Why does thermal expansion matter for bearings?

When a shaft heats up during operation, it expands axially. If both bearings are fixed axially (locating), the expansion creates internal preload, increasing friction and temperature. Proper locating/non-locating arrangement allows thermal growth without damaging the bearings.

What is a locating/non-locating bearing arrangement?

In a locating/non-locating arrangement, one bearing is fixed axially (locating) to position the shaft, while the other bearing is free to slide axially (non-locating) to accommodate thermal expansion. This is the most common arrangement.

What is the CTE of steel?

The coefficient of thermal expansion (CTE) for carbon steel is approximately 11-12 × 10⁻⁶ /°C. Stainless steel is about 16-17, aluminum is 23, and cast iron is 10-11.

How much expansion is typical?

A 1-meter steel shaft with a 50°C temperature rise expands about 0.6 mm. This may seem small but can generate enormous forces if both bearing positions are axially fixed.

What if shaft and housing are different materials?

When shaft and housing have different CTEs (e.g., steel shaft in aluminum housing), the differential expansion must be calculated. The housing expands more than the shaft with aluminum, potentially reducing interference fit.

Free Engineering Tool #054

Bearing Thermal Expansion Calculator

Calculate axial thermal growth of shafts and housings affecting bearing arrangements. Includes locating/non-locating arrangement guide.

δ = L × α × ΔTMultiple MaterialsArrangement Guide

Results

Shaft Axial Expansion δ_shaft

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Housing Axial Expansion δ_housing

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Differential Expansion

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Arrangement Recommendation

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Thermal Expansion Formula

L — length between bearings (mm)
α — coefficient of thermal expansion (×10⁻⁶ /°C)
ΔT — temperature rise (°C)

CTE Values

Material	α (×10⁻⁶ /°C)
Carbon steel	11.7
Stainless steel 304	16.0
Cast iron	10.5
Aluminum alloy	23.0
Copper / bronze	17.3
Titanium alloy	8.6

Locating / Non-Locating Arrangement

ℹ️ The most common bearing arrangement uses one locating bearing (fixed axially in both directions) and one non-locating bearing (free to slide axially). This accommodates thermal expansion without creating internal forces.

Bearing Thermal Expansion Calculator | δ = L×α×ΔT | Free Online Tool

Published by admin on February 15, 2026 February 15, 2026

Results

Thermal Expansion Formula

CTE Values

Locating / Non-Locating Arrangement