of using either a post mount or direct mount design might go against the simplicity and cost reduction goals of that project. Those customers might prefer something simple, inexpensive, and easy to use. Post or direct mount forgings are also subject to failure at the weld from design or fabrication errors. TLDR; you can't apply a blanket solution for all applications.
Back to rumours; I look forward to evolving brake designs that Sram's direct mount design will create.
How many? Cause honestly if it's a handful, they need to rethink that whole flex stay decision and start handing out updated ones with bearing pivots.
Peak bending moment occurs at the axle end of the seat stay. This snapping is unrelated to the flex stay if it's happening at the linkage end. Looks like it's a compression failure in the tube that wouldn't be fixed by adding.the bearing.
Also given the brake mount location the actual angle change on the flex stay is negligible and the 6 bar description is more academic then actually measurable. That said I've not modelled the kinematic myself.