Direct drive trainers vs smart stationary bikes?

Question

I ride up to about 175km / 3500m ascent a week (although lately less as I’ve been doing other sports as well). Basically I’m in good shape, but not a pro.

I’m looking to get a biking setup at home, for when I can’t or don’t want to go out. My choices are a smart static bike (it works with Zwift, etc), or getting a cheap road bike and a Wahoo Kickr Core or (for a bit more) a V5 Kickr (new, on discount). I’d leave the bike mounted to the trainer.

I am basically interested in what the advantages/disadvantages might be between a direct drive Wahoo trainer and a stationary smart bike. I posted the specific stationary bike in another post, which was closed since it was too specific. So I’m trying to make this a general question: how do direct drive trainers compare to stationary smart bikes in general.

Both options seem good. The Wahoo/bike route appeals to me more, but it’s more expensive.

One particular question I had: the smart bike I tried is like a spin bike in that the pedals keep spinning with the inertia wheel, so you can’t ‘coast’ as one can in real life. To stop quickly you have to press a red emergency brake. This bothered me. But I was told that it’s the same with the Wahoo trainers, that is, the pedals have to keep turning with the inertia wheel. Is this true?

Thanks for any info!

EDIT: I'm going to cautiously introduce the name of the smart bike I'm considering, since at this point, having read the answers below, and since people are discussing specific stationary bikes and brands, it seems like a relevant piece of info. It's the ZBike ZCycle. Note, I'm still asking about the differences in general, not regarding this particular bike. It is a Spanish brand, and runs considerably less than the Wahoo and TacX bikes.

Answer 1

I have done both of these. I started out with a CycleOps Hammer with a dedicated bike on it. Eventually I destroyed both the trainer and the bike, and replaced them with a Kickr Bike.

Part of the reason I wrecked my old setup was that I didn't take great care of it. I poured a lot of sweat onto it, and wasn't fastidious about keeping it clean. I am more careful with the new setup, but it's also a lot easier to wipe down.

If you plan on leaving your stationary setup in place all the time (as I do), the smart bike is a little easier to live with. If you need to move it around (for housecleaning, etc), it's on casters and it's one piece, rather than a bike on a trainer, which is very awkward to move around.

In terms of technology, a smart bike and a smart trainer are basically the same.

There are some smart bikes/smart trainers that have what's called "forward driving," which lets you coast "downhill." Looking at this list, it seems the only smart trainer with this feature is the Tacx Neo. The Kickr Bike also has it. It's weird. I get the impression that any trainer with a forward-driving motor is going to have a very light flywheel, and that really changes pedaling feel. If you take a pedal stroke and then back off, the motor takes over to simulate a flywheel effect, but the simulation isn't perfect. I've gotten used to it on the Kickr Bike, but it is a thing to get used to.

However, there is no smart trainer or smart bike that I know of that's a "fixie," meaning that if the flywheel is turning, the pedals are necessarily turning. They all can coast. Unless they have forward driving, they coast down very quickly, even with a massive flywheel.

As to positioning on the bike, it hasn't been issue for me. Apparently the Kickr Bike has a Q-factor 10 mm wider than conventional bikes (which might actually benefit me). I haven't meticulously dialed in my position on it the way I have on my road bike. But I also rarely spend more than 2 hours on it at a time, and that's just not long enough to create biomechanical problems for me.

Answer 2

A smart bike is a unit like the Stages SB 20 or Wahoo Kickr Bike. These tend to cost US$3,000 or more. They can be thought of as high-quality spin bikes, but they have the drivetrain entirely enclosed. You would adjust the smart bike to replicate your own bike's riding position.

One plus for a smart bike is that the drivetrain is enclosed, and you aren't putting wear on your main bike's drivetrain. That said, this is indoor riding, so the bike is exposed to only minimal contamination - this is a big part of what causes wear on a drivetrain. (NB: Smart bikes probably use drive belts, which last a lot longer than chains but aren't amenable to derailleurs - but smart bikes don't use derailleurs per se.) Also, the bike's position is adjustable, which can help with setting the bike up for multiple users.

