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TM-1 Tension Meter Bladed Spoke Calculator

This page describes the use of an on-line tension conversion calculator for the TM-1 Tension Meter. The TM-1 Tension Meter includes a card stock copy of the TM-1 Tension Meter Conversion Table listing sixteen different steel bladed spoke options with tension readings and Kgf values. Download the card stock TM-1 Tension Meter Table here.

The on-line calculator here will produce a column of tension meter readings that correspond to spoke tensions in Kilograms Force (Kgf). This permits the user to create unique tension conversion columns for steel bladed spoke dimensions that are not on the cardstock version of the TM-1 Tension Meter Conversion Table.

To use this calculator, you must measure the dimensions where the TM-1 would be bending the spoke. The post of the TM-1 should be positioned to bend the flat (skinny) part of the bladed spoke. This is the "thickness" of the bladed spoke dimension. The width is measured 90-degrees from the thickness and will be a larger number compared to thickness.

Using a caliper, measure the spoke width and thickness. Take measurements in millimeters, and round the reading to the closest tenth of a millimeter.

Measure spoke width
Measure width of blade

Measure spoke depth
Measure thickness of blade

Enter the spoke measurement dimensions in the appropriate field in the calculator to the right. Click the "Calculate" button.

A column will be displayed below the "Calculate" button that corresponds to the dimensions entered. This page may now be bookmarked and the column data will be saved. To save this column as a PDF, you must use the "print" feature of your computer, selecting "PDF" as the option. For a mobile devices, use the "screen grab" feature or bookmark the page.

The calculator is based on data from TM-1 Tension Conversion Table using steel bladed spokes. NOTE: This calculator is not intended for use with aluminum, titanium or carbon fiber spokes. For the recommended tension on your particular rim, contact the wheel or rim manufacturer.

Bladed Steel Spoke Dimensions*

  • optional - if not round/square

*Spoke Tension Meter Conversion Caveats:
  1. This correlation is for stainless steel spokes.
  2. This correlation is assumes consistent steel quality and grade.
  3. This correlation is based on maximum likelihood estimation assuming uniform, absolute uncertainty in weight and meter reading.
  4. This correlation does not apply to spokes of any other material.
  5. This correlation should not be used on spokes that are substantially dimensionally different from those in the TM-1 calibration table.

Calculations courtesy of:
C. S. Howat & Associates