Trainers can be organized into many different categories, but when it comes to Zwift, you’re either on a “smart” or a “classic” (or “dumb”) trainer.
A smart trainer’s resistance is controlled by Zwift. When the incline of the Zwift course changes, your resistance changes. You “feel” the hills. Additionally, a smart trainer will broadcast your power (and usually cadence) via ANT+ and Bluetooth. So those are the two key things smart trainers do which classic trainers do not: they detect your power (in watts), and change resistance on the hills.
(Note: there are certain smart trainers which are not controllable by Zwift. They broadcast power, but do not change resistance on hills. We call these “non interactive” trainers, but they are rare nowadays.)
Because smart trainers are complex electronic devices, they must either be plugged in or (in the case of a few trainers) powered by the watts you’re putting out.
Popular top-quality smart trainers on Zwift include the Tacx Neo 2T, Wahoo Kickr, Wahoo Kickr Core, Saris H3. and Elite Direto XR.
Check out our Smart Trainer Index for recommended trainers at different price levels.
A dumb trainer doesn’t talk to Zwift – hence the name “dumb.” You may be riding up and down hills on the Zwift course, but you’ll feel no difference in the resistance because Zwift has no way of talking to your trainer or changing its resistance. Dumb trainers also do not detect your power or cadence. All they do is provide steady resistance on your back wheel.
Because of this lack of power detection, using a classic trainer on Zwift requires either a separate power meter (perhaps on your pedals, cranks, or wheel) or a speed sensor on your wheel and what Zwift calls “virtual power.” (Fair warning: virtual power users have a bit of a bad reputation on Zwift because their power is notoriously inaccurate, leading to “flyers” off the front in races.)
Dumb trainers are super simple devices. No power to plug in – just attach it to your bike and go.
Many serious Zwifters still ride classic trainers while using a power meter, because they already had both the trainer and the power meter before Zwift came along. This is a solid setup which produces accurate power readings. The only downsides are a lack of resistance changes on hills, and no ERG mode for workouts.
What’s Best for Me?
This is a question you have to answer yourself! If you have the money, going for a smart trainer will greatly enhance your Zwifting experience. The difference between riding Zwift on a classic trainer and riding it on a top of the line smart trainer is like night and day.
That said, you gotta do what you gotta do. If you can only afford a classic trainer, then go with that! Perhaps in the future you can upgrade to a smart trainer, but at least you’ll be able to hop on Zwift and train right now without breaking your budget.
Many Zwifters begin their indoor riding on a borrowed or used classic trainer, then take the plunge and purchase a nice smart trainer once they got hooked on Zwift.
Hi Eric, as a newbie to zwift your articles are really useful in understanding the delights, details and nuances of Zwifting. On seeing this article I hoped you might answer a question that has been going through my mind regarding the difference between smart trainers and what you referred to as non- interactive trainers. So I have one of these, broadcasting power and cadence, and ride with a couple of friends who have smart trainers. Comparing power outputs when riding together, our watts are comparable but when the hills arrive they suffer the increase in resistance whilst I don’t, I… Read more »
Hi Mike, I’d say it doesn’t give you any advantage. In fact, I’d say the vast majority of the time you’re at a disadvantage, since you have to respond in an unintuitive way in order to keep up on the climbs! Smart trainer users naturally go harder on climbs, just like outside. But you have to up your cadence and/or shift to a harder gear in order to increase your wattage on the climbs – both actions which riders do NOT do when they hit an uphill IRL! The only time it’s an advantage, I think, is if the smart… Read more »
Hi Eric, thought I’d read the other post you gave the link to before replying and it certainly adds to this question. At the end of the day it’s about the wattage each rider puts up to achieve a given speed on any particular section of a course, uphill, flat or down. Assuming two riders of equal weight and fpt, one on smart and one on a non- interactive trainer, on hitting a hill the smart rider will increase effort but may have to shift down to stop going into the red too early or at all and to maintain… Read more »
I do continue to see “dumb trainer” riders taking the jerseys on Zwift jersey segments ex; Green jerseys, KOM jerseys and orange jerseys. Mostly the times recorded are insanely fast or “unrealistic”. Wish Zwift would give them their own leaderboard
I think some of the “unrealistic” times are also from riders riding in “stat together” and getting launched at 60kmh to catch up.
