Events/Mountain Mayhem

Mountain Mayhem

MTBTimed laps

Date

Sat, 19 Jun 2027

Venue

Marston Lodge, Northamptonshire (formerly Eastnor, Gatcombe)

Per lap

8.2km

Climb / lap

191m

Non-stop

24hr

The UK's original 24-hour mountain bike race, run since 1998 and still the biggest in the discipline. Ride an 8.2km cross-country lap as many times as you can, from noon Saturday to noon Sunday.

Create a free training plan for the Mountain Mayhem

7-day free trial, no card required

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The course

One lap, on repeat

A fast 8.2km cross-country lap at Marston Lodge in Northamptonshire: farm tracks, woodland and flowing singletrack with 191m of climbing. You lap it over and over for a full 24 hours, noon Saturday to noon Sunday.

Weather

Mid-June, Marston Lodge

20°CTypical high

10°CTypical low

4°CColdest in 20 years

40%Days with rain

Highs around 20°C and lows around 10°C, but it has dropped to 4°C. Rain on 40% of days.

NASA POWER data, 2006-2025, the week either side of race day

Training

Training for the Mountain Mayhem

We don't do generic plans. We combine deep knowledge of this race's demands with your recent training, then build a plan with you that progresses as you do.

Beina integrates directly with your existing tools to understand your current fitness, and synchronise your planned sessions.

Intervals.icu

What Mayhem throws at you

Typical sessions

Roughly 18 hours of daylight riding, so aerobic durability matters far more than peak power.

191m of climbing a lap stacks to 5,000 to 7,000m or more over 30-plus laps of repeatable effort.

A short but real 5-6 hour night section that needs lights and night vision.

Mud. A wet year hammers grip, drivetrain and morale, and can rewrite your lap count.

What your weeks look like

Typical sessions

Long endurance rides building to 5-6 hours, plus back-to-back weekends of a 5hr Saturday and 3hr Sunday.

Sweet spot 2x20min at 88-93% FTP and Z3 tempo endurance rides for muscular endurance.

Hill repeats of 8-12 x 3-4min, plus climbing intervals tacked onto the end of a 3-4hr ride.

One or two night rides on singletrack to dial in lights, plus fuelling and fast pit-stop rehearsal.

Not a generic schedule

Typical sessions

Built from your current fitness and the time you actually have

Adapts every week as Beina learns how you respond

Syncs your sessions straight to Garmin and Wahoo

One clear next session, never a wall of spreadsheet

Not currently running

Train for the next one.

Not run since 2019. Covid took 2020 and 2021, 2022 came back as a one-off 6hr, and the 25th-anniversary 24hr planned for 2023 was cancelled by the organisers on financial grounds. Nothing has been announced since. The date held here is the traditional midsummer weekend, not a confirmed one.

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