In my view, there are quite a few downsides. Smart bikes cost a couple thousand dollars more than a smart trainer. If you are sensitive to small changes in your position, and many serious cyclists can be, then it's often difficult to precisely replicate your position. Because smart bikes need to be adjustable, the handlebar/stem area is more complex and it may be more flexible than on an outdoor bike. I don't know if this is true of all smart bikes, but I think that at least one model may have a markedly wider Q-factor than standard road or gravel bikes. Also, smart bikes are larger and quite a bit heavier, so they are harder to store off-season.

I put a sweat catcher on my outdoor bike. I haven't had problems with increased drivetrain wear on mine. You should periodically clean the handlebars under the tape, as your sweat can accumulate there and cause corrosion, but you are usually replacing your tape intermittently.

To the question about coasting: I understand that smart bikes can't coast unless you pull the brake lever to stop the flywheel - and this process operates independently from whatever Zwift (or whatever program) is simulating.

On a smart trainer, you can freewheel just as in real life without having to brake. Zwift is not an exact simulation of outdoor cycling. One of the ways it differs from real life is that when you stop pedaling on the flats, your avatar will come to a stop much faster than in real life. Thus, as a result, I usually don't coast in Zwift. In races or in spicy group rides, when you are over 56 km/h and under -3.5% incline, the program simulates you going into a supertuck (a now-banned position IRL). That's the only time I really coast. I don't know how other programs treat coasting. Anyway, you may find the different functionality on smart bikes is something you can get used to.

Answer 3

A spin bike can only be used in one place, whereas a conventional bike can be used on a trainer or reassembled and ridden on the road if necessary.

Additionally, a bike on a trainer shares more parts with other bikes than it does with dedicated spin bikes. If you're handy, then the ability to swap/swipe parts can be useful.

A dedicated spin bike will use about as much physical space as a trainer with a dedicated bike on it, so that's about equal.

Personally I find indoor riding monotonous and boring, but I've also never tried a full setup with sensors, variable resistance and on-line stuff. The cost of trying that is significant, and I still have to get to work anyway.

Ultimately, N+1 applies to all bikes, so if money permits you can own both. Try one and if it doesn't work for you, try the other, and on-sell the one you don't enjoy.

Answer 4

TLDR: smart trainer is a more flexible option.

An element that can help to choose is how accessible is the place where you want to install the "bike/trainer", and how permanently you can leave it installed.

• The smart bike will work best if access is complicated and you can leave it permanently, but not more than a bike + trainer.
• If you can't leave it permanently mounted, a "smart bike" takes a lot of space, whether used or not. If the summer storage is not next to the place it is used, it will hard to move. While with a bike, you can store the trainer and the bike in different places.
• If access is easy, the trainer option is more flexible, and it can even work with one bike.

If you want to buy an additional bike for the trainer, another advantage of the smart trainer option is that you can take a bike with a different focus than the current one. For example, a gravel if you now have a road bike (there might a road bias in the apps though — at least with Rouvy). During the nice season, you can use both, and in winter you can leave one mounted on the trainer and use the other outside.

Now on the two models you mention: for the same budget, it's likely that the smart trainer + bike will give you more bang for your bucks in terms of performance. A lot of the money for the smart bike will be to build the "structure": the power side of of the Zycle seems well below in terms of specs than the Kickr (Core).

Answer 5

I generally agree with the other answers, but in my opinion the choice boils down to a single question: will multiple people be using it?

The dedicated smart bikes are way easier and quicker, and more repeatable to adjust, than a regular bike. That is really their value. Their internals are basically the same as their regular trainer brethren.

Switching fit on a regular bike, or swapping bikes on a trainer, can be enough of a hassle to trigger a riders procrastination, but on the smart bikes, it's always just a few seconds to get setup.

But if it's just you, just do a regular trainer.