Replacing Revelation Dual Air assembly with Sektor U-turn assembly ?- Mtbr.com
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  1. #1
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    Replacing Revelation Dual Air assembly with Sektor U-turn assembly ?

    Hi all,

    I own a Revelation RLT 2011 with Dual Air. Fork is plush, but small bump compliance is not so good like my brothers Tora 318 Uturn 85-130mm and my friends Sektor RL U-turn 110-150mm. I just can't get that level of initial plushness with any settings of dual air.

    So, my friend is changing his Sektor spring to a more firmer. Thing is, my Rev is round 1600g light, and has dual flow rebound that sektor doesn't. With the change it would be round 100g heavier, but more plush as well.

    What problems could I facing during this replacement ? I'm seeing 2-3 possible problems - different thread at the top of the crown, different thread at the lower bolt and the biggest problem - negative spring.

    I've got a solution for the negative spring - either a rubber bumper under the uturn spring or an actual small spring in either rebound part (like sektor has) or under the positive spring/shaft.

    Any other problems that I could face ?

    P.S. I'm aware that I won't be able to get back to dual air cause of the spring damage inside the stanchion.
    Last edited by Vuco; 05-23-2011 at 05:43 PM.

  2. #2
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    What pressure are you running in your + and - chambers?

  3. #3
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    I am in the process of converting a RS fork from a Dual AIr to coil. Parts needed : coil U-Turn assembly, spring base plate (aka neg spring) and U-Turn knob.

  4. #4
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    It would have to be the bumper under the rebound piston... the spring side does not have a seal head. The spring goes through the open stanchion and the only thing preventing the fork from over-extending is the rebound piston+negative spring on the Sektor

    You'd have to mimic that on the Rev. Dang, you got me thinking on converting my Rev again.

    That is if the threads are compatible. They are in the air models as they share topcaps and U-Turn Assy's.... but the coil may be different.
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  5. #5
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    Quote Originally Posted by denjen
    What pressure are you running in your + and - chambers?
    I'm 190lbs and I've tried everything with the fork. RS reccomend minimaln 120psi - this is by far too much. SAG is like, non-existent.

    I have the fork for 5 months now. I've ridden it from 80 to 120psi in positive. Tried higher negative (not so good cause the rebound slows down a lot), even negative and less negative than positive (best results). Don't get me wrong - the fork is plush, but it reacts like a linear spring.

    Today I've tried 85psi positive, 75psi negative. With that I got 30mm=20% SAG in seated position, and 40mm in "DH position" . I get almost full travel (4-5mm left). This is the best I've got by small bump sensitivity, but I'm worried that I don't get the dual flow rebound working at this low pressure. Since I've read they setup the rebound shims to work best with riders from 80-85kg, and for them RS recommends ~120psi. Rebound is proportional to energy in the spring.


    Quote Originally Posted by keen
    I am in the process of converting a RS fork from a Dual AIr to coil. Parts needed : coil U-Turn assembly, spring base plate (aka neg spring) and U-Turn knob.
    Which one ?

    I know that a Pike has the negative spring under the positive (acts like a top out bumper cause it's not so long). Sektor has it on the rebound shaft (also small)
    Quote Originally Posted by Warp
    It would have to be the bumper under the rebound piston... the spring side does not have a seal head. The spring goes through the open stanchion and the only thing preventing the fork from over-extending is the rebound piston+negative spring on the Sektor

    You'd have to mimic that on the Rev. Dang, you got me thinking on converting my Rev again.

    That is if the threads are compatible. They are in the air models as they share topcaps and U-Turn Assy's.... but the coil may be different.
    I'm aware that the dual air has air valve on the lower leg, I hope the shaft/rod is not wider than usual.
    Maybe if I take the top out bumper of the dual air setup, to be my "negative spring" or top out bumper then ?

    My friend told me his new spring is arriving in 20 days, but before that we will probably try to put the spring side inside the stanchion of a Rev. Hope all fits (ie that they have all the same threads on the crown; the ones in the lowers can be managed somehow). Need to be carefull not to scratch the inside of the stanchion.

