A 100mm double reel handle is not necessarily a longer crank than a 60mm single handle. The first number may describe the full distance between two knob centers, while the second describes the distance from the drive axis to one knob center. If a symmetric double handle has a confirmed 100mm center-to-center span, each knob travels around a 50mm radius. A single handle with a confirmed 60mm radius has the longer crank radius.
Before comparing fishing reel handles, establish the endpoints, convert to the same measurement and then check clearance on the complete outfit. This guide explains that purchasing comparison, not a universal handle-replacement procedure.
Measurement endpoints · Worked example · Measurement checklist · Fit check · Reel examples
Three dimensions that should not share one label
Crank radius: drive axis to knob-spindle center
Find the axis around which the handle arm turns. Then identify the spindle axis around which the grip knob itself turns. The straight-line distance between those two axes, viewed in the handle's rotation plane, is the crank radius used here. It is not the length along a curved metal arm.
For a single handle, ask whether the published length uses these endpoints. Do not assume that every maker's word “length” follows this convention.
Double-handle span: knob center to knob center
A double handle may be specified by its full center-to-center span. For a straight, symmetric arrangement with the drive axis exactly halfway between the knob axes, the crank radius is half that span.
For example, Gomexus explicitly labels one double-handle specification as center-to-center wheelbase. This is evidence for that listing's convention, not a universal rule for every handle brand or shape. Confirm the drawing for the actual part.
Overall envelope: outer edge to outer edge
The outside dimensions of knobs, caps and arm ends describe the space occupied by the assembly. They matter for clearance and storage, but are not the same as axis-to-axis radius. A larger grip can increase overall width without moving its spindle farther from the drive axis.
Knob diameter, knob height and handle radius are separate dimensions. A T-bar's width is not automatically its crank radius.
The 100mm-versus-60mm comparison
Consider two hypothetical handles. These are illustrative dimensions, not specifications of the GOOFISH reels linked below.
- Handle A: straight symmetric double handle, confirmed 100mm knob-center-to-knob-center span. Its crank radius is 100 ÷ 2 = 50mm.
- Handle B: single handle, confirmed 60mm drive-axis-to-knob-axis radius. Its crank radius is 60mm.
Handle B therefore has a 20% larger radius than Handle A, even though its advertised number is smaller. Comparing 100 directly with 60 would answer the wrong question.
More leverage also means a larger hand path
For an ideal tangential hand force, handle-axis torque equals force multiplied by crank radius. This follows the basic torque relationship explained by OpenStax.
At an illustrative 1N·m of torque at the handle axis, a 50mm radius requires 20N of tangential force, while a 60mm radius requires about 16.7N. That is about 16.7% less force in this simplified comparison, not 20% less. No fishing load or safe operating setting is prescribed by these numbers.
The knob center also travels farther per turn: approximately 314mm around a 50mm radius, compared with 377mm around a 60mm radius. Real handling includes changing hand position, friction, gearing, line load and grip shape. The calculation is not a fatigue test or a promise that one reel will feel easier for every angler.
A longer handle does not change gear ratio
On the same reel at the same spool fill, changing the crank radius does not change line pickup per complete handle revolution. It changes the hand's motion and leverage. At the same hand speed along a larger circle, completing each revolution takes longer.
Keep radius separate from gearing and spool fill. The related guide to reel retrieve rate and gear ratio explains those other variables.
A five-step measurement check without dismantling
- Identify the exact reel and handle. Record the generation, retrieve hand and installed handle option. For an adjustable arm, record the selected position.
- Make the outfit safe. Remove or securely contain terminal tackle and remove external line load. Support the reel on a stable surface. Do not turn it while a measuring tool is close to moving parts.
- Locate the axes. Use an unobstructed side view. Measure drive-axis to knob-spindle axis, not to the edge of the rubber, cork or metal grip.
- Record the convention and units. Write “60mm axis-to-axis radius,” for example, rather than “60mm handle.” If you measure a double span, label it as a span and verify symmetry before halving it.
- Record uncertainty. If an axis is hidden or perspective prevents a reliable reading, request a dimensioned drawing. Do not remove a cap or knob merely to make a purchasing measurement.
Keep the ruler in the same plane as the measured points where practical. A photograph taken obliquely, with a ruler closer to the camera, can mislead. Do not estimate millimeter precision from a lifestyle photograph.
An offset, swept or asymmetric handle needs its actual geometry checked. Half of an outside width is not a reliable shortcut to the crank radius.
Check the full circle on the complete outfit
A useful dimension is only the beginning. Mount the compatible reel on its intended rod according to the instructions. With hooks contained and the outfit unloaded, check normal winding slowly with measuring tools removed.
Observe clearance at the fingers holding the rod, the reel body, drag controls, clothing and any nearby seat or rail. Check the opposite knob on a double handle as well as the knob in your hand. Repeat from your actual standing or seated position.
If winding is stiff, rough or accompanied by unexplained movement, do not use a longer handle to force it. The separate reel-handle wobble inspection guide addresses unwanted movement rather than sizing.
Two reel examples: grip shape is not a radius measurement
The GOOFISH Edge Jigger 30 jigging reel lists a ball-style metal grip and 4.92:1 gearing. Its four current selections combine Navy Blue/Gold or Pink/Gold with separate left- or right-hand retrieve, all in size 30.
The GOOFISH Abyss Jigger Gen 2 vertical jigging reel lists a T-bar grip and 6.08:1 gearing. Its six selections combine Silver/Blue, Silver/Green or Pink/Gold with right-hand GR500 or left-hand GL500 versions.
These are different complete jigging reels, not a controlled experiment in handle length. Neither current description supplies a confirmed axis-to-axis crank radius. Request that measurement if it matters to your decision; do not rank their leverage from knob shape or photographs.
Choose retrieve hand, line requirements and compatible rod configuration separately. Do not infer that handles interchange between these reels, or that a left-hand version can be converted to right-hand use.
A clear question to send before buying
For this exact reel and handle option, is the listed length the drive-axis-to-knob-axis radius, the full knob-center-to-knob-center span, or the outside dimension? Please identify the endpoints on a drawing and state the selected adjustment position. Separately, please confirm approved compatibility and required installation hardware.
Matching radius does not establish shaft, thread, fastening, offset or clearance compatibility. Use only approved parts and the applicable installation instructions. A larger crank does not upgrade the reel's gears, drag, anti-reverse or the rod's fishing limits.
Reel handle measurement FAQ
Is a 100mm double handle always a 50mm radius?
Only when 100mm is the confirmed knob-axis-to-knob-axis span of a straight symmetric layout with the drive axis at its midpoint. Check the actual drawing.
Does a larger knob increase crank radius?
Not if its spindle remains in the same position. It changes grip geometry and the outside envelope, which can still affect comfort and clearance.
Does a longer arm retrieve more line per turn?
Not on an otherwise unchanged reel at the same spool fill. One complete handle revolution still produces the same geared movement.
Should I choose the longest compatible handle?
Not automatically. More leverage comes with a larger hand path and different clearance requirements. Compare the actual outfit and intended task rather than treating maximum length as the goal.
Compare axes first, radius second and working clearance third. A smaller published number can describe the larger crank. Naming the endpoints turns an ambiguous specification into a useful buying decision.
