I keep reading comments somewhat along the lines of:
- big chainring = faster spinning flywheel with a lot of momentum
- big chainring requires less effort versus little ring because of momentum
- outside momentum on the road means you can hold speed without much effort
Will all that momentum on trainer, it stands to reason the power timeline for big ring would be smoother versus little ring. But it doesn’t for others and myself. Go figure.
The power timeline for my outside rides, both climbs and flat roads, looks similar to big chainring on the trainer (kickr direct drive).
Outside on the flats I apply power to pedals just like when climbing, and I do the same on trainer. I don’t just kick over the top.
I don’t have problems modulating power in big chainring when jumping from rest to work interval. If I did, that might be a reason to use little chainring as I agree that little ring makes it quicker and easier to handle resistance changes.
And I continue to find big chainring on trainer better replicates outside riding conditions.
Just for fun lets play a little matching game using ride data from 4 very different threshold efforts. And a ~5 min power timeline for each effort is below. I didn’t cherry pick, just grabbed ~5 min during a portion of the ride that I was applying constant power near threshold.
a. TR intervals in big chainring (53x15) in Erg mode on Kickr 2017 direct drive
b. Flat training ride into headwind at 4mph (something like 50x14)
c. Steady climb on 6% grade in little chainring (either 34x32 or 34x30)
d. Flat training ride into crosswind at 13mph with 20mph gusts (something like 50x17)
Can you correctly match each effort above to a timeline below?
Ride 1
Click for answer
b. Flat training ride into headwind at 4mph (something like 50x14)
Ride 2
Click for answer
c. Steady climb on 6% grade in little chainring (either 34x32 or 34x30)
Ride 3
Click for answer
d. Flat training ride into crosswind at 13mph with 20mph gusts (something like 50x17)
Ride 4
Click for answer
a. TR intervals in big chainring (53x15) in Erg mode on Kickr 2017 direct drive
They all pretty much look the same to me, and roughly felt the same. Good luck!
Based on these 4 power timelines, I guess that explains why big chainring feels more natural to me. Switching to little chainring would make that one power timeline above smoother, but then it starts feeling artificial to me. As always, your mileage may vary!