Getting a bearing off a shaft is harder than getting it on. The interference fit that holds the bearing in place is designed to resist rotation under load, and it does an equally good job of resisting the puller. Add fretting corrosion from years of micro-motion at the interface, and a bearing that slid on with 2 tons of press force may need 4 tons to pull off.
Knowing the approximate force before you start helps you select the right tools and avoid the two most common outcomes of underprepared bearing removal: either the puller slips off and creates a hazard, or the mechanic resorts to hammers and chisels that damage the shaft.
How to Estimate Press and Pull Force
The press-fit force depends on three things: the amount of interference, the shaft diameter, and the length of engagement (the width of the bearing inner ring). More interference, larger diameter, and longer engagement all mean more force. The formula involves the contact pressure from the interference, the friction coefficient, and the contact area.
For a steel-on-steel interference fit with no lubrication: F = π × d × L × p × μ, where d is the shaft diameter, L is the engagement length, p is the contact pressure from the interference, and μ is the friction coefficient (typically 0.12 to 0.15 for dry steel-on-steel).
Pull-off force is typically 1.5 to 2 times the press-on force due to fretting and settling during operation. For bearings that have been in service for years, the factor can be even higher.
25mm shaft: 0.5 to 1.5 tons
50mm shaft: 1.5 to 4 tons
75mm shaft: 3 to 8 tons
100mm shaft: 5 to 15 tons
150mm shaft: 10 to 30 tons
These are rough estimates. Actual force depends on the specific interference and surface condition.
Bearing Puller Force Estimator
Rule-of-thumb estimator for bearing removal and installation press force. Enter bearing size, fit tightness, and engagement length to get force estimate with tool recommendations.
Choosing the Right Removal Tool
Mechanical jaw pullers are suitable for light interference fits on small to medium bearings (up to about 80mm bore). They are simple, portable, and inexpensive. The limitation is force: most mechanical pullers max out at 5 to 10 tons. Beyond that, the screw becomes difficult to turn and the jaws may slip.
Hydraulic pullers extend the range to 50 tons or more. The hydraulic cylinder applies smooth, controlled force without the vibration of hammering or the jerky motion of a mechanical screw. For medium and large bearings, a hydraulic puller is the correct tool.
Induction ring heaters provide a non-force alternative for removal. A ring-shaped induction coil heats just the inner ring while the shaft stays cool. The inner ring expands and the interference reduces enough to slide or pull the bearing off with minimal force. This method protects the shaft surface and is the preferred removal method for precision shafts and large interference fits.
Estimated force <3 tons → Mechanical jaw puller
Estimated force 3 to 20 tons → Hydraulic puller
Estimated force >20 tons or precision shaft → Induction removal + hydraulic assist
Any bearing where shaft damage is unacceptable → Induction removal