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Mtbman99 what do you gain compared to cable actuated remote lockouts (except at least one battery that you have to charge...)? And what do you gain compared to normal levers on longer travel bikes where you flip the switches less often than in xc?
https://www.incycle.com/products/specialized-stumpjumper-evo-alloy-frm?…
The new Zeb air piston is a spit for Vorsprung's Luftkappe. New pistons for the Lyrik and Pike too.
Edit, nope just realised the air shaft is threaded internally on these vs externally on the previous/current gen air springs
-Looks like the buttercups are a similar size to the C1 footnut so highly likely they'll be retrofittable to C1 air springs-
same bike, with fox 36 vs serviced lyrik and the lyrik sits down in the front and when i measured front end height was as expected - lower. Up the travel 10mm and it sits where it should, i got a DVO to make sure i wasnt losing my mind and it to was sitting higher than the lyrik - this is quite noticable out on the trail an annoys the cr@p out of me
I realise they updated the air springs and i bought 2 air springs for my older ones and my new 2021 already had it...
but why is this?
There is no sag on the new spring (tried and tested). The old spring, while suppler, had a too wrong ratio between the negative and positive chambers and the pressure in the negative chamber got too high at zero travel, so the fork was pulled into the travel a bit.
Any one of these points will about make up (or more than make up) for the weight of the buttercups. If you're shaving grams so far, that you're worried about the buttercups, remove the paint from the lowers or go for the Pike instead of the Lyrik. Or the Sid instead of the Pike.
Those buttercups are, weight wise, a non-issue. They are not zero weight or a net negative, but are also not an issue.
Zeb 150-190
Lyrik 140-160
Pike 120-140
And I not counting grams, only where it matters so unsprung and/or rotational mass. As for thin casings, going anything flimsier than a Lyrik/36 isn't an option for me, it is also pretty fallacious to come up with such arguments when unsprung mass benefit is well documented. Should MX or DH riders put some Sids on their bikes then ? Obviously reduction of unsprung mass is only secondary to rigidity, lack of binding and so on.
Now let's discuss the pros and cons of this buttercup. Those are basically a secondary spring using some oldschool urethan kinda spring. What does it do ? Well since it is a mechanical spring it has low breakaway force, this is basically a bandaid for the poor sensitivity of air springs. Because it is a mechanical spring it is not adjustable so it the rubber puck in there is designed for a rider of 70kg, most likely ligther riders will not benefit from it due to its stiffness and heavy rider will probably neither because they will always be at the bottom of it. So to be really useful you would need different rubber pucks to accommodate rider weight. And you would need to open your lowers to do so. So that let us with:
- low brake away force like a spring
- end of stroke ramp up thanks to air spring
- added complexity so more stuff to give troubles
- adequate for a narrow range of rider weight
- added unsprung mass
Now I now it may sound crazy but to get this low brake away force, company could use this ground brake technology called coil ! It would be interesting to know the added weight of those buttercups and compare it to a Ti spring for instance. Considering that manufacturing of stanchions wouldn't have to be a neat as for air, less precise parts to machine since they don't have to be air tight and less parts all together since no valve, no buttercup and such it might even be cheaper. Rockshox cheap 35 use springs, not air for instance. And since you would need to have the appropriate buttercup insert for your weight for these to make any sense, the fact that you would need to get the right spring isn't a valid argument really.
I do agree with you though that in both cases, small coil or buttercup, it will have to be targeted at a specific rider weight zone that will not provide equal performance across the full rider weight spectrum.
You can easily provide some kind of preload to the system but as we know, that is not the ideal way to increase the spring rate for best performance.
I know this sounds facetious (I do see the irony and 'poking' in what I wrote, which was part of the reason for writing it, but I am also very serious, as it is true), so to maybe go through the longer of your posts:
-the weight penalty of the buttercups will be... 5 grams per side? Maybe 10? If you can feel unsprung weight difference in grams:
+I really hope you cover your fork lowers, caliper, wheelset and tyre (tread included) with silicone spray to prevent ANY dirt from sticking to any part of the unsprung mass
+I hope your local bike shop is not sick of you weighing tyres before buying them (as there is quite a bit of variation within the same model, as in two tyres of the same model, rubber and casing have different weights)
+I'm really interested in which of the rear suspension layouts you run
+do you run specified oil values in the lowers or do you use less oil? How liberal are you with grease application when servicing the fork?
-the intention of the buttercups is to dampen higher frequency vibrations (chatter). As mentioned in the PR stuff, this is a normal thing to do with road cars - everything in the suspension is mounted using rubber bushings (suspension arms and the tops of shock absorbers/springs) to lower NVH (noise/vibration/harshness). There are very few cars on the road that are 'solid mounted', meaning they don't have any (or very little) rubber (or any other flexible material) in the joints. This improves responsiveness and gives a sharper feeling, but also gives a lot of noise, chatter and the like. There's a reason so few cars do this, as they are mostly trackday specials - think GT cars (Cayman GT4, 911 GT3, GT3 RS, GT2, etc.): https://www.youtube.com/watch?v=L9-Sr8RPty4
The relevant bit is at 9:47 (he says ball bearings, but I'm fairly sure rosejoints/rod end bearings/spherical bearings were meant).
-The buttercups are likely VERY stiff. Look at the spring side one, it's a cone. That means an even more progressive force-stroke characteristic, than on the damper side. And even that is a thick puck of rubber, which will be, compressed the way it's mounted, fairly stiff. Depending on the durometer of course, but if they want any reasonable durability, this stuff will be hard (therefore the 'likely very' at the beginning of this point). That way the weight will not be much of an issue. Plus, different weights of riders won't detract from the fact it will be damping the chatter. Rubber (or polymers in general, therefore carbon when done right) also has good damping characteristics.
-There was a mention of stiction in the spring, what about stiction in the bushings?
-As an additional point of contention weight wise, how much do you think the weight penalty (regardless of the weight that I mentioned above) is versus having a longer shaft without the buttercups?
In any case, I'm hoping my next bike will be running the upcoming analogue Lyrik including these buttercups. And it would be interesting to replace them with a solid part to do some A/B comparisons. Luckily I have a lathe and a person who knows how to use it handy. It quite possibly might not be a drastic difference at the end of the day, it's possible that the benefits of the buttercups are more in the marketing than in reality (as in 'look at what we have that the others don't' with little actual benefit in having it), but we do not know that. Very few people outside RockShox rode the new forks and fewer still (zero?) have te luxury of doing an A/B comparison of this feature. And looking at this with proper telemetry (with a high resolution on the travel and a high sampling frequency) might also be useful. Maybe it would be possible to see the fork 'chattering' away with the buttercups installed while remaining 'stiff' without them.