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  1. #1
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    Is it bad to bottom out?

    I bottom out my air Reba rl's at least twice every ride, usually more. Should I change something or is this normal? I've only rode the bike 6 times and it's a brand new stumpjumper comp ht. Thank!

  2. #2
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    Raise the air pressure in the fork. Repeated bottoming out can damage the damper cartridge / fork

  3. #3
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    Yes.

  4. #4
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    you need a shock pump to add air unfortunately. but its cheaper than the fork

  5. #5
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    Quote Originally Posted by skikarl View Post
    you need a shock pump to add air unfortunately. but its cheaper than the fork
    Very true you can get a decent pump for around $20>$25.
    As for adjusting your fork check out this thread to get a starting point then adjust to your liking.
    Depends on your weight and riding style.
    Notice there is a single air and dual air you want the info on single air model.
    Reba fine tuning
    Happy Trails
    ​​
    2012 Stump Jumper Comp 29'er H.T.
    1997 Rock Hopper / Manitou TI Bulge Fork / Shimano STX-3 x 7 P.O.S.​

  6. #6
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    Define bottoming out. It really depends on where and what you are riding. Ideally you want to use all of your suspension, but if you are truly bottoming out hitting the bumpers and feeling a thud then yeah. Not good, you need to add some air. You should really set your fork at about 20% sag. There are some good tutorials out there, just google it. That is a good starting point then you can add or remove air until you find what is optimal for you.

    Having a shock pump is a must have IMHO. You may not use it often once you get your shock/fork set but it is essential to have.
    Sent via my heady vibes from the heart of Pisgahstan

  7. #7
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    Quote Originally Posted by BlueSpecializedFox View Post
    I bottom out my air Reba rl's at least twice every ride, usually more. Should I change something or is this normal? I've only rode the bike 6 times and it's a brand new stumpjumper comp ht. Thank!
    I also have a new 2014 Reba Solo and I used the info off the decal to set my initial air pressure according to my weight. I weigh 180# and set it @ 125...I often use my bike as a commuter and when fork is set @ its most compliant setting it offers a very comfortable ride. I definately use all it's 100mm, but it has never bottomed out. Great fork
    Attached Thumbnails Attached Thumbnails Is it bad to bottom out?-dsc01459.jpg  

    2014 Nail Trail 29er

  8. #8
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    There is nothing wrong with bottoming out your fork once in awhile. It can handle it just fine. But I am guessing that you probably need to add a little bit of air. Go buy a shock pump (can't use a tire pump - too much volume). And try adding a little more pressure. Keep in mind that every time you disconnect the pump, you lose some air so the next time you hook up the pump it will read lower (about 5 psi, I think). I mention that because some people try to check their air pressure regularly and think they are losing air when they aren't.

  9. #9
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    Wrong, you only 'lose' pressure when you connect. This is important to note because it means recording the pressure prior to disconnecting takes priority over what it reads when you hook it back up in terms of making adjustments.

  10. #10
    Trail Ninja
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    Quote Originally Posted by Thor29 View Post
    Keep in mind that every time you disconnect the pump, you lose some air so the next time you hook up the pump it will read lower (about 5 psi, I think). I mention that because some people try to check their air pressure regularly and think they are losing air when they aren't.
    In most cases, that's air pressure from the shock pump's hose escaping when disconnecting. When you attach it to check pressure, once the valve is depressed, air comes out of the fork to fill the hose (or space between the fork's air valve, and the check valve on the pump/gauge). The fork's valve will close when you unthread the pump or pull off the gauge, keeping air in. Basically, you don't lose pressure when you disconnect, instead pressure is lost when you attach something unpressurized to the valve and the air from the fork's air chamber fills it up to try and equalize the pressure (that's how your air pressure gauge gets its reading).

    Trust how much pressure you pump in. Pull off the pump before testing, to ensure that the pump's hose basically doesn't act as an air chamber extension which makes it act as if your fork's air spring had more air volume. If you have released a lot of air from repeated air spring tweaking, you may have noticed that some oil may have sprayed out; once you find an ideal amount of pressure, be sure to replace that oil in the air chamber ensure the air piston seal head glides with minimal friction/stiction. Simple as depressurizing the air chamber, using a socket or wrench to unthread the bigger hex-shaped cap on top of the fork, and just pouring a small amount of lube in. They usually come in 5cc "pillow packs" that cost $2-3.

    Damage from bottom out really depends on how hard you are bottoming out. If you *barely* use full travel on a rare occurrence and don't sense anything that might have clashed and took some impact damage that shouldn't have, you shouldn't be worried, as there's a bottom out bumper in your fork that acts as a limited last line of defense. If you bottom out harshly and hear or feel something clash during that big impact and the bike doesn't run like it usually does, you should be worrying, as it's common sense to know that things will be damaged if you smash them hard enough. You want to prevent/avoid harsh bottom outs and inspect things afterwards if you experience one, for the sake of safety.

  11. #11
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    Re: Is it bad to bottom out?

    You can also have your lbs put some air in it for you, mine did it for free (twice), and I didn't even buy my bike there!

  12. #12
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    Not to go too OT, but do people have any recommendations on shock pumps?
    I have two- a Lezyne that is impossible to read and a Topeak that is easy to read, but doesn't register ANY psi when you hook it up. (Yes, there's air in the shock- I can pump it up, disconnect, reconnect and it still reads zero).