  6. #6
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    Quote Originally Posted by Vuco
    I'm aware that the dual air has air valve on the lower leg, I hope the shaft/rod is not wider than usual.
    Maybe if I take the top out bumper of the dual air setup, to be my "negative spring" or top out bumper then ?

    My friend told me his new spring is arriving in 20 days, but before that we will probably try to put the spring side inside the stanchion of a Rev. Hope all fits (ie that they have all the same threads on the crown; the ones in the lowers can be managed somehow). Need to be carefull not to scratch the inside of the stanchion.
    The lowers on both the Sektor and the Revelation are the same. The differences in P/N's are from colours or axle size, AFAIK.

    Wrap the spring with shrink tape or an old road bike tube (that last one could be a beyotch to put on) to prevent scratches and please let me know your findings.

    Yeah, the negative bumper of your Dual Air could be used in the rebound damper as negative spring. On the Sektor, I don't really think it's a negative spring but rather just a top out bumper. Just check that the rebound rod is long enough to extend properly or you'll be preloading the spring by whatever amount the rebound shaft is not extending.
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  7. #7
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    Quote Originally Posted by Warp
    The lowers on both the Sektor and the Revelation are the same. The differences in P/N's are from colours or axle size, AFAIK.

    Wrap the spring with shrink tape or an old road bike tube (that last one could be a beyotch to put on) to prevent scratches and please let me know your findings.

    Yeah, the negative bumper of your Dual Air could be used in the rebound damper as negative spring. On the Sektor, I don't really think it's a negative spring but rather just a top out bumper. Just check that the rebound rod is long enough to extend properly or you'll be preloading the spring by whatever amount the rebound shaft is not extending.
    Thanks for the tips

    Lowers in my case are not the same, since the Sektor that my friend has is 20mm axle, and my Rev is 9mm. But I hope everything will fit (rods OD and bolt thread).

    Yeah, about the negative spring. I know Fox negative spring is longer a lot than the one in the RS/Sektor. That's why I also think the small spring is just an top out bumper. That's why I think that it would be better than an rubber bumper. So that the positive spring preloads the negative, and not the other way (the rubber bumper won't shrink a millimeter). Except the preload, I would also loose some travel (probably round 1cm, depends on the bumper size).
    Last edited by Vuco; 06-07-2011 at 03:15 PM.

  8. #8
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    Any update on this mod? I am interested in putting a Sektor 150mm coil u turn assembly in a dual air Revelation, but was told by someone at RS tech support that the stanchion lengths of the Sektor and Revelation are different (even though they're both 150mm forks?) and it will not work.

  9. #9
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    Quote Originally Posted by altazo View Post
    Any update on this mod? I am interested in putting a Sektor 150mm coil u turn assembly in a dual air Revelation, but was told by someone at RS tech support that the stanchion lengths of the Sektor and Revelation are different (even though they're both 150mm forks?) and it will not work.
    Dual Position Coil form Sector will work for sure! My friend has converted Dual Position Air to DPC and is happy now!

  10. #10
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    I have a u-turn coil spring in my manitou minute

    RS has been pretty good about cross compatibility with their stuff. Most of the 32mm alu upper stuff will swap to other 32 alu uppers.

    If anyone has a firm 140mm RS spring assembly they wanna dump, I could use another one!

  11. #11
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    I put a 140mm sektor coil in my 09 revelation dual air. I used a regular non-travel adjust coil but I'd assume the other flavors would be similar. Needed the spring and corresponding top cap, that was it. It was pretty strait forward and there's a thread on it some where. For the top out spring I ended up getting one from a pike and putting in on the rebound shaft. Afaik they don't sell the top out spring for the sektor separately. Been running it for several months now, working great. Grab the rock shox spare parts catalog from sram's service page, it has exploded views of all the forks. Pretty easy to see what needs to be changed.

    Andy

  12. #12
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    Quote Originally Posted by phydeaux37 View Post
    I put a 140mm sektor coil in my 09 revelation dual air. I used a regular non-travel adjust coil but I'd assume the other flavors would be similar. Needed the spring and corresponding top cap, that was it. It was pretty strait forward and there's a thread on it some where. For the top out spring I ended up getting one from a pike and putting in on the rebound shaft. Afaik they don't sell the top out spring for the sektor separately. Been running it for several months now, working great. Grab the rock shox spare parts catalog from sram's service page, it has exploded views of all the forks. Pretty easy to see what needs to be changed.

