Kensington Expert Mouse Optical USB Trackball for PC or Mac 64325

My less than perfect rating is for the less-than-fluid turning of the scroll wheel. It sometimes feels like you're grinding coffee when you're turning it. Sometimes it's smooth like butter, other times, it seems to skip a little... and it's not due to debris, since it's been like this since I got it out of the box.

This is something Kensington needs to iron out in their next model.

Despite this one flaw, this is simply the best their is and there's a good reason why this mouse flies off the shelves at nearly 100 bucks a pop - it's because it's the best input device alternative to a mouse - ever - anywhere.

Do your wrist a favor and treat yourself to navigating in joy.


Weird angle of trackball caused me problems   January 20, 2007
Artemis66
37 out of 42 found this review helpful

As a longtime trackball user (with one of my favorites being an older model of the Kensington Expert mouse) I was very excited about this one. The features were outstanding, the trackball movement and precision flawless, and the scroll ring was very useful. However, the trackball housing itself is constructed on a very steep incline. Even with the wrist pad that's included, it put my fingers in a big strain to operate the ball (I have average sized hands). It's tilted up, so that you have to reach up and out to use the ball. This puts strain on the tendons of your whole hand, and also presses the nerve cluster at the base of your hand against the pad or table. After using it for about a week, my hand was in agony.

Earlier Kensington Expert Mice were almost flat, and were very comfortable. It's baffling to me why they made this change in the design.

Kensington did take this mouse back for a refund even though I had used it for a week (all I could stand). It may be that this unit is comfortable for someone with very large hands. I've gone back to my Logitech Marble Mouse, regretfully -- if not for the incline, the Kensington would have truly been the perfect trackball.


it had a lot of potential   April 6, 2006
Nathan A. Sweet (Seattle, WA United States)
20 out of 20 found this review helpful

I got this trackball because of wrist pains in my mouse hand. I will give my complete unbiased review here.

First, it is very pretty. The buttons are nice looking and easily clicked. The ball is a nice size.

The trackball comes with a wrist rest, however it is not comfortable if you use your fingertips to move the ball. In fact, the Kensington documentation states that your hand should "hover" when using your fingertips to move the ball. The reason is, when you move the ball towards you, your fingers have to bend and your wrist bends upwards. In order to keep your wrist straight, you have to hover your palm over the wrist rest. So why did they include a wrist rest?

The only other configuration possible is to rest the blade of your hand, pinky side down, on the wrist rest and use your thumb to move the ball. This position feels good, however I found I am much less accurate with my thumb. Also if you have any thumb pain, this position is not feasible.

The scroll ring is a very nice feature. However, as everyone else has found, it sounds like it has sand in it when rotated. I took it apart and lubed it with a plastic safe grease. Even though I worked the grease into the mechanism, the plastic bearings still make the grinding sound while saturated in grease. I can't get to them to see if they can be replaced without breaking the plastic, which has been melted closed.

The ball was stiff out of the box. The ball sits on three very tiny red balls, which act as bearings. Remove the ball and put a small dab of grease on these bearings, replace the ball and spin it, then remove the ball and clean it. Clean up all the lube from the bearings so they don't get the ball greasy. Then ball is then VERY smooth, with none of the "static friction" that is mentioned in other reviews. The grease to use is Radio Shack Multi-Purpose Lube Gel item #64-2326. Any plastic safe, non-evaporating lube should work.

I imagine after a few hours of use the ball would also become "broken in" and loose, but probably still not as good as with the lube.

After two days of use, two of the three small plastic cups that hold the little red ball bearings for the main ball broke. It seems the only way for this to happen would be if I dropped the ball in the socket very hard, which I did NOT do. The little cups do seem that the are easily broken, though I have not read anyone else having this same problem, so it could be an isolated incident. I have contacted Kensington for a replacement. I hope they can help. If I can keep my broken trackball, I will take apart the scroll ring bearings and see if it can be improved.

The drivers for the device are superb, although the user interface is sometimes awkward. You can set actions for each of the four buttons or when you press the top two or bottom two at the same time. Further, you can have it do different actions when any of those buttons are pressed with ctrl, alt, shift, or any combination of the three.

The actions you can take are extensive. You can run an application, simulate a series of key presses, paste some text, close applications, show a customizable menu, maximize windows, etc. Good job Kensington!

The acceleration settings are very important. The trackball has to be accurate for small movements, yet you shouldn't have to paw at the thing to move the cursor across the whole screen. This cannot be accomplished using any combination of the "fine tuning" controls the driver provides. The acceleration curve they allow you to create is much too linear.

