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I'm not an engineer so I may be wrong on this.
Yes, 400 would be concentric to the hub but moving 426 moves 408 and 410 in a way that isn't concentric with a caliper following a rotor. For example moving 426 from a seat stay where the rotor enters and exits the caliper as we all know and love, to the chain stay means the rotor enters and exits caliper in a much more vertical path and would crash into the caliper. The center of the pistons will be in the right spot because they are rotating concentric to 400 but the angle of attack for the rotor is off.
My simplistic thinking would lead me to believe the only way this truly becomes universal is if 400 is your datum and 426 is referenced against that datum to a very specific location. Any change in 426 location means a new adapter to get the caliper to sit in the right spot.
Am I off in my thinking?
Edit: the more I look at it the more I think you are right about it being concentric and not mattering where 426 is.
This. I once bought an Ibis with a shitty post where the bolt holes weren't perpendicular to the axle. That was my final pinkbike special. All HTs with sliding dropouts use bolt-on brake posts and they never failed me so this is two thumbs up from me.
Quite a few single pivot and hardtail bikes (and Propain) have the caliper mounted between the two stays. It works perfectly fine, inserting the rotor vertically isn't an issue, there's enough space.
The problem with that position is that it is a pain in the ass getting to the caliper bolts with an allen key and you can't see through the caliper to align it properly. Having on the top is much better for servicing.
that point doesn't matter...marketing will find the way to make it better. 😅
That patent may be the worst written and non enforceable patent ever produced by SRAM. Also it appears to have been filed in 2021 before they got their ass kicked by Fox about their Narrow Wide "invention" that was created in the 1800's on a tractor.
Hopefully this one doesn't let air past the main seal into the damper oil. That's all I care about for the next float x2 lol
That was resolved with the MY2024 changes.
What if the whole postmount bracket in this one is the UDH-equivalent but for braking? I.e. still making it possible to mount other brands, but the next Sram brake to be mounted directly to the axle...
No clue how that'd look like, but they did it on the other side already
Yes and no, they resolved it somewhat but the main issue is that the shaft deforms and pushes the seal out of the way, which allows air to push past. Unless they reworked the shaft in the my2024 fix, a new model with a thicker shaft that doesn't deform would make more sense. I think the pictured model might be a float x2 Neo.
They reworked the damper shafts, bearing housing and seal kits. However I’m not clear on specific changes to each of those. Maybe one of the tuners on here can chime in.
Regardless, agreed there’s further room for improvement in the MY26.
Not according to the people who had them around here.
X2 has been "resolved" pretty much every year, just to fail the same, 2024 included. Maybe they last a little longer but not a single 2024 model survived 2024 on my mates' bikes.
The new X2 has plenty of big architecture change's.
Not sure how it was possibly resolved every year as they didn't make any changes from 2021-2023. Those shocks were a real mess.
Everyone in my network has had no issues with MY24-25.
A direct mount (200+ mm) brake seems quite bulky plus you usually have the need to align it to some degree...
Agree, but I'm just a bit cautious this time around thinking they're introducing a new standard solely for the greater good of everyone's convenience without a hidden catch in there somewhere.
Good to know on the Forbidden. Hopefully they incorporate this new 'standard' into their upcoming E-Druid.
Any word on the release date? I'm not in the market for a DH bike, but the sooner the DH sled is released the sooner (hopefully) we'll see a new Enduro.
UHB could really open up the market for aftermarket floating brake arms.
Curious, what's the hidden catch to UDH?
It's keyed to the axle/frame I believe, so I think it may take extensive modification to become floating?
maybe, maybe not? could just have an inner sleeve to it that interfaces with the keyed portion, then a bearing sleeve that rotates around it. obviously this is all conjecture based on the patent diagrams. i'm sure someone with enough ingenuity could figure it out.
The super interesting thing to me about that UBM patent is that it looks like the upper mount is floating and then secured by a pinch bolt the way some forks do.
Theoretically you’d have perfect alignment because the caliper is aligned by the hub endcap and the upper mount is just to counteract the brake torque.
Direct mount transmission. It wasn't really a catch though (unless you like adjustable dropouts), just the ulterior motive of moving everyone to a standardised dropout design.
And Splitpivot?
Yah ok, I wouldn't call that a catch either, and UDH seems like a win all around even tho SRAM had an ulterior motive...
You are right, but I also think most companies were trying to make their current frames work with the UDH and not come up with a long-term solution. There is no way you cannot have both.
I reckon either stay would work. The pivot & bearing would have to increase in diameter to accommodate the sleeve.
Considering split pivot was made to work with UDH, I guess this would work too.
Considering the way split pivot is designed (4-bar braking wise, brake mounted to seatstay) the UBM would have to be mounted to the seatstay, otherwise it would be a normal single pivot.
As for floating brake mounts, mounting UBM in a bearing should cover most of it, I'm only curious if it is bulky enough to handle being a floating arm...
As for fixation, I have another question or doubt. It's a pinch bolt (with an elongated hole by the looks of it to cover the tolerances) which makes it adaptable. But, if the post is inside the diameter of the rotor (at least the larger sizes), it is limited in length it can protrude from the chainstay. Then unless the post is flared at the end, I am wondering if the UBM can pop off it if the seatstay bends out of the way.
Having the UBM mounted mostly to the axle is great as theoretically you'll always have alignment to the hub and rotor, but if it's at the expense of it popping off the torque carrier (post), that's not really ideal... And even if it doesn't pop off, I'm wondering if the post and pinchbolt interface might get worn through time.
Some thoughts regarding that USD-fork-rumor: back when Fox decided against their USD-proto entering series production, they explained they couldn’t make it stiff enough without making it extra heavy with the current-for-that-time tech available. But that was, I think, the time when they were raving about having the stiffest dh-fork on the market - a feat that ended up being not so perfect as some needed flex proved to be beneficial to the riding feel. Since then they’ve incorporated some into their forks, production technologies have made incredible leaps since, so putting 2+2, my bet is on Fox trying to USD-fy their 40 for the second time!