Okay, based on a pretty close approximation (distortion in the photos makes it a real pain to get accurately) here's what I can tell:
- Very progressive leverage rate; more similar to the Aurum HSP than the Range, so the rate of progression increases through the whole travel, but more progressive than Aurum before the sag point (people tended to sag very deep into the Aurum to make the most of the extremely progressive end-stroke because of the high-leverage, linear beginning of the stroke, so this might help a little but it is still probably somewhere between 35-40% progressive). **edited, probably closer to 25-30%, which is more reasonable for sure** It's definitely more suited to a coil shock.
- Low anti-squat (at whatever the sag range is, you're getting anti-squat range of <50% to <-100%) because of the very large idler concentric to the upper pivot. This also gives completely negative pedal kick-back in all gears, but this might make it a pain in the ass to pump (despite the progressive mid-stroke).
- Anti-rise follows the general shape of the leverage rate, with an increasingly steep decline from ~130% to ~10% through the travel, and somewhere around 100% at sag.
I think you can basically make no assumptions about what the kinematics look like. Similar to most 6 bar bike there is a lot of flexibility and sensitivity to the arrangement.
I would guess they want more control over packaging compared to a Range layout (where you are heavily constrained by the linkarm concentric to the BB ). The trade off is more links but it gives you a huge amount of control over leverage with only small changes to the links. Pretty nice for a factory team doing lots of development work.
Looks like a nice large 22 tooth idler as well which is always an improvement over the tiny idlers that are used so much on HP Horst link bikes. Here is a ballpark just to show the links overlayed; I am sure the team is bumping leverage or dropping progression a bit to get a little more travel.
I think you can basically make no assumptions about what the kinematics look like. Similar to most 6 bar bike there is a lot of flexibility...
I think you can basically make no assumptions about what the kinematics look like. Similar to most 6 bar bike there is a lot of flexibility and sensitivity to the arrangement.
I would guess they want more control over packaging compared to a Range layout (where you are heavily constrained by the linkarm concentric to the BB ). The trade off is more links but it gives you a huge amount of control over leverage with only small changes to the links. Pretty nice for a factory team doing lots of development work.
Looks like a nice large 22 tooth idler as well which is always an improvement over the tiny idlers that are used so much on HP Horst link bikes. Here is a ballpark just to show the links overlayed; I am sure the team is bumping leverage or dropping progression a bit to get a little more travel.
What program is this? I like that you can see the photo while editing the linkage, unlike Linkage X3
Those bearings in the shock links are gonna yearn for better days...
It'd be interesting to measure the effective spring rate at the rear axle with a design like this. I wonder if it would be a noticeable difference due to added friction (high link forces, oblique angles, etc.). Sure, ball bearings have fairly low friction values, but a combination of high forces and high leverage ratios might make it noticeable.
it is my educated opinion, after looking at the photos, overlaying in linkage, assessing & comparing the kinematics with my extensive catalogue of images of Sam Hill, numerous CAD reverse engineering and plugging the outputs into my google supercomputer I have come to the conclusion that BIKE LOOKS FUCKIN SICK!
working on a g-out project from national champs (full gallery up later), but these two photos caught my eye w/ the chain slacked out between the idler and the front chainring. is that common? i don't feel like i've noticed that before. it's such a short gap to see significant slack like that. i guess i shouldn't be surprised considering the abuse DH bikes get put through.
working on a g-out project from national champs (full gallery up later), but these two photos caught my eye w/ the chain slacked out between the...
working on a g-out project from national champs (full gallery up later), but these two photos caught my eye w/ the chain slacked out between the idler and the front chainring. is that common? i don't feel like i've noticed that before. it's such a short gap to see significant slack like that. i guess i shouldn't be surprised considering the abuse DH bikes get put through.
Most idler-equipped bikes have either negative or next to zero upper chain growth (it depends on the idler placement/configuration but most bikes on the market follow the same trend), so it isn't under tension in a compression absent other factors. We obviously know chain slap still happens on 'normal' bikes that do have upper chain growth, so I'd imagine that's amplified without any.
working on a g-out project from national champs (full gallery up later), but these two photos caught my eye w/ the chain slacked out between the...
working on a g-out project from national champs (full gallery up later), but these two photos caught my eye w/ the chain slacked out between the idler and the front chainring. is that common? i don't feel like i've noticed that before. it's such a short gap to see significant slack like that. i guess i shouldn't be surprised considering the abuse DH bikes get put through.
I think its pretty common, and why tooth profile and some kind of small guide is crucial for them. I'm not sure how many people are aware of it though, when you consider how many HP bikes come out without a good enough idler design and they have to modify it later.