    Andy
    Hey, how have you found the spring rate for your weight?

    I'm in between according to RS Spring Rates. My "dry weight" is 62-65kg depending on atmospheric conditions and the price of tea in China.

    That would put me in the top end of the X-Soft or the low end of the Soft.

    Any recommendations?
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  13. #13
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    I'm 200lbs dry so I went with extra firm. I never found a chart so I just guessed based on the recommendations for other forks. My sag is slightly less then desirable, I forget where it is exactly. I've thought about switching to a firm and run a few turns of preload but I haven't wanted to spend the money.

    Andy

  14. #14
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    Quote Originally Posted by phydeaux37 View Post
    I'm 200lbs dry so I went with extra firm. I never found a chart so I just guessed based on the recommendations for other forks. My sag is slightly less then desirable, I forget where it is exactly. I've thought about switching to a firm and run a few turns of preload but I haven't wanted to spend the money.

    Andy
    You would have been in between rates according to this table...

    http://cdn.sram.com/cdn/farfuture/w-...4149_rev_c.pdf

    On other sources, I've seen that the springs are a little on the soft side. I guess it depends on weight distribution and such also.
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  15. #15
    "El Whatever"
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    Ok... it can be done.

    I got some unvaluable info from some posters on mtb-news.de boards. Many people over the pond had put either a Dual Position Coil or U-Turn Coil assemblies on Revelations and Sektors.

    I went ahead and put a U-Turn Sektor assy onto a Revelation.

    EI ordered the Soft-150mm spring for the Sektor. It turned out to be 10-13mm longer than the 150 Dual Position Air cartridge it replaced. When you put the thing together, I ended up with 163mm of exposed stanchion (543mm A2C)...

    Don't get too exited... I made a quick check and the stanchions tip may not be inside the lower bushing at this position, so I would not recommend running the fork like that. Definitively, the Revelation may not prepared for being run at 160mm.

    Now... the spring side is continous from crown to foot nut. There's nothing preventing the fork from overextending but the damper. This is the reason Sektors have a spring in the damper, it's a top out bumper, not a negative spring.

    I used some bumpers that probably came from a Manitou Nixon. They were like 10mm tall, so I cut them down to half of it, so it could extend a little bit without preloading the main spring.

    In the end, I decided to run it at 150mm travel, which gives me about 20% sag.

    Now... the important thing. This thing transformed the fork. While the Dual Position Air was just "good", the coil is simply superb.

    I didn't use more than 110mm of travel, but it's not like I asked too much from the fork. This thing is stupid plush in the early travel, it has a very nice midstroke that does not allow the fork to wallow and the bottom part is never harsh.

    Seriously, the fork is so plush, you can push the fork down with your fingers on the bars. You don't get that notchy feeling to start the travel that you get from air forks... and you don't get the wallowy mid-stroke you get from those air forks either.

    Pics...

    In retrospective... I still can't figure out if I would have gone for the 150mm X-Soft or 140mm Soft spring. Bear in mind the Coil U-turn raises the spring rate a little as you wind it down and you have to wind down the 150 Sektor spring to use it in the revelation


    1.- All the parts you need to do the conversion from a Revelation RLT Ti 150mm.
    - Spring Assembly (includes top cap and foot nut in the bag)
    - Coil U-Turn dial.
    - Rubber bumper or spring for top out in damper. (The one I used probably came out of a Nixon). Anything from 3-5mm tall will do.

    2.- Rubber cumper installed on damper shaft as top out bumper.
    Attached Thumbnails Attached Thumbnails Replacing Revelation Dual Air assembly with Sektor U-turn assembly ?-2012-08-23-220-1.jpg  

    Replacing Revelation Dual Air assembly with Sektor U-turn assembly ?-2012-08-23-223-1.jpg  

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    thanks a million for this! How does it feel to finish a project you thought about for over a year

  17. #17
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    Quote Originally Posted by morpheus1029 View Post
    How does it feel to finish a project you thought about for over a year
    Feels awesome, brotha!!

