X-Challenge Rear Air shock settings

Discussion in 'Thumpers' started by Sonymalc, Nov 23, 2007.

  1. Sonymalc

    Sonymalc I'm Just Here

    Joined:
    Jul 10, 2006
    Oddometer:
    441
    Location:
    Sparks NV
    So I have had my rear air shock set to 130 psi cold, I am about 300 lbs and 6 ft 4 inch. This is what according to the book I should be at if not more pressure for my weight. The bike sat really high and stiff. I was out riding yesterday and got into some technical rocky jeep roads. The bike was just a hand full, but would go up the stuff. My dad rode behind me on his 610 and said that the rear was hardly working at all, so on the side of the trail i let some air out. I did not know at the time how much i let out untill I got home and checked. I had it set to about 95 lbs. The bike was completly transformed into a proper dirt bike. The bike sagged much lower and felt strange not sitting so high. The whole rest of the day the bike worked perfectly for all the rock and nasty stuff. It also stayed right with the 610 were as before he was always waiting at the next turn.

    Also noticed that the bike did not work nearly as well on the high speed sections with the lower air pressure. I will bump it up a little to find the happy medium.

    So i figured I would start this thread for Air shock adjustment and what you are all running in it. Please include your weight for refernce to how much air pressure you run, and also what kinda riding you are doing. :deal
    #1
  2. PacWestGS

    PacWestGS Life Is The Adventure!

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    I'm about 225 all kit'd up and pretty happy with 110psi cold. I haven't aired it out yet, but pretty sure it would handle the landings just fine at that.

    I'm liking the soft rebound setting for just about everything as the hard setting is just too hard for normal riding. Must be a race setting since there is not a lot of choices.

    120psi was just too stiff for what I weigh and what I'm doing with the bike.

    Just play around with cold pressure settings until you find what works, trying to adjust hot setting will never be right in the long run...
    #2
  3. GB007

    GB007 Been here awhile

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    I weight about 165 lb, am 5-10. 85 to 90 psi seem to work fine for me. I enjoy the air suspension, the only problem for me was on a long ride in Baja (in a very Hot day) when I arrived to the destination, I could not get off the bike since the pressure went up due to the heat... That's pretty much my only complaint. The more I ride my bike, the better I like it! :rofl
    #3
  4. toofast4uu

    toofast4uu adventurer

    Joined:
    Jul 18, 2006
    Oddometer:
    978
    Location:
    NJ
    I'm 155, 5'7"

    I've tried several settings..First being BMW recommended of 115 or leveling out the level...That's just way too stiff...

    I ride alot of deep sand and big whoops...for that, I use 95psi...If I know it's going to be an easy ride day, then 85psi is really comfortable.

    I prefer the "Hard" setting verse the "Soft", but again, the deep, sandy, whoops at high speed require it, otherwise "Soft" would work fine..
    #4
  5. Slideking

    Slideking Etta

    Joined:
    May 16, 2006
    Oddometer:
    13
    Location:
    Pretoria, South Africa
    I think the level on the bike is incorrect. I am 90kgs and if I pump it to level it is so hard the back doesn't move at all.

    What are your settings for the front rebound and compression?
    #5
  6. Metteke

    Metteke Beemer beat in me

    Joined:
    Jul 8, 2007
    Oddometer:
    209
    Location:
    Flanders Fields
    The air bubble is not correct. There is a measure out now to replace the plastic bracket which holds the bubble to correct its position. Atl least when your bike is in the specified VIN range.

    Better is to use the manual as reference, and then adjust for you. One thing is not so good: measuring a lot. Since the volume in the shock is small; the minor air loss will have a reasonable impact in pressure. So eacht time you measure -pssjt- 300grams of at least. Try to measure the hight of the bike , and not the pressure in the shock.
    #6
  7. Max Kool

    Max Kool Xtankteam™

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    +1

    Adjust the pressure untill the race sag is close to 1/3rd of the total wheel travel and you will be fine.
    #7
  8. Some Dude

    Some Dude what attitude problem???

    Joined:
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    90-100 mm rider sag in the rear is about the sweet spot.

    Be CAREFUL not to let too much air out or ride the bike very long with too low of an air pressure. If you ride the XChallenge with too low of an air pressure, the air bellow will rub the stone/mud gaurd and wear a hole in the shock in short order. Do not use air pressure to lower the bike, that is a bad idea, use the air pressure to obtain 90-100mm of rider sag for your wieght and then adjust slightly to accomodate for temp or conditions. One blip of the shrade valve will loose you alot of PSI very quickly.

