Do Classic Trainers pass Smart Trainer riders going uphill?

I just downloaded the software and and ready to buy my trainer but I have one specific question regarding the difference between classic trainers and smart trainers. 

If a classic trainer does not know you are going uphill the way a smart trainer does. Do then classic trainer riders basically always cruise at the same speed no matter if the course in going uphill or down hill?

And if this is the case, are smart trainer riders and classic trainer riders on the same servers? Meaning, if you hit an uphill and you are on smart trainer, do all the other riders have the increased difficultly going uphill also, or is it a mixed server where some riders are going 20mph+ uphill where other riders are struggling to maintain, say, 5mph. 




Servers are mixed. However, Zwift does not simply take trainer recorded speed and directly translates that to ingame speed. Rather, it takes your wattage on a smart trainer or with a power meter. And alternatively tries to compute a wattage based on trainer model and given velocity.

What you will find however though is that improperly set classic trainers may have overestimated power levels given to them. And as such leaderboard rankings commonly show classic trainers in top positions. Likewise, on smart trainers players tend to under report their own weight, also making them take up leaderboard positions.

If you take the leaderboard positions with a grain of salt however, none of this truly matters.

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> If a classic trainer does not know you are going uphill the way a smart trainer does. Do then classic trainer riders basically always cruise at the same speed no matter if the course in going uphill or down hill?


No. If using a classic trainer Zwift takes the speed of your rear wheel and turns that into a power measurement. Smart trainers report a power measurement to Zwift. This is then fed into the game and the power value and only the power value is used to determine the speed of the rider, so e.g. 200W could have you doing 25mph on the flat but 8mph up hill. This is the same for all types of trainer.


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I have noticed in group rides that riders with a smart meter [in simulation mode] (including myself) tend to maintain speed better at the start of an incline or on hill sections because the resistance of the trainer naturally brings the power output of the rider up (the legs respond just like real life).

I assume that riders with a classic trainer do not feel this and the power output remains constant until they see the drop in their km/h (or that they are falling back) and respond accordingly.

The reverse is true on downhill sections where smart trainers feel the resistance drop and the flywheel kicks in it becomes harder to apply power. Here the classic trainers accelerate (relative to the group) because once again I assume they continue to push a “constant” output.

So, the basic experience is that smart trainers help you climb whereas with a classic trainer it is easier to descend faster.

Of course, experienced riders will take account of this and adjust their output accordingly - meaning that neither set up really gives an advantage.

I have a Kickr Snap and I find it difficult to keep up on the climbs.Earlier today on the Richmond course no matter how many watts I put out my rider would be climbing at around 4mph and would occasionally come to a complete stop even though I was pedaling my butt off.My Garmin speed sensor was showing my speed around 12mph and Zwift would show me at 4mph while every other rider on the course sprinted away.Of course the reverse is true on the downhill as my speed sensor would show 25 mph and Zwift would show 35mph.On level ground is the only time Zwift and my Garmin agree on my speed.

The speed your rear wheel is spinning (which is what Garmin is reading) is of no relevance to anything. Zwift only cares about your power output as that is the only input into the game. 


Put your Garmin away and use a smartphone and Zwift Mobile Link for relevant data.



I already use my smartphone with the Zwift app I was just curious to see how far off Zwift speeds were to what my speed would be out on road.Frustrating to be putting out 8w/k and getting smoked by people putting out 1W/k.Could be something wrong on my end but I’ve tried all of Zwift and Wahoo’s recommendations to no avail.Still enjoy Zwift but it’s nearly impossible to do even an easy pace group ride without getting dropped on the climbs.

Honestly, it sounds like something is wrong with your setup. I have a Kickr Snap and don’t have this experience at all.

The only time the Kickr Snap prevents me from putting down Watts is in ERG Mode (which is during Workouts only). I would open a ticket with Zwift/Wahoo about this - both have quick response times.

If you are putting out 8W/kg then you should see 8W/kg in Zwift. That should not vary whatever the simulated gradient.

My advice would be to turn off all other sensors or third party software. Just run the Snap and Zwift (not the Wahoo Fitness App) and see if the hardware you have is creating a conflict. Sorry - can’t be of more help.

Yeah probably is something going on with my setup.Glad to hear you aren’t having any issues.I will check and see maybe I have EGR Mode enabled.Thanks for the helpful reply.

Michael, you may have already done this, but I (and a bunch of other people) had the same problem. The fix was a USB extension cable to place the ANT sensor close to the bike, where it can pick up power, cadence etc. more efficiently. Hope this helps.