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Bwlch-y-Clawdd Road

4804.4 m · gain 269.9 m · overall 5.6% · Cwm Dâr · Rhondda Cynon Taf

Shape: sustained — 30% of the climbing sits in a quarter of the distance.

Known from: 100 Greatest Cycling Climbs (Simon Warren) — The Bwlch, #99 — which of the three sides Warren describes is unreviewed against our route.

Gradient ladder what do windows mean?

Window	Maximum	Located at
2 m (diagnostic)	16.7%	1844–1846 m
3 m (diagnostic)	12.0%	1844–1847 m
5 m	10.2%	2013–2018 m
10 m	9.5%	1955–1965 m
20 m	8.9%	1954–1974 m
25 m	8.9%	2009–2034 m
50 m	8.5%	1992–2042 m
100 m	8.4%	1945–2045 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

Bwlch-y-Clawdd Road LiDAR hillshade map with contours

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_5_293194_20201224dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_5_293195_20201224dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_5_293196_20201224dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_5_294194_20201224dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_5_294195_20201224dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_5_294196_20201224dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_5_295194_20201224dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_5_295195_20201224dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_5_295196_20201224dtm.tif"
  ],
  "calculated_at": "2026-08-12T09:06:20+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_5_293194_20201224dtm.tif",
    "wg_del_5_293195_20201224dtm.tif",
    "wg_del_5_293196_20201224dtm.tif",
    "wg_del_5_294194_20201224dtm.tif",
    "wg_del_5_294195_20201224dtm.tif",
    "wg_del_5_294196_20201224dtm.tif",
    "wg_del_5_295194_20201224dtm.tif",
    "wg_del_5_295195_20201224dtm.tif",
    "wg_del_5_295196_20201224dtm.tif"
  ],
  "elevation_capture_dates": [
    "24-12-2020"
  ],
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 9.3% over 200 m (Terrain 50), gain 250.8 m over 4320 m way. EXTENDED by graph walk: +4 segment(s) at base, +0 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. ADOPTED (notable slice 2026-08-11): big-gain."
}