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  1. #1
    No, that's not phonetic
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    We the people ... Sultan rocker musings

    I've had 3 sets of rockers on my Sultan now: stock, 5.5 Spot, and Push Spot. They all deliver around 4" of travel on my Sultan. The rockers come from different bikes and produce different average leverage ratios on those bikes:
    • Sultan/Flux 2.67:1
    • 5.5 Spot 2.75:1
    • Push Spot 2.93:1

    I have measured each on the Sultan by flipping the bike over and resting it on the handlebars and saddle (my grips and saddle are level when the bike is right side up, so upside down the bike is still level), and measuring the vertical distance between the floor and the center of the rear wheel axle. I then totally deflate the shock and use a bar clamp to pull the rockers as far towards the seatpost clamp as I can force it until the shock is totally bottomed. Finally, I measure the distance from the floor to the middle of the rear wheel axle again and subtract it from the first measurement. The difference is the effective vertical travel of the rear wheel.

    In the case of the 5.5 Spot rockers I got 693mm minus 599mm giving me 94mm or 3.7" of vertical wheel movement. I did the Push Spot rockers a while back and got exactly 4" of travel. It's been a while, but iirc I got right around 4" with the stock Sultan rockers also. The Push Spot rockers are quite a bit longer in back, but also noticeably longer in front, of the rocking point than the stock Sultan rockers.

    The stock high compression tune RP23 is a pretty overdamped and sorta harsh feeling shock with the stock rockers. With the Push rockers the stock shock does feel better though, and seems to break free more smoothly at sag and offer a bit more action through mid-stroke. The rate curves the two rockers produce must be quite different to make the same shock's behavior feel unique in each case, and to have purportedly different average leverage ratios, and yet produce the exact same amount of absolute travel.

    Darren probably has this all mapped out and could explain it in terms I still wouldn't understand.
    My video techniques can be found in this thread.

  2. #2
    Silence and Thunder...
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    that's all well and good, but the 'bottom' line is:
    What does the seat of your pants tell you when riding?? Which ones just 'feel' better?
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  3. #3
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    Push Shock or Rockers.

    If the Push rockers allow the stock shock to perform more smoothly and a pushed shock may achieve the same, what would be the better choice if forced to pick one?

  4. #4
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    Quote Originally Posted by tscheezy
    In the case of the 5.5 Spot rockers I got 693mm minus 599mm giving me 94mm or 3.7" of vertical wheel movement. I did the Push Spot rockers a while back and got exactly 4" of travel. It's been a while, but iirc I got right around 4" with the stock Sultan rockers also.
    Darren @ Push came up with these numbers:

    Stock: 4.04" of wheel travel
    w/5.5 Spot Rockers: 4.08" of travel
    w/PUSH Rockers: 4.19" of travel
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  5. #5
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    [SIZE=3]Unfortunately, T hasnít accounted for the humidity index of the air within the shock changing over the testing period, which would introduce a confounding variable to the damping properties observation from session to session Ė no way to quantify his results with this variable unaccounted for, therefore I have to consider T's thesis is invalid - for now.

    Please account for this variable, and resubmit.

    >>
    [/SIZE]
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  6. #6
    No, that's not phonetic
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    Here's another tidbit I dug up from Darren where he talks about swapping the stock Sultan rockers with Push Spot rockers:

    Quote Originally Posted by PUSHIND
    - Direct replacement
    - No Geometry Change (BB, HA, etc.)
    - Travel increse of 0.125" (3mm)
    - 5% change in rise of rate (higher from 0.78"/20mm thru 3.1/80mm of wheel travel)
    I am wondering if when they "map" the travel they are measuring along the wheel arc unlike me who is just getting vertical displacement perpendicular to the ground. The wheel moves forward as well as up at the end of travel. Then again I have gotten Turner's published numbers to within a millimeter or two using my method so it has worked well in the past. I also found absolutely no difference in BB height between the Sultan and Push rockers, and only saw about a 1/16" drop moving to the 5.5 Turner rockers.
    My video techniques can be found in this thread.

  7. #7
    rr
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    Quote Originally Posted by jokermtb
    [SIZE=3]Unfortunately, T hasnít accounted for the humidity index of the air within the shock changing over the testing period, which would introduce a confounding variable to the damping properties observation from session to session Ė no way to quantify his results with this variable unaccounted for, therefore I have to consider T's thesis is invalid - for now.