The old Corsair bikes were shockers - they took several iterations to dial in their idlers, they even had a dual chainring set up which was a disaster - the chain would jump out of the sprocket and jam inside the tunnel which was terrifying if you went to pedal out of a corner and it had just locked up!
working on a g-out project from national champs (full gallery up later), but these two photos caught my eye w/ the chain slacked out between the...
working on a g-out project from national champs (full gallery up later), but these two photos caught my eye w/ the chain slacked out between the idler and the front chainring. is that common? i don't feel like i've noticed that before. it's such a short gap to see significant slack like that. i guess i shouldn't be surprised considering the abuse DH bikes get put through.
Chainring isn’t rotating, but the slack and whip in the chain between the cassette and idler would rotate the idler forward and create the slack between it and the chainring.
It has happened to me a couple of times on my Forbidden dreadnought, mostly on bike park days with bigger compressions or impact. The chain even got loose enough one time to almost derail from the top guide and made a sweet gouge on my swingarm. It is less bad now that I've switched to a new chain and the stainless idler (compared to the original narrow-wide idler). The chain seems to be really "active" on this part of the bike (in between idler and chainring)
It has happened to me a couple of times on my Forbidden dreadnought, mostly on bike park days with bigger compressions or impact. The chain even...
It has happened to me a couple of times on my Forbidden dreadnought, mostly on bike park days with bigger compressions or impact. The chain even got loose enough one time to almost derail from the top guide and made a sweet gouge on my swingarm. It is less bad now that I've switched to a new chain and the stainless idler (compared to the original narrow-wide idler). The chain seems to be really "active" on this part of the bike (in between idler and chainring)
Have never had a problem with it on my GT Force. Ran a mrp g5 SL as a lower for a season and now have the MXG (would highly recommend for any high pivot bike, almost no additional drag compared to not running one and haven’t dropped a chain once). Only time i dropped chains with it was before I had any kind of lower guide and it would pop off under high torque pedaling.
Sspomer - the chain goes slack on those bikes because the idler is not concentric to the main pivot, or the rear end uses a layout that is conducive to chain growth (FSR. etc)
Concentric to the pivot, single pivot design, no chain growth
Most of the idler bikes these days have moved the idler away (below) the main pivot modifying the antisquat to add pedal-ability, but have invited chain growth back to the party
They use different chainstays that allow to mount the idler in two different positions. The O-chain makes sense to reduce the feeling of the chain tugging on the pedals (the photos from the US champs clearly shows how much the chain bounces around between the idler and the chainring.
On Pirelli tires: the tires must not suck given riders had good results on them like Revelli's 6th place at MSA last year. However, I don't see how sponsoring a team like Trek can not backfire when their riders will use tires from different manufactures. Regular riders and fans won't even know they are sponsored by Pirelli, and those who actually "care" (like we vitards) will know they use different tires. It's great publicity for Maxxis and Bontrager (I think Bodi Kuhn uses Bontragers) but it's bad for Pirelli. Maybe there is indeed no such thing as bad publicity?
Norco DH bike was revealed on their homepage this morning. Full set of studio photos there.
Glad I saw this right before I was about to pixel-peep the video from the factory team.
here ya go
https://www.norco.com/
and a bit more
https://www.norco.com/now/bike-checks/new-norco-downhill-sled/
I bet this thing eats chunk for breakfast, lunch and dinner!
More fire to fuel the hate for Intense
Okay, based on a pretty close approximation (distortion in the photos makes it a real pain to get accurately) here's what I can tell:
- Very progressive leverage rate; more similar to the Aurum HSP than the Range, so the rate of progression increases through the whole travel, but more progressive than Aurum before the sag point (people tended to sag very deep into the Aurum to make the most of the extremely progressive end-stroke because of the high-leverage, linear beginning of the stroke, so this might help a little but it is still probably somewhere between 35-40% progressive). **edited, probably closer to 25-30%, which is more reasonable for sure** It's definitely more suited to a coil shock.
- Low anti-squat (at whatever the sag range is, you're getting anti-squat range of <50% to <-100%) because of the very large idler concentric to the upper pivot. This also gives completely negative pedal kick-back in all gears, but this might make it a pain in the ass to pump (despite the progressive mid-stroke).
- Anti-rise follows the general shape of the leverage rate, with an increasingly steep decline from ~130% to ~10% through the travel, and somewhere around 100% at sag.
I think you can basically make no assumptions about what the kinematics look like. Similar to most 6 bar bike there is a lot of flexibility and sensitivity to the arrangement.
I would guess they want more control over packaging compared to a Range layout (where you are heavily constrained by the linkarm concentric to the BB ). The trade off is more links but it gives you a huge amount of control over leverage with only small changes to the links. Pretty nice for a factory team doing lots of development work.
