Tonquin Pass

Tonquin Pass cycling climb profile

Tonquin Pass is a Category 1 cycling climb in CA, and the headline number tells you why it needs respect: 14.3 km at an average gradient of 6.51%. That is long enough for pacing errors to compound, and steep enough that riding just above comfort early can become expensive well before the summit.

The climb starts at 1108 m and reaches 2041 m, giving a net elevation gain of 933 m. Over 14.3 km, that average of 6.51% points to a sustained climbing effort rather than a short punchy ascent. The key detail is the maximum gradient of 15.8%. A climb with this average and that kind of peak pitch is unlikely to feel metronomic from bottom to top. Even if much of the climb sits in a manageable climbing rhythm, the steepest sections are hard enough to force a real gear change and a real pacing decision.

How the gradient rides

From the bottom, treat Tonquin Pass as a long aerobic climb first and a steep climb second. The average gradient is demanding but not extreme, which can tempt riders into settling slightly above threshold because the road feels controllable. That is the trap. Over 14.3 km, those small overages accumulate, especially once the road kicks toward its 15.8% maximum.

The available profile data does not identify where the steepest ramp comes, so the safest tactical assumption is that it can arrive after fatigue has already started to build. Ride the lower slopes with enough margin that you can absorb a double-digit pitch without having to surge far above your sustainable power. If you are using /glossary/ftp as your pacing anchor, this is the kind of climb where discipline early matters more than chasing speed on the first sustained grade.

Pacing and gearing notes

Use gearing that lets you keep pressure smooth when the gradient jumps. A 6.51% average over this distance rewards steady cadence, but the 15.8% maximum means you need a low enough gear to avoid grinding if the road steepens suddenly. If your easiest gear only feels comfortable at the average gradient, it is probably too big for the full climb.

Practical approach:

• Start below your target climbing effort, not at it.
• Keep cadence relaxed on the steadier sections so the steep ramps do not force a spike.
• Save your hardest sustained effort for the final portion, once the summit elevation of 2041 m is within reach.
• If riding by feel, cap the early effort at controlled breathing rather than chasing pace.

Tonquin Pass is not defined by one number. The combination of 14.3 km, 933 m of net gain, a 6.51% average, and a 15.8% maximum makes it a climb where the rider who preserves torque and composure early will usually outperform the rider who treats the average gradient as the whole story.