    Please account for this variable, and resubmit.

    >>
    [/SIZE]
    Good point, but I just want to know which setup he likes best so I can go out and buy that combo of shock/rocker and be one of the cool kids here

  8. #8
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    Leverage

    Let me try on this one with a hypothetical:

    Rocker A

    @ 0.5" shock travel, leverage is 3.0/1
    @ 1.0" shock travel, leverage is 2.5/1
    @ 1.5" shock travel, leverage is 2.0/1

    High initial leverage which produces good small bump sensitivity with aggressive rising rate that allows for good mechanical bottoming control. This allows for you to run softer shock settings which aid in traction and bump sensitivity without compromising bottoming control.

    Rocker B

    @ 0.5" shock travel, leverage is 2.0/1
    @ 1.0" shock travel, leverage is 2.5/1
    @ 1.5" shock travel, leverage is 3.0/1

    Lower initial leverage, that falls in rate. This forces the rider to run higher pressures in order to keep the shock from blowing through its travel to easily. This results in difficulty getting good sag measurements as well as a resulting loss in initial small bump sensitivity.

    Using the rule of dividing the wheel travel by the shock stroke, you'd come up with an average rate of 2.5/1 with both bikes, as well as the same amount of travel. The reason I've always argued the "average" leverage rule of thumb is because you can see that the actual leverage of the two examples above would produce a radically different ride characteristic.

    Darren

  9. #9
    rr
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    Which example do the stock rockers resemble?
    Last edited by rr; 04-25-2008 at 09:24 AM.

  10. #10
    Natl. Champ DH Poser/Hack
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    i dunno darren. cheeseys tundra logic and frozen formulas have always been well recieved in the past. sure ya trust this scientific method of yers?

    im kiddin ya both. carry on.
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  11. #11
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    And here I go throwing another in the mix!

    Since I sent my 5.5's to ts to try out, I decided I'd try out a set of 5.3's on my Sultan. Of course I was running it with a coil shock last month with our still colder temps, but wanted to get an initial impression and ferret out any incompatibility issues. No issues so far.

    The notion I had was to see if the added length in front of the mid-rocker pivot would add some leverage to help overcome the high compression damping effects of the RP23, especially with these short stroke shocks. ts also has my air shock, so I'll wait and test for seat of the pants feel as well.

    Of course riding with my coil shock is apples to oranges compared to ts's riding time, but, my gut feel said the advantage to a non-stock rocker is not just the added leverage gained from the rocker's rear half length, but from the added front half of the rocker's length also. Both sets of travel measurements listed by ts and Darren show negligible differences, but change the leverage rates, so why not try the 5.3 as well? I bet I find the ride characteristic with it to be similar to the A scenario Darren mentioned. We'll see. I'll give it a run once ts has satisfied his curiosity. Good stuff.

    Darren, could you plunk in 5.3 numbers for results, or would they pretty much mirror the 5.5 and yours?

    Rando
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  12. #12
    No, that's not phonetic
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    Quote Originally Posted by EndoRando
    Darren, could you plunk in 5.3 numbers for results
    I think he needs to physically have the bike in question in his hands and run it through its paces.

    One other oddity I have noticed is that your shock is about 1/8" longer in i2i than mine (yours measures 6.5 and mine is under). Mine isn't stuck down or anything, it just seems to be a little stumpy for some reason.
    My video techniques can be found in this thread.

  13. #13
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    Quote Originally Posted by EndoRando
    Since I sent my 5.5's to ts to try out, I decided I'd try out a set of 5.3's on my Sultan. Of course I was running it with a coil shock last month with our still colder temps, but wanted to get an initial impression and ferret out any incompatibility issues. No issues so far.

    The notion I had was to see if the added length in front of the mid-rocker pivot would add some leverage to help overcome the high compression damping effects of the RP23, especially with these short stroke shocks. ts also has my air shock, so I'll wait and test for seat of the pants feel as well.

    Of course riding with my coil shock is apples to oranges compared to ts's riding time, but, my gut feel said the advantage to a non-stock rocker is not just the added leverage gained from the rocker's rear half length, but from the added front half of the rocker's length also. Both sets of travel measurements listed by ts and Darren show negligible differences, but change the leverage rates, so why not try the 5.3 as well? I bet I find the ride characteristic with it to be similar to the A scenario Darren mentioned. We'll see. I'll give it a run once ts has satisfied his curiosity. Good stuff.