  13. #13
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    I've only used a Rock Shox model and it's been fine through a year of use, works as expected.

  14. #14
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    I use both the one that came with a RockShox retail fork I bought and a Topeak PocketShock DXG, whichever's more convenient (closer to grab). I like the Topeak far far more. I would re-buy the exact same one if I lost it.

  15. #15
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    Again, using full travel and never feeling it "stop" is good, if that's what you mean by "bottom out" it's good to have this every once and a while.

    If you mean it's abruptly stopping at the end of travel and you feel it stop, that is a bad "bottom out" and will quickly destroy a shock/frame or fork.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  16. #16
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    Quote Originally Posted by Art.C View Post
    Wrong, you only 'lose' pressure when you connect. This is important to note because it means recording the pressure prior to disconnecting takes priority over what it reads when you hook it back up in terms of making adjustments.
    Yes, you guys are correct. My point was that if you pumped your fork to 100psi, rode it, and then hooked up the pump again, it will read less than 100psi. I just wanted to point that out so that the OP doesn't freak out and think that not only is his fork bottoming out, but it's leaking too.

  17. #17
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    Best shock pump: |Fox

    I bottom out my fork regularly. It has a bottom out spring. I like a plush feel but at 200 Lbs if I come up short on a rock or root at full speed she hits full travel. After all with %20 sag my 140mm fork only has 112mm left and if I don't bottom it out once in a while what's to point of riding a long travel 29er?

    That feeling is called forgiveness. You screwed up, came up short on the landing, or mis judged the gap and BANG your fork is offering up itself as forgiveness for your mistake. Beats facial reconstructive surgery hands down...

  18. #18
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    Im not a technician but if I payed the dosh for 160mm im gonna use it all

  19. #19
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    Quote Originally Posted by RRRoubaix View Post
    Not to go too OT, but do people have any recommendations on shock pumps?
    I have two- a Lezyne that is impossible to read and a Topeak that is easy to read, but doesn't register ANY psi when you hook it up. (Yes, there's air in the shock- I can pump it up, disconnect, reconnect and it still reads zero).
    I just want to point out that shock gauges are not really accurate. A lot of forks have pressure recommendations on them but the pressure reading on the pumps can vary from one to the other. Ideally you want to go off of sag and record what pressure you like from a particular pump. I have two pumps, a Fox and a Rockshox, and the Rockshox reads about 5psig less. The best pump would probably be the Fox with a digital readout. Analog gauges lose their accuracy overtime. The mechanism behind the analog gauge is usually fairly reliable but the needle can move on the shaft.
    Killing it with close inspection.

  20. #20
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    Is it bad to bottom out?

    If you never bottom out your suspension then you've got more shock than you need, have too much air in it, or too much compression damping. The above responses are correct that you don't want to experience a jarring bottom out but firmly hitting the max travel every once in a while when you hit the most demanding features you encounter is not a bad thing. It just means you're making full use of the equipment you have. In fact, if I did not use full travel on my more demanding rides I would be making adjustments to soften up the fork.

  21. #21
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    Quote Originally Posted by Ufdah View Post
    but firmly hitting the max travel every once in a while when you hit the most demanding features you encounter is not a bad thing.
    I disagree. You do not want to "feel" it, any "firm" max travel "bottom" transfers a lot of stress to the frame and components (shock bolts, etc) that were not designed for it. This is even true when it doesn't "feel" like much force. Use the travel, but don't "feel" yourself using the travel=perfect. Most modern stuff should allow for a lot of ramp up in the last 10 and 5mm of travel, but if you hit bottom, increase pressure/preload and possibly spring weight.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  22. #22
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    In the moto world, you want to bottom the suspension on the largest or most abusive obstacle.

    I have always run my suspension a little stiff on the bicycle. I never let my forks get (under normal riding) more than 90% of the way through the travel. Reason? Margin for error. In my mind, it works this way - if I get in trouble and slam something, I want that extra 10% normally unused travel to be there to help save me. If I am bottoming the suspension under normal riding, there is no extra travel there in the event of an off line excusion! Right, wrong, or indifferent, it's the way I've ridden.

    Bottoming however is using full travel, sometimes with a bump at the end. You should never feel a SLAM, or feel a harsh stop. If you do, you need to stiffen the suspension. Increase your spring rate (air pressure).

  23. #23
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    It is bad, but just make sure to have the correct psi and also adjust the rebound.
    2013 Trek Cobia- 29er serious mountain bike
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  24. #24
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    Quote Originally Posted by DethWshBkr View Post
    In the moto world, you want to bottom the suspension on the largest or most abusive obstacle.

    I have always run my suspension a little stiff on the bicycle. I never let my forks get (under normal riding) more than 90% of the way through the travel. Reason? Margin for error. In my mind, it works this way - if I get in trouble and slam something, I want that extra 10% normally unused travel to be there to help save me. If I am bottoming the suspension under normal riding, there is no extra travel there in the event of an off line excusion! Right, wrong, or indifferent, it's the way I've ridden.

    Bottoming however is using full travel, sometimes with a bump at the end. You should never feel a SLAM, or feel a harsh stop. If you do, you need to stiffen the suspension. Increase your spring rate (air pressure).
    I like this reasoning. I bumped up the pressure in my reba 10 psi. I prefer riding rigid anyway.

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