Not to beat a dead horse in the wrong forum but...
Pull shocks are superior. Here's why.
Imagine that your shock absorber is a piece of rope. If you try to compress it like a "standard" shock, it wants to deform to the side, not compress. So in a "standard" frame one has to design in extra stiffness into the frame to keep the shock compressing in a straight line. More stress on the frame, seals and mounting bushings.
Now imagine that your piece of rope is a pull shock. The harder you actuate the shock, the more it just wants to be straighter. Frames can be made lighter because they don't have to take care of keeping the shock in line and there's less friction and thus wear on the seals and bushings.
Back in the days of the LOBO and the Lawill Schwinns, I don't recall Rock Shox having any issues with the shocks. Our shop never had to send back a blown one that I recall. Before enduro blew up, a friend at Rock Shox said they were working on a new generation of pull shocks, but that project was sidelined by more enduro products. Now a little bird says that the new pull shock might just be on the way.
Now to dust off that old, pre enduro, full size frame drawing of a high pivot pull shock DH bike and redraw it to fit 29" wheels. Bring 'em on Rock Shox!
While there is a point in the rope analogy I can't help but think that if pull shocks are so vastly superior, why aren't they used in racing? Both motorcycle and car racing.
The present Commencal DH Supreme uses a pull linkage arrangement.
Pull linkage good, pull shock I’m undecided as yet, but it is my belief because of limited usage the forward development of the technology will be limited & not embraced by the masses.
Actually it would only make sense for your post to be true.
Though Dave probably does not post on this forum in an official role, any public communications about future products from a company should be deny deny deny, at least on the record. It's off the record where rumors start.
It doesn't mean Big Bird's statement is true (and that Dave is only covering it), but regardless if RS is in fact making a pull shock or not, this is exactly the scenario of how rumors about (a real) one would start and become more public.
qblambda if you're making that silhouette any more detailed, the bottom link (there should be one connected to the vertical one) should be quite long for the shock to have full stroke.
Developing a complete pull shock chassis for a single frame is a big project for little return in sales. I'm impressed Fox and Cannondale made it happen (DYAD).
We are not working on pull shocks. Imagine how stoked everyone would be if there was a pull shock 'standard'. haha
Actually it would only make sense for your post to be true.
Though Dave probably does not post on this forum in an official role, any...
Actually it would only make sense for your post to be true.
Though Dave probably does not post on this forum in an official role, any public communications about future products from a company should be deny deny deny, at least on the record. It's off the record where rumors start.
It doesn't mean Big Bird's statement is true (and that Dave is only covering it), but regardless if RS is in fact making a pull shock or not, this is exactly the scenario of how rumors about (a real) one would start and become more public.
qblambda if you're making that silhouette any more detailed, the bottom link (there should be one connected to the vertical one) should be quite long for the shock to have full stroke.
ha. pretty sure dave would not have come on here to deny pull shock development if rockshox was actually doing pull shock development. completely different than "deny deny deny" if he was directly asked. i'll take dave's word over conspiracy theory
I can definitely see your point and agree with it.
Though regarding the Cannondale thing, it's not all that uncommon. Granted, the last two generations of Scott's Genius bikes (and all Sparks as well) has used relatively unchanged shock in the grand shceme of things, but they were nevertheless custom. Then you have the pullshocks of the previous two generations of Genius frames. And the wholly custom (but still squish) shock for the Ransom (the Equalizer). Then the current custom Fox shocks for Cannondale, the custom Trek shocks (both the Reactive valving and the current through shaft designs). And let's not forget about Specialized
(And yes, i know there's a ton more of these cases left.)
Olivier Bossard made an interesting comment about how these days nobody develops a complete rolling chassis platform, like they did in the Nico times with Sunn. But i guess there just isn't enough money to do it solely for racing and you can't sell completely custom stuff to the masses, at least because of servicing reasons.
Few minutes of Photoshop later...
[img]https://p.vitalmtb.com/photos/forums/2018/05/23/6338/s1200_newdemo3.jpg[/img]
Few minutes of Photoshop later...
I'm thinking the upper link goes through the seat tube and compresses the shock from the front. The rear end of the shock is attached to the chainstays. It's not a dual short link system, but a Horst Link with the chainstays/main pivot possibly on the bb.
