X-Challenge Air Shock Problems

Discussion in 'Thumpers' started by W8-4IT, Sep 27, 2007.

  1. W8-4IT

    W8-4IT Been here awhile

    Joined:
    Dec 9, 2003
    Oddometer:
    300
    Location:
    Thornville, OH
    I was attempting to get the air shock set right on my X this past weekend. At 90psi I can touch but it doesn't feel like it has enough suspension and at 120psi it feels right but I have a hard time touching. I settled on 100psi but after putting air in it I sat on it and it felt like it had about 80psi in it. It would sag under my weight to the point I could touch fairly well. I thought that was odd so I added air and at 115 it felt the same so I went to 125psi and it still feels the same it sags under my weight. It doesn't seem to make any difference any more how much air is in it. Has anyone else had issues with the air shock. It isn't loosing air either. when I check it it still has 125psi. ???? What gives?:puke1
    #1
  2. flan8tive

    flan8tive Flea Tibet!

    Joined:
    Oct 6, 2006
    Oddometer:
    2,188
    Location:
    Center of the Humidiverse
    What does the dealer say?

    Other than the air shock, I'd love to get your thoughts on the bike.
    #2
  3. W8-4IT

    W8-4IT Been here awhile

    Joined:
    Dec 9, 2003
    Oddometer:
    300
    Location:
    Thornville, OH
    I love the bike. There is just two things that need changed. The air shock I have not liked since day one and the seat SUCKS!!! I know it's not a touring bike and the seat isn't made to sit on. But I ride it to work 3 or 4 times a week which is 40 miles each way and then usually 100 miles round trip to school twice a week. So I do alot of slab riding and I wish there was a seat option. But like I said other then that I love the bike.

    I haven't talked to my dealer yet. I will do that tomorrow, I have known the owner of the dealership for about 12 years or so. He will make it right I'm sure. It just sucks.
    #3
  4. Redbull Addict

    Redbull Addict I need another one...

    Joined:
    Jun 24, 2006
    Oddometer:
    1,262
    Location:
    San Jose / Truckee
    Wait a sec..First you said that at 120 you can barely touch and then you say it feels like 80 lbs. So what changed?

    I'm a light weight. 90-95lbs is plenty for me. The air bubble is right in the middle. The only issue for me is on a hot day after riding the pressure builds and I can no longer touch the ground while seated.

    How heavy are you?
    #4
  5. shardzero

    shardzero I have a bike.....

    Joined:
    Aug 30, 2005
    Oddometer:
    490
    Location:
    Perth
    From my experience, if you cannot comfortably touch the ground when the suspension is maxed out you are always going to have issues.

    The g650x (cross) challenge does 'buck' when you break hard on the front, which for me is only on road. It has no static sag and is really very tall, all exacerbating said 'buck'.

    The point of the bike is more dirt orientated, where, and I may be alone here, I tend to use a lot more rear break and have little or no problem with performance grade riding (ie. fast over bumps)

    Get the ohlins shock if it is ruining your life, or the xcountry.

    Incidentally they have adverised a 'low' seat in the latest BMW equipment catalogue. This may be worth waiting for.

    As for hard seats..... wear bicycle shorts with butt pads, get a fat arse, rebuild the seat, put a sheep hide on it, or man the $%#@ up. :rofl

    I am 186cm and 70kg+10kg riding gear. I like the rear pretty solid so I was running it at 90psi, gets a bit hard when warm but I do plan on an ohlins solution at some stage to make the ride more consistant.
    #5
  6. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    4,762
    Location:
    Los Angeles
    I have the race sag (bike with rider in riding position) set up at 1/3 of the total available suspension travel, which comes down for me at 8 bar. If I shift my weight only 5 cm forward it feels like it's too much pressure, and if I slide more to the back the bike sags to all the something like half the total travel. I have learned myself that when I put a foot down not to shift my weight onto my foot, for then the shock will uncompress to a point where the bike becomes very high. I try to live with it.
    #6
  7. W8-4IT

    W8-4IT Been here awhile

    Joined:
    Dec 9, 2003
    Oddometer:
    300
    Location:
    Thornville, OH
    That is my point something changed and I don't know what it is. It is almost as if the shock is experiencing blow by. If it were a hydraulic unit I would suspect the seals were bad. I just wondered if anyone else had experienced anything similair? Because it used to work fine.
    #7
  8. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    4,762
    Location:
    Los Angeles
    BTW, the air bubble is useless. If you set up your bike according to the air bubble, you'll end up with only like 30mm of race sag, which imho is too hard. I rode like that for a week, and although the bike steered really quick (huh no wonder), the rear was too hard.
    #8
  9. W8-4IT

    W8-4IT Been here awhile

    Joined:
    Dec 9, 2003
    Oddometer:
    300
    Location:
    Thornville, OH
    I have ordered a sheep skin pad that should arrive today and I am in the process of securing a build date from Rezanco for the new seat to be made, that is really not the issue here.

