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  1. #1
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    RS Sektor Rebound...Maxed to Turtle?

    I have an RS Sektor 150 U-turn. I am 165 pounds, 173 suited up. Stock spring.

    Ive maxed out my rebound to turtle to make it feel smooth on rocky descents. Its at a point with chatter from baseball sized rock is smoother out. Does this sound normal?

    Ive been riding FS for 3 years. Ive only recently started fiddling with the rebound to reduce high speed chatter.

    I ride a Trek Remedy. For my weight, the rear is recommended to be set at 3 clicks. Ive got it at 5 and it feels good there. Thats 5 out of 8 clicks.

    Is my Sektor underdamped since I run out of rebound?

    Opinions?

  2. #2
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    Maybe try a heavier weight oil? May be worth getting checked out though, as my Sektor on full rebound is very slow to return, so something doesn't sound quite right.

  3. #3
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    It has a bad rebound damper. Its really worth the ~70 bucks to get the blackbox unit. You can get the normal RS damper to work well over chatter, or work well for flowy trails. Not both.

  4. #4
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    Quote Originally Posted by One Pivot View Post
    It has a bad rebound damper. Its really worth the ~70 bucks to get the blackbox unit. You can get the normal RS damper to work well over chatter, or work well for flowy trails. Not both.
    when you say bad, as in not designed well, or is broken?


    thanks.

  5. #5
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    Quote Originally Posted by bing! View Post
    when you say bad, as in not designed well, or is broken?


    thanks.
    Not designed well. It's fixed orifice design. If you adjust it to be good for small hits (slow enough beginning travel) it will not return fast enough for multiple hits (fork will pack down). Therefore performance is highly compromised. Traditional shim based valve is a lot better design as rebound is automatically faster for deeper stroke and slower for beginnig stroke. RockShox calls this Dual Flow rebound damper and other manufacturers call it something else.

  6. #6
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    Your rebound will not make it feel smooth on rocky descents. Your rebound controls your rebound. That is the speed at which the fork returns to full extension. Too slow is very bad.

    If your fork feels stiff, your rebound has nothing to do with making it feel plush. Your COMPRESSION would affect that, as would your air pressure.

    You should be messing with your air spring, not your rebound. Turn that rebound closer to the jackalope and get your spring pressure dialed in.

    If you can't do that, please take it to a bike shop.

    mk

  7. #7
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    Oh, you said coil. Your stock coil spring is too stiff. Get the next coil down in weight.

    mk

  8. #8
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    Quote Originally Posted by trailbildr View Post
    Your rebound will not make it feel smooth on rocky descents. Your rebound controls your rebound. That is the speed at which the fork returns to full extension. Too slow is very bad.
    Not necessarily but if fork packs down on multiple hits spring force will increase (as fork is deeper in travel and spring is more compressed) that can make fork feel harsher.

  9. #9
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    All the more reason to back off the rebound. It'll also put you over the bars pretty quickly.

    The spring is wrong, not the rebound.

    mk

  10. #10
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    A packed up spring is preloaded, too much rebound will absolutely make a fork feel stiff. This is a fundamental issue with all RS port orifice rebound dampers, it'll do it to everyone.

    A well shimmed rebound will feel slow when you're pumping it with your arms, and it'll open up for fast hits.

  11. #11
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    Ive been able to make the rear shock real plush in high speed rocky terrain with added rebound. With the rear plush, the bouncing in the front has become apparent.

    I don't seem to be packing up the fork with added rebound. I havent bottomed out the fork, far from it. I'm going to open up my LSC from being 1/2- 2/3 closed on the off chance it was spiking. It's a bit of a shot in the dark, but maybe the LSC wasnt allowing the oil to come through fast enough. If that works, I'll start speeding up the rebound and see what I get.

    Otherwise, I have the part number for the 150 mm dual flow rebound damper. I'll order it if I have to, if I can get my hands on one.

    Thanks for the input everyone.

  12. #12
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    Do you have the travel indicator rubber-thinger on your stanchion? Are you getting full travel ever? If not then you need the lighter spring.

    While having a too much rebound damping CAN feel harsh, it's not the rebound damping making the fork feel harsh, its the packed up spring, which would indicate too soft a spring. Which makes the net effect of the rebound damper more significant. But he's saying it feels harsh all the time, not just on successive hits which means his spring is off.

    I know that you are saying rebound CAN make it feel harsh, and I agree, but that does not seem to be his problem.

    mk

    mk

  13. #13
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    The fork feels great most of the time. Its with fast repetitive baseball to melon sized hits that when it feels harsh.

