MTB Tech Rumors and Innovation

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Primoz
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Primoz 8/22/2021 10:03am
8/22/2021 10:03am
Considering it's a high pivot, if you huck to flat, the rearward axle path will transfer some of the load through the swingarm into the bearings and most of it into the shock. With a load perpendicular to the swingarm, all the load goes into the shock, so the further you go into the travel on a high pivot bike, the more load from that huck to flat will be transferred into the shock as opposed to into the frame.

With roots and rocks, you don't usually have high force impacts very deep into the travel, so there's less of a necessity to cater for those situations, maybe.

What I've written above is just thinking out loud, but at the end of the day bike design is a preference and design ethos game. Norco probably had a different set of requirements and went about with a more progressive frame. THat's why the same suspension system from two different brands can feel different (because they had different expectations from the bike) or two different systems can feel similar, if the design brief for the two was similar.
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TheShortestCharles 8/22/2021 11:00am
8/22/2021 11:00am
Primoz wrote:
Might be a consequence (or a necessity) because of the high pivot?
I made some approximations of the Aurum HSP and Supreme DH in Linkage, and from what I can tell it depends more on how the linkage is tuned. Just moving a few pivots around on the Norco, you can recreate the leverage curve of a Forbidden [3rd photo], so it ultimately depends on what the designers are looking for.



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Primoz
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Primoz 8/22/2021 11:19am
8/22/2021 11:19am
Of course. The swingarm (the main for links on a multilink swingarm) define the axle path and thus define the antisquat characteristics through the travel (with an idler, the idler position is a factor in this too of course).

The shock position, the linkage in 'linkage driven single pivot' and the rocker dimensions (on the shock side or any additional linkages - Knolly, Demo/Enduro, Sender, etc.) then define the leverage ratios. A given suspension design will have certain envelopes that you can achieve (general curves of the leverage ratio through the travel), but yeah, fine tuning shock mounting geometries defines the leverage ratio curves.
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pablo_b
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pablo_b 8/22/2021 1:05pm
8/22/2021 1:05pm
Primoz wrote:
Might be a consequence (or a necessity) because of the high pivot?
TheShortestCharles wrote:
I made some approximations of the Aurum HSP and Supreme DH in Linkage, and from what I can tell it depends more on how the linkage...
I made some approximations of the Aurum HSP and Supreme DH in Linkage, and from what I can tell it depends more on how the linkage is tuned. Just moving a few pivots around on the Norco, you can recreate the leverage curve of a Forbidden [3rd photo], so it ultimately depends on what the designers are looking for.



Pretty cool what you did there. Is there any proper Linkage tutorial online?
TheShortestCharles 8/22/2021 1:23pm
8/22/2021 1:23pm
Primoz wrote:
Might be a consequence (or a necessity) because of the high pivot?
TheShortestCharles wrote:
I made some approximations of the Aurum HSP and Supreme DH in Linkage, and from what I can tell it depends more on how the linkage...
I made some approximations of the Aurum HSP and Supreme DH in Linkage, and from what I can tell it depends more on how the linkage is tuned. Just moving a few pivots around on the Norco, you can recreate the leverage curve of a Forbidden [3rd photo], so it ultimately depends on what the designers are looking for.



pablo_b wrote:
Pretty cool what you did there. Is there any proper Linkage tutorial online?
Here's a good YouTube playlist made by Linkage/bikechecker. I still have to guess and check for a bit before getting a good sense of how to achieve certain changes in the leverage rate with any particular system (I've only had the program for a few weeks), but that has already improved with my experience.
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pablo_b
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pablo_b 8/22/2021 2:54pm
8/22/2021 2:54pm
TheShortestCharles wrote:
I made some approximations of the Aurum HSP and Supreme DH in Linkage, and from what I can tell it depends more on how the linkage...
I made some approximations of the Aurum HSP and Supreme DH in Linkage, and from what I can tell it depends more on how the linkage is tuned. Just moving a few pivots around on the Norco, you can recreate the leverage curve of a Forbidden [3rd photo], so it ultimately depends on what the designers are looking for.



