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  1. #1
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    Rockshox Reba RLT Ti 29 Dual Air 140mm

    I got a new Reba RLT Ti 140mm fork for a decent price off ebay and had it mounted on my new 2010 RIP 9 frame.

    When I measure the travel from the outside bottom of the crown to the top of the bottom leg, I only get 133 mm, is that normal for this fork?

    I don't see how it could have 140 mm of travel...kind of makes sense if a 20 mm spacer is installed...two spacers came in a bag with the fork.

    My LBS told me that the fork should have come without any spacer installed when I asked about it before it was mounted. Were they correct, or does a spacer come pre-installed that has to be removed for 140 mm of travel?

  2. #2
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    Quote Originally Posted by jbsocal View Post
    I got a new Reba RLT Ti 140mm fork for a decent price off ebay and had it mounted on my new 2010 RIP 9 frame.

    When I measure the travel from the outside bottom of the crown to the top of the bottom leg, I only get 133 mm, is that normal for this fork?

    I don't see how it could have 140 mm of travel...kind of makes sense if a 20 mm spacer is installed...two spacers came in a bag with the fork.

    My LBS told me that the fork should have come without any spacer installed when I asked about it before it was mounted. Were they correct, or does a spacer come pre-installed that has to be removed for 140 mm of travel?
    Have you checked the air pressure ? Is it pumped up.

  3. #3
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    I put about 135 psi in both the pos and negative according to the chart on the leg (I weigh 245 lbs)...only been for 1 "cross-country" type ride and did not bottom the fork, according to the sag ring I only used about 110 mm of travel.

  4. #4
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    I think your negative air will reduce the travel available. At least I heard that from a mate who ran negative higher than positive to reduce the travel on a Rockshox fork.

    However using all the travel available is another issue. I can't seem to use all of mine either, even with very little air pressure and pushing down hard on the bars in the driveway.

  5. #5
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    I just noticed the same thing with my 140 RLTi fork. I let the pressure out of both chambers (using the shock pump), then refilled the positive, then the negative. I run 10 psi less in the negative chamber. I now have 140 mm of travel.

  6. #6
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    Was the fork new in a box, or a takeoff from another bike? Specialized has been using the Reba 140 for their Stumpy FSR 29er but with a 10mm spacer take it down to 130mm

  7. #7
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    Mine was new in the box.

    I think the fork came with some air in it.

    I think I measured it before I added any air...adding air did not change it.

    The LBS said to add negative before positive, I'm not sure why...

    I will have to try letting the air out later to see if that makes a difference.

    I couldn't find any tuning information in the manual that came with the fork nor on SRAM's website...

  8. #8
    West Chester, PA
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    Running the negative at the same pressure as the positive will pull down the fork a little with most rebas (I've had 3). Let a little out of the negative, I run mine 10 pounds lower than the positive. You probably won't notice any difference in the feel.

  9. #9
    JMH
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    gfs69 is correct IME. You need to set positive pressure first, with nothing in the negative pressure chamber. The closer the two chambers are, the plusher the fork will be but the more likely it is that the fork will settle at about 135mm travel instead of the full 140mm. I run negative about 5-10psi lower.

    JMH
    Last edited by JMH; 09-19-2011 at 01:26 PM.

  10. #10
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    As soon as I let out the negative air, the fork popped up to about 150 mm.

    I ended up putting in 100+ and 90-, now it measures about 145 mm. I measured about 30 mm sag, so I'm going to leave it for my next ride, even though it doesn't match the sticker recommendations for my weight.

    I must have had too much air in the negative chamber.

    Thanks for the help.

  11. #11
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    Quote Originally Posted by jbsocal View Post
    As soon as I let out the negative air, the fork popped up to about 150 mm.

    I ended up putting in 100+ and 90-, now it measures about 145 mm. I measured about 30 mm sag, so I'm going to leave it for my next ride, even though it doesn't match the sticker recommendations for my weight.

    I must have had too much air in the negative chamber.

    Thanks for the help.
    How did 100+ 90- work out for you?
    I^2xR

  12. #12
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    It had too much brake dive.

    I think I'm running about 150 + 130 - now (way less sag), seems to be OK but does not use near as much of the travel.

    There is a new Reba tuning thread...one guy suggested to try putting the negative 10 lbs higher than the positive to eliminate brake dive.

