Bike fit great while sitting - but no longer able to stand-sprint w/o loss of control

Discussion in 'Road Cycling' started by hi gear, Jul 3, 2011.

  1. hi gear

    hi gear New Member

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    Hello,

    Having a problem when I stand and sprint - and lose control of the front. Made a few changes on the bike - that resulted in a BIG overall improvement. Although, where this issue is concerned, I'm thinking that the seat position is irrelevant since I'm standing either way. The other possibility might be that the cleat position on my shoes was moved forward ??? For years I could stand and sprint to my hearts content, but the overall fit wasn't comfortable. Will I adjust with practice? Any thoughts? It's messing with my head a little! Thanks for any input :)
     
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  2. Dave67

    Dave67 New Member

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    What was changed during the fit? If there where major changes made it might a few day to get use to ti.
    When you say you lose control of the front, does the wheel get light or feel like it going to push out?
    I would guess that you might have to change the position slightly.
     
  3. 64Paramount

    64Paramount Active Member

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    Why don't you keep riding it the way it is for a couple of weeks and keep trying to stand and sprint....

    Might just take you awhile to get used to it.

    If you still aren't comfortable standing in a couple of weeks then you can make some adjustments.
     
  4. vspa

    vspa Active Member

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    yes take one day a week for sprints until you get used to it, you can do 8 to 10 repetitions in an hour,
     
  5. hi gear

    hi gear New Member

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    Hi everyone,

    Thanks so much for the replies. I made the changes to the bike about a month ago. The sprinting issue came on very suddenly. The feeling is just an over-gyrating of the front wheel causing the whole bike to move side to side in an exaggerated way (it seems anyway). I know it seems far fetched and completely unrelated, but I'm wondering if my Power Tap wheel could have any bearing. Following my "almost" spill while sprinting, I loosened a spoke in the wheel. Even after truing, I still have the instability issue. I think I'll throw my old wheel back on and just see what happens. I'm up for trying anything!

    If nothing works, I'm hoping that the practice will help me to acclimate to the changes.

    Thanks again for your replies!
     
  6. daveryanwyoming

    daveryanwyoming Well-Known Member

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    What you're describing is sometimes called 'wallow' or the feeling that the front end is collapsing under you when you're out of the saddle and riding hard. It usually comes from too much weight too far forward while climbing or sprinting out of the saddle often combined with too much side to side motion.

    Just raising the bars with the same length stem shouldn't really make your bike wallow and as you pointed out the seat position isn't really relevant as this only happens when you're out of the saddle. I'd focus on not moving so far forward over the bars while standing and keeping more weight on the rear wheel. Many bikes will feel unstable and wallow if you get so far forward that your hips are getting close to, or even over your head tube. Perhaps the changed cleat position makes it easier to get that far forward in which case work on not jumping so far forward when you sprint. Ideally for a really powerful sprint you'll only raise your butt a couple of inches at most above the saddle and stay crouched and low with tense but flexed arms to stabilize your upper body and allow you to pull hard on the bars. Any taller or further forward generally works against both peak power and more importantly peak speed.

    I'd also try not to sway the bike too far side to side. I know a lot of folks sprint that way, some with good results but a lot of riders (somehow lower category and juniors come to mind) think that whipping the bike violently side to side is the key to going fast when it's usually just the key to a big sprint pileup unless they can also learn to maintain a straight line while doing that.

    And of course make sure you don't have a loose or overly tight headset either of which could have happened when they changed your stem spacers during the bike fit.

    Good luck,
    -Dave
     
  7. hi gear

    hi gear New Member

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    Great info!! Thank you for your detailed reply. I'm definitely going to try what you mention (keeping more weight off the front). It makes sense! Unfortunately, this whole experience has messed with my head so much that what used to generate little thought (standing sprints), now has me consumed with angst! Can't wait to get to the bottom of it. I'll keep ya posted :) Thanks again!
     
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