r/XLabsBikes

Picked up my RS7 di2 size medium today after waiting over 3 weeks for LBS to receive their shipment. First upgrade will be the tires from stock to Continental GP 5000s in gum wall. Lets goooooo! Edit: I just realized the bike did not come with the Brants C45 carbon wheels. Instead, they came with the Branta 50 Base. Whoa!

50 mile morning ride yesterday on my GT8 then hit the California Delta with my boy for some fishing

I feel like if you have good flat pedals that are grippy and don't allow your shoes to slide (I use Race Face Chester pedals),there is little difference with clipless. GCN even did a video where they tested it and there was no power or speed difference with and without clipless.

Thoughts?

Wasn’t a fan of the tan side walls on the stock tires for this colorway. I think she’s looking right now.

Loving every Mile !!

Finally, after months of waiting, I got a call from LBS that had 3 GT8's in stock. I had to take her for a quick ride and loved every second of it.

Seen some of the recent posts about the Branta power meters and wanted to actually see how mine performed.

For testing, I mounted the RS7 on a Wahoo KICKR CORE and recorded both power sources independently. The Branta was paired to my Garmin Edge 1050 while the KICKR was recorded separately through Zwift. I turned off Wahoo’s ERG power smoothing, warmed everything up, zero-calibrated the Branta, and compared average power from both devices over the same time periods.
The KICKR was running in ERG mode, giving me controlled, sustained targets for each effort rather than relying on me to manually hold a particular wattage. Importantly, ERG power smoothing was turned off, so the KICKR’s actual recorded averages naturally moved slightly above or below the ERG target (as you can see in the table) instead of displaying an artificially perfect 150, 200, 250 W, etc.
The Garmin and Zwift FIT files were synchronized by timestamp and the averages compared. Across the measured efforts, the Branta consistently came in only about 0.9–1.2% below the KICKR CORE.

Bottom line: at least for my Branta unit, I’m not seeing anything close to the 6–8% under-reading others have reported. Mine is tracking the KICKR within roughly 1%, which is plenty close enough for me

You may have seen my earlier post. This is an update. TLDR: Wahoo Kickr and XLab were far off in my previous test. My Wahoo Kickr and Favero Assioma pedals were extremely close. https://www.reddit.com/r/XLabsBikes/comments/1vgnaib/rs7_power_meter_vs_wahoo_kickr_ugh/

I ran the same test again with the same workout and updated testing conditions based on feedback from the community.

Result:

• Wahoo average: 145.5 W
• Branta average: 135.5 W
• Average difference: 10.0 W
• Branta lower by: 6.9%
• See also, break down by power table below

Updated testing conditions:

• Updated firmware on XLab power meter in the app
• Confirmed correct crank length
• Calibrated power meter and Kickr
• Turned off erg mode power smoothing
• Numbers exclude the first minute and the cool down

Personal conclusion: I still have no regrets about the bike but I am very disappointed in the power meter and will eventually replace it. Part of the reason is that I am a fairly serious cyclist (for an amateur) with seven years of power data. There is no easy way I have found for me to compare my new and old power numbers. As far as I can tell, Branta has no way to do a weight calibration in their app like you can do in the Favero Assioma app to better align it to my Kickr. Alternatively, I could adjust all of my training data but there is no good way that I can find to do this in Strava, TrainingPeaks, or Garmin. I respect anyone's opinion who thinks thinks a 7% difference is no big deal.

Additional Data: Break down by segment (duplicates removed)

Approx. target	Wahoo avg.	Branta avg.	Difference	Branta lower
85 W	85.2 W	81.4 W	3.9 W	4.5%
110 W	110.2 W	103.0 W	7.2 W	6.6%
115 W	114.9 W	104.1 W	10.7 W	9.3%
140 W	140.5 W	131.8 W	8.8 W	6.2%
170 W	170.8 W	159.2 W	11.6 W	6.8%
225 W	227.2 W	210.8 W	16.5 W	7.2%
245 W	249.3 W	231.6 W	17.7 W	7.1%
255 W	254.7 W	244.7 W	10.0 W	3.9%

What do you guys think of the minor upgrades?