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Discussion Starter · #1 ·
Pivot placement of thhe smoothlink suspension.
The Altitude 09 pivot placment (of the Horst link) was on the chainstay.
(I know the Rocky product managers are going to take issue with my using that term).
The 2011 Slayer's pivot looks quit different, as far as functionality.
It looks actually to be know on the seatstay, whereas befoew it was definitely on the chainstay.
So now it looks to be more like a singlepivot than a horst susp.
Maybe this was to satisfy Spesh lawyers ?


I was really excited about this design before, now not so much.
 

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From what I've seen, the pivot on the 2011 Slayer is exactly the same as the Altitude. The pivot is placed "above" the rear axle on the chainstay, as opposed to "below" it as that is what a horstlink patent is. Being above the rear axel actually puts it more inline with the Chainline force, making it pedal better in more gear combinations. As opposed to the horstlink which is at an Asymmetrical to the chainforce at all times..... Hence more pedal induced bob. My local shop has explained this to me, the bikes ride awesome. Check one out you will not be disappointed.
 

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Discussion Starter · #5 ·
If you look very closely at both pivots you will see a difference.
On the Altitude , the pivot is clearly on the chainstay, slightly above the axle.
On the Slayer, however, it has been moved effectively to the seatstay.
It can no longer move independently of the rear dropout. This makes it
more like a single pivot faux bar
 

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Discussion Starter · #6 ·
Another thing is, you can't have drivetrain induced pedal feedback on
a horst linked (chainstay pivot) bike. So as far as that aspect goes
those graphs you posted dont matter. A totally vertical path
would not feel that plush on the sharp edged stuff.
 

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le_buzz said:
Another thing is, you can't have drivetrain induced pedal feedback on
a horst linked (chainstay pivot) bike. So as far as that aspect goes
those graphs you posted dont matter. A totally vertical path
would not feel that plush on the sharp edged stuff.

??? Sure you can. If the axel path is "vertical" (which its not, no matter what Spec marketing says. It may be vertical in the inital part of the travel but not all the way thru) and that axel is moving away from the cranks, stretching the chain, you will feel it in the pedals for sure. If it was vertical, the farther you go into the travel of the bike, the further the axel will move away from the BB.

Are you sure you are looking at the right Slayer? Check out the photos here. I think the axel looks different then the Altitude because of the thru axel.

http://www.pinkbike.com/news/rocky-mountain-slayer-2011-preview.html
 

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The derailleur hanger looks different on the two bikes but the axle to rear pivot is pretty much the same, pretty close to aligning with with the spot between the 5th and 6th cog on the cassette.

Altitude dropout

Bicycle part Bicycle drivetrain part Bicycle accessory Crankset Bicycle

Slayer 2011 dropout

Bicycle part Bicycle accessory Bicycle Bicycle tire Bicycle wheel rim
 

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The pivot location is essentially the same.

The Slayer design requires a bit more space around the axle for the 12mm E Thru axle.

Both are RMB Smoothlink, approx 10mm above the axle.
 

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Discussion Starter · #10 ·
Read p on your mechanical principles. Pedal feedback is impossible on chainstay pivot
frames - because the chain slack is free to affect the axle path - it wont tighten
up like on dual link or singlepivot frames.

Im no expert, but I would bet that Rocky moved the pivot from the
original location due to avoid possible conflict with the big "S".
 

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Apparently there can be pedal feedback in a 4 bar. Like a Spesh Enduro, because the pivot points are still located so that there is chain growth. If there is chain growth it will provide pedal kickback, no way around that.
 

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rockyuphill said:
Apparently there can be pedal feedback in a 4 bar. Like a Spesh Enduro, because the pivot points are still located so that there is chain growth. If there is chain growth it will provide pedal kickback, no way around that.
Hello.
Do you have the same graphs for the 2011 Slayer. Thanks.

Bernardo
 

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le_buzz said:
Read p on your mechanical principles. Pedal feedback is impossible on chainstay pivot
frames - because the chain slack is free to affect the axle path - it wont tighten
up like on dual link or singlepivot frames.

Im no expert, but I would bet that Rocky moved the pivot from the
original location due to avoid possible conflict with the big "S".
Not trying to start a "web war", but sorry your wrong. If there is chain growth, regardless of any suspension platform, pivot locations, etc, you will feel it in the pedals. Hence pedal feedback. I hate pedal feedback, that's why I dig these new Rocky designs.

Rocky was never close to infringing on the SpecialEd's patent. They have owned the ETS patent for a longtime, which warrants them to place a pivot on the chainstay above the rear axel. If it were below the axel on the chainstay, that's a horst link.
 

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rockyuphill said:
Yep, they're already posted below along with the 2007 SXC and Spesh graphs.
I meant the ones with the drawing and the CS, WS, BB etc....
I have some doubts here; what size enduro are you using, because I dont see any enduro with 1167 WB and the chainstay are 425 instead of 419, HA is 66 instead of 66.5, I want to think that the real numbers are different from the geo table (common thing), just want to know if youre using a M or a L to know if the enduro run smaller or bigger that the geo table numbers.
Yesterday I went in to www.bikechecker.com and had some fun playing with the web models, its interesting seeing how different suspensions work (dw, fsr, sp, vpp, etc...), is there a way to know how much brake jack (or squat, or whatever) have each model, I think it has something to do with the forces numbers but not sure how to interpreteate them.
I notice that with more chaingrowth you get more pedal kickback which makes the new slayer good with it, but I also notice that models that are traditional very good DH (nomad and rune) have a lot of chaingrowth and the axel path goes back even after you get 60% of travel.
I dont want to start a discusion saying that the nomad and the rune are better than the slayer or the enduro, I have ridden both and love the plushness going DH but I personaly cant live with CS that long they both are a lot harder to pull into a wheelie or a manual and not as flickable in the air than bikes with CS 17" and under.

Bernardo
 

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RMB-PM said:
I know, I know. Santa Cruz uses chain growth in the kinematics of VPP.
And that was the thing that soured me on my brief sojourn into Santa Cruz land with a 2004 Blur. Drove me nuts with the pedal kickback. I bought a 2004 ETSX and was very happy not to fight the bike all the time.
 

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Discussion Starter · #19 ·
Nope, you can't. As I said before, a chainstay pivot negates any possibility
of pedal kickback no matter whether the path has a partial rearward section or not.
I have ridden the Enduro, owned Chumba XCL, EVO. There is *NEVER* any
pedal kickback with those designs. You are oversimplifying something that
you have no idea of how the susp. mechanics really work.
Do you really know how to interpret that graph ? If you enter the numbers
correctly, you will see that the pedal feedback you're referring to is really zero.
 

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If the distance between the BB and rear axle changes, you get kickback. No 2 ways about it.

The only way around that (that I know of) is a single pivot design, w. main pivot concentric to BB, unless there is a super-so-sneaky linkage, but I've never seen one.

But maybe there are some eggheads out there who can enlighten us further?
 
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