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Thread: Stem Question

  1. #1
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    Stem Question

    I am considering changing my stem on my 06 stumpy (M) Can you tell me the length I have now?

    I am trying to lengthen the cockpit a touch, keep over the front wheel, and keep the front wheel down. It seems to change the seat post will only acomplisgh one of the above.

    Can anyone provide the length of stock stem?

    (I know it is 8* designed for 31.8 os, but dont know the length or ht)

    Thanks

  2. #2
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    Quote Originally Posted by 17J17J
    I am considering changing my stem on my 06 stumpy (M) Can you tell me the length I have now?

    I am trying to lengthen the cockpit a touch, keep over the front wheel, and keep the front wheel down. It seems to change the seat post will only acomplisgh one of the above.

    Can anyone provide the length of stock stem?

    (I know it is 8* designed for 31.8 os, but dont know the length or ht)

    Thanks
    My 2005 medium SJ120 had a 90 mm stem, I swapped it with a Thomson 110 mm (+10 degrees). FYI - I think that the 2005 large came with a 105 mm stem. I found that it made a world of difference for me as I was able to move the saddle a bit more forward (or less rearward I should say), it feels more balanced. I'm 5' 10.5", not sure of my inseam.
    -- 2009 Norco Faze 2 --
    -- 2007 Cannondale Synapse Alloy 2 --
    -- 2011 All-City Nature Boy --

  3. #3
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    17J, it's really pretty simple....

    just get out a measuring tape with inches on one side and cm on the other and measure from the center of the steerer clamp to the center of the bar clamp. That should get you close enough. I do believe the 06 M Stump FSR came with a 90mm stem at about an 8 degree rise. If you are talking the Stumpy hard tail that was a bit different if I remember correctly.

    Anyway a 110mm 10 degree or a 100mm 5 degree stem should accomplish what you are looking to do.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

  4. #4
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    It seems if you were going to go 100mm you would want the 10* and 110 the 5*. Simple math = longer stem will continue to rise anyhow??

    I do appreciate the feedback, and it is a stumpy fsr
    Another question is how many shims between the headset and the stem is everyon running?

    Thanks Again

  5. #5
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    Spacers below the stem is what ever height you want your bars at, it's the same thing as a different rise stem. Hopefully you have enough steerer tube with spacers above the stem to make adjustments if needed.

    MBA feb. issue had a article on different stem lengths.

    At a six degree rise these are the bar height changes for different lenghts...

    70mm - 39.75" bar height
    100mm - 40.75"
    120mm - 41.5"
    130mm - 42.24"
    I can fix it............... my dad has an awesome set of tools

  6. #6
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    Quote Originally Posted by 17J17J
    It seems if you were going to go 100mm you would want the 10* and 110 the 5*. Simple math = longer stem will continue to rise anyhow??

    I do appreciate the feedback, and it is a stumpy fsr
    Another question is how many shims between the headset and the stem is everyon running?

    Thanks Again
    Actually the 100x5 will put your hands in a closer position the the 110x10. without stretching you out too much. The 110x5 would stretch out out more. Not so simple math! Comparing a 100x5 to a 100x10 would net you a full 9.76mm forward gain, comparing a 100x5 to a 100x10 would net you around 4.74mm forward gain. It depends on what you are looking to do. I usually don't recommend much more than a 5 to 10mm change in any direction, up down or forward, when trying out different stem combos. The reason being is that while it doesn't sound like much a 10mm change in hand positions can make a VERY big difference in feel, comfort and handling performance.

    What we do at the shop is listen to what the customer wants or his or her complaints, i.e. feel too cramped, back hurts on rides, bike feels too twitchy, and go from there. I have a stem calculator spread sheet that I use to figure out what I need to accomplish a change. You plug in the current stem lenght and rise, plug in steerer clamp height, amount of spacers used all in mm, then do the same for the new stem and it gives you net forward or back, and up or down gains or losses. It's not infalable, but it gives you an idea of what stem you'll need to accomplish what you are trying to do. It also has a section to imput bar data. That's useful if you can't come close enough with just a stem swap. We then haul out a properly sized loaner stem and let them try it for a day or two before they drop the cash on their new Thomson or what ever. It saves them money in the long run and makes em happy as well.

    Anyway, what I've also found is that in moving your hand position further out you need to compensate a little bit by raising the hand height if you want to maintain the same feel in the cockpit, and maintain your ability to breath properly. The more stretched out (bent over at the waist) you are the harder it becomes to breath. So you need to compensate with a little more rise to the stem or bar. What I was recommending was a range of stems to try, I didn't make that too clear apparently. Anything in the 100x5 to 110x10 would be a good range to start with. Too many people just jump out and go from say a 90x8 to a 120x5, that's nearly a 30mm gain forward!, and then wonder why their hands are getting numb on long rides or why they have to run the seat so far forward as compared to their old set up. The idea with the 100x5 to 100x10 range was to keep the net forward gain to around 10mm.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

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