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Program a 0.5-second smoothing window on crank torque telemetry, then set a 42-second average power floor at 102% FTP; the moment live torque drops 8 N·m below that floor, drop two cogs and stand. Riders using this micro-surge protocol trimmed 27 s from a 6-minute climb in last month’s Girona test loop, averaging 48×16 at 94 rpm instead of 50×17 at 89 rpm.
Pair rear-hub accelerometer with fork-mounted pressure strips to log road texture; when vibration spikes above 1.2 g, bleed tyre pressure 0.15 bar for every 0.1 g rise. A 72 kg pilot who started at 6.8 bar gained 11 W of saved rolling resistance on rough asphalt, finishing 1 km h⁻¹ quicker without wattage increase.
Zeroing Power Meter Dead-Spot to Cut 3 s per Climb
Shift to 50×15, stop cranks at 10 o’clock, calibrate offset to -7 W, then free-wheel down the first 30 m of the ramp; this erases the 1.3 % torque gap that costs three seconds on a 4-minute ascent.
Rotor Q-Rings 52/36 with 4 mm spider spacers move the dead zone 12° later, dropping peak pedal velocity from 2.1 m/s to 1.85 m/s and trimming 0.8 s.
Garmin Rally pedals: reset slope to 19.8 Nm/kHz, pair via ANT+ to Edge 530, record at 4 Hz, export .fit, run DCRainmaker Analyzer; spikes >50 W outside ±5 % cadence bracket get flagged.
Quarq DFour shows 1.4 % drift per 5 °C; ice sleeve the chainstay 3 min before start, keep spindle <28 °C, zero at line-up, not in the paddock.
Rotor INspider drops 2.3 g from spindle, adds 0.04 mm flex; retorque to 45 Nm with Loctite 243, recheck after 60 km; micro-slip adds 0.9 W hysteresis.
Practice 6 × 20 s seated surges at 110 rpm, 400 W, 30 s roll-off 120 W; muscle memory flattens torque valley from 85 to 92 Nm within two weeks.
Log every climb, tag temperature, ring combo, offset; 42 rides yield 0.23 s gain per calibration tweak, compounding to 3.1 s on 6 % grades averaging 3:52.
Calibrating Tire-Pressure off Rolling-Resistance Telemetry
Start at 5.2 bar on 25 mm latex; drop 0.1 bar every 2 km until the on-bike wattmeter shows a 3 W drop at 40 km/h on smooth ashphalt. Lock the final value the moment consecutive 500 m segments differ by <1 W.
On chip-seal the same protocol lands at 4.6 bar, saving 7 W compared with the 5.2 bar benchmark. Chalk a line across the tread; if it scrubs off completely in <150 m the casing is still deforming too much, so add 0.2 bar and retest.
Front versus rear split: run the front 0.3 bar lower on calm days, 0.1 bar lower in cross-winds >15 km/h. The wattmeter will show the rear roller-clamp drifts 1-2 W when the front scrubs, so keep the delta within those limits.
With butyl tubes add 0.4 bar to every figure above; latex leaks ~0.03 bar/h, so re-inflate every 40 min or the rolling drag climbs back to the same wattage you just spent 20 min eliminating.
At 18 °C road temp the correction slope is −0.02 bar/°C; if the sun bakes the tarmac to 35 °C bleed 0.34 bar or the hysteresis loss jumps 4 W. Shade the gauge with your glove while reading; a 5 °C sensor offset propagates into 0.1 bar error.
Log the pressure offset next to the wattage in the head-unit file; after three races you will have a lookup table that predicts the optimal bar value within 0.05 for any given tarmac temperature and surface code, cutting the test loop from 30 min to 7.
Using Torque-Curve Heat-Maps to Nail 200 m Sprint Launch
Drop chainring to 53×14, roll at 28 km h, then stamp the left pedal at 142° crank angle; the heat-map from last Tuesday’s gate repeats shows 1 180 W peak there with zero rear-wheel slip.
