What is radial runout on a shaft?

Radial runout (TIR) is the total variation in distance measured from a shaft surface to a fixed reference as the shaft rotates one full revolution. TIR equals twice the eccentricity.

How do I measure runout with a dial indicator?

Mount the shaft on V-blocks, place a dial indicator perpendicular to the surface, zero it, then rotate one full revolution. The total needle movement is the TIR.

What causes excessive radial runout?

Common causes: bent shaft, manufacturing eccentricity, bearing journal wear, improper coupling alignment, and assembly errors.

What is the relationship between runout and unbalance?

If the mass centre of a rotor is displaced by eccentricity e, the equivalent unbalance is U = e × m, where m is rotor mass. Journal runout can displace the mass centre and thus contribute to unbalance, but measured TIR also includes form error, bend and setup error, so runout and residual unbalance are related yet not equal.

What is acceptable runout for different applications?

The geometric runout tolerance comes from the shaft drawing or the manufacturer's specification, not from ISO 21940-11. As a balance-risk screening value, the unbalance-equivalent TIR is about 40 μm at G6.3 / 3000 RPM, about 3.2 μm at G1.0 / 6000 RPM, and about 80 μm at G6.3 / 1500 RPM. Always calculate for your specific conditions and check the drawing tolerance.

ಉಚಿತ ಎಂಜಿನಿಯರಿಂಗ್ ಟೂಲ್

ಶಾಫ್ಟ್ ರೇಡಿಯಲ್ ರನ್‌ಔಟ್ ಕ್ಯಾಲ್ಕ್ಯುಲೇಟರ್

Estimate the shaft radial runout (TIR — Total Indicator Reading) that corresponds to the ISO 21940-11 residual unbalance limit for your balance quality grade and speed, and screen measured runout for unbalance risk. Note: ISO 21940-11 sets unbalance limits — the geometric runout tolerance itself comes from the shaft drawing or manufacturer specification.

ISO 21940-11 TIR / ವಿಚಲನತೆ Balance-Risk Screening

ಸಮತೋಲನ ಗ್ರೇಡ್ G

ಕಾರ್ಯಾಚರಣ ವೇಗ (RPM)

ಶಾಫ್ಟ್ ವ್ಯಾಸ (mm)

ರೋಟರ್ ಭಾರ (kg)

ಅಳೆಯಲಾದ ರನ್‌ಔಟ್ — optional, for balance-risk screening (μm TIR)

Quick presets

Results

Unbalance-Equivalent TIR (screening value, not a geometric tolerance)

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ಅನುಮತಿಸಬಹುದಾದ ವಿಚಲನತೆ (e_per)

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ಸಮತೂಲ ಅಸಮತೋಲನ (U_per)

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ಕೋನೀಯ ವೇಗ ω

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ಬ್ಯಾಲೆನ್ಸ್ ಗ್ರೇಡ್

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ಅನುಮತಿಸಬಹುದಾದ ವಿಚಲನತೆ

ಸಮತೋಲನ ಗುಣಮಟ್ಟ ಗ್ರೇಡ್ G ಮತ್ತು ಕಾರ್ಯಾಚರಣಾ ವೇಗದಿಂದ:

G — ಸಮತೋಲನ ಗುಣಮಟ್ಟದ ದರ್ಜೆ (ಮಿಮೀ/ಸೆ)
n — ಕಾರ್ಯಾಚರಣಾ ವೇಗ (RPM)
ω — ಕೋನೀಯ ವೇಗ (ರಾಡ್/ಸೆಕೆಂ) = 2πn/60

ಒಟ್ಟು ಇಂಡಿಕೇಟರ್ ರೀಡಿಂಗ್

ಡಯಲ್ ಇಂಡಿಕೇಟರ್‌ನಿಂದ ಅಳೆಯಲಾದ TIR ವಿಚಲನತೆಯ ದ್ವಿಗುಣವಾಗಿರುತ್ತದೆ (ಪೀಕ್-ಟು-ಪೀಕ್):

Scope of this check: e_{ಪ್ರತಿ} in ISO 21940-11 is a permissible residual unbalance (mass-centre eccentricity), not a geometric runout tolerance. TIR = 2 × e_{ಪ್ರತಿ} is therefore a ಸ್ಕ್ರೀನಿಂಗ್ value: if measured journal runout exceeds it, the mass-centre displacement from runout alone could already exceed the balance limit for the selected G grade. It does not replace the geometric runout tolerance on the shaft drawing, and a shaft with low TIR can still be out of balance (mass distribution), while measured TIR can include form error, bend, bearing seating or setup error that does not translate one-to-one into unbalance.

ಸಮತೂಲ ಅಸಮತೋಲನ

ಪ್ರಾಯೋಗಿಕ ಉದಾಹರಣೆ

ಉದಾಹರಣೆ — 3000 RPM ನಲ್ಲಿ ಪಂಪ್ ಶಾಫ್ಟ್ G6.3

Given: ವೇಗ = 3000 RPM, ಗ್ರೇಡ್ = G6.3, ದ್ರವ್ಯರಾಶಿ = 45 kg, ವ್ಯಾಸ = 40 mm

ω = 2π × 3000 / 60 = 314.16 rad/s

e_{ಪ್ರತಿ} = 6.3 × 1000 / 314.16 = 20.05 μm

TIR = 2 × 20.05 = 40.1 μm

U_{ಪ್ರತಿ} = 20.05 × 45 = 902.3 g·mm

Unbalance-Equivalent Runout Reference Table (screening values)

р▓Чр│Нр▓░р│Зр▓бр│Н	ವೇಗ (RPM)	e_{ಪ್ರತಿ} (μm)	Equivalent TIR (μm)
G6.3	750	80.2	160.4
G6.3	1500	40.1	80.2
G6.3	3000	20.1	40.1
G2.5	3000	7.96	15.9
G2.5	6000	3.98	7.96
G1.0	6000	1.59	3.18
G1.0	12000	0.80	1.59

Shaft Radial Runout Calculator — Free TIR Tool | Vibromera

Published by Nikolai Shelkovenko on ಫೆಬ್ರವರಿ 15, 2026 ಜುಲೈ 2, 2026

Results

ಅನುಮತಿಸಬಹುದಾದ ವಿಚಲನತೆ

ಒಟ್ಟು ಇಂಡಿಕೇಟರ್ ರೀಡಿಂಗ್

ಸಮತೂಲ ಅಸಮತೋಲನ

ಪ್ರಾಯೋಗಿಕ ಉದಾಹರಣೆ

Unbalance-Equivalent Runout Reference Table (screening values)

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