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  1. #1
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    RP23 pressure question??

    I just finished building a Mojo HD 140 with the stock RP23 rear shock. I have a couple rides in at my local trail and I'm finding that I need much lower pressure than what is recommended to get near full travel. The sag ends up being a little more than 30% (unscientific measurement) and I'm getting through most of the travel. My local trail is a technical XC type. A few downhills, lots of rocks and roots. I'm not a hucker so I stay away from the big drops. I'm still getting used to the bike so I'm not pushing it hard yet but I'm just a little confused on the pressure. I don't bottom out and I should probably just shut up and enjoy the bike since it feels good but I'm curious by nature. Any input is appreciated.

    I'm around 230 lbs with gear and the shock is at around 150 lbs right now. I started at around 210 and it felt harsh and I wasn't even close to going through the travel. I incrementally backed down to where I am now and it feels pretty good. I used two different shock pumps in case the gauge on the first one was off but they read about the same.

  2. #2
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    150 on the shock and you're 230lbs? You would be at around 45-50 percent sag. That's a lot. You may need a good shock tune to a more plush type of setting. I am struggling with shock settings myself right now. It's great, but could be better. I have mine set at 260 and I am 220lbs right now. My sag is around 20 percent-ish.

  3. #3
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    That's what I'm thinking. It just doesn't seem right. As mentioned, I put 2 different pumps on to see if one was off but that doesn't seem to be the case. I talked to a tech rep (from Santa Cruz bikes, not specifically about my bike) who said they adjust shocks more by feel and proper sag and not by why the gauge says. I agree with that but I would think I would be a little closer to my body weight for the pressure. This all might be moot since I'm thinking of changing everything to set the bike up at 160mm but like I said, I'm curious if anyone else found something similar with their setup.

  4. #4
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    Yeah that's really low setting. Not sure I agree about not using the gauge as, well a gauge, but when I had mine setup the first time, they didn't use a gauge till the very end before they set up the sag by looking and using a tape measure to figure it all out, then gave me a pressure number on both front and back, but have since changed some things around, and now I use less sag in both the front and rear as I keep blowing though it on downhill runs and having trouble getting it to be more progressive, but I may change out to a push tune at some point, and you might want to go that way as well. I hear it really wakes up the bike. Typically the heavier you are, the more benefit you get by using a custom tune.

  5. #5
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    I'm going to keep riding and tweaking it for now. I'm not bottoming out and it still feels good when I'm pedaling/climbing. For whatever reason I'm fixated on the pressure #. Like I said, maybe I should just shut up and ride.

    I've heard good things about the PUSH tune as well. I've also looked into a Marz or X-fusion shock from bikeco.com. I've read on here a few times that they are pretty good at tuning rear shocks for the mojo.

  6. #6
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    From what I have been told, I would not run Marz on it. X-fusion's 13 line up looks really promising, but as of right now, I don't think it's as good as the rp23 for an overall ride. I do not have personal experience with this, just stuff I was told at the shop. Cane Creek is making a 140 set up shock for the HD and it looks like it has a bunch of cool adjustments on it, and on their page, it has a standard setting for the HD under the 160mm setting, but the 140mm is coming soon. Push or Fox have a great tuning center, but the problem is communication. It's really hard sometimes to tell them what you want, because you're not even sure what optimum is, so that's always an issue.

  7. #7
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    150 psi for 230 lbs rider is really low. i weigh 190 lbs and than +/- 10 lbs gear, ride depending. i started with my weight for pressure and ended up at 180 which feels allright for now, i just barely use the whole travel. i have shim kit on the way so will see if i can lower pressure little more.
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  8. #8
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    I also weigh 230, and I had exactly the opposite experience. I had Push convert an older 36 RC2 to a Float, and when I put it on my HD140, I discovered that I was using nearly all of the travel of my RP23 but only half the travel of my fork going down a moderately technical trail. My shock pressure was set at 230 (checked with the gauges on two different shock pumps). As an experiment, I increased it to 250 yesterday, and that put the relative travels of the fork and shock back into balance. I guess I'll probably end up sending my RP23 to Push too.

  9. #9
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    Sounds like there's something wrong with the guage on your pump.

    If you try to set your shock up to use full travel all the time then it's going to be really soft. If that's what you like, fine. If you want more control than add more air.

