Will I Walk? The Cycling Gear Calculator

Why the "Average Gradient" is a liar.

We have all done it. You are planning your big French cycling trip, you look at the profile of a climb like the Col de Pailhères, and you see "Average Gradient: 7%."

You think to yourself, "I can hold 7% all day at home. My 11-28 cassette will be fine."

But the mountain does not care about the average.

The mountain only cares about the Crux, that nasty 3-kilometre section where the gradient kicks up to 11%, just as the midday sun hits 35°C and your legs are already three hours deep into the ride.

I speak from painful experience. I’ve tackled the Pailhères on a few occasions. One attempt in particular stands out, not for a PB, but for a total physiological meltdown in 40°C heat. I was cooking. The gradient didn't feel like 7%; it felt like a wall, and I would have sold my soul for an easier gear.

Then you have the other end of the spectrum.

Take a look at Robert (pictured above). He smashed out 200km with 4,500m of climbing, in that same 40°C heat (#BienCuit indeed!), while averaging 235 Watts. For a rider putting out that kind of power, a standard cassette is fine. He is moving fast enough to keep his cadence high and his knees happy.

But for the rest of us? When the heat hits and the fatigue sets in, the maths changes.

Don't guess your gearing.

That is why I built this free cycling gear calculator, to check your ratios before you travel. It now takes your actual fitness numbers (LT1 and LT2) and pits them against the steepest sections of Europe’s most famous climbs, from the unrelenting forest of Mont Ventoux, to the savage ramps of the Italian Mortirolo, and the deceptive kicks of Mallorca.

How to use this Cycling Gear Calculator

1. The Rider & Machine Be honest here. Input your current weight and your bike’s weight (don't forget full water bottles and saddlebags add about 1.5kg). The calculator uses "System Mass" because gravity doesn't care if the weight is on your hips or your frame.

2. The Engine (Your Power)

• LT1 (Endurance): The power you can hold all day. Use this for "Survival" mode.

• LT2 (Threshold): The power you can hold for about an hour. Use this for "Full Gas" efforts (e.g., trying to set a PB on Alpe d'Huez).

3. The Gearing Select your current setup. We have updated the tool to include modern Gravel and Mullet drivetrains. If you are running a 1x setup with a massive 50t or 52t dinner plate on the back, you can now select that here.

4. The Winding Roads Factor This is where reality hits.

• Wind: A strong Mistral headwind on Ventoux acts like a brake.

• Heat: Above 30°C, your body diverts blood to cooling, reducing power to the legs.

• Fatigue: Are you hitting the climb fresh, or is this the final climb of the Etape?

Understanding The Verdict

🟢 The Safe Zone (> 70 rpm) This is where you want to be. If your lowest gear lets you spin at 70rpm+ on the steepest ramps, you have a "safety buffer." You are relying on your aerobic system (lungs) rather than pure muscle force, saving your legs for later in the ride.

🟡 The Working Zone (60 - 70 rpm) This is reality for most of us on steep mountains. It is heavy, and you will feel the torque in your quads, but you are moving well. Just be careful, if the gradient kicks up another 2%, you have no gears left to drop into.

🔴 The Danger Zone (< 60 rpm) At this cadence, you are no longer "spinning"; you are pushing weights. The pedal stroke bogs down, relying entirely on muscular force. This spikes fatigue rapidly and puts immense strain on your legs, you risk injury. If you are here on the average gradient, you will likely be walking on the steep sections.

Need help building a specific plan for the mountains? Drop me a message.

Message Paul