Llanberis Pass
1716.3 m · net rise 85.9 m · overall 5.0% · confidence: high · Gwastadnant · Gwynedd · share
Shape: sustained — 32% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 37 m.
Matches: Wikipedia, Another 100 Greatest Cycling Climbs (Simon Warren) — Llanberis Pass — articles in English and Welsh; route-line 3 m from the pass point — No. 189, Llanberis Pass (official app, 2026 numbering).
Gradient ladder what do windows mean?
| Window | Maximum | Located at | |
|---|---|---|---|
| 2 m (diagnostic) | 13% | 1252–1254 m | |
| 3 m (diagnostic) | 13% | 1252–1255 m | |
| 5 m | 12% | 1249–1254 m | |
| 10 m | 12% | 1247–1257 m | |
| 20 m | 11.5% | 1240–1260 m | |
| 25 m | 11.3% | 1240–1265 m | |
| 50 m | 10.2% | 1220–1270 m | |
| 100 m | 8.2% | 1178–1278 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.
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© 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_11_261356_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_261357_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_262356_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_262357_20210302dtm.tif"
],
"calculated_at": "2026-08-12T02:15:23+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_11_261356_20210302dtm.tif",
"wg_del_11_261357_20210302dtm.tif",
"wg_del_11_262356_20210302dtm.tif",
"wg_del_11_262357_20210302dtm.tif"
],
"elevation_capture_dates": [
"02-03-2021"
],
"climb_origin": "discovered",
"notes": "Coarse pass: max 9.3% over 200 m (Terrain 50), gain 42.0 m over 829 m way. EXTENDED by graph walk: +1 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 1 overlapping proposal(s): discovered-lane-53-0943-4-0634",
"renamed": "2026-08-13: RENAMED per identification-certain policy: route-line 3 m from the Wikidata pass point; en+cy Wikipedia articles",
"license": "ODbL-1.0",
"license_url": "https://howsteep.org/licensing.html"
}