Pogo problem during climbing

hurri47

Well-Known Member
My first Cruzbike is a conversion kit on a dual-suspension mountain bike (Cannondale Super V). I rode upright bikes until about six years ago when I went recumbent. I ride a variety of recumbent geometries but no high-racers and no suspensions. My normal cadence is in the high 80s and low 90s, so I'm not a mad spinner, but not a grinder either.

The first thing I learned about climbing on the Cruzbike is how much higher a gear I can use (compared to other recumbents) because I'm allowed to pull on the bars. This gives me some impressive uphill speeds on the short hills I've tried so far (including not downshifting at all from flat-ground gearing), but the conventional wisdom on both conventional recumbents and Cruzbikes is, "spin, don't mash." The problem I'm having is, when I drop to what seems like an appropriate spinning gear, the front end bounces up and down like crazy.

I've done a search on this site for the word "pogo," and it always seems to refer to what happens at the rear of a suspended mountain bike under heaving pedaling. This effect is allegedly all but eliminated due to Cruzbike geometry, so what I'm experiencing may need a different name.

This front end bouncing can't be good. I suppose I could apply some experimental science (instead of guessing at a good "spinning gear") and do hill repeats in progressively lower gears to see what kind of crossover point there is between smooth climbing and bouncy-bouncy. I should probably also mount a cadence meter - I'm running instrument-free so far on this bike.

But first - has any one else dealt with this? Do I more likely have a problem with technique or equipment? Could it be the Cannondale non-adjustable and non-lockable Headshok? The 175mm cranks? (All my other bikes are 170mm.) Or do I just need to learn to pedal rounder circles?

-Dan
 

John Tolhurst

Zen MBB Master
Are you clipped into the

Are you clipped into the pedals? Doing so usually smooths the action, as does shorter cranks. I think sometimes there is a harmonic sweet spot that crops up, and you may be touching on it. Changing cranks lengths may alter the result, clippign in would retain the harmonic coincidence but at lower amplitude, unless being clipped in changed the cadence. Damping in the fork would also help, sounds like it may be just on springs now?
 
Hill climbing

I had my first longer organized street ride this past weekend. I noticeably picked up speed on downhills compared to standard DF riders, presumably due to the much greater bike weight and the nice coasting capability of the Sofrider.

Uphills are another matter, lugging that weight. Especially on trail rides. I am not getting a pogo action on short, steep hills, but I am spinning out, losing traction. Sometimes I can stay in a higher gear and be okay. On steeper hills I just stop. I did convert to clipless a couple of months ago and the overall riding is better. Stalling while clipped is a little nerve racking.

I've been looking for a discussion of this issue elsewhere.
 

Lief

Guru Schmuru
Climbing technique

Halfheartedcards,

Check out this thread - from Dan Fallon a while back.
Had some good conversation on how to A) use more upper body when climbing but also B) how to position yourself on the bike so you don't spin as much/often.

http://cruzbike.com/climbing-your-whole-body

In summary - on steep hills:
* Lean forward
* Lower gear
* Smooth, pretty high, cadence with pushing and pulling, even effort all the way around, - clipless is best.


Lief
 
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