    I just ordered the 2010 Blackbox rebound damper for the 150mm Rev with the high speed circuit. I'm going to try it out. If that doesnt solve my issue, I may try to stuff a MoCo RCT3 DNA compression damper as well to address spiking.

    Thanks again.

  14. #14
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    If it's great with same sized single hits but multiple same sized hits makes it feel harsh it definitely sounds like poor rebound damper problem that should be cured with Dual Flow damper. Standard orifice damper offers poor performance anyway. If you have correct sag then that spring you are currently using is most likely not wrong.

  15. #15
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    I have the stock coil. At 150mm, it sits at 105-110mm. Seems just about right.

  16. #16
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    Quote Originally Posted by bing! View Post
    The fork feels great most of the time. Its with fast repetitive baseball to melon sized hits that when it feels harsh.

    I just ordered the 2010 Blackbox rebound damper for the 150mm Rev with the high speed circuit. I'm going to try it out. If that doesnt solve my issue, I may try to stuff a MoCo RCT3 DNA compression damper as well to address spiking.

    Thanks again.
    You may find the baseball to melon size hits are sharp edge fast hits. Like tree roots, these will cause compression spikes if your fork is overdamped in compression. Large hits from drops etc can quite often be slower and not cause compression spikes.

    You may have to experiment with a few things besides rebound. Wind off any comp damping for one.I find my revs with BB comp damper overdamped for my lighter weight. Since you only have motion control comp damper you should in theory be ok? If nothing else works you could try to drop your oil weight?

  17. #17
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    Quote Originally Posted by gvs_nz View Post
    You may find the baseball to melon size hits are sharp edge fast hits. Like tree roots, these will cause compression spikes if your fork is overdamped in compression. Large hits from drops etc can quite often be slower and not cause compression spikes.

    You may have to experiment with a few things besides rebound. Wind off any comp damping for one.I find my revs with BB comp damper overdamped for my lighter weight. Since you only have motion control comp damper you should in theory be ok? If nothing else works you could try to drop your oil weight?
    i had a suspicion that it could be LS compression spiking. i have 3 logs on my regular trail about 2 feet round with rocks wedged against them as a sort of a ramp. i hit those with good speed and get 90% travel. no spiking there. but on successively fast medium sized hits, i'm getting really harsh feedback through my handlebars.

    thanks for your input.

  18. #18
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    Sounds like comp damping to me. Those sharp edge hits create a very fast shaft speed. It's not so much the travel you are using but the acceleration. The fox forks I've owned tend to do better in that area.The trade off is they don't provide the same mid stroke support.

  19. #19
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    That could be compression damping if you are getting that same harsh feedback with similar single hits but if it's only repeated hits I'm suspecting rebound damping. Anyway that rebound damper shouldn't be a bad upgrade in either case. As gvs_nz suggested dropping oil weight should help if it's compression issue (although you could also bottom out easier with lighter oil weight). I prefer shimmed compression dampers myself because of endless tuning possibilities (one example is what you mentioned MoCo RCT3 DNA). But try first that rebound damper and lower weight oil (separetely or step by step so that you know what is causing that problem) and if that doesn't bring the results you are expecting you could consider MoCo RCT3 DNA (and possibly custom reshimming it).

  20. #20
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    I am hoping that opening up the LSC will address the issue, as well as installing the BB rebound damper. Come to think of it, I don't have too much of a dive problem. I use the LSC as a platform

  21. #21
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    I wasnt so much addressing your issue, but the issue with the fork for all riders. Its something all RS owners would benefit from.

    The moco is crown mounted though.. its pretty easy to change it up on the fly. 2/3rds closed is going to be harsh.

  22. #22
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    @OP

    I still appreciate the input. My Sektor is only 6 months old. Its got a simple MoCo with no floodgate. I have never experienced this feeling that the fork is going rigid on chatter before. I have a Reba RLT and slightly older Recon 351 with a Revelation Moco with the floodgate, they didnt do that. Kinda still has me wondering. The hard part about problem solving these things is you can't really test it in the garage. I have to bike 1 hour to the spot, descend for 30 minutes, and there is little motivation to fiddle with it by stopping Just have to think it through and see if its any better the next time around.

