The 6 Inch Trail Marathon takes place primarily on the Mundi Biddi mountain bike track. This track has some shorter bits of narrow and sometimes very rutted single track, quite a bit of wider track, and some gravel road sections. There are some short rocky sections and a lot of pea gravel. The gravel is quite slippery on steep descents.
Several years ago a section of Munda Biddi track was rerouted due to bushfires. In order to keep the racecourse consistent, we run the original track. The course will be well marked with flour where it deviates from the new Mundi Biddi markers. While you are in the old bushfire section you may see some burned markers, as well.
The 46k race results in about 1150 meters of elevation gain and 1000 meters of loss. The starting elevation is approximately 75 meters above sea level and the start consists of a very steep climb up Goldmine Hill on Whittaker Road. The steepest climb is approximately 140 meters over 1500 meters. Around the 2k mark you will see a few tracks on your left and right, which are marked with numbers, as they enter private homes. Continue straight on. The track levels off slightly but continues to climb to approximately 300 meters above sea level at approximately 3k into the race.
Around the 4k mark the Munda Biddi track enters Whittaker Road from your left. You will reach a road crossing here as well (with a few dead cars at last look). Continue straight across the road through the white gate up ahead, noting the Munda Biddi marker that directs you this way. You are now passing through Whittakers Mill campground. Watch for race markings (floured arrows) through the campground. If you are on the right track, you will pass a toilet on your right as you are nearing the exit. From the campground, you exit onto Whittaker Road and turn right. In a few hundred meters the Munda Biddi (and race course) leaves the road on the left.
The next section starts with a long uphill and then downhill to Torrens Road. Watch closely for Munda Biddi signage in this area! Remember that sometimes the trail in front of you continues straight on but the Munda Biddi sign is directing you to turn! If you don’t see a floured arrow telling you otherwise, you should be following the blue Munda Biddi markers. If you haven’t seen a Munda Biddi marker on a tree for a few kilometres, you might be off course. Try looking behind you to see if you can see any markers on trees to confirm you are still on course.
There is another climb out of Torrens Road and some more ups and downs to the South Dandalup River bridge and Del Park Road. Exercise caution crossing this road, as there are no traffic wardens. At approximately 23k you will arrive at Aid Station #1, near the junction of Turner Hill Mountain Bike Trail.
The trail climbs again as you run parallel with the Alcoa conveyor belt for over 2k. Then you’ll come to Scarp Road. Turn left and enjoy the nice downhill run over the conveyor belt. Another kilometre or so should have you at the big wooden “Oakley Dam” sign. Here, the Munda Biddi marker will direct you straight ahead along Scarp Road. However, you need to turn right (following the Oakley Dam arrow on the sign). Descend into the Oakley Dam area (this is where the bushfires were). Then climb up the short, steep single track section back towards Scarp Road. At the Scarp Road junction, turn right. Continue to follow the main BLUE Munda Biddi markers. Wherever you see green markers you should ignore them. The green markers are for the “touring” routes – easier cycling. You are to stay on the BLUE route at all times (and follow any floured markings).
The trail leaves Scarp Road again to your right for a few kilometres. There is a slight overall descent in this section that takes you back out to Scarp Road. Here you will find Aid Station #2. Continue on towards Grey Road, where you will see the green touring route coming in from your left. There is a hard “switchback” at this point. You come down a steep bit and should turn sharply to your right. Then continue approximately 3k and the trail brings you out underneath a powerline. Turning hard right, enjoy the nice downhill run (provided you’ve still got agreeable legs at this point) under the powerline for approximately 600 meters. This is the least sheltered area from the sun. At the bottom, take a left and head into Marrinup Campground. Continue on the road through the camp (don’t get onto the Marrinup Mountain Bike Trail). Continue along Marrinup Road, following the Munda Biddi markers (they’re all blue through here). Run alongside a dam on your right. Follow a hard righthand turn and continue with that dam on your right again (from the other side now!). Follow the markers along a lovely section of track coming in towards the finish. You will run past the edge of the Dwellingup Caravan Park property. At this point the trail branches out with four options. The left two take you into the Caravan Park. The third one takes you into town via the actual Munda Biddi trail. Unfortunately, at last check the markers here are lying on the ground (as they have been for over a year). But you will find floured arrows to guide you. Several hundred meters forward gets you to the Del Park Road junction. You will see the town proper now. Look right, left, and bolt across the street for your big finish in the park opposite.
To view an interactive map, click here. For Garmin GPS, download the 6 inch TCX route file, click here. To download a GPX file click here. (Right click, select "SaveTarget As").
It is recommended to carry a map of the Munda Biddi Trail. You need Map 2: Jarrahdale to Nanga. You can order one here.They are also available at many oudoor stores like Ranger Camping as well as bike shops.