AAA Sales & Engineering: Skate Retarders

Model FS4 Fail-Safe Skate Retarder	view parts

The FS4 skate retarder is designed to stop cars and hold them in position. The FS4 is weight responsive, providing more braking force to heavy cars and less force to lighter cars. Built on the same proven platform as the F4, the Fail-Safe option adds positive stopping power in the event of a power loss.

Retarder Rating (MPH)
Retarder Length	No. of Lever Units	Maximum Entering Speed
Retarder Length	No. of Lever Units	33 Wheels	36 Wheels	38 Wheels
4' – 7"	2	3.0	3.0	2.9
9' – 2"	3	4.3	4.2	4.1
13' – 9"	4	5.2	5.12	5.0
18' – 4"	5	6.1	5.9	5.8
22' – 11"	6	6.8	6.6	6.5
27' – 6"	7	7.4	7.2	7.1
32' – 1"	8	8.0	7.8	7.7

Field studies verify that the 8 lever FS4 retarder applies nearly twice as much braking force as an AR2 retarder and 2/3 more braking force than our competitor.

Field Test Performance
Retarder	Squeezing Force (lbs)	Friction Coefficient	Friction Force (lbs)	Advertised Energy Removal
AR2	29.333	0.42	12,319	350,000 ft lbs
Competitor	34,000	0.42	14,280	Not Known
F4 (Light Car)	9,457	0.42	3,971	1.99 feet Velocity Head
F4 (Heavy Car)	56,745	0.42	23,832	1.99 feet Velocity Head