Newbie - Budget Start Up

Morning all,

I am a newbie to Zwift and still in the free trial mode. I have started to use this as what I hope is a fun and interactive way to be healthy. However, I am on a tight budget and simply cannot afford to make large investments until I know for sure I will stick to it.

I currently use a spin bike (JLL IC 300 pro). It has it’s own computer - not ANT+ or Bluetooth.

I have attached a cadence sensor to the crank, when using Zwift I can tell that the RPM it shows in the app is accurate (it matches the RMP on my bike’s computer).

Now the issue:
Power and Speed. I did attach a speed sensor to the wheel and I know this is inaccurate. I read forums that said it was kind of pointless putting one on a spin bike. The speed it shows is much faster than what I am actually doing (when I check against the speed on the bike’s computer).

  1. How is the power calculated with the set up I have? It seems quite high
  2. Can anyone suggest how I make this better? I would like to track progress and also participate in workouts/races
  3. I was about to get a HR sensor - will this help?
  4. I know people have suggested power pedals - but I can’t afford that at the moment.

So i’d like to know the best combo I can use for the relatively cheap sensors of cadence/speed/hr
I don’t need it to be 100% accurate but I’d like to use the workouts and participate in races and routes just to see how I improve.

Many thanks.

PS on another note when I log in it says
“KM logged 3km and 17 mins”
However, under activity it states 5.1KM and 10 Mins avg watts 163
Can anyone shed any light on this??

Searching YouTube video’s on spin bike setup in Zwift might be of some help. I can tell you that the free trial that Zwift offers is crap. You will burn through quickly and you will not be notified when your free trial is over. The avatar will just stop moving.

Watts within Zwift for your setup is calculated the following way. Zwift takes the wheel speed and the power curve of the trainer selected and converts that to watts. Since the wheel size of your trainer is smaller than any within Zwift the watts are going to be inaccurate. Also, Zwift does not have a power curve for your trainer so again the watts are going to be inaccurate for that. Put those both together and you are going to see some unrealistic watts (and speed) within Zwift.

The speed within Zwift and the speed reported by your bike will hardly ever match.

The only way you are going to be able to participate in races within Zwift without being disqualified is getting a power meter (either a one-sided or pedal based).

With your setup you can still do workouts and ride within Zwift as long as your setup is consistent from one ride to the next, but it will not be accurate.

Train via HR with this setup would probably be a better option. FYI, Zwift does not have HR based training plans so you would have to come up with your own zones and training plan.

The difference in distance and time is an known “bug”, the data is pulled from 2 different sources that is why you are seeing 2 different values.

appletv 4k works great and is not expensive. Wheel on trainer is also where I started…they’re loud and not as accurate but good to start. Bet you could get one used easy.

what kind of budget are you looking at? ie, what would you be willing to sink into it? $100? $200? that might help get you better recommendations.

Thanks all for your responses.
I had a good look around on YouTube for a suitable set up.

My current spin bike is approx. £250 and has a built in computer - but not Ant+ or Bluetooth so I wondered if I could replace that?

I purchased a speed sensor and a cadence sensor already - spent around £60. The cadence works fine but as mentioned the speed is way off.

I mount an iPad and used that for my first ride.
I was going to get a HR sensor (probably Wahoo).

I only really want to spend another £80-100 and I can’t get any power meter pedals for that much. I was thinking of the PowerTap (cyclops) PowerCalc which apparently is the worlds first HR monitor that also creates Power metrics too. However the reviews seem hit and miss. It’s about £60 and I am not sure if it’s still valid.

So in short I have a spin bike with decent computer, a Wahoo cadence sensor (accurate), a wahoo speed sensor mounted on my flywheel (way off), and contemplating to get a heart rate sensor or powercalc. Any other ideas?

I’d like to do routes and track progress (time etc), perhaps participate in a race. Or what is the most ‘fun’ optimal use I can get.

I guess you didn’t read my reply.

I doubt you can replace ANYTHING on that spin bike to make it broadcast watts to Zwift.

The PowerCal HRM does work with Zwift, but is only available on the secondary market.

Without a real power meter you will get disqualified from races, but you can do them. You could also get flagged by the Zwift system.

Again, training via HR would be your best option with this setup due to your inaccurate watts and your budget. Even with the PowerCal I would still suggest training with HR. If you want to train with power you would need a smart trainer or power meter.

You are very limited in your options with that budget.

Hi Paul

Apologies I did read your reply. Juts read some mixed reviews around the PowerCal… Was hopeful and then not. Just don’t want to splurge if I am not sure how well I would like it.

By training with HR - do you recommend other apps that have HR based training ?

Also, currently with my Zwift set up… What is it that is making my Avatar move? The Cadense Sensor or the incorrect Speed sensor?

Read my first post. Watts is what makes your avatar move. I will post what other variables effect your in game speed.

I use Zwift for HR training. I know my zones and just monitor them and make sure I am in the correct one for the workout.

Ok, how in-game speed is determined.

For virtual power like yours:

Zwift takes the wheel speed broadcast by your speed sensor and the power curve of the trainer you select on the Pairing Screen and converts that to virtual watts. With those watts, the weight entered, height entered, in-game bike used, in-game drafting (Tri and TT bikes get no drafting boost), in-game wheel set, in-game road surface, and in-game virtual elevation changes your in-game speed is determined.

Thanks Paul

Unfortunately there is no easy fix for a spinning bike. I went through a intense exercise to make it work but it never was a success. As Paul said there is no power speed curve for the spinning bike.

I ended up using a old bike on a dumb trainer that gave me better results and experience.

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So whilst it is apparent that my current set up absolutely needs a power meter. And it seems that all good cycling apps (Zwift, Peloton, sufferfest etc ) work well with a power meter.

Do you think a Power Meter Pedal or Crank would be the cheapest and easiest option. I think pedal is easiest but crank appears to be little cheaper approx. £180. Not now but in the future.

Page 3 shows my spin bike… And it looks like I’d need a 170*27 crank and the left side would be better?

Many thanks, once again


Yes a left sided powermeter will be the cheapest option, but it will depend on the type of bottom bracket if you can get something compatible.

Do you have a road bike you can use?

Gerrie what kind of trainer did you use?

Sorry, What do you mean by the type of bottom bracket?

I do have a specialised hybrid bike, however, I didn’t fancy hauling it in the spare bedroom when I only recently spent £280 odd on the spin bike! Hindisght is a great thing!

It was a magnetic resistance trainer, way before Zwift, lol. I upgraded that to a wheel on smart trainer.

The bottom bracket is the shaft that your crank arm attach to. Most spinning bikes use square taper and power cranks use more modern splines.

Your local bike shop should be able to help.

Ok, thank you

Hi Reena, how did you get on in the end?

I have the same JLL spin bike and am also wondering if there’s a good way of setting it up to play nicely with Zwift :slight_smile:

Many thanks, Rob