    I work away from home and have limited time for bike stuff. So, every little thing I can do bike-wise feels like an achievement.

    Other folks here and in other places (the customization you can see in mtb-news.de is mindblowing, unreal!) have really done great things. This is just a parts swap.

    I'm still puzzled as of why the U-Turn spring gives 10mm of travel more on the Revelation than the Sektor.

    A2C is the same, lowers are the same, the cart goes from head to toe of the leg... yet, the Sektor spring has to be compressed to get 150mm in the Revelation.
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  18. #18
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    I"m looking to purchase an Revelation and do this same thing. Gonna use the u-turn out of a Pike though. Glad to know it works. Now to find a Rev with tapered 20mm.

  19. #19
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    Quote Originally Posted by OffCamber View Post
    I"m looking to purchase an Revelation and do this same thing. Gonna use the u-turn out of a Pike though. Glad to know it works. Now to find a Rev with tapered 20mm.
    The Pike has a slightly different system, as it uses a baseplate to contain the spring inside the stanchion. In the Sektor the spring goes from crown to foot nut.

    In the Pike th spring goes from the crown to the bottom of the stanchion.

    It should work, at any rate. Threads should be the same and the revelation has a groove at the bottom of the stanchion for the circlip that holds the baseplate.

    You would not need to do anything to the damper side in that case.
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  20. #20
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    Just a side note as I've got my two forks pulled apart:
    1-Revelation world cup DP air
    2-Sektor 150mm Uturn coil.

    I hopefully plan to turn the rev into a uturn coil. Tthe stancion length is indeed different between the two as the sektor's are 2-3 mm longer. And the sektor as stated a few times before, does have a top out assembly that is similar to the lyrik, and it is located on the rebound side, not the spring side. Pics to come soon! Trouble will be replacing that top out assembly with a suitable bumper, as I plan to sell the sektor intact.

  21. #21
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    Quote Originally Posted by c-dale99 View Post
    Just a side note as I've got my two forks pulled apart:
    1-Revelation world cup DP air
    2-Sektor 150mm Uturn coil.

    I hopefully plan to turn the rev into a uturn coil. Tthe stancion length is indeed different between the two as the sektor's are 2-3 mm longer. And the sektor as stated a few times before, does have a top out assembly that is similar to the lyrik, and it is located on the rebound side, not the spring side. Pics to come soon! Trouble will be replacing that top out assembly with a suitable bumper, as I plan to sell the sektor intact.


    The only concern would be that the internal face of the stanchion on the spring side of the Sektor would be scratched so the DPA would not hold a seal.

    But if that the case, try to switch the damper to the spring side and the DPA to the damper side. The seal is not that critical on the air side. Check also that the bottom of the spring-side stanchion has a suitable groove for the circlip of the damper's baseplate.

    Best of lucks!!!
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  22. #22
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    Thinking about doing this to my dual air rev but am having a hard time finding a 150 soft yellow spring from a US vendor. Anyone know where I can get one?

  23. #23
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    Quote Originally Posted by kan3 View Post
    Thinking about doing this to my dual air rev but am having a hard time finding a 150 soft yellow spring from a US vendor. Anyone know where I can get one?
    I ordered mine from bike-components.de

    They have a page in english, shipping was cheap and everything went smooth. They don't have it in stock, though. You will have to wait.

    Anyone with a QBP or such account can order one. Just get in touch with a shop that is willing to take a is willing to order one and provide them with the SRAM Part Number.

    I weigh 140 and I get 20% sag out of the Soft 150mm, FYI.
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    Thanks for the response, I didn't even see that you replied

    Do you happen to remember how many millimeters you had to turn down the 150 spring to get it to work for the rev? I'm thinking about grabbing the 140 instead. I can always make a small spacer if I need to. I weight the same as you as well.

  25. #25
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    Quote Originally Posted by kan3 View Post
    Thanks for the response, I didn't even see that you replied

    Do you happen to remember how many millimeters you had to turn down the 150 spring to get it to work for the rev? I'm thinking about grabbing the 140 instead. I can always make a small spacer if I need to. I weight the same as you as well.
    Mmmmmhhh.... Nah, I don't remember, to be brutally honest.

