Whither 1x10?

[100Tours]

There have been a few posts on choosing between 10 and 11 recently, so here’s a more technical take on things.

 

I’ve been playing around with gear ratios on various different bikes for a while now, and I’ve tried to assess how the end product might perform when choosing a 1x setup for any particular build. I’ve also been wanting to write it up, so bear with me J

 

First up my normal, comfortable cadence is between 80 and 100, or maybe 105 rpm (and if you want to get your cadence up think about buying a shorter crank, or vice versa), and I tend to refer everything back to my familiar 2x or 3x setup.

 

Here’s my Campy 2x11 gearing (53/39 up front and 11-25 in the rear):

 

 

A few noteworthy points –

1. There is a nest of closely spaced gear curves, thus the opportunity to go 1x anything.
2. Top pedaling speed is 61kph at 100rpm in the 53/11 (or 67kph if I manage a 110 cadence), and slowest is 16kph at 80rpm in 39/25 (or 11.9kph at 60 rpm).
3. The cadence difference between the gears to match the speed of the higher gear on a downshift is about 7.3rpm for the smaller sprockets (e.g. shifting from the 11 sprocket to 12), and 9.4 rpm for the larger ones (e.g. shifting from 17 to 19). This is important because you don’t want to have big leg speed changes between gears.

 

I got the idea in my head to build a 1x10 road machine, and to build it for some pretty steep climbing (the A’ngliru in Asturias in Spain, which tops out at 23.5%), so here’s the gear chart for this bike built with a 48 chainring and a 11-42 cassette. And yes I made it up on a 1x10 without a foot down.

 

 

1. The top end is good, topping out at 56kph (or 61.6kph if I get up to 110rpm), which surprised me. I imagined that I would give up a more of the top end with a 48t front ring, but not a problem (either on paper or on the road)
2. The climbing range is similarly good – my bottom end speed is 9.5kph at 60rpm, or 11.7kph at 80. This is equivalent to a 37 in the front and a 32 at the back in 2x11 terms.
3. Up and downshifts (real world experience) can be a bit jarring. The steps between gears can be as much as 15rpm cadence to match speeds. This becomes noticeable. Incidentally I have the same kind of steps on my 1x10 mtb – up to 17rpm to match speeds across gears – but on the road this is really noticeable, especially holding a bunch or closing down your ride buddy’s attacks.

 

So what does 11s do for you, basically the cadence steps are down to 11 rpm, or in the case of the SRAM cassettes no more than 10 rpm between sprockets, except for the granny gear. Shifting happiness, especially after a few hours when the leg effort to keep gear shifts smooth starts to count. The ‘granny gear’ is usually a few teeth bigger too, but that’s probably less important.