Commin Road
1344.2 m · net rise 119.2 m · overall 8.9% · confidence: high · Bargod · Gwent · share
Shape: stepped — 45% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 278 m.
Found purely from mapping and LiDAR data, and not yet matched against books, race records or lists — it may be well known to locals under a name we've never heard. It was cross-checked against the OS road network, surface models and map tags, but a discovery can still be an artifact of the terrain model or the map. Treat it as a well-evidenced hypothesis until someone has ridden it. If you know this road, tell us what you found — photographs, corrections and local knowledge all welcome; the map links below let you scout it first.
Gradient ladder what do windows mean?
| Window | Maximum | Located at | |
|---|---|---|---|
| 2 m (diagnostic) | 23% | 114–116 m | |
| 3 m (diagnostic) | 23% | 124–127 m | |
| 5 m | 21% | 123–128 m | |
| 10 m | 21% | 136–146 m | |
| 20 m | 21.0% | 129–149 m | |
| 25 m | 21.0% | 124–149 m | |
| 50 m | 20.5% | 105–155 m | |
| 100 m | 20.1% | 95–195 m |
Map
Check this route yourself: Google Maps route via their router · Street View at the base where coverage exists · geojson.io our exact measured line · OpenTopoMap
This climb's data: OCL JSON — the full gradient ladder, quality flags and provenance in the OpenClimb Ladder format.
Measured, not vetted. This page records what the laser record shows about the road's shape — nothing more. Nobody has necessarily ridden or inspected this road for the survey, and a page here is not a recommendation and no guarantee that the road is open, surfaced, rideable or safe. Gates, private sections, missing rights of way and hazards do not show up in elevation data. Check access and conditions on the ground and make your own judgment.
Ridden it, or know better? Submit data for this climb no account needed · Share this climb
© OpenStreetMap contributors · topo tiles © OpenTopoMap (CC-BY-SA) · vector tiles OpenFreeMap
Profile
Provenance
{
"analysis_version": "0.1.0",
"sample_interval_m": 1.0,
"interpolation": "bilinear",
"smoothing": "none",
"gradient_windows_m": [
5.0,
10.0,
20.0,
25.0,
50.0,
100.0
],
"diagnostic_windows_m": [
2.0,
3.0
],
"elevation_crs": "EPSG:27700",
"elevation_resolution_m": 1.0,
"elevation_tiles": [
"data/cache/wales/dtm_1m/wg_del_10_315200_20210227dtm.tif",
"data/cache/wales/dtm_1m/wg_del_10_315201_20210227dtm.tif",
"data/cache/wales/dtm_1m/wg_del_10_316200_20210227dtm.tif",
"data/cache/wales/dtm_1m/wg_del_10_316201_20210227dtm.tif"
],
"calculated_at": "2026-08-12T09:06:24+00:00",
"road_source": "OpenStreetMap (local PBF extract)",
"road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
"osm_pbf_path": "data/cache/pbf/wales-2026-08-11.osm.pbf",
"osm_snapshot": "2026-08-10T20:21:40Z",
"elevation_provider": "Welsh Government",
"elevation_dataset": "Welsh Government LiDAR 1m DTM (2020-2023)",
"elevation_licence": "Open Government Licence v3 \u2014 \u00a9 Crown copyright Welsh Government",
"elevation_catalogue_layer": "geonode:welsh_government_lidar_tile_catalogue_2020_2023",
"elevation_tile_ids": [
"wg_del_10_315200_20210227dtm.tif",
"wg_del_10_315201_20210227dtm.tif",
"wg_del_10_316200_20210227dtm.tif",
"wg_del_10_316201_20210227dtm.tif"
],
"elevation_capture_dates": [
"27-02-2021"
],
"climb_origin": "discovered",
"notes": "Coarse pass: max 9.1% over 200 m (Terrain 50), gain 30.9 m over 499 m way. EXTENDED by graph walk: +8 segment(s) at base, +3 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 1 overlapping proposal(s): discovered-lane-51-6952-3-2281 ROAD-REVIEW: way 717159845: unnamed service way; way 717159845: service way, surface untagged ADOPTED (notable slice 2026-08-11): clean-steep.",
"license": "ODbL-1.0",
"license_url": "https://howsteep.org/licensing.html"
}