Say hello, wave 'one-by'

Category_Bike Category_Tech

Ok, ok, I've given in! Over the last year my friends have been having a great time out there on trails and bridleways, and I’ve missed out because I’ve only had a road bike - until now! To see what this off-road riding experience is all about, I've dipped my toe and bought an entry-level cyclocross bike - and so far, I'm happy. The upright geometry and wide, flared bars make for a comfortable riding position and the 30c tyres are brilliant on ropey surfaces. I can double it up as a commuter bike, and yet it still feels close enough to a road bike to bag a few PRs on; it’s no slowcoach. But the one thing I'm still getting to grips with is the 1x10 drivetrain.
1x, or 'one-by', drivetrains still have 9, 10 or 11 sprockets in the cassette but have a single ring up front - there's no front derailleur.
They're popular with cyclocross riders because they are less likely to get jammed when muddy or drop the chain on bouncy surfaces. They are also really easy to maintain and have a simple, clean aesthetic. Obviously you get half the number of gears than you would with a double chainring, but the range of gears from top to bottom is not that different. Let's look at some numbers to illustrate that:
  • On my cross bike, I've got a 42T chainring and a 42t largest sprocket, giving me a ratio of 1:1 in my easiest gear (one turn of the cranks produces one full turn of the wheel)
  • On my road bike, I've got a 36T small chainring and a 34t largest sprocket, giving me 1:1.05 in my easiest gear - it's a difference that's barely noticeable if I'm honest. So while I was instantly drawn to the dinnerplate-sized cassette on my cross bike for a helping hand on the hills, in reality it's not really any easier than on my road bike; it’s just all the other aspects of the bike (tyres, brakes, riding position) that will allow me to tackle a different kind of climb.
Gear changes are managed from a single shifter (small push for up, full push for down). It looks clean and works effectively. The one thing that a 1x drivetrain isn’t though, is subtle. Because the range of gears is roughly the same as with a double chainring, but the number of gears is halved, you get a bigger jump between the sprockets. You really notice when you've changed gear, and sometimes, there isn't quite the right gear available to feel that you're riding optimally in terms of speed and/or effort. You can be on the upper limit of effort in one gear but just one shift would be too much, and leave you spinning.
So if you’re like me you stay in the gear that's slightly harder than you’re comfortable with, and ride out some unintended strength training benefits.
But there's a price to pay - that uses more effort and you're likely to fade more quickly. Of course that’s not an issue for cross riders who race in short bursts but if I’m going to use this bike for long adventures I’ll need to learn how to ride it efficiently. It’s easy to see why the pro peloton’s brief dalliance with a 1x fleet didn’t last - despite lots of excited chatter at the time about being disruptive, innovative and challenging the perceived wisdom of 'traditional' drivetrains. Not long after that, as Team Aqua Blue folded after a disastrous season, pro rider Adam Blythe publicly slammed the choice of the 3T Strada (the 'one-ring wonder') for the team bike as a contributing factor to their failure. Even as an amateur it's easy to imagine how challenging it would be to manage energy output efficiently and race effectively over long distances on a 1x bike - particularly if you’re the only team in the peloton that's doing so. Of course, all riders have different physiology and preferences but that's where the subtlety of running 20+ gears allows everyone to find their optimal place. But aside from the microscopic attention to technical detail that the pro world has to obsess over to find those marginal gains, on an everyday basis, I'm finding my 1x a pretty good ride. On tarmac, I'm pushing a little bit harder than usual which I think will help with developing strength. On all other surfaces, I'm just appreciating the new opportunities that having a cross bike has opened up for me - everything I used to love about horse riding until a couple of falls broke my confidence. Last weekend I set out on one of my regular road routes, but this time after 5 miles of tarmac I turned off onto a bridleway. Riding across fields, away from cars, into the heart of the country, I lost count of the number of rabbits in the verge, and lost track of the time I spent just breathing.

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