Cadence – where should I max out?

It sounded from vvill’s comments on another thread that you can spin a lot faster on FG?

For me, I think 120rpm is about where things start to get hard to maintain w/o getting bouncy. Spinning faster for short stretches works ok — e.g. on the SS MTB, I spin fast and rest to max out my speed on pavement. Calculator suggests that I’m probably doing 130-140rpm to get to speeds above 20mph (32:18 gearing, 2.3″ tires) in those cases, but I can’t sustain that for more than bursts.

I think there’s some debate over the value of pedaling at high cadence. E.g. I think there used to be a thought that you should learn to spin faster, but other studies show that lower cadence produces same wattage with lower heartrate and you can go longer before fatigue sets in. Kinda makes sense. Another study recently (can’t remember who did this one) just said “you will be most efficient at whatever cadence feels best to you”. So, in short, I stopped paying attention to cadence.

I wouldn’t want to cruise around at 115 for hours, but it’s not particularly high for me. The fastest I’ve gone on fixed is 41mph, so that’s 180rpm on 48×17. Tiring, but not particularly bouncy. Where I start to get bouncy is when I get a little lazy and let the cranks push my legs around. But if you are more active in your pedaling and keep power to the pedals through the whole revolution, you may notice things start to smooth out.

@jrenaut 112995 wrote:

180rpm sounds completely insane, even for a very brief period. I was thinking with some work I could maybe hit 120, 130…

Maybe two wheels is using Forum speed (denoted as S x 1.20).

@ShawnoftheDread 113004 wrote:

Maybe two wheels is using Forum speed (denoted as S x 1.20).

Is that not S.O.P.?

@hozn 113015 wrote:

You are going all-in on the power meters!

I’m on the waitlist for the 4iii for the commuter, but at their current fulfillment rate it looks like I may be on that list awhile. I’m loving the Quarq on my road bike.

Somewhat more relevantly, the Quarq crankset I have has 172.5mm arms; I’ve always used 175mm arms (and debated 180mm for the mtb). I don’t have numbers behind this assertion, but my feeling is that I have an easier time spinning faster on these shorter cranks. So crank length is probably a factor here too. Anyway, I like this shorter length on the road bike [where my chest would otherwise be a lot closer to knees at top of pedal stroke].

Ooops, I meant to say crank ARM based! It’s just the Stages. Although to be honest I do want a crank based one – but I’ll wait for when I get my road/gravel/cx do-it-all bike.

Yeah I think it’s accepted that spinning is easier on shorter cranks. I actually think I would do better with 165mm cranks in general after digesting various web “literature” on crank length fit, but it’s close enough to 170mm I haven’t bothered trying 165.

I used an online cadence calculator after the Tri360 hill ride today, and found I topped out at 160-something for 33 MPH, and it happened a lot on that ride. I don’t have any trouble staying with the high cadence, but I can’t go very long without getting pretty tired from it: there’s definitely no resting at that cadence. I have 165 cranks, which probably helps a lot with spinning. 46/18 gearing for today’s ride.