Looks like a nice large 22 tooth idler as well which is always an improvement over the tiny idlers that are used so much on HP Horst link bikes. Here is a ballpark just to show the links overlayed; I am sure the team is bumping leverage or dropping progression a bit to get a little more travel.
When I see bikes like that (and the new Pivot, Demo, intense etc.) it makes me appreciate what Neko is doing with Frameworks even more.
What program is this? I like that you can see the photo while editing the linkage, unlike Linkage X3
It's called syn (syn.bike), made (presumably) by @synDev! Not sure what you mean about being unable to see the photo in Linkage, though:
Those bearings in the shock links are gonna yearn for better days...
It'd be interesting to measure the effective spring rate at the rear axle with a design like this. I wonder if it would be a noticeable difference due to added friction (high link forces, oblique angles, etc.). Sure, ball bearings have fairly low friction values, but a combination of high forces and high leverage ratios might make it noticeable.
Rock Shox new product launch Thursday, July 20th at 10am EST.
it is my educated opinion, after looking at the photos, overlaying in linkage, assessing & comparing the kinematics with my extensive catalogue of images of Sam Hill, numerous CAD reverse engineering and plugging the outputs into my google supercomputer I have come to the conclusion that BIKE LOOKS FUCKIN SICK!
Oops, guess I haven't found that feature yet. Syn is pretty cool though!
100%. Nothing will ever convince me to buy anything other than std linkage SP or DW variant etc
Hate?
working on a g-out project from national champs (full gallery up later), but these two photos caught my eye w/ the chain slacked out between the idler and the front chainring. is that common? i don't feel like i've noticed that before. it's such a short gap to see significant slack like that. i guess i shouldn't be surprised considering the abuse DH bikes get put through.
Most idler-equipped bikes have either negative or next to zero upper chain growth (it depends on the idler placement/configuration but most bikes on the market follow the same trend), so it isn't under tension in a compression absent other factors. We obviously know chain slap still happens on 'normal' bikes that do have upper chain growth, so I'd imagine that's amplified without any.
Those are very different suspension design philosophies,
why is that?
full g-out gallery is up
https://www.vitalmtb.com/g-out-project-u-s-mtb-national-championships-dh
I think its pretty common, and why tooth profile and some kind of small guide is crucial for them. I'm not sure how many people are aware of it though, when you consider how many HP bikes come out without a good enough idler design and they have to modify it later.
The old Corsair bikes were shockers - they took several iterations to dial in their idlers, they even had a dual chainring set up which was a disaster - the chain would jump out of the sprocket and jam inside the tunnel which was terrifying if you went to pedal out of a corner and it had just locked up!
Would have been great if there was a pic of the Vitus prototype smashed to its maximum in these photos… 😁
Chainring isn’t rotating, but the slack and whip in the chain between the cassette and idler would rotate the idler forward and create the slack between it and the chainring.
The Vitus prototype is currently on the other side of the Atlantic!
It has happened to me a couple of times on my Forbidden dreadnought, mostly on bike park days with bigger compressions or impact. The chain even got loose enough one time to almost derail from the top guide and made a sweet gouge on my swingarm. It is less bad now that I've switched to a new chain and the stainless idler (compared to the original narrow-wide idler). The chain seems to be really "active" on this part of the bike (in between idler and chainring)
Have never had a problem with it on my GT Force. Ran a mrp g5 SL as a lower for a season and now have the MXG (would highly recommend for any high pivot bike, almost no additional drag compared to not running one and haven’t dropped a chain once). Only time i dropped chains with it was before I had any kind of lower guide and it would pop off under high torque pedaling.
Sspomer - the chain goes slack on those bikes because the idler is not concentric to the main pivot, or the rear end uses a layout that is conducive to chain growth (FSR. etc)
Concentric to the pivot, single pivot design, no chain growth
Most of the idler bikes these days have moved the idler away (below) the main pivot modifying the antisquat to add pedal-ability, but have invited chain growth back to the party
From the other site: Interesting to see the modified idler position with an o-chain. Also nice “pirelli” rubber on there.
They use different chainstays that allow to mount the idler in two different positions. The O-chain makes sense to reduce the feeling of the chain tugging on the pedals (the photos from the US champs clearly shows how much the chain bounces around between the idler and the chainring.
On Pirelli tires: the tires must not suck given riders had good results on them like Revelli's 6th place at MSA last year. However, I don't see how sponsoring a team like Trek can not backfire when their riders will use tires from different manufactures. Regular riders and fans won't even know they are sponsored by Pirelli, and those who actually "care" (like we vitards) will know they use different tires. It's great publicity for Maxxis and Bontrager (I think Bodi Kuhn uses Bontragers) but it's bad for Pirelli. Maybe there is indeed no such thing as bad publicity?