We’ve already discussed how Zwift has increased the rolling resistance of dirt portions of Watopia for certain tires/wheels. But we haven’t yet talked about the one bike in game which is set up to roll faster in the dirt: the new Zwift Mountain bike!

According to my sources inside Zwift, every wheelset except the new mountain bike wheels is using the same rolling resistance right now, meaning all the road bike wheels are going to roll pretty slow on dirt.

This isn’t immediately obvious unless you ride a long stretch of dirt, like the all-dirt Jungle Circuit. Here, riders are finding their speeds with road wheels to be 6-8km/hr slower than tarmac speeds.

So we did some test laps with various road setups, as well as the Zwift Mountain bike, to find out if the mountain bike was really faster in the dirt, and if so, by how much.

The Results

At 300 watts steady (4w/kg) the Zwift Mountain bike turned in a Jungle Circuit time of 13:47.

The Tron bike (and other fast bikes) come in right around 15 minutes flat at the same power levels.

No bike/wheelset combination comes close to the Zwift Mountain setup when riding the Jungle Circuit… at least not right now. Of course, Zwift will be releasing more wheels that roll better in virtual dirt. Then things will get interesting!

But for now, if you’re heading to a race on the Jungle Circuit, you’re going to want to try the Zwift Mountain bike! Here’s how to unlock it.

How Does It Perform on Tarmac?

The mountain bike doesn’t perform well on tarmac–it’s by far the slowest bike on pavement, turning in a lap time of 38:34 on a single lap of our Volcano Climb test route (at 300 watts, 4w/kg steady).

For comparison, the fastest road setups finish this route in 35 minutes flat, while the slowest finish it in just under 36 minutes.

Thoughts On Dirt Strategy

This sets up an interesting race situation in which riders may choose a fast road bike setup for racing the Jungle Circuit in hopes of dropping the mountain bike riders before hitting the dirt circuit.

Will that strategy work? Possibly, depending on how many Jungle Circuit laps the race includes. Most races involve 1.5-2.5 laps around the Jungle Circuit. With only ~5 miles of tarmac leading into the Jungle dirt, road riders will have to push hard from the start to drop mountain bikers and create a big gap before hitting the dirt circuit. Then it will be up to the mountain bike riders to reel in the roadies on the dirt. It’ll be a battle!