BETA — measurements and names under active refinement. Seen a sign, a gate, or a better name? Submit an update no account needed · photos welcome via GitHub

Old Largs Road

3251.0 m · net rise 192.6 m · total ascent 199.0 m · overall 5.9% · confidence: high · Overton · Inverclyde

Shape: sustained — 36% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 124 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)	18%	1184–1186 m
3 m (diagnostic)	17%	1239–1242 m
5 m	17%	1239–1244 m
10 m	17%	1240–1250 m
20 m	16.4%	1237–1257 m
25 m	16.3%	1238–1263 m
50 m	15.7%	1230–1280 m
100 m	13.6%	1228–1328 m

may_start_earlier Extent detection suggests reviewing where this climb starts/ends.

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.

Ridden it, or know better? Submit data for this climb no account needed

Old Largs 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": 0.5,
  "elevation_tiles": [
    "data/cache/scotland/phase-6/dtm/NS27SE.tif",
    "data/cache/scotland/phase-6/dtm/NS27NE.tif"
  ],
  "calculated_at": "2026-08-18T18:38:41+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/scotland-2026-08-14-roads.osm.pbf",
  "osm_snapshot": "2026-08-13T20:21:01Z",
  "elevation_provider": "Scottish Remote Sensing Portal (AWS Open Data, srsp-open-data)",
  "elevation_licence": "Open Government Licence v3 \u2014 \u00a9 Scottish Government, SEPA and partners; Crown copyright",
  "elevation_dataset": "Scottish Public Sector LiDAR Phase 6 50cm",
  "elevation_tile_ids": [
    "NS27SE",
    "NS27NE"
  ],
  "route_summit_trim_m": 635.6,
  "route_summit_trim_loss_m": 11.7,
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 13.6% over 200 m (Terrain 50), gain 99.1 m over 2896 m way. EXTENDED by graph walk: +14 segment(s) at base, +0 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 3 overlapping proposal(s): drumfrochar-road, murdieston-street, papermill-road ADOPTED (Scotland launch 2026-08-18): big-gain."
}