    Darren, could you plunk in 5.3 numbers for results, or would they pretty much mirror the 5.5 and yours?

    Rando
    I ran the 5.3's for a while. I easily prefer the 5.5's to them tho.


  14. #14
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    Quote Originally Posted by tscheezy
    I've had 3 sets of rockers on my Sultan now: stock, 5.5 Spot, and Push Spot. They all deliver around 4" of travel on my Sultan. The rockers come from different bikes and produce different average leverage ratios on those bikes:
    • Sultan/Flux 2.67:1
    • 5.5 Spot 2.75:1
    • Push Spot 2.93:1

    I have measured each on the Sultan by flipping the bike over and resting it on the handlebars and saddle (my grips and saddle are level when the bike is right side up, so upside down the bike is still level), and measuring the vertical distance between the floor and the center of the rear wheel axle. I then totally deflate the shock and use a bar clamp to pull the rockers as far towards the seatpost clamp as I can force it until the shock is totally bottomed. Finally, I measure the distance from the floor to the middle of the rear wheel axle again and subtract it from the first measurement. The difference is the effective vertical travel of the rear wheel.

    In the case of the 5.5 Spot rockers I got 693mm minus 599mm giving me 94mm or 3.7" of vertical wheel movement. I did the Push Spot rockers a while back and got exactly 4" of travel. It's been a while, but iirc I got right around 4" with the stock Sultan rockers also. The Push Spot rockers are quite a bit longer in back, but also noticeably longer in front, of the rocking point than the stock Sultan rockers.

    The stock high compression tune RP23 is a pretty overdamped and sorta harsh feeling shock with the stock rockers. With the Push rockers the stock shock does feel better though, and seems to break free more smoothly at sag and offer a bit more action through mid-stroke. The rate curves the two rockers produce must be quite different to make the same shock's behavior feel unique in each case, and to have purportedly different average leverage ratios, and yet produce the exact same amount of absolute travel.

    Darren probably has this all mapped out and could explain it in terms I still wouldn't understand.
    Tscheezy,

    The average leverage ratio you reported for those rockers is on different bikes with a linkage that is different from the Sultan. If you are correct and the total travel for given shock stroke is identical with two different rockers on the Sultan, the average leverage ratio of the linkage will be identical.

    Here is the setup I use to map out linkages:



    I can change the i2i distance a few mm at a time and measure the vertical displacement of the axle. I do not own a Sultan, and my measurements have been on a 5-pack and RFX with PUSH and 5.3in rockers. The main difference between the two I measured (other than the total amount of travel) is that the leverage ratio starts higher with the PUSH rockers and ends almost exactly at the same place as the 5.3in rockers. The 5.3in rockers have a very linear behavior throughout the shock stroke. Those results are summarized in this thread:

    06 RFX/5 pack leverage curves and geometry measurements

    Again, I am not claiming that these results hold exactly for the Sultan linkage, I am just sharing how those rockers affect suspension characteristics in a couple of other linkages.
    Just yesterday I received my 5.5in rockers, soon I'll measure the 5-pack linkage with these rockers and update the thread comparing all three 5in rocker options with a Spot rear triangle.

    Miles measured the total travel on his Sultan with a 1.75in stroke shock and reported his results in this thread (I am referencing the relevant posts):

    http://forums.mtbr.com/showthread.ph...48151#poststop
    http://forums.mtbr.com/showthread.ph...48523#poststop

    If someone wants to ship me a medium Sultan for a couple of weeks I'll be happy to map the linkage with all the rockers (for both a 1.5in and 1.75in stroke shocks) ...

  15. #15
    No, that's not phonetic
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    Quote Originally Posted by nybike1971
    The average leverage ratio you reported for those rockers is on different bikes with a linkage that is different from the Sultan. If you are correct and the total travel for given shock stroke is identical with two different rockers on the Sultan, the average leverage ratio of the linkage will be identical.
    Exactly. That's sorta why I opened this can of worms. It is hard to pull rockers off another bike and predict exactly what they will do on a different model that has most of the other pivots in different locations and runs a different stroke shock. The 2" stroke shocks on the Spots would cause the rockers intended for that bike to go through 25% more rotation than they would when mounted on the Sultan, so things would have to feel pretty different.

