Spinning on hills. Grinding on flats. What’s going on?

Been at all time high ftp for last few months. 3.5w/kg. Feeling great.

Finding I cannot hold sweetspot or threshold unless cadence drops to 75-80 going fast. However, no issue spinning 90+ when the road points up until say >7% for extended periods. And no issues with indoors.

I am not struggling to reach power at the low cadence, but I physically can’t get my legs turning faster.

Anyone have similar experiences? Any thoughts what’s going on or ways to address?

I don’t want to use gearing as an excuse but I use a 50/34 with a sram 11-36. I only need the 36 for super steep and long. On the other end I am probably in the 12, 14, 16. On flats at higher power.

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Try doing some high cadence work on the flats.


Not quite sure what the problem is? Just ride at 75-80 rpm, there’s nothing wrong with it.

As for why, it sounds a bit like you need the higher resistance to get power out, on the flat, a slightly higher gear will do that, on the hill, the gradient does it for you.

I generally feel better/smoother at ~85. And I tend to do longer events where I feel prolonged lower cadence saps my leg strength.

Whenever I start “bogging down” some focused spinning brings back a wider cadence range. Something like 5-min (low) tempo at 100-110rpm followed by 5-min endurance at normal cadence. Several sets. I’ll also do 60-90 minutes of high cadence during weekly long endurance workout.


In the same way that we know that gearing changes ‘where’ in the pedal stroke power is applied in erg mode, I suspect it does outside too. For instance, 100rpm at x watts @ 25mph on the flats will feel differently than 60rpm at x watts on a hard climb at 8mph. It may be that you’re capable of generating the power more easily when the muscle groups recruited with higher cadence’s are more at play as a function of the momentum.


Two things: there is nothing wrong with unusual cadences per se. However, I would still recommend that you broaden the range of cadences you feel comfortable at.

If you want to extend your range of cadence, then I recommend you do that during endurance rides. Assuming you are on a smart trainer for at least some of them, try to shift to a taller gear to simulate the same (high) inertia as on the flats and then deliberately go a little out of your comfort zone. Start with about 3–8 rpm above what you feel is comfortable. Many of TR’s endurance workouts change wattage after 15 minutes, so I would aim to hold that uncomfortable cadence for a 15-minute stretch. If you can’t do it, take a few brakes in between.

Do the opposite to simulate climbing at lower cadences: shift to a very easy gear and then spend at lower rpms. Again, don’t do anything extreme, e. g. if you prefer to spin at 90 rpm, don’t start with 55 rpm, start with 60 rpm. Importantly, do all this at moderate power levels.


Is this a cadence or gearing question. At 3.5 watts / kg, on a 7% grade, you are probably gearing limited if you want to have a cadence in the 90s. That is: a cadence in the 90s with your gearing on a 7% grade is most probably an above threshold effort. So I’m not sure what the issue is / what your concern is

Thanks. The issue is on the flats and descents I have a hard time finding a good, steady cadence to hit target power. I often find I am constantly switching between 2-3 gears where I am either in a hard gear at 75 or an easier gear spinning 95-100 to hit target power. And I find I just can’t sustain 95+ In terms of leg speed. So I go back to 75 or lower.

This still sounds like a gearing problem to some extent. If a cadence of 75 in gear “H” and 95 in gear “L” produce the same power on the same stretch of road, and assuming these two gears are next to each other in you cassette, this means that gear “L” has roughly 30% more teeth that gear “H” which is a big jump. The normal jump between cogs in a cassette is on the order of 10% / low teens.

Do you happen to know which cogs you are switching between?


That sounds a bit odd. Even when the cassette has larger gaps, there should be a gear between a cadence of 75 or 95+, probably 2. 75 rpm sounds too low on the flats, you’d put too much stress on your joints.

What gearing do you have (i. e. chain ring(s) and cassette)? What is your self-selected cadence on a climb? And on the flats?

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I think you have to use it as an excuse. Given that you mention 12-14-16, I’m thinking you’re on a 10-speed setup, in that case 11-36 has some pretty wide gaps between gears. That means that if you’re doing 75rpm on the flat and switch to a lighter gear to get higher cadence, the difference is going to be too big and you’ll feel like spinning out initially, i.e., instead of making smooth transitions from 75rpm to 80 to 88, your going from 75 directly to 88 which will feel like spinning out…

Start the flat sections in a lighter gear. Start in your 16, and only go to your 14 when you reach your 90+ cadence, but note that even that will mean you’ll drop your cadence to 80. (see http://www.ritzelrechner.de if you want to do your own calculations).

Or switch your cassette to something with a 30 a max. Still get up your hills, and have smaller gaps for the flats…

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Thanks! I had replaced a Shimano 11-34 because the SRAM added a 12t sprocket, reducing the gap (the Shimano adds 2t from 11-27). However, at my current FTP it seems I am still using gears with 2t gaps (13-15-17 - I made a mistake earlier), rather than the 12-13 I was betting on to reduce gaps.

I like your tip and will give that a try on my next ride, and to be more cognizant of which gears I am in.

Thanks. On extended climbs it would be 80-85. On flats, that is where I am struggling to get a feel right, but would think 90 would be preferred.

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I’m going to go back again to how to dig yourself out as I sometimes fall into grinding. My coach gives me undergear and overgear workouts when it becomes obvious that I’m grinding a bit too much. Or if I notice, I’ll incorporate undergeared cadence drills into my endurance workouts.

My rule of thumb for endurance workouts on the flats is a 10rpm difference when shifting from 21 to 19, or 19 to 17, or 17 to 15 (SRAM 12 speed with 10-33). And about 5rpm with the 1 tooth jumps (10-15) at higher speeds. That is something you can figure out while riding, or using Cadence at Speed calculator like BikeCalc.com - Cadence at all Speeds for any Gear and Wheel

These undergeared workouts exaggerate that 10rpm difference, in order to increase ability to pedal smoothly and powerfully across a larger cadence range.

Here is an example of an undergear workout:

My natural cadence on the flats is around 84rpm, if I had to pick a number. So when I do these undergear intervals, I’m targeting 105rpm for 5 minutes, and then 85rpm for 5 minutes.

First interval I generally settle in just above 100rpm, and by the last interval I’m trying to push 110rpm. But more importantly, its about control. So if I’m bouncing at 105rpm, then I reduce cadence to reinforce proper pedaling mechanics. And continue to work on cadence, week after week. The overall goal of my undergear and overgear workouts is to increase usable cadence range from say 60rpm to 100rpm (although at 3W/kg I go even lower on steep climbs).

Hope that helps.


wow! thanks so much - this makes it tangible and actionable. I will try with this level of discipline and keep better track of which gears I am using and the tooth jumps. Makes sense.

With the nicer weather and kids out of school I have been trying to do more workouts outside which should help. I seem to have both a much higher average (+10 RPMs) and top sustainable cadence (>100) inside. I generally use ERG mode and I have tried various gearing but not noticed a ton of difference in feel (Kickr SNAP).

Very helpful, thank you!