The skinny on Anti Reverse Bearings

Anti Reverse Bearings (ARB's) are a misunderstood device that gives our reels the sensation of tight slop free spool and crank control. They also absorb tremendous shock and provide redundant anti reverse for more reliable reel performance.

Since they are a critical and pricey part of our gear they are worth the effort to understand how they are used and function in out gear. ARB's are used as part of the anti reverse mechanism that prevents the spool/ crank from turning backwards. They are usually used along with anti reverse pawls as the ARB is a friction device and will slip at very high loads. They produce the feeling of infinitely fine detente where the pawls produce a ratchet type detente . They do more that just add feel they act over a small but finite reverse movement that produces a cushion or springy feel that is capable of reliably absorbing repeated high shock loads that could damage a pawl type anti reverse. The location of the ARB is usually in the handle crank shaft and acts directly on the handle motion. This means that the anti reverse loads act on the spool through the gears rather than directly on the spool drive (drag is in between). It is a good thing that the ARB's absorb shock as it would damage gears if the were not shock absorbing. In my personal opinion the ARB would be best placed as part of the spool pinion support so it could act directly on the spool drive and support 3x to 6X more drag and reduce shock induce gear damage.

ARB's are not real bearings. The closest thing that is a bearing is the plastic cage that acts as a sleeve.
ARB's are really over run clutches that transfer energy in one direction of rotation and and free run in the other direction. They are typically used in higher power applications like the starter overrun clutch on the pinion or in automatic transmissions to keep the planetary from rotating backwards. The rollers do not roll (they do but only for a very short distance) but mostly slide against the shaft. They are not very good as bearings.

The design is simple and utilizes roller bearing/needle bearing parts. The rollers are held in a plastic spring loaded cage that pushes them in the direction that matches the direction of shaft rotation where the clutch is engaged. This means that the default state of the ARB is in the engaged state. The outer 'race' is a series of ramps (one ramp per roller) where the high side if the ram pushes the roller to the center of the ARB (this is the engaged side of the ramp). The low side of the ramp allows for free play when the shaft direction is in the overrun or free state. To Get into the free state the cage springs are compressed until the shaft slides and can no longer produce pressure to compress the spring any further. With this in mind the result is the free state is a state of sliding friction on the shaft. When engaged the rollers are literally jammed between the ramps and the shaft and the clutch mechanism is the metal to metal friction between the rollers, ramps, and shaft. All these parts are hardened and usually made of a high carbon steel.

Steel!!! yes that means that they will rust. A little corrosion pitting is really not a problem as the ARB's are a friction device. The problems in our reels is with accumulation of rust compacting around the rollers and springs (plastic wing like things in the cage) that inhibits the free movement of the rollers causing them to either not engage or possibly not to fully run free in the free state.

If you need to service ARB's what you are doing is:
Lubricating to allow free movement of the rollers.
Removing deposits that are inhibiting the roller movement up and down the ramps in the outer race.

How to clean:
The proper way is to pick out each roller from the cage. Clean the cage and the ramps as well as the rollers. treat all metal parts with a corrosion inhibitor (corrosionX and or TSI). DO NOT GREASE! Grease is too heavy and will inhibit proper motion of the rollers. Light oil or a very light grease/oil blend. Reinstall the rollers. Insert a shaft and test. In the engaged state they should not slip under heavy load. If they do the ramps and or the rollers are damaged beyond serviceability.

The quick and dirty is: Apply a penetrating/cleaning oil to the bearing. Run the shaft in and out and in the engaged and free directions. Clean out the residue with a cleaner (I use carb cleaner under low pressure) and pull a rag thrugh the bore to dredge out more junk. Repeat until you stop producing rust and goo. Lube and test.

An important note: The rollers are only loosely held in place and can be blown free easily. They are extremely hard to find if they fall out (small and don't make noise when landing). The ARB only work if all the rollers are in place. Loosing one will ruin the ARB. In desperation you might have a chance finding a lost roller with a big magnet sweeping the area (they are made of steel).

Jim N.

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