Kensington Expert Mouse Trackball Review

Trackballs are often recommended as an ergonomic alternative for mouse sufferers. The Kensington Expert, with its extra-large ball, scroll wheel, and programmable buttons, is frequently held up as an example of trackball greatness. There is much to like about the latest version of this venerable device, but also one or two drawbacks to consider.

Big trackball, big benefits

The first prototypical trackball, invented in far-off 1952, used an actual regulation bowling ball for its business end. In a smaller scale of the same sporting tradition, the ball of the Expert Mouse is identical in size to one used for billiards – literally identical; on the old mechanical Expert model you could actually substitute a billiard ball and it would still work. This jumbo sized ball is a large part of what makes the Expert Mouse worth its considerable price tag.

Kensington Expert Mouse - Side view

The Kensington Expert Mouse trackball used in this review.

Generally speaking, input devices are considered more ergonomic when they can be driven with big motions of large muscle groups, and less ergonomic when they must be manipulated with minute movements of weaker muscles. To illustrate this, imagine trying to do CAD with a tiny, thumb-operated trackball or finger joystick such as the ones featured on early laptops. I don’t know about you, but just thinking about it makes my finger hurt. In contrast, the large ball of the Expert can easily be driven with three fingers, your whole hand, or even your whole arm. These motions are not only expansive and easy to do, they’re also easy to change up while you work – helping to undermine the “repetitive” in Repetitive Strain Injury.

Kensington Expert Mouse Trackball
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If you have a large monitor, you’ll appreciate the ability of the Expert Mouse to cover ground with just a slight push of its large ball. If you have several large monitors, the ability of a trackball to spin infinitely – where a mouse would hit the edge of the pad and have to be reset – is nearly indispensable.

Most importantly for the Photoshopper set, the size of the Expert Mouse increases its potential for precision. Trackballs in general are not very accurate, but the Expert is precise enough that many people have reported being able to do pixel-perfect work with the thing. This is, of course, very much YMMV. Personally, I’m keeping my Wacom tablet handy for the fine details.

Padded wrist rest

Kensington Expert Mouse - Disassembled with wrist rest

The wrist rest attachment plate, shown here already pegged onto the trackball body, holds the wrist rest with two plastic posts.

The Kensington Expert Mouse doesn’t have a hand-conforming shape, and thus gives no clue as to where your hand should park while using it. By default your wrist is likely to end up on the desk, which is bad – and bent back due to the slope of the trackball, which is worse.

Enter the padded wrist rest provided with the Expert – big enough to accommodate any choice of operating position, and thick enough to reduce back-bending on the wrist. It’s spongy soft compared to many wrist rests, and covered with a smooth leatherette-type surface similar to that of the Microsoft Natural 4000 keyboard.

The downside, if there is one, is less than consequential. The wrist rest – which looks like it should nest tightly over the front of the trackball but doesn’t – is attached by a thin plastic plate. With its four short posts sticking up, this plate reminds me very much of the display stands used with small action figures. It also feels like that grade of quality. Provided you don’t pop the wrist pad off on a daily basis, though, you should be fine. There are no inherent stresses of use on this component that I can see.

Merrily we scroll along

Or not so merrily. There’s good news and bad news about the Expert’s scroll wheel. The good news is, it has one. Most trackballs don’t, instead using the ball itself for scrolling when a special combination of buttons is pressed. As I mentioned in my review of another wheel-less device, the 3M ergonomic mouse, I think scroll wheels are pretty important. That’s one reason I love the Kensington Orbit – a smaller, less-expensive cousin of the Expert Mouse that features a slick scroll ring around its ball. Having used this device, I was disappointed and puzzled by the wheel on the twice-more-costly Expert Mouse. The bad news, you see, is that the wheel on this trackball grinds, with a sound and feel that many users describe as sand in the bearings. Worse, it seems to skip, stick, and pause for breath during use – leaving me with a profound lack of confidence that it will actually work when required.

The best I can say about this scroll wheel is, it’s better than nothing. I’ll probably never understand why Kensington could not simply enlarge the wheel from the Orbit and mate it to the Expert for an incomparable trackball experience.

Programmable buttons

Where many trackballs skimp on the number of buttons available due to their shape and size, the Expert Mouse features a respectable four buttons. Better yet, it’s compatible with the latest upgraded version of Kensington’s free TrackballWorks software. Running in the background of your Windows or Apple computer, this program enables you not only to adjust things like the pointer speed and acceleration, but also to reprogram the four buttons any way you like. I, for example, set the top-right button to primary click so I could hit it with my strong middle finger and avoid wearing out my thumb on the default bottom-left click setting.

