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 Meter...

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! ...

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 ea...

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 pow...

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 o...

Your bike's Q-Factor is the width of your crankset or the distance from the outer edge of one crank arm to the other.   More important is the measurement of stance.  That's the distance between the centre of each pedal. Getting your stance the same across bikes can make riding more comfortable while potentially avoiding knee, hip and back problems associated with less than optimal bike fit. Most of us can agree: Overall bike fit is critical. I described my method in a previous post: Better Bike Fit .  Getting the  stance the same between bikes is a probably less critical but still worth doing . Measuring Stance Road bike stance is easy to determine since the bottom bracket centre aligns with the rear wheel. Just measure from the spoke nipple centreline to the middle of each pedal. Indoor bikes, like my Stages SB20, don't have a definitive centre line so you need to measure the distance between the centre of each pedal. No big deal.  A ruler and set square ...

My Indoor Bike has 2200 Watts. I'm good, right? Answer: Maybe. Indoor Bike Resistance Let's first understand how an indoor bike creates the resistance that makes riding more realistic. 🔔 In this post, I use the term indoor bike to refer to smart bikes and trainers . My indoor bike is the Stages SB20 smart bike . I use it in most examples. Eddy Current Brakes Modern indoor bikes use an "eddy current brake" to produce resistance. It's a near magical device. An aluminum disk spins past one or more magnets that creates resistance thanks to eddy current waves . Resistance increases when the disk spins faster or the magnetic field strength is increased. That's somewhat counter-intuitive when you consider that aluminum is not magnetic. Eddy current brakes provide the smooth and progressive resistance that makes indoor riding so much better than even a few years ago. 🔬 Faster spinning = more resistance.  Keep this in mind.   Later, we'll see how lower RPMs c...

Riding inside can be tolerable - and even fun - when software, hardware and environment is right 🚴🏼‍♂️.   Here are 10 improvements I made for better indoor riding . 1.   Multiple Displays 2.   USB Upgrade 3.   On / Off Switch & Wireless Charger 4.   Improved Shifting 5.   Better Fitting Zwift Play Controller 6.   Better Internet Connections 7.   Better Bike Fit 8.   Fans 9.   Let's Talk About Sweat 10.  SB20 Rocker Plate

10 of 10 - Leaning one way and another Rocker plates make indoor riding more realistic. I'm not entirely convinced. Indoor bikes struggle to recreate outdoor resistance, road conditions, pedalling dynamics and acceleration. I'm not sure that side-to-side movement helps with realism. My personal take is more conservative. Two years of rocker plate riding has improved my overall comfort and helped with out-of-saddle sprints.   My Journey I began experimenting with different rocker plate designs in 2021, starting with the following requirements: ✓ Progressive side-to-side movement that offers stronger resistance as you move from the upright or vertical position. ✓ Forward-and-back movement. Many riders claim this is a critical element in real-world riding simulations. ✓ Small footprint. Commercial products are often quite large to accommodate a wide range of bikes. A custom design for my particular bike should be smaller. ✓ It should remain easy to get on and off the bike. ...

9 of 10 - A Sweaty Problem When I added fans to my indoor bike, I thought my problems with sweat had been blown away. There was less sweat on the floor mat but it still dripped from my chin directly onto the bike. I didn't give it much thought until I read that many people were seeing rust on their indoor bikes. After observing moisture patterns for a month, I came to realize: Sweat on my Stages SB20 bike could be an issue. I don't think sweat problems are unique to my brand of bike. Many of the issues and fixes described here will also apply to other brands. Sweat Patterns In my case, about 20% of sweat production falls over the handlebars, 50% in the middle of the frame and 30% nearer to the seat post.   Depending on your physical measurements and riding style, you may see sweat distributed in different proportions. Where does Moisture Go? Ideally, sweat should go nowhere . You wipe down your bike after each ride and the problem is solved.  The reality is: You can miss some...

8 of 10 - Fans! My journey towards multiple fans started in 1990.  Indoor riding was just getting started. As a competitive rider who also did indoor training, I was invited to Western University to take part in a study on... wait for it... indoor fans . Researchers wanted to know if fans were needed for optimal indoor bike workouts.  Here's a summary of the study and related criteria.  1. Maintaining core body temperature is critical for a good indoor workout. Let it rise and you do less work as your body uses energy to restore proper core temperature. 2. Air volume (Cubic Feet per Minute) rises with fan diameter. You need to move sufficient air to cool the rider and keep core temperature under control. In general: the bigger the fan, the better. 3. As important as air volume, is air speed . Faster moving air cools better. Velocity drops with the square of the distance. This means: the closer the fan, the better . 4. Also important is air dispersion . Fans need to...

7 OF 10 - BETTER BIKE FIT Indoors and out, my bike position changes a small amount each season.   My road bike tends to define my optimal position at the end of the summer. It includes  millimeter  adjustments made over the course of several thousand kms.  Similarly, my indoor bike defines my optimal position at the end of the winter. When I have settled on a new optimaI position, I like to transfer it to my other bikes, including: road, gravel, indoor and time-trial .   Transferring Bike Measurements Assuming you have one bike with your optimal position , you need a method for transferring the riding position to multiple bikes.   Prerequisites and Notes: Cranks -  All bikes have same crank length.  Watch for small differences in pedal platform height. Saddles vary -  They can have different lengths and widths. To create a standard measurement position on all saddles, I use the top of the saddle  where it touches the pelvic bone . Th...

6 of 10 - Better Internet Connections Zwift leverages wireless connections that include a mix of Bluetooth, Ant+ and WiFi. They tend to be concentrated in the busy 2.4 GHz wireless frequency band. As we will see below, it's a good idea to move these connections to the less crowded 5 GHz band. Overcrowding in the 2.4 GHz band causes data dropouts, decreased performance and failed connections. Bluetooth and Ant+ use the 2.4 GHz band. WiFi ( to and from the Internet ) can use 2.4 GHz or 5 GHz depending on the device. The SB20 bike and HRMs use multiple Bluetooth and Ant+ connections. Zwift Play controllers use one Bluetooth connection per controller. All in the 2.4 GHz band. This is not a big concern since the volume of data transferred by these devices is minimal. All these devices combined transmit only a few thousand bytes per second.  In contrast, the Zwift App and the Zwift Companion app can transfer millions of bytes per second. Performance gains can generally be found...