Resistance Levels and Drop Out

(Andrew Layton RCC Oxford) #1

I noticed a significant improvement in the resistance levels on ascents today - very good.   However, my KIckR has started to drop out more often, despite being in exactly the same physical location in relation to my macbook; equally, Zwift doesn’t appear to be self fixing.  

Minor or observations in relation to a fantastic product.  Keep up the good work.


(Klaus US (VICCRD)) #2

Hi Andy - do you mean by resistance level improvement - that you can now feel the differences between flat and climb more than before on your kick  ? -

(Andrew Layton RCC Oxford) #3


There is now a more realistic resistance on the KickR on the steeper gradients than before - very good.  There is also a slight delay in the reduction of resistance as you proceed downhill after riding flats/climbs, although the cause of this may well be my Computer, a 2011 Macbookpro. 

I would add that it appears that the power output figures generated by Zwift are a tad optimistic (in the region of 25W) in comparison to my powertap pro hub; I realize that these figures may be within the margin of error.  Equally, such a minor disparity in no way detracts from a fantastic product.


(Christopher Pallotta) #4

25 watts? That’s not a tad, that’s a tow truck. Even a 5 watt difference can have a big effect on your performance on Zwift, for example, a top ten finish vs. 30th+. 

I love Zwift, and I really feel like I’m riding with others, but I always have to remind myself that it’s not representative of the real performance of others. In the real world, I’m much more successful with KOMs and segments. True, my local area isn’t as densely populated with riders from around the world, but it’s more than that. 

Here are the issues:

Kickrs are inaccurate: My experience and that of many others is that the Kickr reads wattage about 25-30 watts too high compared to an actual calibrated power meter. I use an SRM, which is considered the gold standard. Out of the box, with repeated spindowns and using the calibration kit, I’ve had two Kickrs that verify this. 25-30 watts = ridiculous advantage on Zwift.

Estimated power is high. To test estimated power, I dug out my Kurt Kinetic and ran it on Zwift while also capturing the data from my SRM with a Garmin. At first, estimated power was about 50 avg. watts higher than the SRM. I was getting a lot of tire slip errors on that first trial, though, and I diagnosed that the issue was that the ANT+ stick was dropping out. On on the next trial, I moved the stick closer to the speed sensor and the errors stopped. The final result after several laps: Average estimated power was +8 watts higher than actual. Another very significant advantage. 

I also have a Stages power meter on another bike and I get the same results.