Season ΣI · Stage 4

DIRT Racing Series Season ΣI Stage 4: Three Sisters

Tuesday 20 October 2026

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Stage 4 is a mountain stage in Watopia: 21.3 km with 769 m of climbing, and a finish on top of the Radio Tower, the steepest climb in Zwift. Three climbs are scored: the Hilly KOM for FTS inside the first kilometre, the 9.5 km Epic KOM for FAL, and the Radio Tower for FTS. The finish line is at the top of the Radio Tower, so the last climb pays FTS and the 120 finish points together.

The course

Three Sisters is normally a 48 km loop over Watopia's three original climbs. DIRT has cut it to 21.3 km, which is two of the three: the Hilly KOM straight out of downtown, 8 km of flat road, the Epic KOM, and the Radio Tower, with the line at the top. The Volcano KOM and the long descent are not raced. These are the parts that decide the race:

The Hilly KOM

The race starts with the Hilly KOM, 600 m from the start: 0.9 km at 5.5%, in two parts split by a flat stretch through the hairpins, with the last 200 m nearly flat. It is scored FTS, on your time from bottom to top, and it comes so early that everyone is fresh and the group is at its biggest. The fastest times will come from riders who go hard from the gun. The flat 200 m before the banner is where a group re-forms, so if you have gone deep for the time, get back on a wheel there.

The Epic KOM

After the descent there are 8 km of flat road along the coast to Sequoia Circle, where the Epic KOM starts at 9.7 km. It is 9.5 km at 3.9%, and the average hides its shape: a pitchy, winding start up to the suspension bridge, a long steady climb through the tunnel, then rollers along the ridge with a brief downhill, and a final push to the banner. Expect 17 minutes for the fastest and 25 or more for most. The draft helps on the shallow parts and barely at all on the ramps, so the group thins all the way up.

It is scored FAL, on the order across the Epic KOM banner at 19.1 km. First across takes 10 points, tenth takes 5. Everything that happens on the climb is for that one line and for position going into the Radio Tower.

The Radio Tower

Four hundred metres after the Epic KOM banner, turn left onto the Radio Tower: 1.16 km at 12.8% on an icy road that rolls slower than tarmac. Nothing else in Zwift is this steep for this long. Riders will be doing 8 to 12 kph, and there is no draft to speak of at that speed, so it is pure watts per kilo for six to ten minutes.

It is scored twice. FTS pays the ten fastest times from the bottom to the top. The finish line is at the top, and the order across it pays the finish points, 120 for first and 95 for tenth. One climb, two scores.

Power-up and equipment

The only power-up is the feather, which cuts your weight by 10% for 30 seconds. Use it on the Radio Tower, where weight matters most: it is worth the most on the steepest road, and the Tower is where the finish and the FTS are decided. The Hilly KOM is a shorter and smaller prize. DIRT hasn't said whether you get one in the pen or one at each arch, so check at the start.

There is no draft boost and no aero helmet.

This is a climbing race, so ride the lightest setup you have. In Zwift Insider's climbing tests the S-Works Tarmac SL9 is the best climber as it comes, and a fully upgraded Specialized Aethos is better still, about 21 seconds an hour faster on a climb. Put light wheels on it, not a disc: the Princeton Alta 3532 or Zipp 353 NSW if you have them. The 8 km of flat is the only place an aero bike would help, and it is ridden in a group.

Where the points are

The finish pays three times as much as all the segments put together. The most one rider can take from the segments is 40 points, and the gap between 1st and 10th at the line is 25 (DRS rules and scoring).

Miss the time cut, 135% of the winner's time, and you lose your segment points but keep your finish points. On a stage this hard the cut is real: a winner at 40 minutes puts the cut at 54. Four riders score for each team.

How it will be raced

• The first kilometre is a sprint uphill. The Hilly KOM starts at 600 m and pays FTS. Go from the gun if you want it, then get back in the group on the flat before the banner.
• The flat is a truce. 8 km along the coast in one big group, because nobody gains from pulling before a 9.5 km climb.
• The Epic KOM is the race. The group breaks up on the ramps and the ridge decides the FAL order. Ride your own pace: a minute lost on the Epic KOM costs less than blowing up before the Tower.
• The Radio Tower decides everything. Six to ten minutes at 12.8% for the FTS and the 120 finish points. Whatever you have left, spend it here, with the feather.
• Weight wins. No draft, no aero: the lightest riders with the best W/kg take the stage.

Before the race

Start times in UTC: Atlantic 09:45, Central US 11:00, EMEA C 17:15, EMEA W 18:30, US E 23:30, US W 01:30 (Wednesday in UTC). Your slot and pen show on Teams, then Rider Dashboard, once the race pass arrives.

• Heart rate monitor on and sending to Zwift. No HRM means an automatic DQ, though your team captain can ask for a review.
• Power sending to Zwift, or it is a DQ.
• Don't change height, weight or other settings between the pen and the finish, or it is a DQ.
• ZwiftPower registered with data sharing on, and your DIRT account showing your full name and Zwift ID.
• Keep your Zwift FIT file. Race Control can ask for it within 24 hours, and not supplying it is a DQ.
• Save the ride as public.

Running Sauce for Zwift? Open the free Race Report mod before the start, and afterwards relive the race: where the splits happened, which group you were in, and how the finish played out.

Sources

• DIRT Racing Series Season ΣI Stage 4 stage page
• DRS rules and scoring
• Zwift Insider: Three Sisters, its segment pages for the Hilly KOM, Epic KOM and Radio Tower, its power-up guide and its climbing bike tests
• What's on Zwift: Three Sisters for segment positions