Watts seem really low

(Jeff Shafer) #1

Hi, Just started using Zwift and I am really enjoying it so far, but I seem to be getting a really low watts reading.  I am 5’11 173lbs and use a Cyclops Fluid 2 trainer.  I am no speed demon, but everybody, just about, is flying past me.  I use TrainerRoad and when that gives me a reading of 120watts, Zwift shows about 80, and 140 of TR yields about 100 on zwift.  I’m I doing something wrong?  The delta appeared to reduce between the two as the watts got higher, but the wide disparity seemed odd and I figured I’d see others on the course traveling at similar speeds.





(Ian Fripp) #2

You’re not imagining things Jeff.  As the fluid in the resistance unit heats up, it gets harder to drive the wheel.  The result is that zPower shows a gradually decreasing power curve.  I’m also noticing that the power curve for cycleops fluid2 is lower than others.  It is frustrating to see everyone passing me by but I wasn’t getting the workout on my Elite trainer.  So I’m toughing it out for the sake of a good workout even though I can climb a 7.5% HC in the real world at 220 watts solid for over an hour but in Zwift I seem to average about 140 watts going uphill (on my first lap) and it’s much shorter.


The bright side is, that it makes you feel awesome when you hit the road and your performance is much better in the real world!


(Todd Bondy) #3

I am noticing the same issue WITH a Cyclops G3 power meter…


(Todd Rogers) #4

I am having the same problem with my cycleops trainer. I’m not using a power meter, but I’ve noticed it almost impossible for me to push over 500 watts even while sprinting and using a high gear. 



(Todd Rogers) #5

(Eric ) #6

How much pressure is on your tire from the resistance unit? It may be on too tight.


(Todd Bondy) #7

Eric, is that question for me or Todd Rodgers? 



(Eric ) #8

Todd Rogers. If you have a PowerTap, I’m not sure why it would be reporting low wattage as we read the wattage directly from the PowerTap itself without any modification.


(Todd Bondy) #9

The live watts on the screen report low but then the data after the ride reports what I would consider typical readings.



(Todd Rogers) #10

I have mine set up to the manual specifications (touching tire, then 2.5 turns). Even when at that resistance I am often spinning out in my harder gears, especially when I attempt to go for the sprint and etc. 


For reference, I went for the sprint jersey the other day. I was in one of the higher gears on my big ring and was barely getting up to 500 watts while my cadence averaged 134 and had a max of 150.


(C) #11

HI folks - interesting thread. I’ve ridden Zwift several times now, using a CycleOps Fluid 2 (from around 2004 or so), and a Garmin heart-rate monitor, speed sensor, and cadence sensor.

I’m definitely not in shape, but I’m a long time cyclist, and I can’t hang on to anybody in Zwift… except for those who I suspect are having the same technical problems I am.

Anyway - my wattages seem really low as well. I can only really handle around 1.5 to 1.9 watts / kg during my 45 to 60 minute rides, and I’m not sure if I’ve been able to break through 200 watts yet. I’m even cheating slightly with my trainer and not tightening to the full 2.5 turns (after the drum hits the tire).

Anything I can do to improve the experience? I am indeed running a 23cm CycleOps trainer tire, and have it inflated up past 100psi.



(Eric ) #12

Hi Chris,

  1. Don’t inflate it PAST 100 psi. Keep it at 100psi.

  2. Is the Garmin speed sensor one with a magnet? Or is it hub-based?

  3. Is your height/weight accurate within Zwift?



(C) #13

Hi Eric - thanks very much for responding.

Yeah, the speed sensor is hub based… it’s this one (or this set) as found on the (Canadian) Mountain Equipment Co-op site.

Okay… I’ll check my psi and keep it at 100. My height/weight is indeed accurate in Zwift.

Thanks again.


(Phil Ball) #14

I used Zwift for the first time today. I’m a lapsed cyclist so am not in great shape but have been out more recently so know what output I should would be getting from 160bpm and a cadence of 80-100 but my performance today in Zwift was less than half what I expected and everyone else was flying past me and I was struggling to make 2mph on the climb! Im using a nonspecific trainer and will try again tomorrow, another fail and I’ll be lobbying for a reliable Watopia bus service. 


(C) #15

I still don’t know what to make of my watts readings, using the sensors that I’ve  mentioned above. I did the fitness test today and could really only handle 150 watts over the 20 minutes. which translated to right around 2w/kg for me. Short of going out and buying a power meter, I don’t know how I’d get a more accurate watts rating in Zwift.


(J im Hubbard (D)) #16

This low watts has been a known problem for a long time , with dumb trainer and Zpower. I am using a KK road machine and power # 's are low compared to real world . The people passing you are using a power meter to broadcast to Zwift .


(Tony Otero) #17

I also have the same issue with the 2004 CycleOps Fluid 2 (blue version with black tightening hand-bolt, otherwise the flywheel and fluid unit look identical to today’s Fluid 2). I am 57 and weigh 165 lbs and consider myself a B rider. I notice that my rides on Zwift with Fluid 2 and ZPower average 100-110 Watts at about 12-13 mph while my 1-2 hour outdoor rides in my area (moderate rolling hills of North-Central New Jersey) average about 15-17 mph and about 150-160 Watts (per Strava Premium estimate).I won’t even mention my FTP test but it was not good.  Everyone seems to blow by me and I can’t seem to hold a B ride on Zwift. That takes the social fun out of the game. I am wondering if the Power Curve for this Trainer is harder than today’s Fluid 2, which is what Zwift may have been calibrated for? Did anyone buy a new trainer and have a better experience?

I found my email receipt on my trainer (it was advertised during the TdF around 2003-2004):

Item Title: CYCLEOPS Fluid2 TT Ltd Trainer '04 Model*NEW*

Item Number:362624500

I put in an email to Zwift and they asked for some of the log files and said they will try to look into it. CycleOps just said it is the Fluid2 but provided no further info and, frankly, the support did not really understand what I was asking or care to support me.

Anyone have any suggestions?


(C) #18

Hey Tony - well, it sounds like we have the same problem. My Fluid2 (from about the same time) is probably the same one you have.

To be honest… I’ve kind of resigned myself to biking at the speed I’m biking at in Zwift. I hover around 2w/kg and tons (and tons!) of people blow by me… but there are all levels of riders on Zwift, and usually I find someone who is going roughly my speed, and I hang out with them for a while.

On Facebook there are several Zwift groups… and one of them is a Zwift Sub 2 watts / kg group. They organize rides for people going at that speed. If you wanted to try and join those “club” rides.

So, no great advice here. I haven’t found an answer to the problem either.



(J im Hubbard (D)) #19

I have tried using this gear ratio / Cadence / Speed calculator


 To compare what gear x rpm = mph . to see if Zwift matches . Maybe over simplifying things but this may be helpful


(Jeff Shafer) #20

My Fluid 2 is newer.  Bought is used but it the gray one w/ the yellow tightener.  Like I said when i originally opened the thread, the lower end especially really seems off  seeing 100 when TrainerRoad shows 140.  I have been living with it am currently under a 2 month free window due to my Strava Premium membership, but unless something changes or am told an alternate trainer to select that with pretty accurately reflect my watts, I doubt I will subscribe.  When using it for free I can’t complain too much, but currently I am just not able to experience a lot of the benefits that Zwift offers… I truly hope a solution can be found because it would be great to use this tool for my tri training in 2016, but may have to go elsewhere .