What is the point of the vertical piece then? Plus if you look closely at the photo, you can see the vertical link gets thicker or bigger towards the bottom, where the shock eyelet is. There is no such thing on the chainstay visible.
Plus that having a link on the chainstay on such an angle would put immense stresses on the chainstay (with it being just a link between two pivots, it's in fact mainly a 'pull link' only, plus the torsional stresses - having the shock mounted to it would cause severe bending stresses, making the part heavier to carry to loads).
And given the top link and shock orientation, the top link would have to be bent upwards quite a lot to get the ETE of the shock in. That would mean the shock would be mounted in both ends (by the chainstay and by the rocker) at very shallow angles, which is never a good thing for force transfers (you would be having massive axial forces in all links when squishing the shock).
It's possible of course, it just doesn't make sense.
I'm thinking the upper link goes through the seat tube and compresses the shock from the front. The rear end of the shock is attached to...
I'm thinking the upper link goes through the seat tube and compresses the shock from the front. The rear end of the shock is attached to the chainstays. It's not a dual short link system, but a Horst Link with the chainstays/main pivot possibly on the bb.
I was wondering the same, like a bigger rocker linkage til I noticed the front shock mount is actually attached on the downtube. You can see it bulky there, looking like the previous generation of Demo.
And like Primoz said, that vertical link would have no sense then. Some pivots might be hidden around the bottom bracket...
Sorry, I ditched my photoshop talents for that one. It might be that way
[img]https://p.vitalmtb.com/photos/forums/2018/05/23/6341/s1200_IMG_20180524_084636.jpg[/img]
Sorry, I ditched my photoshop talents for that one. It might be that way
Yup, you're right guys. Having two links scissoring the shock forward (one running from the seatstays/upper link to the shock, another from the shock to the BB area) when the wheel moves upwards makes sense. I didn't notice the forward shock mount until you mentioned it.
Saw that Isak was running a prototype of that on his Pole endurobike in Nesbyen a couple of weeks back. Didn't have time to take a photo of the bike as it hang on the shuttle rack, but the stem-combo basically consisted of a metal block right on the top of the steerer tube, with holes drilled for a DM-stem a bit _behind_ the centre of the steerer tube. Basically like putting a stem on backwards.
The stiffness + alignment "issue" in normal compression shocks is actually because of bad fundamental engineering, for example, the 2010-2014 Demo breaking CCDB's shafts. It is not an advantage for pull shocks but rather an excuse to call compression shocks "bad" or "flawed". This "issue" is very easily and cheaply solved by using ball joints (spherical bearings) instead of bushings/bearings. Everyone in road racing uses ball joints, it is just that for some reason mountain bikes have gone the other way.
Well you have the Pivot Phoenix that requires an air shock due to a larger shaft size to provide additional stiffness in the frame. That and the in-plane nature of mountain bike suspension (in principle) compared to a much more 3D geometry of practically any car suspension design. That's why they need ball joints and mountain bikes possibly don't need them.
EDIT: every WP suspension shock on their site uses bushings, not ball joints. Plus a ball joint will not prevent side loads in shocks, they will still require thicker shafts, more bushing overlap and the like to work properly. With normal bushings and with a stiff enough frame design, you could actually prevent binding in a shock since each eyelet would hold it in line instead of the shock buckling. But that last part is more theory than practice i suppose
[img]https://p.vitalmtb.com/photos/forums/2018/05/26/6343/s1200_99451F2E_ABB2_4AFA_B66D_B9E6AC447B13.jpg[/img]
New V10 front end with lower stand over? Might also explain why they were all on last years frames at Losinj.
New V10 front end with lower stand over? Might also explain why they were all on last years frames at Losinj.
I sure hope so! It will allow shorter people to size up in frame! Now they just have to add some rear tire clearance and come out with an aluminium version and I might consider getting one
Pull shocks are superior. Here's why.
Imagine that your shock absorber is a piece of rope. If you try to compress it like a "standard" shock, it wants to deform to the side, not compress. So in a "standard" frame one has to design in extra stiffness into the frame to keep the shock compressing in a straight line. More stress on the frame, seals and mounting bushings.
Now imagine that your piece of rope is a pull shock. The harder you actuate the shock, the more it just wants to be straighter. Frames can be made lighter because they don't have to take care of keeping the shock in line and there's less friction and thus wear on the seals and bushings.