    Use Travel and Sag as a starting point then increase or decrease pressure a bit to get it to where it feels the best.

  10. #10
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    When I was running an RP23 I was using about my riding weight in PSI, 220lbs.
    I always adjusted pressure by how the bike rode. Once I got to the right PSI I'd remember it, and that's when the gauge would become useful. After maintenance I could always get it back to the right pressure, assuming I always used the same shock pump.
    150psi for a 230lb rider seems way low. That's about 20psi more than my 130lb girlfriend runs on her mojo.
    Those who know, ride a Mojo AND a Mojo HD.
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  11. #11
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    Just adding a little here: note that full travel does not move the o ring to the end of the shaft. Full travel on that shock is 2", leaving about another 2.5 - .3" or so before the o ring makes it to the end.

    At 150 psi I would expect you to be bottoming out easily. Maybe there is something wrong with your shock. Try letting the air out and see if it bottoms (tire very near the seat tube) without air. If not, there might be some oil in the air chamber limiting the travel. You might get some oil squirting out with the air when you discharge the shock as well if that is the case. If so, we should work on getting your shock rebuilt or exchanged.

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  12. #12
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    Thanks for all the replies!

    Hans, here is a pic of what i got after my last ride. I kept going up and down a higher speed downhill section with some roots and rocks to see how the shock was cycling and it is a good representation of the worst I'd ride on a regular basis, not counting the occasional trip to a bike park. This was with (according to the gauge on 2 shock pumps) around 150 lbs. I was going up and down in pressure with each run to see what change it made. I am definitely not bottoming the shock. When I get some time I'll try what you suggested with letting the air out. Thanks!

    RP23 pressure question??-imageuploadedbytapatalk1337638658.837900.jpg

  13. #13
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    That's pretty close to BO. How is the ride? Any bobbing while peddling? I'm bottoming out with little progression is my issue. I have had 2 rp23's doing this, so I think I need to send mine to push or fox for a tune to my riding style. Still rides fine 90 percent of the time, I just need a different shock and better tuning.

  14. #14
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    Mazspeed, it's definitely close to BO but I'm not hitting the end (not that I want to). It rides well, not much bob. I'm coming off of a Nomad with a coil rear shock so even at this setting I think the mojo feels better climbing.

    Hans, I let the air out and didn't notice any oil coming out when releasing the air. The shock bottomed without any air in it and put the o ring right at 2".

    RP23 pressure question??-imageuploadedbytapatalk1337640290.038509.jpg RP23 pressure question??-imageuploadedbytapatalk1337640311.009255.jpg RP23 pressure question??-imageuploadedbytapatalk1337640336.268726.jpg

  15. #15
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    So let me throw this out there. My method for tuning a shock has always been to get it as close to BO without actually bottoming out during my typical riding conditions. I never saw the point of setting it so I'm only getting 80% or less of the travel on any given ride. I want to get 90-95% and save a little for a missed landing or big hit to prevent BO. Again, I normally keep the rubber on the ground as much as possible so I'm not doing big drop or jumps. Is this wrong?

  16. #16
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    That all looks correct. I have no idea why you are not getting full travel.
    Do you have any way to do a shock swap with someone, just to AB them?
    Shop or riding buddies with the same shock....
    H
    Hans
    Ibis Cycles, Inc.

  17. #17
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    Hans, honestly it feels pretty good as is and I'm happy with the amount of travel I'm getting. It just seems strange that it is at such a low pressure. As of right now I'm the only one in the area with a mojo and I bought the frame from Briarcliff bike works which is about an hour and a half away. I'm sure I could take a ride to the shop and Lou would let me try a different shock if need be. My LBS said that they are working on setting up an account with you guys but I don't think they have plans on ordering a bike for their inventory right away. I'm trying my best to spread the word of ibis around here for you! Thanks for all the input, I'll keep playing around with it. No matter what the gauge says it's still a ton of fun to ride!

  18. #18
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    It may just be that without jumps and G-outs you're just not getting the force up enough to get into the last 25% of the travel. Maybe head out with that in mind and find something that pushes everything a bit more. For example, stay in the saddle going down into a dry creek bed or transition from dh to up hill and see what it does.
    H
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  19. #19
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    Will do! Thanks everyone

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