Rear Wheel Comparison: 148 vs 157

Symmetry strength

PMR

Stiffness and spoke-tension engine ported from Matt Ford's bike-wheel-calc (Mode Matrix method, Ford 2018) and verified against it to floating-point precision. Strength figures are first-spoke-slack thresholds built on those stiffnesses.

EI_lat (N·m²)
EI_rad (N·m²)
GJ (N·m²)
EA_rim (MN)
Modes N
Spoke count
EI_lat

Rim lateral bending stiffness — resists the rim bowing sideways. Typical alloy double-wall rims: 40–80 N·m².

EI_rad

Rim in-plane bending stiffness — how the rim spreads load around its hoop. Usually 3–10× EI_lat (100–300 N·m²).

GJ

Rim torsional stiffness. Because the rim is curved, bending and twist are coupled, so GJ shapes lateral flexibility more than EI_lat does. Typical: 15–35 N·m².

EA_rim

Rim hoop (axial) stiffness, used for the rim's in-plane response and the tension-softening terms. Typical alloy: 8–15 MN.

Modes N

Fourier modes in the Mode Matrix sum. Harmonics used to approximate the rim's deformed shape. Accuracy converges by N~16–24; higher settings add no meaningful precision.

Rim defaults: DT Swiss TK540 (EI_lat 50, EI_rad 150, GJ 22 N·m², EA 11.5 MN). Both wheels always share the same rim and spoke count, so differences below come from hub geometry, wheel size, spoke gauge, and DS tension only. DS tension is set per wheel now, not shared — see the "DS tension" field on each card below. That's a deliberate change: a wheel size this tool lets you pick on one side but not the other (26–32″) doesn't buckle at the same tension, so one shared value silently penalized whichever size buckles sooner. Each side defaults sensibly for its own size and can be moved independently.

Drag the wheel sideways to orbit it

Rear wheel · lateral strength
—kgf
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—kgf
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to first slack spoke
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This project could not have been possible without the work of Mechanical Engineer Matt Ford.
Boost axle
Wheel size
DS tension (kgf)
Defaults to 100 at 32″ (lower buckling margin at that size), 120 otherwise. Change wheel size to see the default follow it, or set your own.
Hub
Spoke ⌀ DS (mm)
Spoke ⌀ NDS (mm)
NDS tension at 100 DS —kgf
Average radial tension —kgf
Super Boost axle
Wheel size
DS tension (kgf)
Defaults to 100 at 32″ (lower buckling margin at that size), 120 otherwise. Change wheel size to see the default follow it, or set your own.
Hub
Spoke ⌀ DS (mm)
Spoke ⌀ NDS (mm)
NDS tension at 100 DS —kgf
Average radial tension —kgf
Headline result · lateral strength
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148 —
157 —
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Sideways push at the rim before the first spoke goes slack — —
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kgf · 148
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kgf · 157
148157
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Vertical hit at the contact patch before the first spoke goes slack — —
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kgf · 148
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kgf · 157
148157
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Resistance to side-to-side flex when cornering or landing off-line
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N/mm · 148
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N/mm · 157
148157
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How evenly the two sides share spoke tension — higher means the slack-prone side holds more
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148 hub
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157 hub
148157
—Dished MTB rear wheels typically land between 55–75. Shown for context, not as a pass/fail line.

Method. Tension balance, lateral stiffness K_lat, radial stiffness K_rad, and buckling tension T_c are computed with a JavaScript port of Matt Ford's open-source bike-wheel-calc library (Mode Matrix method; Ford 2018, A Theoretical Analysis of the Bicycle Wheel, Northwestern University) using smeared spokes, N Fourier modes, tension softening, and the linear buckling approximation. The port matches the library to floating-point precision across the full hub catalogue. Strength figures (F_lat, F_rad) are not library outputs: they are linearized first-spoke-slack thresholds — the load at which the lowest-tension spoke at the load point reaches zero tension — marking the onset of lost preload, not wheel collapse. Spoke geometry uses the rim beam-centroid radius (ERD/2 + 11 mm) per Ford §3.2; 3-cross lacing; steel spokes, E = 210 GPa. Hub flange dimensions compiled from manufacturer documentation. This project could not have been possible without the work of Mechanical Engineer Matt Ford.