Welcome to Boot Lab, our monthly deep dive into getting boot fit right! Every month one of us picks apart a bit of boot fitting that customers ask about constantly but rarely get a straight answer on. First up: flex rating, probably the most talked-about number on the box and the least understood.
What does ski boot flex rating actually measure?
Before you can pick the right number, it helps to know what it's actually telling you.
- How much resistance a boot gives when flexed forward at the ankle
- Tested by each manufacturer individually, not standardised across brands
- A guide, not an exact science, so treat it as a starting point rather than gospel
What flex rating should I choose?
As a rough steer, here's where most people land, though it's always worth getting checked in person.
- Beginners and lighter skiers: roughly 60-80
- Intermediates: roughly 80-100
- Stronger, more aggressive skiers: roughly 100-130
- Weight matters as much as ability, a heavier skier generally needs more flex than a lighter skier of the same ability for the same feel
What happens if I choose the wrong flex?
Get it wrong in either direction and you'll feel it within the first run.
- Too stiff: you fight the boot, legs tire faster, harder to control at low speed
- Too soft: vague, delayed feedback at higher speeds, the boot folds before the ski does
Does temperature affect boot flex?
This one catches people out more than you'd think.
- Yes, plastic stiffens in the cold
- A boot can feel noticeably stiffer on a freezing morning than in the shop
- Worth factoring in if you're between two flex ratings, especially for early season or altitude skiing
Pop in and we'll flex-test boots against your actual weight and ability rather than just handing you the number you ask for. Next month's Boot Lab covers last width!