Note: the data below is outdated, since Zwift released the Drop Ship and changed weight/aero values for many frames and wheelsets. That said, the principles explained below are still valid, so we’re keeping this post up.

See more current speed test info here >

We have completed an extensive series of test laps to provide hard data quantifying the impact of watt, weight, and equipment changes in Zwift.

View data for all test laps >

Weight/Watt/Height Observations

  • A 75kg rider completes a full lap at 4 w/kg 3:40 faster than a lap at 3 w/kg. Therefore, each increase of .1 w/kg makes a difference of approximately a 22s in your full Richmond lap time in this weight and power range.
  • If we look at the lap times for a 250w lap for riders of 100kg and 83.3kg weights, we can surmise that in this weight and power range, each kilogram of weight you lose will cut 5.8 seconds off your Richmond lap time.
  • If w/kg stays constant, the heavier rider will always be faster, even up hills. At 3w/kg a 100kg rider finishes a full Richmond lap 3:45 seconds ahead of a 50kg rider.
  • Increasing your wattage makes you faster–and the heavier you are, the more difference it makes. The same wattage increase (from 200 to 250 watts) tested with different weights resulted in very different Richmond lap time spreads.
    • At 50kg a difference of 2:36
    • At 75kg a difference of 3:11
    • At 100kg a difference of 3:50
  • As wattage increases for riders of various weights their speeds get closer together. Anywhere over 400 watts riders of various weights travel at essentially the same speed, while at 150 watts a 50kg rider is 8:28 faster than a 100kg rider over a full Richmond lap.
  • The taller you are, the slower you’ll go. The test laps we’ve done show that it works out to ~30 seconds longer on a full Richmond lap for each 15cm (approximately 6″) of height added. Or to put it another way: a 5′ rider will be ~1 minute faster than a 6′ rider (all other things being equal).

Equipment Observations

  • Equipment does matter–especially wheels! The Zipp 808’s (the level 10 unlock) are 19 seconds faster over a full Richmond lap than the “stock” 32mm carbon wheels. The fastest bike available to all riders (other than the TT bike) is the Tron bike, which is 68 seconds faster than the stock Zwift Carbon over a full Watopia Figure 8 lap.
  • The difference between the stock setup (Zwift Carbon and 32mm carbon wheels) and the fastest race-legal setup (Tron bike) over one hour of riding is approximately 60 seconds.
  • The Zipp 808’s are the best wheel on all current courses. In the real world you might choose to avoid such a deep wheel due to wind/handling issues, but on Zwift this isn’t a factor so aero wins the day. They may be a bit heavier in Zwift’s calculations than a wheel like the Zipp 404 or 202, but the aero advantage wins out when all your courses are loops.
  • Upgrading your bike and wheels has a synergistic (not just an additive) effect. That is, the overall lap time saved by upgrading your bike and your wheels is more than what you would get if you added the savings of just upgrading the bike to the savings of just upgrading the wheels. Who knows why? It just works.
    • Baseline Richmond lap time (Zwift Carbon, 32mm carbon wheels): 29:39
    • Cervelo S5 with 32mm wheels: 29:28 (-11s from baseline)
    • Zwift Carbon with Zipp 808 wheels: 29:20 (-19s from baseline)
    • Logically combining Cervelo S5 with the Zipp 808’s would save a total of 30 seconds. But instead, it saves a total of 33 seconds. Total lap time with Cervelo/808’s is 29:06.

 

Riding up Libby Hill at 150 watts and 100kg is a slooooow process!

Riding up Libby Hill at 150 watts and 100kg is a slooooow process!