    Although I am in awe of your ability to grasp the obvious, I was asked my overall opinion of the bike (anyone paying attention will notice the difference here). Anybody that says they like that seat is either lying or they enjoy having a 2x6 shoved up their keester while they ride.

    The real topic is the air suspension and I have contacted Wilbers who can make a rear shock custom valved to your weight and include fork springs that lower the seat height 2" overall which I will be doing in the spring.

    So in the mean time if you do not have anything of value to add to the conversation then please run along and let the grown ups talk.:eek1
    #9
  10. Hair

    Hair Talking Head

    Joined:
    Dec 18, 2003
    Oddometer:
    17,295
    Location:
    Northern New Mexico
    In the air/oil shock world if the rebound damping is set to high the shock will load up and not fully rebound. This condition would eventually lead to the shock riding near the bottom of its stroke.
    #10
  11. beefjerky

    beefjerky Long timer

    Joined:
    Dec 4, 2003
    Oddometer:
    7,248
    Location:
    Atlanta baby, yeah!

    Get ya some bike shorts. or quit being a sissy. :rofl

    I kind of like the air shock, and I've figured out that the harder you ride, the better it handles. I keep it @ 110 psi. Kind of scary because I find myself hauling more ass than I normally would.
    #11
  12. W8-4IT

    W8-4IT Been here awhile

    Joined:
    Dec 9, 2003
    Oddometer:
    300
    Location:
    Thornville, OH
    This weekend will be my first real off road test with the bike.:clap I am looking forward to it. There is the possibility that the air shock is fine and I am off half a bubble.:lol3 While the static sag still seems to be off from where it was originally the suspension acted perfectly normal on the ride to work today. So I say it's covered by warrenty take it out and ride it like you stoled it.:wink:
    #12
  13. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    4,762
    Location:
    Los Angeles
    I second (and third) that! the air shock ONLY surprises me when I back off where I should better have nailed it some more. What is cheaper? Ride harder or buy a new shock? :lol3
    #13
  14. beefjerky

    beefjerky Long timer

    Joined:
    Dec 4, 2003
    Oddometer:
    7,248
    Location:
    Atlanta baby, yeah!
    Are we counting medical bills into the equation?
    #14
  15. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    4,762
    Location:
    Los Angeles
    ** knock on wood **
    #15
  16. Hoots Magoon

    Hoots Magoon Hey ya'll, Watch this!

    Joined:
    Mar 22, 2007
    Oddometer:
    1,259
    Location:
    Redneck in New England
    That is a huge shift in pressure in the rear shock. I suggest you set the pressure to the setting suggested in the owner's manual. Once this is done, it will take several rides to tweak it to your riding style, but you would have to do this for a normal shock as well.
    #16
  17. 5 speed

    5 speed Long timer

    Joined:
    Sep 12, 2006
    Oddometer:
    1,039
    Location:
    Orlando Florida
    Air suspesnion is always a bad idea, on anything. never seen one that you could get right because its not progressive as far as spring rate and two, never met one that didnt leak at some point. Fox tried air shocks back in the 80's, I would look to replace with a standard shock; heard Ohlins may have a replacement.
    #17
  18. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    4,762
    Location:
    Los Angeles
    That's very well motivated. I know it works at least on trucks, buses, limos and luxury vehicles (Audi A8 for example).

    As a matter of fact, an air spring is ALWAYS progressive (it's the nature of using gas as a spring) and most wound coils aren't. Which for instance is why playing with the air gap in a front fork can make such a difference in the feel of a fork. :huh

    yes Ohlins does a replacement, but I can't justify one yet. BTW, I have yet to see a BMW with a blown air shock and apart from a kickback now and then I like the Xch ride. The ride feels plush in midstroke, but still it doesn't bottom out on sudden loads, which is what I like about it. It seems to give good traction because of the fine response. Yes it looses some air after a few days, but that is easily compensated for with the pump that came with the bike.

    I still like it better than I hate it.
    #18
  19. Venteuri

    Venteuri I don't give a shit

    Joined:
    Sep 3, 2007
    Oddometer:
    18,648
    Location:
    Queretaro , Mexico
    ????? NUTS
    #19
  20. beefjerky

    beefjerky Long timer

    Joined:
    Dec 4, 2003
    Oddometer:
    7,248
    Location:
    Atlanta baby, yeah!
    I blew one.....

    I think the mudflap rubbed a hole in it.
    #20