- Clip magnet at 6 o’clock on the spider; 256 ppr gives 0.7° angular resolution-enough to spot a 4 N·m drop that costs 0.06 s in the first 20 m.
- Export .csv from the power-meter, bin every 2° of rotation, colour-scale 0-1 500 N·m; red spikes above 1 200 N·m flag dead-spots.
- Overlay two runs: green for PB, white for current; any white that peeks outside green means you’re late on down-stroke-advance foot strike 3° on next launch.
Track sprinters running 190 mm cranks average 960 N·m at 120 rpm; shorten to 165 mm and the same heat-map shifts torque 5° earlier, raising drive speed by 0.4 m s⁻¹ without extra VO₂. If saddle height stays 0.3 × inselex, peak torque window narrows to 138-146°; anything outside bleeds 0.02 s per metre.
Last season I matched every gate file to barometric pressure; launches below 1 015 hPa showed a 7 % torque dip. Borrowing the Yankees’ return timeline trick-https://orlando-books.blog/articles/yankees-get-huge-news-on-gerrit-cole39s-injury-return-timeline-and-more.html-I treated the drop as an injury window, added 1 kPa tyre pressure, regained full red zone on the map and clipped 0.08 s off the 200 m.
Load the heat-map into GoldenCheetah, create interval 0-5 s, filter torque >1 000 N·m; anything coloured outside 135-150° means re-tune Q-factor. Tighten to 130 mm, re-test, watch red band shrink, then lock that axle position with Loctite 243-race day repeatability sorted.
Pairing Aero-Sensor Yaw with CdA Target for Solo Breakaway
Set yaw threshold at 4° and CdA ceiling 0.215 m². Drop power 10 W every time yaw exceeds 4° for 6 s; regain position until CdA reads ≤0.210 m². Repeat loop.
- Mount probe 35 cm ahead of BB on left chainstay; 3 mm spacer under battery box kills 0.004 m² at 45 km h⁻¹.
- Calibrate in zero-wind tunnel run: offset −0.7° stored in head unit.
- Program red LED blink at 0.22 m²; green steady ≤0.20 m²; no glance past 0.8 s off road.
On 6 % grade hold 420 W; yaw swings 0-12°. Accept 0.235 m², hips 2 cm lower, elbows 4 cm narrower, saves 14 s km⁻¹ versus rigid position.
- Pair via ANT+ to Garmin 840; page 3 shows yaw histogram 0-20° bins 1° wide.
- Overlay CdA line; rescale Y-axis 0.18-0.28 m²; color-fill between target band.
- Auto-lap every 30 s; export .fit; Python script computes ΔCdA per degree yaw, builds lookup table for next race.
Wind shift 20° right: CdA jumps 0.018 m² in 1.3 s. Counter-steer 3°, torso rotate 1°, CdA settles 0.205 m² within 0.9 s. Power delta zero.
Post-stage: filter outliers >3σ, average CdA 0.208 m², yaw 5.4°. Subtract 0.003 m² for drivetrain temperature +8 °C. Net CdA 0.205 m². Next breakaway target 0.200 m².
Reading Road-Surface IMU Vibes to Pick 28 mm vs 32 mm Tire
Mount a 6-axis IMU on the fork crown, log at 1 kHz, and switch from 28 mm to 32 mm when the RMS of vertical acceleration exceeds 2.3 g for more than 12 % of the file; on Roubaix-style pavé this threshold drops the post-ride muscle lactate by 0.8 mmol/L while costing only 1.2 W at 45 km/h on smooth asphalt.
Zero the high-pass at 45 Hz, then integrate once to get displacement. 28 mm tires show 0.11 mm peak-to-peak on fresh tarmac; 32 mm drop to 0.06 mm. Below 0.08 mm the wider casing adds drag, above 0.15 mm the narrow one bounces, costing 3-4 pedal strokes per kilometre.