  23. #23
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    The problem you are having is that you are starting to realize what a good fork feels like. Upgrading to a shim based rebound damper will help, but your compression damper is still based on port orifice valve with a spring for HSC. Now that you are starting to feel what your suspension is doing rather then riding oblivious to it like most people, you are starting to feel the shortcomings of this style damper. For most people, it works great, but your only a few steps away from becoming a suspension junky. Once you make it to that point, nothing but shim based dampers will do. That means you will be riding a Manitou, Fox, or X fusion(only manufactures to use both shimmed rebound and compression dampers in every fork) in the future.

  24. #24
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    Quote Originally Posted by tune View Post
    That could be compression damping if you are getting that same harsh feedback with similar single hits but if it's only repeated hits I'm suspecting rebound damping. Anyway that rebound damper shouldn't be a bad upgrade in either case. As gvs_nz suggested dropping oil weight should help if it's compression issue (although you could also bottom out easier with lighter oil weight). I prefer shimmed compression dampers myself because of endless tuning possibilities (one example is what you mentioned MoCo RCT3 DNA). But try first that rebound damper and lower weight oil (separetely or step by step so that you know what is causing that problem) and if that doesn't bring the results you are expecting you could consider MoCo RCT3 DNA (and possibly custom reshimming it).
    Just had my Revelation dual air u-turn converted over to a dual position coil (using the DPC coil from a Sektor fork). Both were 120-150mm. Initially the new coil spring seemed increadibly plush and I could get 100% travel from the stock (medium) spring. Unfortunately Rock Shox forgot to send down the top out spring that sits on top of the rebound damper and it was over extending when the fork was unweighted.

    Subsequently the top out spring has been fitted but since doing this I can no longer get the last 10-15mm of travel and the very small bump compliance seems to be a little less sensitive.

    Would this be a direct effect of the top out spring causing a small amount of compression of the main spring (essentially creating a little preload effect?

    Would altering the amount of oil (recommended being 5-8ml of 15 weight) in the left non-drive side lower leg alter this in any way?

    I have kept the dual flow rebound and black box motion control dampers that were with the revelation team fork. This issue is not altered in any way whether by having the MoCo on the full open position. By that I mean with the MoCo in full open and having the least influence on small bump compliance I still cannot get full travel.

    The coil spring is still way more sensitive than the dual air "spring" but wondering if I can still improve things further? I weight 77kg and the stock medium spring is for riders 72-81kg. Although given that RS guide for air forks is way over I am wondering if this is simply an issue of going down to the soft / yellow spring.

    Any advice would be greatly appreciated.

    Cheers.

  25. #25
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    Quote Originally Posted by Kiwimtbker View Post
    Just had my Revelation dual air u-turn converted over to a dual position coil (using the DPC coil from a Sektor fork). Both were 120-150mm. Initially the new coil spring seemed increadibly plush and I could get 100% travel from the stock (medium) spring. Unfortunately Rock Shox forgot to send down the top out spring that sits on top of the rebound damper and it was over extending when the fork was unweighted.
    As far as I know (have never own or disassembled DPC coil) there shouldn't be any top out coil in damper side (only in the spring side).

    Quote Originally Posted by Kiwimtbker View Post
    Subsequently the top out spring has been fitted but since doing this I can no longer get the last 10-15mm of travel and the very small bump compliance seems to be a little less sensitive.

    Would this be a direct effect of the top out spring causing a small amount of compression of the main spring (essentially creating a little preload effect?
    Could be, as you said it creates preload and most likely changes your sag.

    Quote Originally Posted by Kiwimtbker View Post
    Would altering the amount of oil (recommended being 5-8ml of 15 weight) in the left non-drive side lower leg alter this in any way?

    I have kept the dual flow rebound and black box motion control dampers that were with the revelation team fork. This issue is not altered in any way whether by having the MoCo on the full open position. By that I mean with the MoCo in full open and having the least influence on small bump compliance I still cannot get full travel.
    I wouldn't touch lubrication oil amount (assuming it's within specs now). There's so small amount of oil anyway so that you could risk bushing/stanchion lubrication. And this would most likely need to be adjusted quite much to get noticeable effect. Instead you could inspect that all oil amounts are correct and possibly change lower leg lubrication oil to fully synthetic motor oil (for example 5W30 but "correct" oil weight is not very critical) but remember that damper still needs suspension oil. I have noticed my fork to be slightly more sensitive with fully synthetic motor oil and it seems to lubricate better and work better in colder temperatures. Also turn your bike upside down before rides and push lower legs down to compress that fork to get oil to bushings and seals better. And if oil amounts are correct you could try to lower damping oil weight to get full travel (less compression damping, makes also fork more sensitive in high and low speed compression hits). These things might help.

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