Bearing Analysis · DWG LS-017

Bearing internal clearance & drive-up calculator

SKF mounting clearance reduction and residual internal clearance for cylindrical and tapered-bore bearings — unmounted RIC, interference-fit reduction, hot/press/freeze/hydraulic mount targets, and axial / angular drive-up — plus NTN running checks for clearance lost to ring temperature difference and the shaft interference a load needs. Bearing designation and bore prefill from your selected bearing when a calculation string is active.

Maker method (SKF, NTN, NSK)Last reviewed

Source: NSK CAT. E1103 Appendix Tables 9 & 10, shaft and housing tolerances, ISO 286 (PDF) · SKF Bearing Maintenance Handbook (PDF) · NTN catalogue 2203E ch.7 Bearing fits (PDF) · NTN catalogue 2203E ch.8 Internal clearance (PDF)

The check that compares fit interference with the load and temperature loss (ΔdF + ΔdT) is LubeSuite’s reading of NTN’s procedure.

Validation
  • NTN running checks match hand calculations of the NTN equations: 6309 with a 5 °C ring difference gives Do 89.0 mm and δt 5.56 µm; Fr 5,000 N with C0r 31.5 kN gives ΔdF 7.59 µm; a 30 °C rise gives ΔdT 2.03 µm. Inch mode gives the same results.

How calculators are checked: editorial standards.

1 — Bearing Specification
Applies to cylindrical and tapered bore. Leave blank for solid shaft.
At a glance Results update as you type

Enter bore and clearance class above — the key numbers show here, full results below.

Full results ↓
2 — Shaft & Housing Fit
Tolerance limits from ISO 286 as tabulated in NSK CAT. E1103 Appendix Tables 9 & 10 (shafts / housings), for the entered diameter. Clearance fits on the housing (H7, H6, G7) contribute zero RIC reduction.
3 — Mounting Method
Added above minimum. Typical: 50°F
Results
⚙

Enter a bore diameter and clearance class — results appear here on their own, no button.

4 — Running checks: ring temperature & fit for load NTN method · optional
Two checks the mounting numbers above don't cover: clearance lost when the inner ring runs hotter than the outer ring, and the minimum shaft interference needed so the inner ring doesn't creep under the radial load and temperature. Bore, units and bearing type come from section 1.
Clearance lost to ring temperature difference
Outer ring usually runs 5–10 °C (9–18 °F) cooler; more with a cooled housing or heated shaft.
Enter the residual you expect after mounting to see what is left running.
Shaft interference needed for load & temperature
Fit smoothing loss (NTN: ground 1.0–2.5 µm, machined 5–7 µm); we use the top of the range.

Enter bore (section 1) plus OD and a ring ΔT for the temperature check, or width, Fr and a bearing − ambient ΔT for the interference check.

Method & sources NTN 2203E ch.7 & ch.8

Ring temperature difference — δt = α·ΔT·Do, α = 12.5×10⁻⁶ /°C (bearing steel), ΔT = inner − outer ring temperature, Do = outer ring raceway diameter ≈ 0.20(d + 4.0D) for ball and spherical roller bearings, ≈ 0.25(d + 3.0D) for other roller bearings (d, D in mm; δt in mm). NTN eqs 8.5–8.7, 2203E ch.8 “Bearing Internal Clearance and Preload”, p. A-93. Steel bearing, shaft and housing only. CARB has no NTN equivalent; we use the “other roller” form for it.

Interference for load — required effective interference ΔdF = 0.08·√(d·Fr/B) µm when Fr ≤ 0.3·C0r, and ΔdF = 0.02·Fr/B µm when Fr > 0.3·C0r (d, B in mm; Fr, C0r in N). Solid shafts only. Interference for temperature — ΔdT = 0.0015·d·ΔT µm, ΔT = bearing − ambient temperature in °C. NTN eqs 7.1–7.3, 2203E ch.7 “Bearing Fits”, p. A-77. NTN also says the fit's interference falls by about 1.0–2.5 µm on ground and 5–7 µm on machined seats (smoothing), and that the maximum interference should stay under about 1/1000 of the shaft diameter.

Fit-band limits are the same ISO 286 numbers section 2 shows. Comparing the minimum fit interference, less smoothing, with ΔdF + ΔdT is our reading of NTN's procedure. NTN doesn't print that comparison, so treat a shortfall as a reason to review the fit rather than a hard fail.

Job / work order optional · goes on the printed record
Job / Work Order Information