Fortunately there is still hope. On Windows, in your user's home directory, look in Application Data\Kensington\MouseWorks. You will find a KMW_Preferences.xml file. Edit this file with a text editor and you can define your own acceleration curve. To do so, under "Acceleration" set the "Level" to 1, then modify the numbers of the first "Multipliers" entry. I found 1, 3, 4, 5, 6, 8, 13, 20, 26, 36, 90, 90 to work exactly like I want. After editing and saving the file, run the kmw_prb_xml.exe file in your MouseWorks installation directory. This will causes your changes to the XML file to be applied. Then if you go to the acceleration page in the driver, you will see your custom acceleration curve on their little graph!

With my custom acceleration curve I can accurately make small movements for clicking links, menu items, and expanding folders while navigating a filesystem. Also, I can travel the whole screen height with just one movement of the trackball. Perfect! Kudos to Kensington for allowing the preferences file to be customized so easily and for providing such great options for configuring the button presses.

The device had a lot of potential. If Kensington would make the scroll ring silky smooth and make the little red ball bearings more durable, the product would be amazing. As it is now, the scroll ring is cheap feeling and annoying, but it is a great feature to have. A scratchy scroll ring is better than none and it can be lived with.

The durability of the bearings is still a question I have. I hope to find a positive response from Kensington regarding my replacement inquiry and hopefully the next one I get won't break.

The only other negative aspect is the wrist rest is useless for 80%+ of people who will use the trackball with their fingertips. In fact it is better to not attach the rest because you will find yourself using it, putting your wrist in a bent position.

It would be great to have a trackball that could be used with the fingertips and had a rest for the wrist. To see what I mean, detach the wrist rest that comes with the Expert Mouse. Put a book under the rest and use it that way. Pretty comfy huh?

In all, it is a good device. If my suggestions are fixed in the next version, it would be a KILLER device. Granted, I don't think there is another trackball as good as this one, but that doesn't mean this one should not be improved. As is, it is a bit overpriced. The ball, buttons, and plastics are nice, but the scroll ring and bearings don't have the quality of a $100 device. A more realistic price would be $45-$50. I see it can currently be found for $60 from Amazon after a mail in rebate, so that is an ok buy.

Please Kensington, please fix the problems above and provide us with the BEST mouse replacement the world has ever seen!

UPDATE: I sent Kensington an email regarding my broken trackball and 90 minutes later they responded and have shipped me a new trackball. Now that is great service!

I took apart my broken trackball and inspected the bearings for the scroll ring. It uses rubber rollers on one side and tiny white plastic ball bearings for the other side. The rollers don't make any noise, the problem is the plastic bearings rub against plastic and metal. Greasing it does not help. The design is flawed and there is no way possible to fix the scroll ring so it rotates smoothly. Another reviewer mentioned that taking out the magnet helps. I don't recommend this as it does not reduce the noise and makes the ring rotate too easily (possibly on accident).

So Kensington has something to improve on, though even with its noise, I am glad to have it.


Be warned.... this is an incredibly imperfect product   July 5, 2005
T. J. Kramer (Ft. Walton Beach, Florida USA)
17 out of 24 found this review helpful

recognize that less than stellar reviews are almost labeled as 'not helpful' because people somehow take it personally that another person has disparaged some product that they want positive validation on. So be it. Here's the honest review of the Expert Mouse nonetheless.

For $80.00, I'm shocked. This is an incredibly cheapo feeling product. My purpose in going this route was to eliminate some growing wrist pain. I can already tell that a trackball is going to help; but it won't be this trackball. My days are spent with Photoshop, InDesign, and a myriad other applications that demand extremely precise cursor and tracking accuracy. This trackball rests on tiny plastic/nylon bearings that either do not rotate or do so VERY poorly. All of which leaves the trackball to herky jerky around. Yes, there are extensive settings in the driver software to fine tune some the actions for your personal needs. But understand this very clearly, the fine tuning is meaningless because the actual mechanical workings of the ball are sooooooooo poorly designed. Both the ball itself and supposedly magnificent scroll wheel operate with the feeling and sound of grinding coffee. Overall the operation is typical of a mouse costing maybe $12.00, not a penny more. I realize this is sad news for those of you really looking for a positive review. And believe me, I have reviewed things for Amazon very favorably, but for $80.00 this particular item is just very close to being as useless as it can be.