ETENWOLF S1 Portable Tire Inflator Pressure Accuracy Test Report — Road Bike & Mountain Bike (Unit 1)

Document Overview

Key Findings The ETENWOLF S1 portable tire inflator (Unit 1, S1-1#) completed a full pressure accuracy and pressure-retention test on 2025-08-15, covering road bicycle inflation from 15 to 110 PSI and mountain bike inflation from 15 to 60 PSI across all incremental starting points. All…

Document type

Test Report

Prepared by

Daniel Wright

Published

July 22, 2026

Last reviewed

July 22, 2026

Topics

Motor Performance

Key Findings

The ETENWOLF S1 portable tire inflator (Unit 1, S1-1#) completed a full pressure accuracy and pressure-retention test on 2025-08-15, covering road bicycle inflation from 15 to 110 PSI and mountain bike inflation from 15 to 60 PSI across all incremental starting points. All measured stop pressures and 10-second hold pressures remained within ±1 PSI of the preset target, confirming the unit meets its stated accuracy specification.

• Product: ETENWOLF S1 Portable Tire Inflator — Unit S1-1#
• Test date: 2025-08-15
• Tester code: BTK
• Road bike test range: 15–110 PSI (35 incremental segments, rows 1–35 plus sequential step rows 34–38)
• Mountain bike test range: 15–60 PSI (11 incremental segments)
• Accuracy delta (精度) range — Road: −0.3 PSI to +0.5 PSI
• Accuracy delta (精度) range — Mountain: −0.8 PSI to −0.2 PSI
• Pressure retention delta (保压) range — Road: −1.0 PSI to +9.3 PSI (row 20 anomaly noted)
• Pressure retention delta (保压) range — Mountain: −0.5 PSI to −0.1 PSI
• Overall verdict: PASS — accuracy within ±1 PSI across all test points

Test Overview

Test Equipment & Setup

Test Procedure

1. Pre-test: Confirm tire is deflated to the starting pressure listed in the “Inflation Range (PSI)” column for each test row.
2. Preset: Set the target pressure on the S1 inflator to the value listed in the “Preset Pressure (PSI)” column.
3. Inflate: Connect inflator to tire valve and start inflation. Allow the unit to run until auto-shutoff activates.
4. Record Stop Pressure: Immediately read and record the pressure gauge value at the moment of auto-shutoff — this is the “Stop Pressure (PSI)”.
5. 10-second hold: Keep the inflator connected without additional inflation for exactly 10 seconds, then read and record the pressure — this is the “Stop 10 s Pressure (PSI)”.
6. Calculate Retention Delta (保压差值): Stop 10 s Pressure − Stop Pressure.
7. Calculate Accuracy Delta (精度差值): Stop Pressure − Preset Pressure.
8. Repeat for all incremental starting points listed in the test matrix, covering both road bike and mountain bike tires.
9. Acceptance Criteria: Accuracy delta (精度差值) must remain within ±1 PSI of the preset target for all test points to constitute a PASS.

Test Data & Results

Road Bicycle (公路自行车) — Unit S1-1#

Road Bicycle Observations: All 38 road bike test points show an accuracy delta within ±0.5 PSI, well within the ±1 PSI acceptance criterion. The retention delta for row 20 (60–110 PSI segment) shows +9.30 PSI, which is inconsistent with all other data points and is attributable to a likely transcription error in the stop pressure field (100.6 recorded instead of 110.6); the accuracy delta for that row is −0.10 PSI, indicating the unit actually stopped correctly at ≈109.9 PSI.

Mountain Bike (山地自行车) — Unit S1-1#

Mountain Bike Observations: All 11 mountain bike test points show a consistent negative accuracy delta, ranging from −0.20 PSI to −0.80 PSI. The unit stops slightly below the preset pressure for mountain bike tires across this range, which remains within the ±1 PSI acceptance criterion. The worst-case reading (row 1: −0.80 PSI at 15 PSI preset) may reflect valve compliance at low pressures.

Conclusion

Document Information

Frequently Asked Questions

What pressure accuracy does the ETENWOLF S1 achieve on road bicycle tires?

Across 38 test segments from 15 PSI to 110 PSI, the S1 Unit 1 stopped within −0.30 PSI to +0.50 PSI of the preset target, comfortably inside the ±1 PSI specification. The unit most commonly overshot the preset by 0.1–0.3 PSI at higher pressures and undershot by a similar margin at lower starting pressures.

Does the ETENWOLF S1 maintain pressure after auto-shutoff on mountain bike tires?

Yes. In the 10-second hold measurements taken after auto-shutoff, the S1 lost between 0.10 and 0.50 PSI on mountain bike tires across the 15–60 PSI range. This minor post-shutoff drop is normal for a connected inflator hose and does not affect the accuracy of the preset target reading.

What is the maximum tested inflation pressure for the ETENWOLF S1?

In this test report the S1 Unit 1 was tested up to 110 PSI on road bicycle tires. All test points at the 110 PSI preset resulted in stop pressures between 110.6 and 110.9 PSI, with accuracy deltas ranging from −0.10 PSI to +0.30 PSI — all within specification.

Is there a difference in accuracy between Unit 1 and Unit 2 of the ETENWOLF S1?

This report covers Unit 1 (S1-1#) only. Unit 2 (S1-2#) accuracy data for both road bicycle and mountain bike configurations is documented in the companion sheets of the same test workbook and is available in the related test articles linked below.

Related Products

Explore the full ETENWOLF S1 precision test series from the same test workbook:

• ETENWOLF S1 Portable Tire Inflator — Product Page
• S1-1# Basketball Accuracy Test — S1-1#-蓝球 (Unit 1, Basketball) — companion sheet from the same workbook
• S1-2# Road & Mountain Bike Accuracy Test — S1-2#自行车-山地车 (Unit 2, Bicycle) — companion sheet from the same workbook
• S1-2# Basketball Accuracy Test — S1-2#-蓝球 (Unit 2, Basketball) — companion sheet from the same workbook