I’m just over a year into a SB20 - coming from a gen 0.5 Kickr (my Kickr was older than the date listed for the gen1 Kickr) - and I’m very happy with the purchase. It has been problem free with the exception of having the belt cover rub problem when I got it - about 20 minutes of googling and futzing around solved this problem. So it was only a minor annoyance.
The ERG stability has been much better than my Kickr, and has gotten better over time with the subsequent firmware upgrades. The only annoying item is that the crank power meters seem to burn batteries faster than I would expect. I just replaced both the left and the right this week, and that is like the 3rd battery for each. When a crank arm power meter battery is very low, it’s pretty noticeable as setting the zero offset is hard, and the power seems off - higher RPE for the displayed power.
Is there any visual way of telling when the battery’s are running low? I download the “StagesPower” app so I could connect to the power meters individually and that shows a battery status indicator but not sure if It is to be trusted…
The only physical indicator I’ve found is that the cranks power meters have LEDs, and when you spin the cranks when the battery is low, the number of spins it takes to get the power meters to wake up and the LEDs to light up increases.
I’ve actually found the Stages Power app does a good job of knowing when the batteries are low. Even better is a Garmin. When my wife rides the SB20, she uses her Fenix 6, and that pretty reliably alerts when one of the batteries is low. Unfortunately it doesn’t tell you least or right, just that one is low.
yes, this. the stages power app works well in showing battery, but i try to avoid the stages apps when possible. you can also view your battery information if you sync your rides to the stages link website. they not long ago moved the battery info to the paid subscription tier (i just don’t understand stages and their strategies whatsoever. you need to pay to see your pm battery life??? i digress…), but there’s a bug/workaround that still makes your battery voltage visible while still in the free tier
the best indicator though is if you’re also using a garmin computer or watch. both my edge 830 and my tactix delta tell me when the batteries are low and due for a change. i’ve tempted fate after these warnings and they basically tell you with enough time to finish your current session with room to spare. start another session though and your pms will die halfway through…
I’ve figured out what is causing my SB20 to overreport power. I have varus knees and a wide pedaling stance. The Stages cranks (gen3 hardware) seem to be including lateral (off-axis) force vectors when it should only be accounting for axial forces in its power calculations. When I pedal with an exaggerated stance as if I’m pushing my knees+lower legs outward, my the SB20 inflates my power relative to either my Vector/Rally pedals or my Assioma pedals. When I pedal with an exaggerated inward pushing motion as if I’m trying to crush a watermelon between my lower legs, the SB20 reports lower relative power vs the pedals.
If anyone else has both an SB20 and power pedals, I would be grateful if you could perform a similar test, recording two FIT files for direct comparison.
I am really good at turning wrenches, but suck the llamas ass when it comes to fit and measurements – so my expectations of ‘comfort’ are pretty low for this inaugural ride.
Its taken me a good few rides to get myself in a similar position to my road bikes. Fortunately making adjustments is so easy with the SB20 that you can tweak till your hearts content
This is what I’m experiencing. I have just installed new Sony Lithium batteries and reset the PM’s. Not sure if it’s making much difference yet, but tbh, I’m kinda frustrated. Compared to my Quarq’s (on two different bikes) I’d say the RPE on this Stages bike is close to 10% higher. I’m not sure how to resolve it, other than temporarily knock down my FTP so I can complete these workouts better.
Have you checked the L/R balance with the Stages app to see if it is grossly off? When the RPE is off for me, the L/R balance being way off is always a sign.
The power to RPE being off is compared to the SB20. It’s a sign that something is up with the crank power meters. E.g., one side has a very low or dead battery.
Today I tried a bunch of crap and just got angry. I reset the PM a few times using Stages Power, and always got the same numbers (see attachment). I confirmed the app was off before starting a TR session in ERG mode, with only the bike paired via Bluetooth. The power meters were not paired to TR.
RPE was way too high – and even a stupid warmup at 160w felt wrong — like almost 200w.
I pulled the right-side PM battery and chucked it at my dog. Started pedaling again and things were only moderately better for a very short period of time. Within a few minutes RPE was high again and it ‘felt’ like a Sweet Spot 5.0 (Chopaka -1) was basically threshold work.
After pulling the CR2032 battery from my dogs mouth (see above). I just knocked the whole f-ing workout down to 70% to see how it would feel. OK, so a 10-minute effort at 247w was now 173w. This was brainlessly easy and I could have played a game of Jenga at the same time. I bumped it up to 80% to see how it would feel. My 247w SS interval was now effectively running at 197w. Still, RPE was too light for sweet spot.
I kept bumping the TrainerRoad thing upward until about 93% when I realized I was on my last interval. Frankly, this was still a smidge too light based on my experience with Sweet Spot. Maybe I should have gone to 95%. I dunno.
Bottom line? I’m pretty hacked off. With that right-side battery removed, the data looks like sh%t, with all the screwing around on power targets, this workout is a steaming dung-pile. (I strongly believe that pulling one battery from the PM was a lousy experiment.)
Is my SB20 somewhere 5%-10% off from the Quarq(s) and Kickr I’ve used for years? New batteries made no difference, gently ‘pulling’ the battery tabs made no difference, BLE/ANT made no difference, etc. etc.
If I need to just knock my ftp down 5-10% that’s fine — but my TSS will get all f’ed up and my outdoor Quarq-based rides will be a mess.
I think you need to create an account and login to access these.
Also make sure coin batteries are not coated. Some are coated with a bitter tasting substance to prevent kids or pets from swallowing them. Stages says no to those.
I spent a long time this morning with a ruler, protractor, slide rule, and Visicalc 1.0. Tons of fit adjustments, and things are much better in terms of RPE. Firmware + zero-ing didn’t make much difference, and the right/left imbalance still seems way out of whack. I’ll contact Stages today and see what they suggest. But clearly, fit matters.
BUT, the good news is that I was able to do a VO2 (4.2 progression) this morning without resorting to tears.
Because the bike pairs to the crankset power meters, and does its own power match. So you are in effect running two power match algorithms on top of each other. It can work, but at least when I did this by accident when I first got mine, the feeling was pretty bad.