pablo_b wrote:
Pretty cool what you did there. Is there any proper Linkage tutorial online?
TheShortestCharles wrote:
Here's a good [url=https://www.youtube.com/playlist?list=PLQlp0YtmKz0wMN0iU6yoS-TvlLdZ2G7Zd]YouTube playlist[/url] made by Linkage/bikechecker. I still have to guess and check for a bit before getting a good sense of how to...
Here's a good YouTube playlist made by Linkage/bikechecker. I still have to guess and check for a bit before getting a good sense of how to achieve certain changes in the leverage rate with any particular system (I've only had the program for a few weeks), but that has already improved with my experience.
thanks!
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Martin_Prophet 8/23/2021 6:51am
8/23/2021 6:51am
sspomer wrote:
a bunch of detail pics of jannick lange's crazy commencal gearbox from spicak...he placed 20th on it. (i know it's been discussed here already) https://www.vitalmtb.com/photos/features/A-Commencal-and-a-Gearbox-Walk-Into-a-Bar,13467/DIY-Commencal-Supreme-DH-with-Pinion-Gearbox,146707/sspomer,2 [img]https://p.vitalmtb.com/photos/forums/2021/08/23/11345/s1200_commencalgearA.jpg[/img]
a bunch of detail pics of jannick lange's crazy commencal gearbox from spicak...he placed 20th on it. (i know it's been discussed here already)

https://www.vitalmtb.com/photos/features/A-Commencal-and-a-Gearbox-Walk…


And this man got super POV Videos on YouTube.
The Bike is insane !!!
Snfoilhat
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Snfoilhat 8/23/2021 9:49am
8/23/2021 9:49am Edited Date/Time 8/23/2021 9:50am
Re Brayton's setup: Are the collars inboard of each grip just there to keep the grips from migrating inward?
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TayRob
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TayRob 8/23/2021 2:11pm
8/23/2021 2:11pm
Snfoilhat wrote:
Re Brayton's setup: Are the collars inboard of each grip just there to keep the grips from migrating inward?
I would imagine.
I've been running push on grips with a single inboard ODI lock ring collar for like 10 years now to do exactly that. Pair that with a bolt in style end plug and the grips go nowhere.
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LookinForIt 8/23/2021 8:24pm
8/23/2021 8:24pm Edited Date/Time 8/23/2021 8:25pm
brash wrote:
the future is gearbox?

https://www.instagram.com/p/CS6H_6KsEPu/?utm_source=ig_web_copy_link
Maybe when they finally adopt the typical style of trigger shifters. It can be done, these people did it:
https://www.instinctiv.bike/m-drivetrain/

It is also interesting how they moved the chain tensioner to the rear wheel. I like that, as all the bottom-bracket located tensioners always have me nervous. I understand that it gives you minimum unsprung weight but... Putting the tensioner on the rear wheel just makes the most sense. Happy to see it.
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Nzdinosaur 8/23/2021 9:17pm
8/23/2021 9:17pm
Oh, its just like Zerode and Rob Metz did a decade ago...
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Primoz
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Primoz 8/23/2021 9:44pm
8/23/2021 9:44pm
I have no idea who thought the gearbox mounted chain tensioner was a good idea... Having it that low and right next to the tyre as opposed to hiding it near the rear axle, where it's fairly safe (truth be told, modern derailleurs stick out far more than a tensioner would and hardly ever get knocked off in the grand scheme of things).

A trigger shifter would help (or electronic shifting for the pinion, which shouldn't be that hard to do), but I'm still reserved about what will happen with gearboxes, modern drivetrains work more than well enough and the design and manufacturing of complete bikes is set up, which would mean gearboxes would disrupt those channels a lot... Plus there's the fact it's quite a bit of a novelty for the users as well...
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mrks
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mrks 8/23/2021 10:55pm
8/23/2021 10:55pm Edited Date/Time 8/23/2021 10:57pm
Another shot of the new Top Fuel


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Sonofbovril2 8/24/2021 12:10am
8/24/2021 12:10am
sspomer wrote:
Brayton's Dissent w/ a bunch of pics of those Hope proto brakes here https://www.vitalmtb.com/photos/features/Adam-Braytons-Nukeproof-Dissent-with-Prototype-Hope-Brakes,13468/Adam-Braytons-Nukeproof-Dissent-with-Prototype-Hope-Brakes,146712/sspomer,2 [img]https://p.vitalmtb.com/photos/forums/2021/08/23/11352/s1200_20210821_EDC_Spicak_84T9114.jpg[/img]
Brayton's Dissent w/ a bunch of pics of those Hope proto brakes here
https://www.vitalmtb.com/photos/features/Adam-Braytons-Nukeproof-Dissen…


