Dirty 30 Gravel Grinder: Course, Elevation & Route Profile

Course & Elevation

Start and finish are in downtown Saranac in Ionia County, a short hop from Grand Rapids. The loop first follows the Unclean 16 course east through open farmland with barns and field roads before turning more wooded. It runs on open roads: mostly gravel and hard-packed farm roads, with short stretches of pavement and, depending on how wet it is, some dirt. Late March here means rain, cold or even snow, and the race goes ahead regardless.

For the first two thirds the profile stays calm, with a ramp of just under a kilometre around km 21 as the only climb of note. The Dirty 30 then adds about 14 miles of extra gravel rollers to the short loop, and that is where the work sits: a short ramp at km 35, a steeper one at km 37.5 with pitches above ten percent, and from km 42 Ivan Road, a little over 1.2 km and 60 metres of climbing with sections near twelve percent.

From the top it is about five kilometres back into town. The Dirty 30 is the short-course round of the Michigan Gravel Race Series and, by the organisers' account, by far the most popular race of the day.

Pacing Strategy

The first 30 kilometres are mostly flat to gently rolling and tempt you to ride too hard in a group. On gravel every surge costs more than on pavement, and the wind across the open fields makes shelter valuable. Ride in the bunch here, but below threshold, and take the ramp at km 21 seated.

The race is decided in the last 13 kilometres, where three climbs come close together. If you are already at your limit at km 37, you lose more time on Ivan Road than you gained earlier. Treat Ivan Road as the one hard effort of the day: steady into the lower part, then over the steepest metres with cadence rather than force, so the rear wheel does not spin on loose gravel.

The trap is the weather. In wet and cold conditions the pace feels easy for a long time until the fuel runs out; eat and drink on the quiet early kilometres even when it is cold.

Training plan for Dirty 30 Gravel Grinder: 12-week build

For most amateur riders the Dirty 30 takes between just under two and three hours. The effort is mostly aerobic and steady, broken up by short, hard spikes on the ramps in the final third. What it asks for is an endurance base plus the ability to ride five minutes well above threshold when already tired.

The decisive section is Ivan Road after about 42 kilometres. Build your long endurance rides so they finish with hard climbs of three to six minutes, and ride them on gravel, where you can practise traction both seated and standing.

Late-March conditions in Michigan are a training focus of their own. The organisers race in rain, cold and snow, so train outside in bad weather too, test clothing, gloves and tyre pressure on wet gravel, and get used to eating regularly when it is cold.

Because much of the winter is often spent indoors, it pays to get as many hours as possible on loose surfaces in February and March. Gravel handling and muscular endurance on rough roads cannot be simulated on a trainer.