The 1 in 20 is a well-known road-cycling climb along Mountain Highway from The Basin towards Sassafras. Its forest setting and sustained gradient make it a popular way to test climbing fitness on the western side of the Dandenong Ranges.
This is a public road shared with motor traffic. Plan the ride around your own ability, road conditions and the return journey, rather than treating it as a closed cycling course.
The Climb from The Basin
The recognised climb is approximately 6.8km long, gaining about 274 metres at an average gradient of roughly 4%. It is classed as a Category 3 climb. The average describes the whole route; individual sections vary. A gentler section partway up changes the rhythm before the road resumes climbing towards Sassafras.
The starting area is on Mountain Highway near the eastern end of The Basin’s shops, with the climb continuing towards Sassafras. The recognised segment starts near the end of the shops and finishes before Sassafras village. Establish the exact start and finish you intend to use before comparing distances or timing a ride.
The road winds through forest, with fern gullies and changes in canopy along the way. That scenery is part of its appeal, but bends and passing vehicles still require attention throughout the ascent.
Pacing and Fitness
A sustained climb rewards a steady pace more than a fast opening effort. Select gearing that lets you keep turning the pedals comfortably and leave energy for the upper section. A familiar short hill may not prepare you for several kilometres of continuous work.
There is no useful completion time that suits every rider. Fitness, bicycle gearing, traffic and stops all affect the outing. Allow generous time for your first attempt and assess your comfort before adding other climbs.
Make any rest stop in a safe place clear of moving traffic. If riding with friends, agree on regrouping points so that slower riders do not feel pressured to take risks or continue beyond their ability.
Road Conditions and the Descent
Check your brakes and tyres before departure. Carry water, a repair kit and clothing suitable for the cooler forest environment. Wet leaves, rain and shaded corners can change grip substantially.
The return descent needs controlled speed and attention to sightlines. Keep enough margin to respond to traffic and surface changes rather than using the downhill as an opportunity to recover time lost on the climb.
Use lights and visible clothing suited to the conditions. Check current road works or closures before travelling, particularly after severe weather. A familiar route can still have new hazards.
Starting in The Basin and Finishing Near Sassafras
If arriving by car, use lawful parking around The Basin and check restrictions. Keep equipment, bicycle loading and group gatherings clear of shops, driveways and road space.
The village areas can provide a refreshments stop before or after the ride, subject to individual business hours. Carry what you need for the climb rather than relying on a particular cafe being open when you arrive.
Daylight is the practical choice for a recreational first attempt. Plan the complete ride, including your descent or onward route, with enough time to finish comfortably.
1 in 20 FAQs
Where does the 1 in 20 climb begin and end?
It follows Mountain Highway from the eastern end of The Basin shops towards Sassafras, finishing before the village. Use the recognised segment boundaries when comparing times, rather than including a different approach or village stop.
How long and steep is the climb?
The recognised climb is about 6.8 kilometres, gaining roughly 274 metres at an average gradient of 4%, and is listed as Category 3. Sections vary, so the average does not describe every bend or the gentler stretch partway up.
Is it a separate cycling trail?
No. Mountain Highway is a public road shared with motor traffic. Stay alert through bends and forest shade, choose safe places to stop and ride considerately around drivers and other cyclists.
How fast should I try to climb it?
Choose a pace that lets you complete the sustained effort comfortably with energy for the return. Fitness, gearing and conditions vary widely, so a first visit is better planned around steady riding and generous time than a fixed target.
What should I prepare for the descent?
Check brakes and tyres before departure and control speed through corners with limited sightlines. Rain, wet leaves and shaded surfaces can reduce grip, so leave enough margin to respond to traffic and changing road conditions.
Can I combine it with a cafe stop?
The Basin and Sassafras have village refreshments options, subject to individual business hours. Carry water and what you need for the climb, and plan lawful parking and the full return journey if starting by car.
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