    As Darren has said, sometimes you just get lucky and it works out for the "better."
    My video techniques can be found in this thread.

  16. #16
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    what I take away from all this rocker arm talk is that, unless you have a reason to need a higher leverage ratio, all you need to do is stick with the stock Sultan rockers, and if the $$ is available or the need is there, tune the RP23 with a PUSH treatment.

    i.e. for the XC focused rider, the stock rockers are perfect
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  17. #17
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    Quote Originally Posted by GreenLightGo
    what I take away from all this rocker arm talk is that, unless you have a reason to need a higher leverage ratio, all you need to do is stick with the stock Sultan rockers, and if the $$ is available or the need is there, tune the RP23 with a PUSH treatment.

    i.e. for the XC focused rider, the stock rockers are perfect
    I really disagree. I'm not necessarily sure with regard to Tscheezy's findings, becuz I am running a pre-production Sultan frame & I know the bb pivot was moved prior to production...that said: my bb height dropped nearly .5" from the stock rockers to the 5.5's. I also think that the 5.5 rockers have much better ramp up at the end of the stroke as well as handling g-outs. This allows me to run a bit less pressure & still not bottom out excessively. I have the 5.5/ 5.3 & stock rockers available (heck I even tried out the 08 rfx rockers ), but the ones I prefer most are the 5.5's. My $.02 & ymmv.


  18. #18
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    Quote Originally Posted by jncarpenter
    my bb height dropped nearly .5" from the stock rockers to the 5.5's. I also think that the 5.5 rockers have much better ramp up at the end of the stroke as well as handling g-outs. This allows me to run a bit less pressure & still not bottom out excessively.
    This matches my experience with my production Sultan. I don't recall the exact change in BB height, but it sure seems like it was closer to .5" than 1/16"; 3/8" I wanna say. I'm pretty sure it was at 13.25" with F135, 5.5 rockers & RP23, then 13 5/8" with the longer CCDB on, which is about what it comes out to with a F135 and the stock shock/rockers.

    I only had one ride with the 5.5's and RP23 before the CCDB came in, but I remember being able to run the pressure ridiculously low (and I like a soft rear end ) w/o bottoming, as was also the case on a few rides I did with the 5.1's and RP23.

    The increased stiffness with the 5.5's was noticable too.
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  19. #19
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    Miles and JNC: I have no doubt that you guys are correct in your assessment. My questions for you are:

    1) Is there any fork/shock combination for which you would prefer the stock rockers?
    2) Why do you think DT specs the Sultan with the Sultan/Flux rockers instead of the 5.5in Spot rockers?
    3) Is there a downside to the 5.5in rockers on the Sultan?

  20. #20
    No, that's not phonetic
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    Umkay, I swapped back to the stock Sultan rockers and measured veeeery carefully. I got 335mm BB height with the 5.5 rockers and 338mm with the Sultan rockers, a 3mm difference, or under 1/8" if you don't like metric. That's with a White Bros F135 fork and WTB Stout 2.3s front and back.
    Last edited by tscheezy; 04-25-2008 at 08:50 PM.
    My video techniques can be found in this thread.

  21. #21
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    Quote Originally Posted by nybike1971
    Miles and JNC: I have no doubt that you guys are correct in your assessment. My questions for you are:

