The Tumble (SW #97) Bike Climb - PJAMM Cycling

The Tumble (SW #97)

United Kingdom

All the cycling data and info you'll need to climb The Tumble (SW #97)

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Climb Summary

Climb Summary

 Keeper’s Pond near top of climb

The Tumble is the second most difficult climb in Wales after Bwlch y Groes and one of our favorite Welsh climbs.  The climb is a good distance at nearly 5 kilometers and averages just over 8% average grade.  There is a 2.5 kilometer 10.5% segment beginning 600 meters from the start that puts us to the test right away.  

This climb has been included in many British cycling events and that is obvious from the start which has a “Start of Climb”  sign designating the beginning of the 2018 Iron Mountain Sportif and also a cycling summit sign at the climb’s finish.


No question where climb begins.


Monmouthshire and Beacon Canal at 400 meters.

Forest and tree coverage first third of the climb.


That’s a wrap!  4.9 km at 7.9%.

Simon Warren writes of the climb:

“One of the most feared and fequently raced climbs in Wales.  The Tumble offers an excellent challenge to any rider.”  100 Greatest Cycling Climbs, A Road Cyclists Guide to Britain’s Hills (Simon Warren, 2010, pp. 164-165).


Steepest kilometer begins at 700m (11.3%) writes of this climb:

“I was staying in Forest of Dean this weekend, so I thought I’d cycle out to the Tumble – a climb that has featured in many Tour of Britain’s and something I’ve watched quite a few times on the TV.

In theory, it was 25 miles from the Forest of Dean to the base of the Tumble in Govilon, Abergavenny. But, I trusted my instinct of ‘remembering the roads’ from five minutes of studying the map, rather than taking it with me. I once did the National 50 mile TT on the A40 around Raglan. But, that wasn’t much help, and I ended up taking a long detour on an unknown Welsh road to Usk. I kept hoping to cut across to Blaenavon, but didn’t have much luck. At one point, I went a long way up a mountain road to be greeted by a dead end sign – right at the end of the road. 40 miles later I did finally make it to Gavilon, and in between hail showers climbed up the Tumble.

It’s a good climb. The first half is a consistent 10% up a few hairpins, perhaps steeper in parts. As you go out of the trees, the gradient eases off a little and if there’s a tailwind you can pick up a little speed. It’s quite exposed at the top. It was popular with other cyclists, I must have seen a good 20-30 on various parts of the climb. I managed to overtake a couple on the way up. I had forgotten my cycling jacket so was just wearing loose under clothes, and had a camera swinging from thigh to thigh on the way up, which was irritating. I didn’t look the part, but still went up in a respectable time for February, on a winter training bike.”  Read more 

This climb is in the eastern section of Brecon Beacons National Park, Wales, 134,420 hectares (332,160 acres), established 1957:

“The Brecon Beacons National Park was established in 1957, the third of the three Welsh parks after Snowdonia in 1951 and the Pembrokeshire Coast in 1952. It stretches from Llandeilo in the west to Hay-on-Wye in the northeast and Pontypool in the southeast, covering 519 square miles (1,340 km2) and encompassing four main regions – the Black Mountain in the west, reaching 802 metres (2631 feet) at Fan Brycheiniog, Fforest Fawr and the Brecon Beacons in the centre, including the highest summit in the park and in South Wales at Pen y Fan 886 metres (2,907 feet) and the confusingly named Black Mountains in the east, where the highest point is Waun Fach 811 metres (2,661 feet). The western half gained European and Global status in 2005 as Fforest Fawr Geopark. This includes the Black Mountain, the historic extent of Fforest Fawr, and much of the Brecon Beacons and surrounding lowlands.

The entire National Park achieved the status of being an International Dark Sky Reserve in February 2013.

Most of the National Park is bare, grassy moorland grazed by Welsh mountain ponies and Welsh mountain sheep, with scattered forestry plantations, and pasture in the valleys. It is known for its remote reservoirs, waterfalls including the 90-foot (27 m) Henrhyd Waterfall and the falls at Ystradfellte, and its caves, such as Ogof Ffynnon Ddu. The Brecon Beacons Mountain Centre was opened in 1966 to help visitors understand and enjoy the area.

Due to the relative remoteness and harsh weather of some of its uplands, the Park is used for military training. UK Special Forces, including the SAS and SBS hold demanding selection training exercises here, such as an exercise called the Fan dance. The infantry regiments of the British Army train at Sennybridge, where NCO selection also takes place.

In 2006 and 2007, controversy surrounded the government decision to build the South Wales Gas Pipeline through the Park, the National Park Authority calling the decision a ‘huge blow’.”  
Wikipedia - Brecon Beacons National Park