Kensington TrackballWorks

You can remap and reassign buttons on the Expert Mouse with the free Kensington TrackballWorks software. Shown here are the settings I created.

Combinations of buttons are also supported through TrackballWorks. I created a behavior to register double-click when the top two buttons are pressed at once, and found it worked quite well. You can also map these combinations to different system actions and commands, such as starting a frequently-used program or minimizing all windows. In case you’re wondering, you don’t have to press both buttons in the same nanosecond; the software is quite smart about distinguishing concurrent clicks. I do wish that Kensington would expand the combinations available, allowing custom actions for both right buttons, both left buttons, and even diagonal mixups. Currently you’re limited to the top and bottom pairs only.

No go for on the go

Kensington Expert Mouse Trackball
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Portability is not a strong point of the cumbersome Expert Mouse, particularly if you use the wrist rest with its flimsy attachment plate. Even if you don’t, there’s still the problem of the ball. Unlike any other trackball I know of, the Expert holds its ball in by gravity alone. Turn over the body and out comes the ball, ready for a game of billiards – or more likely hide and seek, as the surprised user hunts for it under the desk. While this “easy” removal is great for the occasional cleaning all trackballs require, it makes the Expert Mouse a two-piece carry – one piece of which will always be trying to roll away.

If mobile work is your thing, do yourself a favor and get a Kensington Orbit Scroll, that smaller cousin we talked about earlier. With its low profile and tight construction, the Orbit is perfect for portable situations (and not half bad for primary desktop use, by the way).

My takeaway

People switch to trackballs for a lot of reasons. Reduced wrist motion, easy movement over multiple screens, and desk space economy are some of the most common. In all of these areas, the Kensington Expert Mouse hits it out of the park. The scroll wheel issue is a drawback, but in my opinion not necessarily a deal-killer. The Expert is comfortable to use, very cool, and even a little bit fun. If there’s a trackball in your future, it’s definitely worth considering the Kensington Expert Mouse.

Disclosure: This review was made with a complimentary sample from Kensington.

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  1. Howard
    Posted February 23, 2016 at 2:29 am | Permalink

    Had a Kensington Expert at work many years ago and once I increased the cursor acceleration, the relaxed control it gave over the mouse had me sold.

    Using only laptops over the years, and with the proximity of keyboard and trackpad, and just simplicity, I never purchased a trackball for home use, but am considering one, now that I’m getting into Ableton.

    I’m checking online and would like either like the largest ball possible or the 6+4-button Expert or Turbo Mouse Pro (just for that many programmable options)… Although it looks like it has a considerably smaller ball. Could you speak more to the difference between the ball size of the Orbit and Expert?

    Lastly, I’ve read in a user review that sometimes a lighter touch on the scroll ring eliminates the grinding feeling.

    • Jason
      Posted February 23, 2016 at 10:14 am | Permalink

      I don’t have a pair of calipers handy, but I’d say the diameter of the Orbit ball is about half that of the Expert. And while there is a scroll wheel on the Orbit (one that doesn’t grind), it has only those two buttons.

      Have you checked out the Contour RollerMouse? If you can afford the price tag, I consider it a more capable and modern successor to trackballs in general. The RollerMouse is what I use for my everyday work, and I believe it’s quite popular among audio/video types as well.

      • Howard
        Posted February 29, 2016 at 7:35 pm | Permalink


        About half the size is what it seems from pictures. Did it make a big difference in usage?

        RollerMouse looks intriguing, but definitely more than I want to spend on an input device I may not use much. (If anything, I’m wanting to spend less time on my computer.)

        That said, I appreciate the point of your blog. The more time we spend with devices, for better or worse, the more important ergonomics becomes.

        And your comment on “large movements with large muscles vs. small movements with weak muscles” was interesting. Could you suggest any articles that give an overview of ergonomics for the curious?

        • Jason
          Posted March 1, 2016 at 1:53 pm | Permalink

          There is a pretty big difference in usage between the Expert and Orbit; the larger ball improves precision and lowers effort required. Also, I like having the option to click different ways on the Expert, rather than just by thumbs on the Orbit.

          If you’re curious enough to geek out on some academic stuff, Cornell University has compiled a bunch of ergo information here. Kind of dense, but backed by research.

  2. Julian Pereira
    Posted September 5, 2015 at 3:27 pm | Permalink

    Have you ever tried out the Logitech M570? I would like to hear your thoughts on that trackball. Also, which do you think is better ergonomically – Thumb or Finger operated Trackball?


