1/4 in Thrust Bearing & 2 Washers

This is a 1/4 in thrust bearing set: a needle-roller cage that sits between two flat washers, as you can see in the photo. Blue Alpine lists it as part F00103-00, and the set is $4.54. You get the cage and both washers, which is what you want, because the three parts wear together.

Axial load, and what a thrust bearing is for

Most bearings you come across carry radial load. That’s force pushing sideways across a shaft, like the weight on a wheel axle. A thrust bearing handles the other direction: axial load, meaning force along the line of the shaft, pressing two parts together while one of them turns.

Think of a screw tightened down against a plate, or a part that has to rotate while it’s clamped. Without a bearing between them, the two faces rub. They wear, they heat up a little, and it takes more effort to turn. Put a bearing in between and that load rolls instead of sliding.

What it won’t do is keep the shaft centered. A needle thrust bearing has next to no radial capacity, so the shaft or bolt passing through it has to do that job. The thrust bearing article covers the other types (ball, tapered roller and so on) if you want to compare.

Needles, cage and two washers

The cage holds a ring of small cylindrical rollers, set radially like the spokes of a wheel. Each roller is long and thin. That shape is why a needle thrust bearing can be so slim for the load it carries. The cage keeps the rollers evenly spaced and stops them skewing.

Rollers need a hard, smooth, flat surface on each side to run against. The two washers provide that. They act as the races, and in needle thrust bearings they’re normally hardened steel, since the rollers would wear a groove into anything softer. That’s also why an ordinary flat washer from the hardware drawer is a poor stand-in. Plain washers aren’t made to be bearing races.

More on the roller side of things in the needle roller bearing article.

Measuring before you order a 1/4 in thrust bearing

Bearings are generally named by their bore, the hole in the middle. A quarter inch is 6.35 mm. Before you order, take three numbers off your old set:

• Bore (ID). Use the inside jaws of a caliper on the washer hole, or measure the shaft or bolt the bearing slides over.
• Outside diameter (OD) of the washers.
• Stack height: cage and both washers, measured together.

We don’t publish the OD or stack height on this page. If either matters for your fit, call +1 (443) 514-5708 with your measurements and we’ll check them against the part.

Lubrication and fitting

A needle thrust bearing shouldn’t run dry. Wipe the parts clean, then give the washer faces and rollers a light, even coat of general-purpose bearing grease. You’re after a film, not a packed lump. Too much grease tends to hold on to grit.

Assemble it washer, cage, washer. If the two washers look different from each other (one with a slightly smaller hole, say), put them back the way the old ones came out. Once it’s in place, spin it by hand. It should feel smooth all the way round, with no clicks or tight spots.

Signs your old thrust bearing is done

• A rough or notchy feel when you turn it
• A visible track, pitting or rust on either washer
• A cracked cage, or rollers missing or loose
• Blue or brown discoloration from heat

If the washers show wear, replace the whole set. A fresh cage running on scored washers won’t last long.

Quick questions

Can it take sideways load?

Not really. Keep it to axial load and let the shaft handle the rest.

Where’s the other hardware?

Bolts, washers and nuts are in fasteners and tools. Unsure about a fit? Send us your numbers through the contact page.