    On the other hand we decided to try out an Ohlins in place of the air shock and I really like it on the XChallenge, really made the bike more predictable on and off road, albeit for almost a $1000
    #8
  9. lkongo

    lkongo Roxen rider

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  10. GB

    GB . Administrator Super Moderator Super Supporter

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    All good info for an X-C wannabe noob :thumb
    #10
  11. Sonymalc

    Sonymalc I'm Just Here

    Joined:
    Jul 10, 2006
    Oddometer:
    441
    Location:
    Sparks NV
    Currently for my front suspension I am 4 clicks down on compression and 2 clicks up for rebound from stock. I am still tuning that however.

    All great info guys. keep it coming.
    #11
  12. oggi

    oggi Adventurer

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    Mar 5, 2007
    Oddometer:
    73
    Location:
    nyc
    please...can someone please help me with my rear shock. Im 190lbs, running 91psi and have the damper on full, it still bottoms out on bumps and sounds horrific when jumping, the 'clunk' sound of it topping out in the air makes me feel like something is gonna break off. the feel of the suspension is not great, but the wheesing and cluncking of the rear shock is disturbing.
    #12
  13. GB

    GB . Administrator Super Moderator Super Supporter

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    Moved your post to this thread where you may get some ideas and responses. :thumb
    #13
  14. Flo_Evans

    Flo_Evans Been here awhile

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    Apr 25, 2008
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    431
    Location:
    St. Louis, MO
    I am a total dirt n00b, and just got the bike this week so I am using the air pressure recomended in the manual. Around 230lbs. so I set it at 125psi. Still getting to know the bike but I think I will try running a little less air.
    #14
  15. GB

    GB . Administrator Super Moderator Super Supporter

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    Keep in mind as the air in the shocks heats up and expands, the shock will get stiffer. I would also recommend you replace the stock shift lever as soon as possible, quite a few people on here have broken off the shift shaft to which the lever attaches, because the cast lever is very stiff and does not bend, transmitting the force to the shifter's shaft.. The steel one from the F650 will fit it.
    #15
  16. TL Mac

    TL Mac TL Mac

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    21
    Location:
    Northern California
    I just returned for a Death Valley trip. During one of my rides I was getting beat up by a wash board road. I adjusted the rear shock up to 130 psi. I'm 6' 02", 195 lbs. (without gear) and had a tail pack with water and tools. I set the rebound in the hard position. This set up seemed to be OK - I'm still tying to figure out this air shock; it wasn't consistent though. My rear shock also has a loud, high pitch squeek when it's working and has been since new. Just returned from the BMW shop and they were baffled. They are sending a message to BMW to see if there are any other problems similar. They'll replace the shock - but are waiting for a reply first from BMW.
    #16
  17. Max Kool

    Max Kool Xtankteam™

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    Are you sure it's the airshock, and not the joint of the exhaust header and the end can? Although I know the airshock can sqeak, in some cases it's the connection of the exhaust.

    Further more about the airshock, some like it, some don't. I tried over a year to get used to it, but gave up and bought a normal coil-over. It surprised me too many times throwing me nearly over the bars, especially on series of whoops. Felt like lack of rebound damping.
    #17
  18. TL Mac

    TL Mac TL Mac

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    Mar 10, 2008
    Oddometer:
    21
    Location:
    Northern California
    It's the shock. When the bike is off I can stand on the pegs and work the rear shock up and down - I'll start squeeking. I thinks it's the bottom pivit point on the shock. The shop is not so sure. We'll see.
    #18
  19. johnnydanger

    johnnydanger Dangerous!

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    Oddometer:
    62
    Location:
    Bellingham, WA
    Clocking in around 240 with gear I find 115psi and the SOFT setting to work quite well offroad. Flip it to HARD setting on the road for a firmer ride. I think it works pretty good at that setting. Probably would work better with less air on the really nasty big rock stuff but find 115psi to be a good general setting. I didn't like how the shock modulated over water bar bumps with a lower setting.
    #19
  20. CapeG650X

    CapeG650X Been here awhile

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    Mar 28, 2009
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    Kalgoorlie
    Wd40 on lower shock mount fixes mine when it squeaks.
    #20