How to choose the right chainring for a gravel race

On a 1× drivetrain, your chainring is the single biggest decision you make about how your bike feels. Go too big and you'll grind to a halt on the steep stuff. Go too small and you'll spin out the moment the road tips down. The right answer isn't a rule of thumb — it's hiding in the data from your own rides.

The two moments that decide your gearing

Every course has two gearing-defining moments: the slowest sustained climb, where you need a low enough gear to keep pedaling without bogging down, and the fastest sustained section you're actually pedaling, where you need a tall enough gear to put down power instead of spinning out.

Pick a chainring that keeps your cadence inside your comfortable range — for most riders somewhere around 70–95 rpm — at both of those moments, and the gears in between take care of themselves.

Why coasting throws people off

Here's the trap: your fastest speed of the day is almost always a descent where you're freewheeling, not pedaling. If you size your chainring around that number, you'll end up with a gear that's far too tall for the parts of the course where you're actually working. The fix is to look at your fastest pedaling speed — the quickest stretch where you were still putting power through the cranks — and ignore the coasting.

Do it with your own data

Rather than guess, upload a ride file from a course like the one you're racing and let the numbers tell you. I built a free tool that does exactly this: it finds your slowest 2-minute climb and your fastest 5-minute pedaling effort (filtering out coasting automatically when you have power data), then tells you which chainring keeps you in your cadence range — and shows how much time you'd spend in each gear.

When one ring can't do it all

Some courses are just too varied for a single ring to nail both ends — a brutally steep climb and a long fast pedaling section. When that happens you've got three honest options: a bigger ring that favors the fast sections, a smaller ring that favors the climbs, or a middle ring that splits the difference. The tool lays out all three so you can choose based on what your event actually demands.

Want help dialing the whole setup?

Gearing is one piece. If you want your tire pressure, position, pacing, and training all working together toward your next event, that's what I do as a coach. Reach out for a free intro call and let's make you faster.