This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Rally RS200 on Kickr Core: 10% difference

Just bought a set of Rallys and tested them on my Kickr Bike to check if everything's running normal. 

After my Zwift run (Alp D'Huez) I noticed that the average values on the Kickr are about 20W higher (just had a look at the average) and the max value is 13W to low. (Average in kickr is 203 and Rally's show 184, so 10% is way more than I would accept).

Crank arm length is correct. I didn't tighten the pedals too hard because I switch them around quite a bit (but this shouldn't matter??)

I calibrated them properly on the connect app with my phone.

Workout was done with my Fenix 6s (I did not calibrate the pedals there)

The only thing that might be: my basement is a bit cooler (3-4° probably) than my flat and I only waited about 10 mins till I started the run. 

My last FTP Test on Sufferfest is about 6 weeks old and I am quite certain it's correct with it's 196W, so the 184 seems rather wrong. I did a lot of training so the 200 average seem about right for the 64min run...

What could be the problem here?

  • I finally got around to a Factory Spindown on my KICKR Core. As a side note I am also now using longer cranks, which are properly input into my Rally calibration. I did the factory spin down per the instructions. So I simply followed the 3 min warm-up then did the spin downs. I then did a TrainerRoad Ride with PowerMatch. I used Zwift to record my KICKR Core output.  Below is my DC Analyzer File for your viewing pleasure. Looks to me like it's reading pretty well. 

    Goat Citidel RallyXC200 / KICKR Core

  • if You are doing powermatch, then the power values will be identical everywhere... You must test it WITHOUT any powermatch in ERG, or in SIM mode (there is no powermatch), that will give You valid power numbers and difference.

  • That's not how I understand it looking at the data, but will re-look at it.Perhaps I am confused on some aspect of PowerMatch.

    My Rallys report directly to TR and my Edge. TR controls the Kickr Core. My Kickr Core #s are reported to Zwift. So as I understand the data. TrainerRoad is telling my KICKR to hold some resistance based upon what it reads on my Rallys. I'd expect the KICKR to then report that # to Zwift and thus compare what my Rallys show on my Edge to what my KICR shows on Zwift.

  • what You dont know when the powermatch is active that what is the presetted power in Core to hold exactly that power what the Rally's needed (so probably when your Rallys need 250w as presetted in Trainerroad, then the powermatch is continously adjust the Core's resistance to get this 250w on the pedal, for this the Core's resistance is set to X to hold ~247-248W /pedal minus drivetrain loss/ and report this 247-248W also to zwift too. But we wanna know the Core's own preset power (the X) in this case , maybe it is 260w or similar, just it is not shown, not reported to nowhere) . With powermatch the 2 (3) numbers are identical, the difference is only the drivetrain loss between pedal and trainer but it is obvious. So this is why You must test without powermatch in ERG training, it will give You real difference between the 2 powermeters. (Pair the Core power and trainer only in TR /and Rallies not!/ and control via this setup, and the Rally's power should record with your Garmin headunit. After upload the 2  FiT files to dcanalizer and share the link .

  • But I do know what the Rallys are reporting via my Ant+ connection to my Edge1030. And I do know what my Kickr Core is reporting on Zwift. The iPad recording on TrainerRoad can be ignored for my purposes as all it does is change the KICKR resistance for a give reported number from the Rallys. So, in a perfect world Rallys would match the KICKR. As my data looks now, the KICKR is reporting 1-2% less than the Rallys which, is exactly what I'd expect. 

  • Ok. (You dont understand but i gave up) Ride On.

  • Ok. I apologize that I don’t understand what you are saying. I just am not sure that PowerMatch on TR works exactly as you described. I’m not trying to be argumentative.  In any case I did perform the Advanced Spindown and it helped my KICKR Core I believe. Thanks for your time and input. I do appreciate it. 

  • What luko79 says about how powermatch is working is not true.

    Power is reported by the pedals to the computer and then the resistance of the trainer is changed up or down by the computer until the pedals report the required preset power.

  • Good morning Cristox. That is also how I understand it and I've since had this discussion on another forum dedicated to indoor cycling training with the person whose software I used to compare the data.Thanks for the reply. My RallyXCs seem to do a good job overall with just a couple of nuisance issues I believe are related to signal interference indoors at some locations. 

    Cheers,

    Tim