I know a bit about the race, including having seen it livestreamed, but I haven’t ridden it. I was going to guess something along the lines of what Claude says … but Claude says it better (and there’s nothing I disagree with):
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Great questions — the Crusher is a brutal, unique event and the gear/tire choices matter a lot. Here’s what the evidence says:
1x Gearing
The overwhelming lesson from racers who have done the Crusher is: go lower than you think you need. The Col d’Crush is so hard that even experienced racers found their gearing wasn’t enough.
The race founder himself has weighed in directly: the key piece of advice is to make sure you have at least a 1:1 gear ratio for the climbing — in other words, a cog in the back that is at least as large as your chainring up front. He personally runs a 1×11 setup with a 40-tooth chainring and an 11-42 cassette, which gives enough range for climbing while still allowing him to pedal at 35+ mph on the flatter sections.
For a reasonably fit amateur, the clear consensus recommendation is a 40t chainring paired with a 10-50t or 10-52t cassette (if running SRAM Eagle or a mullet setup). Having the extreme low end of a 52t cassette was described as “nothing less than a lifesaver, several times during the day” at the Crusher, and over the paved flat sections a 40t chainring with the three smallest cogs provided ample top-end speed. If you’re running a standard gravel cassette topping out at 42t, a 38t chainring is the safer choice for an amateur to ensure that 1:1 or better ratio.
The key point: the first year one racer ran a 36t front chainring with an 11-28 rear cassette and found the gearing was not enough for the Col d’Crush — his 2017 setup of a 40t chainring and 11-36 cassette was the result of that trial and error. An amateur will want even more range than a pro.
Tire width
Tubeless tires of 38c or higher are a must at the Crusher. Skimping on tire width could mean a very long road trip ends in a very short bike ride — riders would do well to err on the conservative side.
The sweet spot for amateurs is 40–42mm, run tubeless. Some pros run a 43mm tire on the front for extra cushion on the brutal washboard sections, while sticking with a 38mm on the rear — a mixed setup that prioritizes front-end stability and comfort on the descents. For an amateur who will be on the course longer and suffering more on those descents, going 40–42mm all around is the more sensible call.
In summary: 40t chainring / 10-50t or 10-52t cassette, and 40–42mm tubeless tires — and don’t second-guess yourself into going smaller on either.