    I haven't experimented with it enough yet.

    I'm probably eventually going to end up running my WB 150 on the RIP instead of the Reba.

  13. #13
    JMH
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    Quote Originally Posted by jbsocal View Post
    It had too much brake dive.

    I think I'm running about 150 + 130 - now (way less sag), seems to be OK but does not use near as much of the travel.

    There is a new Reba tuning thread...one guy suggested to try putting the negative 10 lbs higher than the positive to eliminate brake dive.

    I haven't experimented with it enough yet.

    I'm probably eventually going to end up running my WB 150 on the RIP instead of the Reba.
    Your goal should be to get rid of dive independently of air pressure. Increasing the negative pressure simply makes it more likely to dive and increasing positive means you don't get full travel. The best method is to find a spring feel you like that allows full travel, then tune out dive with low speed compression. Manufacturers could make it easier on us by providing a real LSC knob that is independent of platform but the Black Box damper on the Reba gets the job done.

    Try this:

    Set Spring: Go back to the positive pressure and sag that allowed full travel. Adjust the negative according to feel, either equal or 10psi lower than positive. Yeah, lots of folks run pressures well outside this range, but this is the sweet spot IMO.

    Set Damper: (1) Open floodgate (Gold Knob) all the way (counter-clockwise) (2) Close your lockout carbon knob all the way as if you intended to lock the fork. (3) Start by turning the floodgate knob 1.5 turns clockwise and compress the fork. Locked out? or just really firm?. (4) Bounce away on the fork and adjust the floodgate until your fork feels pretty firm but still works, i.e. maybe just barely locked out. If you tune the floodgate so that it supports out of the saddle hammering but still allows the fork to compress at full lockout, you now have 5 or 6 clicks of useable platform to work with that will allow you to get rid of fork dive and the fork will ride higher in its travel.

    A lot of folks run a huge amount of floodgate and use the indexed carbon knob as a full On Off switch, which doesn't take advantage of the adjustment range.

    If you already tried all this stuff, then disregard.

    JMH

  14. #14
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    Quote Originally Posted by JMH View Post
    Your goal should be to get rid of dive independently of air pressure. Increasing the negative pressure simply makes it more likely to dive and increasing positive means you don't get full travel. The best method is to find a spring feel you like that allows full travel, then tune out dive with low speed compression. Manufacturers could make it easier on us by providing a real LSC knob that is independent of platform but the Black Box damper on the Reba gets the job done.

    Try this:

    Set Spring: Go back to the positive pressure and sag that allowed full travel. Adjust the negative according to feel, either equal or 10psi lower than positive. Yeah, lots of folks run pressures well outside this range, but this is the sweet spot IMO.

    Set Damper: (1) Open floodgate (Gold Knob) all the way (counter-clockwise) (2) Close your lockout carbon knob all the way as if you intended to lock the fork. (3) Start by turning the floodgate knob 1.5 turns clockwise and compress the fork. Locked out? or just really firm?. (4) Bounce away on the fork and adjust the floodgate until your fork feels pretty firm but still works, i.e. maybe just barely locked out. If you tune the floodgate so that it supports out of the saddle hammering but still allows the fork to compress at full lockout, you now have 5 or 6 clicks of useable platform to work with that will allow you to get rid of fork dive and the fork will ride higher in its travel.

    A lot of folks run a huge amount of floodgate and use the indexed carbon knob as a full On Off switch, which doesn't take advantage of the adjustment range.

    If you already tried all this stuff, then disregard.

    JMH
    Probably one of the most comprehensive easy to read posts on tuning the Reba. Thanks.
    I^2xR

  15. #15
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    Quote Originally Posted by bikin View Post
    Probably one of the most comprehensive easy to read posts on tuning the Reba. Thanks.
    For real.

  16. #16
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    I changed my settings tonight...is it normal for some oil to come out of the negative - air?

    Thanks for the help.

  17. #17
    JMH
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    Quote Originally Posted by jbsocal View Post
    I changed my settings tonight...is it normal for some oil to come out of the negative - air?

    Thanks for the help.
    Yes, a little bit sometimes spurts out. You can avoid this by turning the bike upside down for a few minutes before adjusting the negative air. It's really not a big deal though unless it gets on your rotor and you don't notice.

    JMH

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