2019 Stumpjumper Evo

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2019 Stumpjumper Evo
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Posted: Feb 12, 2020 at 9:43 Quote
R-M-R wrote:
It's more than some and less than others. And the damping force at the wheel is lighter than most.

I'm not saying it's a bad bike or your link is a bad product, just helping people understand the kinematics.

Oh no I know you weren't trying to poke at the link or anything. I figured it would be worth mentioning because SC says nothing about their leverage curves and it would give people something to compare to when reading reviews since they are bikes with a similar intended use.

Posted: Feb 12, 2020 at 10:03 Quote
CascadeComponents wrote:
R-M-R wrote:
It's more than some and less than others. And the damping force at the wheel is lighter than most.

I'm not saying it's a bad bike or your link is a bad product, just helping people understand the kinematics.

Oh no I know you weren't trying to poke at the link or anything. I figured it would be worth mentioning because SC says nothing about their leverage curves and it would give people something to compare to when reading reviews since they are bikes with a similar intended use.

Fair enough. If the goal is to inform people, we should be careful about calling a more progressive motion ratio "better", as it's not intrinsically better. Granted, most people do prefer a moderately rising motion ratio, which the Cascade link delivers; just looking to be objective before moving into the subjective.

It's also important to discuss total force at the wheel. The low damper force on the Stumpjumper, which is marginally reduced with the Cascade link, decreases the energy required to bottom-out the suspension, relative to most competitors.

Posted: Feb 12, 2020 at 10:38 Quote
wrote:
R-M-R wrote:
Oh no I know you weren't trying to poke at the link or anything. I figured it would be worth mentioning because SC says nothing about their leverage curves and it would give people something to compare to when reading reviews since they are bikes with a similar intended use.

Fair enough. If the goal is to inform people, we should be careful about calling a more progressive motion ratio "better", as it's not intrinsically better.

It's also important to discuss total force at the wheel. The low damper force on the Stumpjumper, which is marginally reduced with the Cascade link, decreases the energy required to bottom-out the suspension, relative to most competitors.

While it's true that the damping force at the wheel is decreased since the average shock speed is decreased, the intention is to not rely on damping to prevent bottom outs. Essentially the amount of energy that can be stored by the spring increases and the amount of energy dissipated by the damper changes sees a small decrease so there's a net increase in bottom out resistance. The other thing worth noting is that since damping force is speed sensitive it doesn't do much to prevent bottom outs in g-outs whereas a the spring force is only position sensitive. I've always found running excessive damping makes the bike feel much more harsh than a more progressive curve, less damping, and a stiffer spring. It's The change in damping force due to shock speed can be offset by adding a few clicks of LSC.

Posted: Feb 12, 2020 at 10:57 Quote
I don't disagree, though I give a little more credit to the role of damping in preventing most bottom-out events - g-outs excepted.

As I noted before, I'm aware the change in damping force with the Cascade link is extremely small. As you noted, the higher spring rate required to maintain the same sag will more than compensate.

"Harshness" is a difficult thing to capture:

• If there's minimal support until deep in the travel, the force will be low until deep in the travel, at which point a greater maximum force will occur. Our hands and feet will tell us the bike is less harsh, but our ankles may not love it.
• Consistent support throughout, such as from lower spring force and higher damper force, is great for chassis pitch control and should lower the maximum force, but moderately high forces occur more often.

The optimal balance will vary by rider and by trail.

Posted: Feb 12, 2020 at 11:50 Quote
I'm thrilled that a link is available and whatever the Cascade link adds is surely going to help the rear end.

I have both a coil shock with various springs and a Super Deluxe with MegNeg to try out with it. Stock - the big air shock works the best for me. I'm looking forward to figuring out what combination works the best.

Posted: Feb 12, 2020 at 14:29 Quote
CascadeComponents wrote:
Benduro83 wrote:
Is this linkage suitable for use with cane creek progressive rate spring? Looking forward to trying this out when it's available

In my opinion yes. The one thing that becomes tricky is dialing in the ride height. You don't really want to use preload to set ride height and there currently isn't a huge selection of progressive springs finding one with the perfect initial spring rate is harder. If one of the offered initial rates has the proper ride height it will feel very bottomless though.

Youve got colour for the link?
Im tending between the blue and black one- the blue should be somewhat more nice with the chameleon blue?

Posted: Feb 12, 2020 at 14:38 Quote
R-M-R wrote:
I don't disagree, though I give a little more credit to the role of damping in preventing most bottom-out events - g-outs excepted.

