Bwlch Penbarras

Overview

Bwlch Penbarras is a Category 3 climb in Great Britain. It runs 5.7 km from a start elevation of 46 m to a summit at 335 m, giving a net elevation gain of 289 m at an average gradient of 5.05%. On paper that is a moderate mid-length climb, the kind you can settle into rather than survive.

The paper figure hides something, though. Total ascent over the climb is 332 m, which is 43 m more than the net gain of 289 m. That gap means the road does not rise cleanly to the top: there are dips and false flats where you give back height, then have to re-earn it. Those 43 m of "extra" climbing are effort you pay for without the reward of a higher summit, so the climb feels harder than a smooth 5.05% grade would suggest.

How the Gradient Unfolds

An average of 5.05% across 5.7 km is not a number you will actually ride for long. The undulation splits the climb into distinct sections, and the maximum gradient of 17.22% is more than three times the average, so the steep pitches are short but sharp.

• Flatter and recovery sections where the grade drops well below average and briefly gives back height
• Repeated short climbs stacked between those dips, which is where the extra 43 m of ascent accumulates
• The steepest ramp at 17.22%, a wall that forces a gear change and demands you are not already redlined

Pacing Notes

On a rolling profile like this, chasing an even speed is a trap: you will over-push on the ramps and coast the flats, burning matches you need later. Ride to an even effort instead, holding a steady sustainable power output through the whole climb and letting your speed rise and fall with the grade.

Practically, that means easing slightly before each dip so you carry momentum, then holding power rather than surging on the 17.22% pitch. If you do not know your ceiling, run the FTP estimator first and set a target you can defend for the full 5.7 km, not just the opening kilometre.

Gearing

Gearing here is governed by the 17.22% maximum, not the 5.05% average. A compact or sub-compact chainset paired with a wide-range cassette will keep your cadence up on the wall: a 34×32 is a sensible floor, and 34×34 gives more margin if you tire late or ride loaded. The goal is to spin the steep ramp seated rather than grinding it out of the saddle. Check your setup before the ride — confirm the cassette and chainring you expect are actually fitted, because there is no fixing it on the climb.

Summary

• Length: 5.7 km
• Average gradient: 5.05%
• Maximum gradient: 17.22%
• Net elevation gain: 289 m
• Total ascent: 332 m
• Category: 3

Bwlch Penbarras rewards riders who respect its undulation. Pace to even effort, gear for the 17.22% ramp, and treat the 43 m of hidden climbing as part of the job, not a surprise.