Bouncy Langster Single Speed <bouncy bouncy bouncy>

roryh
roryh Posts: 40
edited September 2011 in Road beginners
ello,

Been thinking recently how annoying it is when getting my 2007 Langster single speed up to top speed (40kph-ish for me) how bouncy the ride gets. The bounce seems to come from my posterior, so I'm guessing that its the saddle/seat post? Alternatively, it could be my cadence is too high?

Any ideas? The bike is below.
http://www.specialized.com/us/en/bc/SBC ... nuItemId=0
Saddle - Specialized Comp Road, full padding
Seat post - Specialized carbon fiber

Option A
Get a new, stiff and unpadded road seat. Any ideas?

Option B
Get a new, stiff and unpadded road seat and a new seat post. Any ideas? Are the Ritchey ones in the Planet X sale any good?

Option C
Sod the above, and get a bigger chain ring, as the bounce would be eliminated with a lower cadence.

Any comments and suggestions gratefully received!
______________
Planet X SL ProCarbon - SRAM Red
Specialised Langster

Comments

  • 120 rpm???
  • keef66
    keef66 Posts: 13,123
    I too start to bounce at a particular cadence. Fortunately I have another 29 gears and hence cadences to choose from.

    Given your gear choice of 1 perhaps you need to learn a smoother, circular pedalling technique
  • dawebbo
    dawebbo Posts: 456
    Option D : practice pedalling smoothly
  • Switch the cadence before spunking on a new saddle, get a smaller sprocket on the back. no need for an expensive new chain ring.
  • g00se
    g00se Posts: 2,221
    Could your saddle be a smidge too high or too low? If it's too low, that could lift you up to bounce down again as you extend a leg. If it's too high, maybe you're rolling you hips and that's setting up the bounce?
  • keef66
    keef66 Posts: 13,123
    I find it's when I start to spin out in a particular gear and my legs are descending against almost no resistance, that's what starts the bouncing.

    Not a problem on a geared bike but tricky on a SS.
  • Learn to pedal smoothly. I've got my Langster Steel, with the same gearing as you (42x16), up to 36mph (58kph) without it feeling bouncy, and I regularly trundle along at 25mph smoothly.

    Just concentrate on getting a smooth, circular peddle motion going and then, if that doesn't solve it, play with the saddle height a bit. There's no need to buy a new saddle - especially a stiffer one, wouldn't that make the problem worse as there would be nothing to absorb any motion?
  • Monty Dog
    Monty Dog Posts: 20,614
    It's a normal phenomena with riding fixed/singlespeed at high cadence - I usually find if you push-through and try and keep it smooth it calms again - for me it's about 150rpm that causes me problems but smooths out again at 160.
    Make mine an Italian, with Campagnolo on the side..
  • Monty Dog wrote:
    It's a normal phenomena with riding fixed/singlespeed at high cadence - I usually find if you push-through and try and keep it smooth it calms again - for me it's about 150rpm that causes me problems but smooths out again at 160.

    Seems a bit like resonant frequency, which makes sense.
  • roryh
    roryh Posts: 40
    Thanks follks! Sounds like it might be worth my while chucking my cadence sensor on it for a bit, and working out the cadence where its an issue. Probably is a crap pedal motion!

    Cheers....