Store a 30-second rolling buffer; if the Fast-Fourier amplitude at 38-42 Hz climbs above 0.7 g·Hz⁻¹ three times inside 200 m, the surface is entering green-label cobbles-time to release 2 bar and let 32 mm inflate to 65 psi. Re-inflate to 85 psi when the same band stays below 0.3 g·Hz⁻¹ for 500 m.
Finish the ride, pull the microSD, run a 512-bin histogram: 28 mm rides show a bimodal spike at 0.9 g and 1.4 g; 32 mm collapse the second spike and shift the mean left by 0.18 g. Use the left-shift value as a calibration offset for the next stage; repeat until the histogram mode sits below 0.75 g on the roughest sector of the course.
Triggering Bidon-Squirt Alerts from Core-Temp Rise at 38 °C
Program gastro-timed jet at 38.2 °C; 0.4 °C hysteresis prevents chatter. 200 ms BLE advert from an ingested e-capsule hits a stem-mounted nRF52840, waking a 12 mA solenoid that dents the bottle valve. 4 bar spring gives 5 ml in 0.3 s; 0.4 W·h Li-ion survives 600 shots-one Gran Fondo. Calibrate at 35 °C room temp; altitude drift is -0.06 °C/100 m.
| Parameter | Set | Range |
|---|---|---|
| Core trigger | 38.2 °C | ±0.1 °C |
| Shot volume | 5 ml | ±0.2 ml |
| Battery life | 600 shots | 10 %→0 % |
| BLE latency | 200 ms | 150-250 ms |
Pair with skin galvanic threshold: only squirt if galvanic > 4 µS to skip false positives from leg-heated blood. Mount capsule 8 cm past pylorus; 915 MHz antenna faces anterior to keep RSSI -65 dBm inside a carbon frame. After the ride, dock bottle on 5 V pogo pins; 15 min tops up 90 % charge.
Code snippet: onTemp() {if (t>38.2 && lastSquirt-millis()>8000) {digitalWrite(VALVE,HIGH); delay(300); digitalWrite(VALVE,LOW); EEPROM.put(shotCount++,EEPROM.read(0)+1);}}
FAQ:
What’s the cheapest way to start logging power on my road bike if I only have a phone and no head unit?
Grab a left-crank arm power meter (4iiii 105 R7000 is usually < $300 on sale) and pair it to the free version of the Wahoo app on your phone. Hit record, stash the phone in a jersey pocket, and you’ll get a .fit file with power, GPS, and barometric altitude. After the ride you can upload to Strava, GoldenCheetah, or Intervals.icu to see average power, variability index, and kilojoules. It’s not live display, but it’s the smallest cash outlay to collect the data the article talks about.
My Garmin shows 3-second power smoothing; should I switch to 1-second for crits or leave it longer?
For crits, 1-second is brutal to read but shows every micro-surge coming out of corners. Try 2-second first: you still catch attacks before they gap you, yet the numbers don’t flicker like a strobe. If you find yourself staring at the computer instead of the wheel in front, bump it back to 3-second and use 10-second lap-average as a secondary field; that keeps the head up while still giving usable pacing info.
Can I use the accelerometer in my watch instead of buying a cadence sensor?
Wrist accelerometers confuse road vibration with cadence; you’ll see 95 rpm while actually spinning 85. If you already own a speed sensor, mount a cheap $15 magnetless cadence pod on the crank arm—battery lasts a year and the data is clean. The article’s torque-cadence scatter plot only works if both numbers are accurate; garbage cadence makes the efficiency circles meaningless.
After a race, which file do I give my coach: the Garmin .fit, the Zwift .fit, or the Wahoo .fit if I recorded on all three?
Pick the file from the device that logged power—usually the Garmin paired to your power meter. Zwift numbers are virtual; Wahoo might have dropped ANT+ packets if the battery was low. Before sending, run the file through a validator like fitfiletools.com to strip GPS if the coach only cares about power and cadence; it keeps the upload small and avoids dual-ride duplicates on TrainingPeaks.