    1) Is there any fork/shock combination for which you would prefer the stock rockers?
    2) Why do you think DT specs the Sultan with the Sultan/Flux rockers instead of the 5.5in Spot rockers?
    3) Is there a downside to the 5.5in rockers on the Sultan?
    1) Set up for racing, with a Reba on front, the stock rockers are fine. The give a firmer feel but still allow for full travel. I'll be trying a Fox soon though, and wonder if I might prefer the geometry of the 5.5 rockers with it since the way they slacken the front end would help counter act the quicker steering (presumably) provided by the shorter fork and increased offset.
    2) I think it was probably a pretty easy decision to keep the same suspension design as the 4" travel 26" wheeld bike (Flux) for the 4" travel 29" wheeled bike. And of course DT designed the geometry from the ground up to work with those rockers, as opposed to our chop shop approach to customizing the geometry. Plus, I don't know if anyone (even DT) seriously thought the longer rockers would be compatible at all with the Sultan until JNC bolted on some 5.3's about a year ago. Now that it's pretty well established that they do work, and work well for many riders, I suppose it would be a nice factory option, although that might just confuse a lot of riders.
    3) They're ~1/4 lb. heavier, more expensive (aftermarket, and presumably for Turner too), and as with any geometry change (see the new RFX thread ), what works for some riders may be the opposite of what others want.
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  22. #22
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    Quote Originally Posted by jncarpenter
    I really disagree. I'm not necessarily sure with regard to Tscheezy's findings, becuz I am running a pre-production Sultan frame & I know the bb pivot was moved prior to production...that said: my bb height dropped nearly .5" from the stock rockers to the 5.5's. I also think that the 5.5 rockers have much better ramp up at the end of the stroke as well as handling g-outs. This allows me to run a bit less pressure & still not bottom out excessively. I have the 5.5/ 5.3 & stock rockers available (heck I even tried out the 08 rfx rockers ), but the ones I prefer most are the 5.5's. My $.02 & ymmv.
    interesting, did not know about the ramp up at the end. I moved to the Sultan from a 5x5 26" bike that used a Rock Shox MC3.3 (which I quite liked) , it was plush initially with ramp up at the end, rode like a plush trail bike/light AM ride. Initially, I was a bit put off by the amount of 'feel' I was getting from the Sultan until I managed to dial in the RP23 to my liking. It's not as plush as my old ride but much more competent, I guess. I was looking for a bit more XC ride and only running 5 gears out back, I tend to like the stiffness now but do notice that I am using all the travel when I'm hammering the downhill sections of rooty trails here in AL. I don't physically feel a bottom out but I'm also conscious that it's not the pillowy smooth action, an almost detached feel, that my previous ride had. I have grown to like the feedback as I'm more aware of what the rear end is doing and can adjust body weight when necessary, it's actually helped me go faster. Side effect of Sultanism I guess - unexplainable gain in speed.

    That being said, this is only my second FS ride and it's hard to compare a 5x5 26" bike to a 4x4 29" bike - too many other variables. I'm so satisfied with the setup and performance of the Sultan for the type of riding I do and my riding style that I don't see changing anything in the near future, with the exception of PUSH'ing the shock when it's time for a service and adding one of those sexy new Reba 120s with a Maxle.

    One Q though - on my RP23, there is a small sticker with three graduated hash marks, the small hash mark on my sticker is white, the medium and long hash mark are gray - what is that indicating?
    Happiness depends more on the inward disposition of mind than on outward circumstances. Benjamin Franklin

  23. #23
    No, that's not phonetic
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    There are usually some words printed next to that little bar graph you are referencing. It will say "compression tune" or "rebound tune" and it basically tells you what sort of background valving the shock has from the factory. You can twist knobs to change the shock's compression or rebound to some degree, but the general behavior is set at the factory. The tall bar being filled in with white means it has the highest amount of damping, the low bar indicates the least damping. In your case it may be the rebound as Turner spec'ed the rebound to have the lowest (fastest) tune and the compression to have the highest (firmest) tune. Some of the "firmness" you feel may be the constant background damping in the shock even when the propedal lever is flipped to the "off" position because of the high compression tune (if you have one of those shocks).
    My video techniques can be found in this thread.

  24. #24
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    Quote Originally Posted by tscheezy
    There are usually some words printed next to that little bar graph you are referencing. It will say "compression tune" or "rebound tune" and it basically tells you what sort of background valving the shock has from the factory. You can twist knobs to change the shock's compression or rebound to some degree, but the general behavior is set at the factory. The tall bar being filled in with white means it has the highest amount of damping, the low bar indicates the least damping. In your case it may be the rebound as Turner spec'ed the rebound to have the lowest (fastest) tune and the compression to have the highest (firmest) tune. Some of the "firmness" you feel may be the constant background damping in the shock even when the propedal lever is flipped to the "off" position because of the high compression tune (if you have one of those shocks).
    actually, it doesn't say compression or rebound anywhere, just "propedal tune" on the red/white opposing 'P' emblem. I'm running the rebound damping on 8, (with 1 being no damping, 10 being fully damped as I only had 10 clicks on the red rebound knob) so what you say about Turner's rebound specs makes sense.
    Happiness depends more on the inward disposition of mind than on outward circumstances. Benjamin Franklin

  25. #25
    No, that's not phonetic
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    I think if the early shocks had a bar graph, it referred to compression.
    My video techniques can be found in this thread.

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