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If you have too much AS then you'll lift yourself up in the travel with every pedal stroke and have bob but in reverse and it's just as inefficient as not having enough. Ridden a couple of bikes that do that.
Tends to be longer travel bikes with AS that falls a lot through the stroke - horst link, KS link (banshee). To get the AS they want in the midstroke so it doesn't wallow on the climbs, it's too high at the top of travel and bobs on the flat. It could be one reason why SC seems to be sticking with VPP for longer travel and moving to horst for shorter travel.
Being able to have a solid ~120-130% AS through the entire travel without high levels of associated kickback is one reason why I actually quite like true high pivot trail bikes for climbing, even though the drivetrain isn't as efficient. The bike can be extremely responsive and stiff under the pedals, but the wheel still glides its way over anything, and you gain some "efficiency" back because you don't have to put as much body-english into managing your grip or preventing stalls.
edit: sorry Mr Suslab, restated your point because I hadn't refreshed my page.
Following two experts is a bit intimidating, but as far as the Tallboy, the curves match a lot of other pedal-focused bikes and I think may be the current consensus on the kinematics for that genre I've always understood that the lower anti-squat pairs with the lower starting leverage ratio, and the lower leverage ratio is the first domino in that chain. Because leverage is lower, you don't need as much anti-squat. Then you rely on the lower volume air shock to ramp up to prevent bottom out. I don't know enough to have a truly informed opinion on whether this is actually "better" for a bike like the Tallboy. Obviously this doesn't apply for the Nomad.
What does seem a bit strange to me is that they shifted the kinematics of the Tallboy in a very XC direction while also upping the travel and biasing the geometry more towards descending. The travel probably has a lot do with travel numbers on the Blur and Hightower. Regardless, I think I may be into it. I'm interested in adding a more XC bike to my fleet, but don't want to be in an XC position on the bike. With the stack on the Tallboy, seems like you could set up the suspension on the firm side, build the frame up light-ish, and get the bike I'm interested in.
Lower anti-squat pairs best with a more progressive bike due to the increase in mid-stroke support. If there's more support when you're bobbing, you don't bob as much so less anti-squat is fine. The actual leverage ratio number isn't hugely important so long as the shock is tuned properly for it and the rider is able to get settings within an reasonable range. The previous rendition of the Tallboy didn't have crazy high anti-squat and the new version doesn't have crazy low anti-squat so to me it's just a different spin on how you prioritize pedaling. In my mind it's more in line with the model of predominantly pedaling while seated. I believe you need slightly higher anti-squat if pedaling standing is a priority since it's harder to be smooth in that scenario.
I too find it interesting that the kinematics went in a XC direction while other aspects of it went the other way. Although you could say the braking behavior of a Horst link bike is more suited to lower angle terrain so that's a little more XC as well.
Just wanted to express my gratitude for everything shared in here. It has been insanely huge for helping me learn along the way.
Lol yeah I do the same thing - I'll have a page open all day and write a reply after its moved on several posts or pages!
And yeah the Banshee bikes had a really strong pedalling reaction like that - so did a lot of Mondrakers. They might have changed things recently but that was definitely the trend for a while. I remember when the MS team first switched to the Summum I found it was a super fine line where a 325 spring was plush and pedalled well, and a 350 was better suited for big bumps and speed but bounced wildly on the pedals
@Shinook copying this over to here so as to not continue blowing up tech rumors...
What I read into this is it's a case of stiff compression tune being used to provide the necessary bottom out resistance. Tires can be quite effective when it comes to ironing out the really little stuff. Square edge hits require a high shaft speed for the wheel to clear with minimal disruption to the chassis. The shock has no way of discerning between high shaft speed because of a drop or similar and high shaft speed because of a square edge. So the stiff damping tune that prevents bottoming also causes it to kick/hang up on square edges more.
A bunch of comparisons mainly looking at wheel force because that's what you really feel not the leverage curve.
160 mm bikes with different progression amounts normalized for identical sag at the wheel. Including -4%. The wheel force plot is purely looking at wheel force due to the spring. As you can see, there is a very significant difference at bottom of travel. If you were to zoom in on the sag point, you can easily see that a more progressive bike has a lower force at all points before the sag point and a higher force at all points after the sag point compared to a less progressive bike.
Wheel damping is the other interesting one. This plot just compares how the leverage curve influences damping force as felt at the wheel. Keep in mind these curves can all be more or less adjusted up and down with damping tune. It's set so that it would be comparing the same tune with the adjusters in the same place. To me the cool thing with a more progressive leverage curve is that you get a ramp in the damping force as you feel it at the wheel. You could argue that, because of this, a bypass shock wouldn't be useful as you already experience different damping responses at different points in travel. I'm not really sure why anyone would want the damping tune to feel softer as you get deeper in travel.
There was another comment about progression vs travel in the other thread. Same comparison as above but with identical progression and different travel and shock sizes. I don't really see a reason you'd want to pick progression numbers so that the derivatives of each of these curves would be identical. The shorter travel bike is already giving up a ton of bottom out resistance. I know a shorter travel bike shouldn't be ridden like a downhill bike, but there are still a lot of fun things to do on 140 mm bikes that requires significant bottom out resistance.
The damping plot. You really don't need a longer travel bike to feel as stiff so you could maybe say using the same damping tune one these different setups makes sense.
I conceptually knew that high progression changed damping but its cool seeing an example of it.
Related to bottom out, do you have any sense (either in % of wheel force or a rough number) that most HBO shock systems exhibit?
Is this value greater or less than foam bottom out bumpers? I'm guessing the answer is, it depends. I'm aware of the tradeoffs of bumpers (namely they increase rebound speed.
HBO can exert anywhere between way less and way more force than a rubber bumper since it’s dependent on the speed of compression. And then, like you said, it doesn’t increase rebound speed compared to a rubber bumper. The one argument you could maybe make for rubber bumpers is that there are some scenarios, like a long sweeping berm, where having additional support from the shock that isn’t speed dependent is beneficial. If shaft speed is near zero then HBO offers very little additional support so you’d continue to settle into travel. That would actually be a bigger deal on a more linear bike since they tend to blow through travel in berms more.
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