If you’ve ever spent time around rotating machinery—whether in a manufacturing line, a car’s transmission, or even a small farm tool—you’ve probably glanced at a bearing without giving it a second thought. As a thrust ball bearing supplier, I get asked this question more than any other: Can thrust ball bearings withstand axial load only? It’s not a trivial question, either. I’ve had engineers call me panicking because they thought they could cut costs by using a cheaper bearing that only handles axial loads, only to end up with a failed machine mid-shift. Or they’ll specify a thrust ball bearing for an application that throws in a hidden radial load, and wonder why their equipment is wearing out months early. Today, I’m breaking down exactly what thrust ball bearings can (and can’t) handle, sharing real-world lessons I’ve learned from customers, and making sure you don’t make the same mistakes I’ve seen hundreds of operators make over the last decade. Thrust Ball Bearings
Let’s start with the basics, because this is where most confusion happens. Thrust ball bearings are designed specifically for loads that run parallel to the axis of rotation—axial loads. Think of the force pushing a gear backward along a shaft, or a press tool being driven straight down into material. Unlike radial ball bearings, which support loads perpendicular to the shaft (like the weight of a fan blade pulling down on a motor shaft), thrust ball bearings are built to resist that along-axis force. But here’s the part that trips people up: “axial only” doesn’t mean “no other loads at all.” It means their primary purpose is axial, but that doesn’t mean they can’t handle tiny, incidental radial loads—up to a point.
I remember a customer a few years back, a small aerospace parts shop, who installed thrust ball bearings in a precision riveting machine. They called me a week later saying the bearings were seizing, and the rivets were coming out crooked. When I asked if they’d accounted for any side load, they laughed and said, “It’s a straight push—there’s no side force here.” When I visited their shop to take a look, I saw the problem immediately: the machine’s shaft was slightly misaligned, just by a fraction of a millimeter, so every time the rivet tool pushed down (axial load), there was a tiny radial component that the bearing couldn’t handle. That’s a classic mistake. Thrust ball bearings, especially the single-direction variety, only have contact on one side of the balls, so their ability to resist radial force is extremely limited. That customer ended up having to switch to a cylindrical roller thrust bearing, which can handle both axial and small radial loads, and their failure rate dropped to zero.
Let’s get into the engineering to back that up. Thrust ball bearings are made of two washers (sometimes called races) and a set of steel balls held in a cage. For single-direction thrust ball bearings, one race is a flat plate that sits flush against the housing, and the other has a shallow groove that the balls sit in, angled to take axial force. This groove is what allows them to carry axial load, but it also means that when a radial force is applied, the balls don’t seat evenly. The radial force pushes the balls against the edge of the groove, creating uneven stress that leads to pitting, spalling, or even cracking of the raceway. I’ve seen this first-hand: when radial load exceeds 5% of the axial load (that’s a rule of thumb I use with all my customers), the bearing’s life expectancy drops by more than 70%. There’s just not enough surface area or structural support to handle anything more than a tiny incidental side load.
Double-direction thrust ball bearings are a little different, right? They’re designed to handle axial loads in both directions, so they have two sets of balls and a central washer. But even they can’t handle meaningful radial loads. A lot of people mix these up with angular contact ball bearings, which are designed to handle both axial and radial loads. Angular contact bearings have balls that sit in a deeply angled raceway, so they can distribute both types of force evenly. Thrust ball bearings, though, are purpose-built for only axial force. I once had a customer from a food processing plant try to use double-direction thrust ball bearings in a conveyor system that had a slight side pull from the belt. The bearings failed in three months, whereas if he’d used angular contact ball bearings, they would have lasted years. He saved a few bucks on the initial bearing cost, but lost thousands in downtime and product waste. That’s the kind of tradeoff I always warn people about.
Another common myth: if a thrust ball bearing can handle some radial load, why not just use it for everything? The answer comes down to efficiency and lifespan. When a thrust ball bearing is subjected to even moderate radial load, it creates extra friction, which generates heat. That heat builds up, especially in high-speed applications, and can cause the bearing to seize or wear out quickly. I had a customer in the packaging industry who used thrust ball bearings in a high-speed filler that ran 24/7. He kept having to replace bearings every two weeks, until we sat down and looked at his setup. His shaft was a little loose in the bearing housing, so every time the filler moved, it wobbled, creating a radial load on the thrust ball bearing. Once he added a small radial bearing alongside the thrust ball bearing to take the side load, his bearings lasted over a year. It was a simple fix, but it required understanding exactly what each bearing is designed to do.
Let’s talk about applications where thrust ball bearings work perfectly, because they’re not useless—they’re just not for every job. Thrust ball bearings shine in applications where there’s pure axial load, no side force, low speed, and moderate to high axial load. Like, for example, a screw jack that lifts a heavy load straight up and down—no side pull, just a straight axial force. Or a clamp in a woodworking tool that presses down on a workpiece, only moving along the shaft. I supply thrust ball bearings to a lot of small machine shops that use them in these exact applications, and they work flawlessly as long as the setup is right. The key here is verifying that there’s no significant radial load, and that the shaft and housing are perfectly aligned. If those two conditions are met, thrust ball bearings are one of the most cost-effective options out there.
So, circling back to the original question: Can thrust ball bearings withstand axial load only? The short answer is, they are designed to withstand primarily axial load, but they can handle a tiny, incidental radial load—only if that radial load is less than 5% of the axial load. If you have any meaningful radial load, or high speeds, or misalignment, you need a different bearing type. That’s the truth that a lot of cheap bearing suppliers won’t tell you, because they just want to make a sale. As a supplier who’s been in this game for 12 years, I’d rather lose a sale than have a customer come back with a broken machine because I sold them the wrong bearing.
Cylindrical Roller Bearing I’ve seen too many businesses cut corners on bearing selection, and the results are always the same: unplanned downtime, costly repairs, lost productivity. I want to help you avoid that. If you’re working on a new project, or troubleshooting a failing bearing in existing machinery, don’t guess. Reach out to me to talk through your application. Tell me about the load, the speed, the shaft size, the alignment—all the details—and I can help you pick the right bearing that will last, save you money, and keep your machinery running smoothly. No pressure, no sales pitches—just honest advice from someone who’s seen the good, the bad, and the ugly when it comes to thrust ball bearings.
References
- Thorbjörn, L. (2007). Rolling Bearings: Theory and Design. John Wiley & Sons.
- American Bearing Manufacturers Association. (2018). ABMA Standard 9: Angular Contact Ball Bearings and Thrust Bearings.
- Harris, T. A., & Kotzalas, M. N. (2007). Rolling Bearing Analysis: Advanced Concepts of Bearing Technology (5th ed.). CRC Press.
- Shigley, J. E., Mischke, C. R., & Budynas, R. G. (2004). Shigley’s Mechanical Engineering Design (7th ed.). McGraw-Hill.
Shandong Weike Bearing Electromechanical Co., Ltd.
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