    • Jason
      Posted September 7, 2015 at 1:15 pm | Permalink

      For me personally, a thumb-operated trackball is a non-starter. My thumbs are extremely vulnerable, and I put them to as little work – especially precision work – as possible. I don’t even like to click with my thumbs, which is one reason I don’t use a trackball. For that reason, I haven’t tried the Logitech M570.

  3. Jerry Shoaf
    Posted June 1, 2015 at 3:21 pm | Permalink

    I have ET and can’t seem to find an IBM adapter for my mouse. I read an article wherein the author suggested using the ExpertMouse Pro. Any comments?


    • Jason
      Posted June 2, 2015 at 7:06 pm | Permalink

      Not sure I understand the question. Can you provide a few more details?

  4. voxleo
    Posted February 5, 2013 at 9:17 pm | Permalink

    Do you have one of the older versions to compare size with? I’m not entirely certain that the modern Expert Mouse (version 7) ball IS idententical to the pool/billiard sized ones of the past opto-mechanical (version 5) variety. I was under the impression that the optical version 7 ball size is JUST a smidgen smaller by about 2mm, or you could replace it with the older red balls from the version 5 which would likely be able to be read by the optical sensors just as well as the grey ones with the opalescent tigers-eye pattering they have. That opalescence, which billiards don’t have would be the only other reason you could not use one of those if they were the same size, but I don’t think they actually are… quite. If they were, though, I might consider picking up one if the version 7 Experts myself, as I have several of the pearl-like red balls from the version 5’s.

    Is there any specs that can confirm or deny the sizing being the same?

    • Jason
      Posted February 6, 2013 at 4:34 pm | Permalink

      I’ve got a question in to Kensington on the ball size, but they need to know the SKU of the “version 5” trackball you’ve got. A serial number would be even better, if you’ve still got at least one of the bodies.

  5. Scott
    Posted September 22, 2012 at 3:40 pm | Permalink

    I’ve now had experience with two different Kensington Expert Mouse trackballs, one from 2006 and one from 2012. They’ve been generally alright except for a couple of issues, both of which you touched on already.

    First, in defense of the Expert Mouse, I should say that the movement of the scroll wheel, just as with the ball itself, got much freer after using it for a while, so the “moving in sand” feeling wasn’t an issue after a week or so.

    As for the clicking/popping/sticking, my 2012 Expert Mouse has exactly that same issue, while my first one has never had that problem. Maybe they’re manufactured differently now, or the quality control isn’t as good.

    As for the wrist rest, all I can say is “Use with caution.” Don’t put it on really firmly unless you plan on using it that way permanently. Otherwise, when you try to take it off, the posts are liable to brake off and get stuck in the holes on the underside of the main unit. When that happens, they can’t be removed easily.

    • Jason
      Posted September 22, 2012 at 6:00 pm | Permalink

      Scott, thanks for taking a moment to share your experience. I had to smile when I read your word of warning on the plastic posts. It came a bit late for me, as I already swapped off the wrist rest once too often and ended up with a three-posted connector plate to prove your point. (Plus that remnant stuck in the trackball body – haven’t tried removing that as yet.)

      I’m glad the scroll wheel smoothed out to your satisfaction. My test unit, however, has been used for a number of months by someone who uses it almost exclusively for a scroll wheel, and I still find its action quite grainy.

      When I used the Expert again for a week or so last summer, I don’t remember noticing any skipping and sticking, so maybe that problem straightened out on its own, or maybe the USB hookup was routed differently and that fixed it.

      • Scott
        Posted September 26, 2012 at 4:16 pm | Permalink

        Now I think I understand what you meant by “sticking.” What I’ve experienced in my new Expert Mouse is mechanical, like hitting a small snag when you turn the wheel. I was wondering if your test model had that problem when you were using it.

        Maybe I should have said that the scroll ring movement might get looser eventually. My six-year-old Expert Mouse scrolls really easily; but then again maybe something has changed in the manufacturing process since then. Their new SlimBlade trackball has no scroll ring at all: you just twist the ball.

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  • About The Blogger

    Jason, the All Things Ergo bloggerI'm Jason, a user of many ergonomic devices by necessity and choice. I'm also a partner in a business that operates a number of commercial enterprises, including All Things Ergo.

    I have no particular training or expertise in the area of ergonomics. My views are based on my own personal experience, and what works for me won't necessarily work for you.