    However, I remember that if I leave the spring to extend the fork freely, it will end up with 163mm of exposed stanchion (and with only like 15mm of bushing overlap).

    So, the 140mm spring COULD work and still give you 150mm... but it's a wild guess.

    For starters, I can't understand how the Sektor 150mm spring gives 160mm on the Revelation. The chassis is basically equal.

    My theory (and I don't have a Sektor to prove it) is that on the Sektor the spring in the damper side actually keeps the fork from extending to 150mm and the spring is permanently pre-loaded 10mm.

    Why would RS do that? I don't have a clue. Maybe the spring is shared with the Lyrik and/or the Domain and just the top-cap changes??
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  26. #26
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    Well, I have finished the conversion, and took it for a ride...it's simply amazing. I love the sektor but the blackbox/dual flow rebound in the rev is so much better. And the rev air was amazingly light, but the coil is so much more fun, and fluid.

    Warp, I've compared just about everything from the sektor to the rev, (by my rev has the carbon crown/steerer, so don't know if that's different than the aluminum steerer).

    The sektor has 160mm of exposed stanchion, but the uturn mark is clearly at 150mm .

    The sektor rebound overall length is longer than the rev dual flow rebound length, so that's how they get away with the 9mm long top out spring. And that's why when I put my 9mm bumper on the rev rebound, it preloaded the rebound too much and only left me with about 140mm of travel vs the 150mm it was originally designed for. But I cut my bumper to about 2mm and it's find now .

    I'll get around to some pics when I can....but the rev coil is so much better than a sektor coil.....or just upgrade your sektors to blackbox damping

  27. #27
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    Ok, so I picked up a 140mm fixed length spring with preload cap off ebay and here is findings. The spring allows roughly up to 12mm of extension or preload with the adjustment screw. The rebound rod is roughly 13mm longer than the rod at 0mm preload.

    This means if you turn the preload cap you actually just extend the fork instead of adding any preload to the spring. The length of the bumper you add to the rebound rod will actually determine the max amount of travel the fork has. Past that you'll start to add preload to the spring. The fork sits around 145mm of travel with preload cap set at 0mm.

    The 140mm fixed length spring actually seems like the ideal spring to use instead of the uturn spring. It weights less and you can still adjust the fork for 145-153mm of travel, assuming a 2mm bumper.

  28. #28
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    Resurrecting this old, moldy thread. Anyone still around that can speak to this conversion??

    I have a 2012 Rockshox Revelation Dual Position Air. The air rod needs to be replaced, but is very expensive. I'd like to try out this conversion to the coil system.

    From what I gather, it's an easy swap, but have to switch the existing rubber bumper from the negative air chamber of my air rod, over to the rebound damper rod.

    I would also likely buy the 140mm length coil to avoid any overextension issues.

    Anything else I'm missing?

    Thanks in advance.

  29. #29
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    Mine was a 2011 dpa rev rlt ti.

    I used a small pipe cutter to remove 10mm of the spring shaft on a 150mm sektor dual position coil. NO bumper on the rebound needed!

    This gives a 150mm travel fork, with dual positions, and coil. I absolutely recommend it!

    If you don't cut it, and use spacers, you can a ton of preload. Like a crazy, harsh amount.

  30. #30
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    Quote Originally Posted by One Pivot View Post
    Mine was a 2011 dpa rev rlt ti.

    I used a small pipe cutter to remove 10mm of the spring shaft on a 150mm sektor dual position coil. NO bumper on the rebound needed!

    This gives a 150mm travel fork, with dual positions, and coil. I absolutely recommend it!

    If you don't cut it, and use spacers, you can a ton of preload. Like a crazy, harsh amount.
    Thanks for the info. Perhaps this is a dumb question, but on that dual position coil, where do you adjust the preload?

    If I didn't want to cut off 10 mm of the 150, could I just buy a 140mm travel with the same results? Another dumb question, but from which end does the 10mm need to be removed?

  31. #31
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    No preload on the dual position. I haven't found this to be a problem though. I really like the dual position feature.

    And yup, you can absolutely just use a 140mm fixed spring for a 150mm rev conversion!

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