As I noted before, I'm aware the change in damping force with the Cascade link is extremely small. As you noted, the higher spring rate required to maintain the same sag will more than compensate.

"Harshness" is a difficult thing to capture:

• If there's minimal support until deep in the travel, the force will be low until deep in the travel, at which point a greater maximum force will occur. Our hands and feet will tell us the bike is less harsh, but our ankles may not love it.
• Consistent support throughout, such as from lower spring force and higher damper force, is great for chassis pitch control and should lower the maximum force, but moderately high forces occur more often.

The optimal balance will vary by rider and by trail.

The bit about ankles not loving us is why the smoothness of the progression is important. Bikes where the derivative of the leverage curve becomes too large will feel have the feeling of the first bit of travel being super soft/nonexistent and the end being where all the energy is absorbed. YT bikes have fairly steep leverage curves so a lot of people feel this way about them.

The reasoning behind wanting to decrease damping forces is bikes with such short shocks often times bottom out very easily if they are sagged at 30% unless more damping than desirable is ran. Energy stored in a spring is proportional to the compression squared so as shock stroke decreases the energy the spring can store drops off very quickly. Some damping is required, but the amount to prevent bottoming is higher than ideal because of the smaller amount of energy the spring can store. Amounts of damping this high make the bike unable to respond well to high frequency low amplitude impacts like rocks, roots, braking bumps, and such. These are the impacts that create the harshness that kill your hands, which is why Whistler makes hands so tired. The body is actually quite good at absorbing high amplitude low frequency hits. Your ankles really start to feel it on bottom outs so preventing harsh bottom outs is what will save them above all else.

Some of the draw backs with high damping lower spring rate is where ever shock speeds are slow (such as corners and g outs) the support is poor so the bike will blow through travel easily and the suspension is more likely to pack up on successive hits because wheel force becomes more speed dependent and less position dependent.

Posted: Feb 12, 2020 at 14:42 Quote
NotNamed wrote:
Youve got colour for the link?
Im tending between the blue and black one- the blue should be somewhat more nice with the chameleon blue?

Just got this sample back from the anodizer today!
Blue Stumpjumper LT link

Posted: Feb 12, 2020 at 14:43 Quote
CascadeComponents, I don't think anything we've said is incompatible.

Posted: Feb 12, 2020 at 14:47 Quote
R-M-R wrote:
CascadeComponents, I don't think anything we've said is incompatible.
No not at all. I think the points should agree nicely. I'm not trying to argue with you so sorry if it's coming off that way. Just adding bits I've found. As we know it's always a balance and running more/less damping for example has trade offs.

Posted: Feb 12, 2020 at 15:46 Quote
There will always be trade-offs between chassis stability and comfort, with less emphasis on comfort for top racers in short format races (ex. DH) and more emphasis on comfort for recreational riders and long rides, including long days of lapping the bike park.

The ability to choose spring type and compression ratio add some fun variables. As you said, if, near the end of the travel, the first derivative of motion ratio curve is high and / or the second derivative stays positive, it could feel mushy for most of the travel, then hit a wall of support near the end of the travel. Within reason, of course, a curve of this nature can work well with a coil spring and / or a less digressive piston. As long as the force at the wheel does what it should do, it doesn't matter what combination of parameters created the result!

Posted: Feb 13, 2020 at 1:37 Quote
CascadeComponents wrote:
NotNamed wrote:
Youve got colour for the link?
Im tending between the blue and black one- the blue should be somewhat more nice with the chameleon blue?

Just got this sample back from the anodizer today!
Blue Stumpjumper LT link
Damn- I think blue it will be then

Thanks Smile

Posted: Feb 13, 2020 at 1:55 Quote
Just found out my upper/front shock pivot bolt is slightly bent.
Anyone ever had this?

Posted: Feb 14, 2020 at 7:49 Quote
Arierep wrote:
Just found out my upper/front shock pivot bolt is slightly bent.
Anyone ever had this?

Just had this sorted by local Specialized, no questions asked, just reported the issue and was given a new bolt. Top service

Posted: Feb 16, 2020 at 20:37 Quote
Looking for a size recommendation on the 27.5 Stumpjumper evo. I'm 5'9", 160 lbs. coming from riding a Norco range medium and wondering if I should be on an S2 or S3.

Anyone else out there around my size that can give me a recommendation?

Thanks


 
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