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I've noticed while cycling on my road bike that, when I try to pedal very quickly, I start to 'bounce' a little in my seat. As in I'm lifting off the seat a little with each pedal, so feel I'm not harnessing the full strength of my legs.

To avoid this, do I need to adjust my bike seat/handlebars? Or is this more relating to good cycling form? Or, perhaps, I just need to go up a gear at this point?

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4 Answers 4

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Always have in mind that: Due to the mechanics of a bike, pedalling fast doesn't always mean you are biking faster. In fact this is the very same reason why changing cogs of a crankset or cassette renders the bike easier or harder to bike uphill.

From your comment I would assume you may be pedalling too fast, i.e. you are not maintaining your cadence within your optimal "speed" (60-100 RPMs depending on your fitness, technique, etc).

As far as I understand - I am not a pro - when pedalling, you try to find a balance between strength and cadence. Bike too fast with little load on your legs and you will be bouncy, bike slow with too much load and you will exhausted faster than needed.

Therefore I would suggest you ask yourself: Are you using adequate load when biking "fast"?

If not, I would suggest you pedal a bit slower but with more load (be that by shifting the front or rear speeds).

Hope this helps

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    A well-known song that represents a fair "upper limit" for pedal RPM is "The Gambler" by Kenny Rogers. It has a speed of 95 BPM and if you're spinning faster than that, its definitely time to change gear.
    – Criggie
    Jun 19, 2020 at 12:42
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    95 is oddly low. For maximum power output, the optimum number is somewhere around 120 or above for many people and maximum somewhere past 150.
    – ojs
    Jun 19, 2020 at 13:24
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    @ojs is 95 considered low ? My lower end is 70 and my higher end is 125. However when I go for a cycle I don't aim for speed.
    – Dan K
    Jun 19, 2020 at 14:27
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    Research I saw about 25 years ago indicated that a cadence over 100 is counter-productive. This was with skilled riders in a test environment where their output per minute could be measured. Jun 19, 2020 at 20:36
  • That dirty yellow texan put a blight on the concept of pedalling cadence. Higher RPM was not the secret of his power, it was merely a disguise. But the idea that "more revs is faster" has persisted, perhaps because it is valid in electric and liquid motor engineering.
    – Criggie
    Jun 19, 2020 at 21:21
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In my experience I start to bounce at a high cadence (over 125-130) because even with some training it's hard to switch from pushing to pulling on the pedal that fast.

If you think about pedalling at a cadence of 120, that means 2 pedal strokes per foot per second, with each lasting about 2/10ths of a second. So you have less than 1/10th of a second to come off your power stroke for the return. If you're even 1/30th of a second late, your push will start to lift you off the saddle. And you bounce a bit before you can recover.

With training, and even just experience building muscle memory, you'll be able to smoothly pedal at higher cadences, but you may not need to. Most riders never need to be able to pedal over 100-110. Being clipped in will help to, since instead of switching from "push" to "neutral," you switch from "push" to "pull" and engaging the opposing muscle groups will help with fast changes.

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  • From what I've heard the whole pulling up on the pedals isn't really done that much. They've tested pros in the lab and they don't tend to pull up much. You do want to make sure you're sweeping back through the bottom of the stroke though. Personally my pedalling got a lot better when I rode a fixie for a while as it forces you to move in circles at a constant rate.
    – Kibbee
    Jun 19, 2020 at 20:30
  • @Kibbee You're right; for power the important point is to drag your foot back through the bottom of the arc. That's part of what I meant by "pull," but without wanting to get too technical. My point here was more about being able to change the direction of thrust faster by having all of your muscles engaged. Again, in my experience, thinking about the action of pulling up helps me get my foot to the top of the pedal stroke with my toes slightly high, so I can start the push a bit earlier - over the top as it were - for a bit more momentum on the down.
    – DavidW
    Jun 19, 2020 at 20:45
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I've noticed while cycling on my road bike that, when I try to pedal very quickly, I start to 'bounce' a little in my seat. As in I'm lifting off the seat a little with each pedal, so feel I'm not harnessing the full strength of my legs.

To avoid this, do I need to adjust my bike seat/handlebars? Or is this more relating to good cycling form? Or, perhaps, I just need to go up a gear at this point?

Most likely, you should just simply switch to a higher gear. A needlessly high RPM is just wasting energy moving your legs up and down. This energy is not usefully utilized to propel the bicycle forwards.

However, do check your seat height. Either too low or too high seat can cause problems.

I had a 5-year break from cycling. Now when I started cycling again (I have only cycled 100km after the break), I noticed my pedaling RPM is significantly lower than it used to be. If I try to pedal at high speeds, I feel I am unable to produce the needed power without rapidly tiring my legs. I suspect my optimal RPM will go up as my muscles get used to cycling again after the break.

This legs-rapidly-tiring phenomenon is different from "bouncing". If your legs are not strong enough, you feel you are just unable to produce useful power at high RPMs. You don't "bounce".

So, your "bouncing" means that you are either using so ridiculously high pedaling speed that no active cyclist would use, or either your seat height needs to be adjusted.

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As stated in other answers, the bouncing is coming from the pushing and pulling. As also stated, it's possible to mitigate this over time by building muscle memory however, I think that the solution has to do with gearing. Instead of pedaling faster, consider shifting into something that takes a little more strength so that you can get the desired power without the bouncing.

It also may take time to build up the strength to achieve the point where you're going at a comfortable speed at a comfortable level of muscle discomfort. In my experience, I usually see beginners bouncing in their seat while charging the first portions of a hill. They don't quite have the strength built up to take it at a harder gear, but still want to go fast. So they shift into something less difficult and pedal fast, but end up with the bounce.

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