PedalSmart.blog

The Stages SB20  indoor smart bike was released in 2020. Let's take a look at the electronics that enable it  on platforms like Zwift.com and TrainerDay.com. An external power supply routes power to different bike components through a series of printed circuit boards (PCBs). The bike also includes two battery powered crank-based power meters. Here's an overview the basic functions: USB Board - Wedged vertically under the phone tray. It powers 3 USB ports. Upper Board - Fastened horizontally under the phone support rail. This System On a Chip (SoC) handles wireless communication and controls the bike itself. Switch Board - This wire distribution board sits inside the aluminum handlebar stem. It routes connections for the brake level controls  and under handlebar tape "blip" shifter buttons.  Lower Board - This mainly analog circuit board is attached to the flywheel / electronic brake unit. It controls bike resistance and sends power to other PCBs. Power Meters - A

For almost two years, the SB20 bike has had an issue connecting to Zwift.   On seemingly random occasions, the  Stages Bike  is not shown as a  Resistance  option on the Paired Devices page. This bug is easy to reproduce on iPads and iPhones using Bluetooth. I'm not sure about any other devices or ANT+. Recreating the SB20 Resistance Bug Before starting make sure the SB20 is turned on and you have woken-up the cranks by doing a few pedal revolutions. 1. Open the  Paired Devices  page.   2. Select the Left Crank for both Cadence and Power Source.   3. You will likely see the Stages Bike  in the Resistance box. 4. Don't continue in Zwift .  Instead, exit  and restart the Zwift app. Here's the Bug: 5. Return to the  Paired Devices  page.  6. You will see  Left Crank  automatically selected for both  Cadence  and  Power Source. 7. The  Resistance  box is now empty!  Clicking Search shows nothing. Workaround for the Bug: 8. While still on the  Paired Devices  page, click t

When doing my 3 month test on Batteries and SB20 Power Meter Accuracy  I did many power meter battery changes. Here are some interesting things I found. Button Cells Stages power meters use CR2032 button cell batteries. Their naming is logical enough.  The first letter for  chemistry : C=Lithium, L=Alkaline and S=Silver, is a bit confusing.      "Mark" Batteries Before Using Them I paint unique markings on all new batteries  before installing them.   I changed batteries from new to old - and back - dozens of times in the past few months. I dropped batteries on the floor more than once. A unique mark lets me distinguish new from old . Easy Battery Removal I stumbled on this Stages battery removal trick:  Push the battery inward , opposite the side contact.  Rejuvenating Battery Contacts My power meters are 3 years old. Its battery contacts have become slightly flattened . Pushing them back to their original position is a delicate but easy task to complete. Steps: 1. Hold dow

Today's question: How does battery level affect SB20 power meter measurement? Let's do a deep dive and find out! Replaceable Batteries The Stages SB20 power meters have replaceable batteries. An advantage: No degradation of built-in batteries as the power meters age. A disadvantage: No ability to top up batteries to 100% whenever you wish. Battery Life CR2032 button cell batteries are used in the SB20 power meters. Stages says they should last 150-200 hours . Let's verify this claim with bench tests and torque measurements. Estimating Remaining Capacity The StagesPower  app, and others like BT Inspector, report battery capacity. They use the Bluetooth Low Energy (BLE) wireless protocol to ask each power meter for a battery life estimate.   🔬It doesn't matter which app you use.  All apps report the estimate returned by the power meters. Why Battery Estimates are so Bad Many people complain that battery life estimates from the power meters show 100% most of time. The

In a previous post, I showed how to record data from two power meters and analyze results in a spreadsheet: Comparing Power Meters with a Spreadsheet . Today's post shows how to do power meter comparisons using ZwiftPower - and no spreadsheets 🤓. ZwiftPower Dual Power Meter Analysis Tool The ZwiftPower.com web site has a tool for comparing power meters. It works best with a Zwift activity (race, workout, group ride or whatever) although the method described here lets you compare any FIT activity files from other sites like Rouvy.com or TrainerDay.com .  Note: Comparing power meters is only useful if one or more of the power meters has been calibrated with a torque test . Skip this test and you won't know which power meter is incorrect when differences are found . Comparing SB20 Smart Bike with Garmin Rally Pedals In this example, I use my Stages SB20 smart bike to compare power readings with a set of Garmin Rally pedals.  I do a structured workout where Zwift records powe

Like many riders, I use the same saddle on both my indoor and outdoor bikes. I had the option to buy a cheaper and heavier version of this 3D printed saddle for indoors. That was nice. Zeus 3D Printed Saddle I bought the $50 nylon frame version for indoors and the lighter $65 full carbon version for outdoors. The outdoor saddle is 2 years old with 12,000 kms and still looks like new. The indoor saddle will likely outlast me.  For the small price difference, I recommend the carbon version. I just wanted to say I paid less for the heavier indoor saddle 🙂. This is the most comfortable saddle I have ever used. That's personal of course. The saddle is average width with wider than normal nose. I had no idea this design was good for me until I tried it. At 165 grams for the outdoor carbon version, it's also the lightest saddle I've owned. For those who care... The Ensolite-like  honeycomb padding is 3D printed.  It is bonded to a carbon fibre or nylon outer frame, depending on