Hi Eric, another great article, I starting zwifting on a dumb trainer but the lack of resistance was really boring and led me to, first bought a wheel on smart trainer, and later a direct drive, and this was a really gamer changer on my training, improved a lot after this, seeing my fitness and my irl rides gain some solid achievements. Keep up the good work!
ZP shouldnt be allowed in races; period – just have their own hackfest of pretenders
One thing about “dumb” trainers – they are usually pretty solid and stable.I have a Kurt Kinetic Rock and Roll, so I can get out of the saddle with no trouble, bike has lateral movement on trainer, whereas I’m not sure smart trainers have this.
I have borrowed friends smart trainers both wheel on and off, I bought a dumb trainer and have got going for $275 using a cadence/speed sensor. As mentioned I’d see the point of power metre and dumb trainer in temperate climates but if I lived somewhere with long cold winters I’d probably skip to a smart bike to limit the wear on the real bike.
Also,… If you do structured intervals on Zwift a smart trainer behaves exactly like a ‘dumb’ trainer. Ie, there is no variable resistance, you just have to hit your watt numbers and intervals….. So if you mainly do training plans and intervals there is no reason to go for a ‘smart’ trainer.
That’s not true. Smart trainers let you do workouts in ERG mode, where they force you to hold the prescribed wattage. Dumb trainers make you manage that wattage yourself, and you’ll never be as precise as an ERG mode effort.
Sorry, I should have been more precise. I was not addressing erg mode, but structured intervals like ‘5x4min at 225watt’…. Where you yourself manage your cadence and try to hit the required watt numbers, or thereabouts …. Some days you struggle with 225watt, but 220 watts is ok, some days 225watt is easy and you can push 230watt, as long as you hit suitable interval around 225watt you’re fine training wise …. ERG mode is a different beast, it forces you to do 225watt no matter what.
Erg mode is over rated.No such yhing in real life cycling outdoors or traing or racing outdoors.
It’s supposed to help you with workouts. Zwift isn’t real-life.
Eric, I would like to clarify one part of the dumb trainer experience. I ride on one and have cadence and wheel speed sensors on my bike. Zwift easily connects to them and I have no trouble with my cadence showing up in the game. The program uses an algorithm to determine my watts based on wheel speed and cadence. Then converts that to mph based on watts and incline. I believe the watts are not 100% accurate but they should be close. I ride against myself so if I improve my watts, that means I’m getting faster/stronger. Also, I… Read more »
@Joe. Exactly. I used a KK dumb trainer w virtual power and cadence on Zwift znd Trainer Road for a couple of years. It was awesome. In game experience in Zwift was about 80% as fun as w a smart trsiner I now use. I still love the feel of my “dumb” KK trainer and do go back to it at times. Dont automatically believe the repeated hype about “…absolutely having to have a smart trainer, otherwise Zwift will be absolutely boring…
Eric, first of all thanks for all of your work! General question. I have a wahoo kickr and also garmin vector power pedals. The pedals “give me” around an extra 5-10 watts, I believe the difference is down to the loss via the drive train so numbers are likely accurate. Question is for racing is it poor form to use the garmin vector pedals to gain these extra few watts and use the smart trainer for training. I use the pedals outside so would be useful to have correlating data but feel right thing is possibly to stick with the… Read more »
I don’t think it’s bad form. Some might disagree. And I think in the big high-level Zwift racers, riders are required to use their trainer as their power source, with pedals, etc as a secondary source just to show the trainer power is legit.
I’m in the same boat as you – I use pedal power meters outdoors, and want my numbers to match up. So I use my pedals as my primary source. (I also can’t help but thing pedal-based power meters with actual strain gauges are more accurate than power estimated from belt speed…)