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Two Important Factors: Surface & Hardness

How to install our Sprag Clutch Elements.

The raceways of the clutch and roller bearings must be hardened and ground. The hardening depth (Eht) for surface hardening must be 1.3 mm for transmitting full torque. Lower torque requires correspondingly lower depths.

  Hardness Surface Tolerance
Series 400 HRC = 60+4
Eht >= 1.3mm
RZ>=1.6mm bore DL = H6
shaft dl = h5 (series 400)
Series 800 HRC = 60+4
Eht >= 1.3mm
RZ >= 1.6mm bore DL = H6
shaft dl = h6

Free-wheel Clutch and roller bearing require a collar, ring or snap ring (round edge towards Free-wheel Clutch) as a guide. For ease of mounting, shaft and bore should have a chamfered edge.

Roller bearings:

The rollers of the roller bearings RL 400 can be ordered in eleven different tolerance classes, in steps of 2 microns ranging from +10 to -10 microns.

Order example:

50 roller bearings with 34 mm diameter x 42 mm diameter and tolerance class of +4 microns: 50 RL 442 +4.

If there is no tolerance ordered rollers of tolerance ± 0 microns will be delivered: 50 RL 442

Maximum radial clearance pending application 0.04 mm.


All insert elements and roller bearings are shipped rust protected – not lubricated.

Engagement direction:

Engagement direction “right”: When the shaft is driving to the right (clockwise) and the outer ring is driven through the sprags, (direction of view from the mounting side) suffix “R” not necessary.
Engagement direction “right”: When ordering a Free-wheel clutch with opposite engagement, the suffix “L” must be placed after the catalog number.


Mounting instructions – FE 400 M/Z/Z2:

For easy and safe installation, Free-wheel Clutches FE 400 and FE 400 Z/Z2 are delivered on hard paper tubes.

FE 400 M:

Only clutches of model FE 400 are surrounded with colored rubber rings, keeping the sprags in a disengaged position, so clutches can be mounted easily. Color of rubber ring for engagement direction: right = red left = light green or transparent

Push Free-wheel Clutch off of the paper tube over the shaft, into the housing. After removal of the rubber ring, push Free-wheel Clutch into final position.

In the event that the insertion of the Free-wheel Clutch from the paper tube is difficult due to larger depth, use an adapter sleeve for ease of mounting.

FE 400 Z/Z2

Free-wheel Clutches FE 400 Z/Z2 can be installed for left or right engagement.

Place Free-wheel Clutch in the housing and secure (retainer). Insert shaft with a turning and pushing motion.

In the event that the shaft and outer part can not be chamfered, place Free-wheel Clutch halfway on the shaft. This causes the sprags to tilt and reduces the diameter in relation to the size of the clutch frame. Now push shaft with the Free-wheel Clutch in place.

Mounting instructions – FR 400/FRN 400


thin walled ring with press fit bore D = H6
thin walled ring with press fit shaft d = h5
ring with keyway shaft d = js5 (k5)

Maximum radial clearance pending application 0.02 mm. Keyway specifications according to DIN 6885, Bl. 1 (P9) with back clearance.

Machine parts, in which Free-wheel Clutches are pressed in or on can be of ferrous or nonferrous material. If you considered to use nonferrous material please contact our technical staff first.

For pressed in or on Free-wheel Clutch rings no retainers are necessary for axial or radial security. The inner rings with keyway (type FRN) have to be secured in the axial direction.

Attention: Please take care for total cleaning of Free-wheel rings and mating parts before press fitting (no grease particles left in the press fit area).

Lubrication: All insert elements and roller bearings are shipped rust protected – not lubricated.

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