Mountain bike setup geometry basics

Discussion in 'The Bike Cafe' started by marcts, Aug 28, 2005.

  1. marcts

    marcts New Member

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    Hi Everyone,

    For the last two years I have been mainly riding on the road. Yesterday I went up to the mountains in north Georgia to do some riding. Trail has steep climbs, and steep technical downhills. After not being on the mountain bike in a year, I really lost a lot of technique, and fell several times!

    Anyway, I have a 2003 (I think) Cannondale jekyll 900sL bike. It has full suspension, with an adjustable rear shock, and geometry.

    Can someone explain the basics?

    The rear shock can be switched off, to fix the rear wheels. In what kind of terrain is this usefull, other than the road, climbing, descending?

    The front shock can be switched off. It seems that this should only be done on the road?

    The rear shock has a spring adjustment fast/slow. What are the advantages of fast/slow and in what kind of terrain should they be used?

    The geometry of the rear can be changed, but rotating the rear shock (screw). Looks like this moves the rear tire closer up under the rider. Would this be beneficial for climbing?

    I am 5'10 about 190 lbs if that makes any difference.

    thanks,

    Tim
     
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  2. rsprenkle

    rsprenkle New Member

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    The adjustable geometry is to customize the bike for the particular terrrain/ way in which you want to ride so baiclly the steeper head tube angle is for cross country type riding and the slacker adjustment is for more all mountain riding (keeps your weight more towards rear wheel). You are correct in assuming you only switch the shock on smooth trails/fireroads. As far as rebound for the shock goes you want to keep it as fast as possible, if you get it to slow you could experience compacting where the shock does not fully extend before hitting your next bump. I would start off at about 2 clicks towards full fast and go from there. I am curious as to what type of rear shock and fork are on your bike, that information will also prove valuble in setting up your bike.I also have a jekyll and if you have anymore questions let me know. I am knew to road riding perhaps you can give me a few tips. Have fun riding:cool:

     
  3. EX2

    EX2 New Member

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    The fast/slow dial is for the speed of the compression damping too slow and the shock will pack down and too fast the rear end will skip all over the place. I would have a play around and see whats best for you. I normally have mine set about 3/4.

    The screw that changes the geomatary is for setting the sag in the rear shock this is so the rear wheel can track down into hollows. You should set this so when you sit on the bike you should compress the rear shock to about one third of its travel.

    Hope this help's
    Dean.
     
  4. rsprenkle

    rsprenkle New Member

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    Ex 2 I am not trying to be argumentative but the screw that changes the geometry on the jekyll does just and only that! The sag is set by ajusting air pressure or tension on the spring of the shock depending on what type of shock he has. Once again I don't mean to be rude but just want to make sure he gets the right info.
     
  5. EX2

    EX2 New Member

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    Thats cool not had much to do with cannondale's and was just trying to help.

    Dean.
     
  6. moto

    moto New Member

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    I have heard of the lockouts being useful for climbing up steep trails where pedal bobbing becomes noticeable. Personally I like a little compliance in the rear suspension on climbs, but locked-out is more energy efficient. This is where the old "climbs like a hard-tail" analogy originates.
     
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