Sonic Frequency Method · Deflection Force Method · Field Inspection Checklist
Two tensioning methods in one tool — use your sonic tension meter or a standard belt tension gauge / spring scale, then document the inspection
| Section | AKA | g/m | kg/m |
|---|---|---|---|
| 3VX | XPZ | 53 | 0.053 |
| 5VX | XPB | 131 | 0.131 |
| 8VX | — | 486 | 0.486 |
| 3V | SPZ | 94 | 0.094 |
| 5V | SPB | 186 | 0.186 |
| 8V | — | 596 | 0.596 |
| AX | 4LK | 93 | 0.093 |
| BX | 5LK | 161 | 0.161 |
| CX | — | 282 | 0.282 |
| A | 4L | 100 | 0.100 |
| B | 5L | 168 | 0.168 |
| C | — | 296 | 0.296 |
| D | — | 671 | 0.671 |
Formula: f = (1/2L) × √(T/m) | Mass source: Gates 550C Sonic Tension Meter Manual
| Small Sheave Dia. | Initial (lbs) | Reten. Min | Reten. Max |
|---|
* For D, E, 8V: ½ force may be used if deflection distance is changed to Span ÷ 128. For banded belts multiply by number of belts.
Belt must contact both sidewalls — not the bottom. A bottomed-out belt means a worn sheave that must be replaced. A mismatched section slips and wears prematurely.
At mid-span, apply force perpendicular to the belt. The belt should deflect exactly K ÷ 64 inches. Example: 38" span = 0.594" deflection. Use a belt tension pen or spring scale with a ruler.
Worn sheaves have rounded or cupped groove sidewalls. A worn sheave cannot grip the belt properly and will destroy a new belt quickly. Use a sheave gauge to measure wear depth — replace if worn more than 1/32".
| Check | Belt 1 | Belt 2 | Notes |
|---|---|---|---|
| Cracking / Fraying | |||
| Glazing or Slipping | |||
| Correct Seating in Groove | |||
| Matched Set / Replace All | |||
| Tension — Before | |||
| Tension — After | |||
| Within Spec? |
| Check | As Found | As Left | Acceptable? |
|---|---|---|---|
| Angular Misalignment | |||
| Parallel / Offset | |||
| Straight Edge Check (flush?) | |||
| Sheave Wear / Belt Depth |
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