Thank you for the quick response. I don’t do the single leg work often, but Trainer Road does incorporate them into some of the workouts. The power dropping makes this skills work something that can’t be worked on. Seems like something is not correct. I do have a ticket in with Stages.
With the latest ‘discount’ (new pricing €2099 in NL) I decided to jump the gun. I recently sold my spare bike and I wanted to have my road and gravel bike both at my disposal in the garage at any given moment.
I’ve done 2 rides on it now and played a bit with ERG and resistance mode. So far I’m quite happy with it. I recognize all the feedback regarding slow responsiveness, but it doesn’t bother me too much.
Two questions regarding trainer modes:
- In Resistance Mode, what’s the recommended percentage? And how to test what is? I have a hard time understanding it with the info on the TR website.
- I don’t see ‘Standard mode’ at all, is that normal?
Thanks!
On Standard Mode: it isn’t there
Setting Resistance level is best done by selecting a Free Ride in TR, and then changing the resistance level up / down to get to a point where you like the combination of it plus your FTP so you feel like you can change gears and get acceptable changes in power.
For Reference: I have the Resistance level set at 20%
2 Likes
I’m also experiencing odd LR balance behaviour. I regularly see 52/48 with my trusted Quarq spider, yet the Stages reads closer to 60/40 when pedalling normally. Indeed if I try single leg work it drops to zero if pedalling with the right, so it seems the left is the ‘master’ but this doesn’t explain the exaggerated balance? An issue with one of my crank PMs?
First off your Quarq is producing a true L/R balance but an estimate since it only directly measures the force on the chainrings and then estimates L/R balance from assumptions about which leg produces forces during which phase of the full chainring revolution.
The only thing AI can think of is to record the SB20’s power meter output with a device that will record the output from each crank power meter. A Garmin Edge or Wahoo will do this and look for any anomalies.
Or reach out to Stages support
@dcrainmaker and @gpl,
Did either of you do any accuracy testing of different crank length positions for the SB20? If not, and you still have access to one, could / would you?
Thanks
Here’s hoping you get around to this testing. I’m currently using the 170mm setting and thinking of trying 165 as an easy way to try out 165mm cranks. But I’d hate for any conclusions to be marred by issues just tied to power issues with the crank
Does crank length actually affect accuracy?
Joe
Anecdotally people have said SB20 accuracy is affected by which crank hole - determines effective crank length you are using - you use. As I don’t have power meter pedals to test this - I ride time Time pedals - I’d like to know if this is true or not.
Yeah I’d like to know too, definitely. I have had mine at 170 and 175 and certainly couldn’t feel any difference in any way but I’d never notice a few watts.
Joe
This is after setting the correct crank length in the app you mean?
Yes.
Does (has) anyone use a Garmin device to do structured workouts with the SB20? If so, how do you have the SB20 connected to your Garmin device?
This is for my wife who is looking to be able to use her Garmin Fenix watch with the SB20 and execute Garmin structured workouts on the SB20
Does anybody have any experience changing crank lengths?
I’ve changed the physical crank length (to a shorter setting) and then changed the setting in the Stages Link app. After quitting the app and power cycling the bike it seems to remember the setting.
However, I just smashed some 3 min power PBs (as recorded by my Garmin) by over 20W which is making me worry that something isn’t quite right and wondering if I’ve missed or misunderstood something.
My next steps will probably be to re-zero them and failing that, put my Assiomas on there which used to match very well and compare.
Hopefully it’s just the effect of a rest week after a block where I focused on VO2 work, but I’ve been doing this for long enough to be skeptical!
Does anyone else run into times where it feels like you are pedaling through mud when in ERG Mode? That is: it feels much harder to pedal at a given power level then it should? This is really no matter the power level (e.g., 60% of FTP or 100% of FTP). If so, any solutions?
Yes, I think I know the feeling you’re talking about.
My solution is to insert new batteries.
There is this blog which delves deeper into that topic:
https://pedalsmartblog.blogspot.com/2023/12/batteries-and-sb20-power-meters.html
Batteries were my first thought, but I checked my tracker, and I installed the current batteries (both left & right) on Aug 21, and they only have ~32 hours of ride time on them. So really hoping battery life isn’t this short now. The previous set of batteries lasted for ~51 hours before I changed them.
Has anyone ever run into an issue in which resistance drops out completely? Basically it seems like the gearing resists to the easiest gear.
This is a real problem when I do Zwift races. I don’t feel the issue is correlated with battery life on the PM or distance of the ANT+ sensors (I have two, placed about a foot away from the base of the bike). I’ve had the issue for years and it’s not predictable.
I had this issue two weeks ago. Two of the electronic shift button failed so were always trying to shift. Bad fix but I went in the app, disabled those shift buttons, works “fine” now.