Why are climbing cadences often lower?

[dominikk85]

Hi I'm new here, I recently started road cycling again after a longer layoff.

I have a question:

Why are uphill climbing cadences often lower than flat riding cadences?

If you watch the pros obviously there are some exceptions like Lance or froome who used to have very high cadences or also more recently pogacar but overall it seems most pros seem to be a little lower (like mid 70s to 80s) on a climb vs 90 to 100 on a flat ride.

I also tend to climb at a lower cadence than riding flat (but with me currently it is more mid 80s on flat and 60s on climb since I'm out of shape working my way back to higher cadences).


Obviously a climb is harder than a flat ride but couldn't you just use a lighter gear and pedal the same wattage and cadence as you do in the flat?

 

[King Boonen]

I don't think it's 100% known, but higher torque at lower cadence will recruit more muscle fibres and you have the added issue of overcoming gravity. Increased torque puts more strain on your joints, and I would think in most people there's some compensation going on between what is possible based on the cardiovasculr system (shallower climbs) and what requires more muscle recruitment. It's also worth considering that the peloton is rarely going full out on the flat (the power required to sit in the bunch all day is actually quite low) whereas when climbing the effort increases a lot, that's why people get dropped so easily.

 

[JayKosta]

There are several different types of muscle fiber, and which type is activated varies depending on the amount of power that is to be generated. Each type has its own best (efficiency, effectiveness, endurance, etc) cadence. The cyclist will usually adjust the cadence according to the feedback (pain and fatigue) from the effort.

 

[dominikk85]

What I have read is lower cadences are more efficient for the cardiovascular system but it will fatigue the muscles more so fit riders should try for a higher cadence on longer races. Is that correct?

 

[Nick2413]

I’ve researched this and I believe rotational inertia has a lot to do with this, but I’m not good at explaining it. Basically, you are putting in effort more fully around the pedal stroke and the resistance comes back to you more due to gravity than when pedaling against purely air resistance.

 

[dominikk85]

Would you recommend a recreational rider to try to aim for a smaller gear and similar cadence (maybe a bit lower but not much) as you do in the flat or would you recommend to lower the cadence ?

 

[JayKosta]

Would you recommend a recreational rider ...

I recommend using lower gears. Trying to push a gear that is higher than what is manageable could lead to extreme exhaustion, muscle / joint problems, etc. Also make sure that you really have good control of the bike , safety might require stopping for rest or walking.

 

[dominikk85]

I recommend using lower gears. Trying to push a gear that is higher than what is manageable could lead to extreme exhaustion, muscle / joint problems, etc. Also make sure that you really have good control of the bike , safety might require stopping for rest or walking.

It's interesting that pros use smaller gears too in mountains nowadays, I think now most are like 39/29 or even 30 but in the old days it was 42/23 even in mountain stages.

Why did that change or better: why didn't pros of yesteryear use smaller min gears for mountain stages?

 

[JayKosta]

...
Why did that change or better: why didn't pros of yesteryear use smaller min gears for mountain stages?

'back in the day' bikes had 10 speeds with 5 cogs in the rear. Having a large rear cog would then only allow 4 other choices for the rear. They would rather 'tough it out' on climbs rather than not have the best ratio for the longer flat / rolling sections.