In these pics it looks like the pistons are the same size, so either the new lever is being used with the E4 caliper or maybe that is a newer caliper with both pistons the size of the larger one from the V4?
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Will_Narayan 8/24/2021 3:07am
8/24/2021 3:07am
The most interesting thing about this concept, if I got it well, is not the gearbox, it's the possibility to build the frame to rider's size on order.
If I get it right, both toptube and downtube have a constant radius curved end (seattube side) which means they could be kinda-mass produced and then cut to fit the rider's size.
The headtube is then milled to fit both tubes (so it's made of alloy ?).
mtbkluth
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mtbkluth 8/24/2021 3:44am
8/24/2021 3:44am
by the time pinion manages to come out with a trigger shifter, bikeframes wont accept cables anymore because everyone shifts electronically…
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Primoz
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Primoz 8/24/2021 4:45am
8/24/2021 4:45am
mtbkluth wrote:
by the time pinion manages to come out with a trigger shifter, bikeframes wont accept cables anymore because everyone shifts electronically…
NEVER!!
3
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derelict
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derelict 8/24/2021 5:17am
8/24/2021 5:17am
brash wrote:
the future is gearbox?

https://www.instagram.com/p/CS6H_6KsEPu/?utm_source=ig_web_copy_link
For gravity racing, the gearbox always will be the future. At least that is my opinion. Weight lower down. Less unsprung weight. The ability to run a belt (how many broken chains do we see per event ruining peoples run?). Crank to a gear in anticipation of the section where you might need it. There is not that much pedaling so gear drag is not really an issue (although I bet the pits would come up with a way to run the gearboxes in to alleviate that issue before installation).

I really, really would like to try a trail gearbox bike.
3
jonkranked
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jonkranked 8/24/2021 5:23am
8/24/2021 5:23am
sspomer wrote:
more of that...vid shows it move a few slides in
interesting concept. i'm assuming its just a 3d printed mockup. would be curious to see how much the design changes after FEA, testing, and manufacturability analysis.
nskerb
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nskerb 8/24/2021 7:01am
8/24/2021 7:01am
brash wrote:
the future is gearbox?

https://www.instagram.com/p/CS6H_6KsEPu/?utm_source=ig_web_copy_link
derelict wrote:
For gravity racing, the gearbox always will be the future. At least that is my opinion. Weight lower down. Less unsprung weight. The ability to run...
For gravity racing, the gearbox always will be the future. At least that is my opinion. Weight lower down. Less unsprung weight. The ability to run a belt (how many broken chains do we see per event ruining peoples run?). Crank to a gear in anticipation of the section where you might need it. There is not that much pedaling so gear drag is not really an issue (although I bet the pits would come up with a way to run the gearboxes in to alleviate that issue before installation).

I really, really would like to try a trail gearbox bike.
It makes sense for gravity racing i.e. short sprints. But any sustained efforts and a gearbox is basically the worst possible thing you can have. The drag those things produce is exponentially more than that of a normal chain and cog. with the current manufacturing tolerances to produce a gearbox that can match the efficiency of a chain driven dsetup would cost 5 figures.
2
mcozzy
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mcozzy 8/24/2021 7:22am
8/24/2021 7:22am
It is the future. Now merge the gearbox with an electric motor and we are there.
1
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baronKanon 8/24/2021 7:25am
8/24/2021 7:25am
mcozzy wrote:
It is the future. Now merge the gearbox with an electric motor and we are there.
That is called a motorcycle
25
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derelict
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derelict 8/24/2021 10:05am
8/24/2021 10:05am
nskerb wrote:
It makes sense for gravity racing i.e. short sprints. But any sustained efforts and a gearbox is basically the worst possible thing you can have. The...
It makes sense for gravity racing i.e. short sprints. But any sustained efforts and a gearbox is basically the worst possible thing you can have. The drag those things produce is exponentially more than that of a normal chain and cog. with the current manufacturing tolerances to produce a gearbox that can match the efficiency of a chain driven dsetup would cost 5 figures.
No doubt there will be some drag. I have read that the gears seat in and the drag becomes less noticeable. I have rebuilt a few car transmissions before. The gears and synchros are always very tight and sharp at first but then wear, while still remaining within tolerance, and turn a bit easier.
1
Primoz
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Primoz 8/24/2021 12:42pm
8/24/2021 12:42pm
mcozzy wrote:
It is the future. Now merge the gearbox with an electric motor and we are there.
I can't imagine why Pinion is selling their e-bike strategy with an in-wheel motor. Apparently they are very commuter oriented. For e-MTBs it would make so much sense, but... no, apparently.
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