Back in the days of the LOBO and the Lawill Schwinns, I don't recall Rock Shox having any issues with the shocks. Our shop never had to send back a blown one that I recall. Before enduro blew up, a friend at Rock Shox said they were working on a new generation of pull shocks, but that project was sidelined by more enduro products. Now a little bird says that the new pull shock might just be on the way.
Now to dust off that old, pre enduro, full size frame drawing of a high pivot pull shock DH bike and redraw it to fit 29" wheels. Bring 'em on Rock Shox!
Pull linkage good, pull shock I’m undecided as yet, but it is my belief because of limited usage the forward development of the technology will be limited & not embraced by the masses.
Though Dave probably does not post on this forum in an official role, any public communications about future products from a company should be deny deny deny, at least on the record. It's off the record where rumors start.
It doesn't mean Big Bird's statement is true (and that Dave is only covering it), but regardless if RS is in fact making a pull shock or not, this is exactly the scenario of how rumors about (a real) one would start and become more public.
qblambda if you're making that silhouette any more detailed, the bottom link (there should be one connected to the vertical one) should be quite long for the shock to have full stroke.
We are not working on pull shocks. Imagine how stoked everyone would be if there was a pull shock 'standard'. haha
Though regarding the Cannondale thing, it's not all that uncommon. Granted, the last two generations of Scott's Genius bikes (and all Sparks as well) has used relatively unchanged shock in the grand shceme of things, but they were nevertheless custom. Then you have the pullshocks of the previous two generations of Genius frames. And the wholly custom (but still squish) shock for the Ransom (the Equalizer). Then the current custom Fox shocks for Cannondale, the custom Trek shocks (both the Reactive valving and the current through shaft designs). And let's not forget about Specialized (And yes, i know there's a ton more of these cases left.)
Olivier Bossard made an interesting comment about how these days nobody develops a complete rolling chassis platform, like they did in the Nico times with Sunn. But i guess there just isn't enough money to do it solely for racing and you can't sell completely custom stuff to the masses, at least because of servicing reasons.
Noah Sears
MRP (Mountain Racing Pullshocks)
Plus that having a link on the chainstay on such an angle would put immense stresses on the chainstay (with it being just a link between two pivots, it's in fact mainly a 'pull link' only, plus the torsional stresses - having the shock mounted to it would cause severe bending stresses, making the part heavier to carry to loads).
And given the top link and shock orientation, the top link would have to be bent upwards quite a lot to get the ETE of the shock in. That would mean the shock would be mounted in both ends (by the chainstay and by the rocker) at very shallow angles, which is never a good thing for force transfers (you would be having massive axial forces in all links when squishing the shock).
It's possible of course, it just doesn't make sense.
And like Primoz said, that vertical link would have no sense then. Some pivots might be hidden around the bottom bracket...
I dont mind the bike, its actually pretty nice but that bar stem setup... no thanks!
With a regular stem setup its a seriously good looking bike!
Saw that Isak was running a prototype of that on his Pole endurobike in Nesbyen a couple of weeks back. Didn't have time to take a photo of the bike as it hang on the shuttle rack, but the stem-combo basically consisted of a metal block right on the top of the steerer tube, with holes drilled for a DM-stem a bit _behind_ the centre of the steerer tube. Basically like putting a stem on backwards.
The stiffness + alignment "issue" in normal compression shocks is actually because of bad fundamental engineering, for example, the 2010-2014 Demo breaking CCDB's shafts. It is not an advantage for pull shocks but rather an excuse to call compression shocks "bad" or "flawed". This "issue" is very easily and cheaply solved by using ball joints (spherical bearings) instead of bushings/bearings. Everyone in road racing uses ball joints, it is just that for some reason mountain bikes have gone the other way.
EDIT: every WP suspension shock on their site uses bushings, not ball joints. Plus a ball joint will not prevent side loads in shocks, they will still require thicker shafts, more bushing overlap and the like to work properly. With normal bushings and with a stiff enough frame design, you could actually prevent binding in a shock since each eyelet would hold it in line instead of the shock buckling. But that last part is more theory than practice i suppose
New V10 front end with lower stand over? Might also explain why they were all on last years frames at Losinj.
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