One thing that the majority of our customers prefer is to get the lowest possible friction. Certainly, not everyone wants this, but it makes sense given the popularity of lightweight mice: by reducing friction on mouse feet, you can effectively get even more reduction to the amount of force needed to move the mouse.
(A small downside to very low friction that's worth pointing out: it can lead to stuttering on your display since the mouse is unable to easily stay still at rest. In addition to introducing motion blur, it can make it difficult to hold corners in FPS games.)
How do you get the lowest possible friction with Sapphireskates? The principles in this guide can be applied to any pairing of mouse skates with a mousepad, but it's written specifically for optimizing Sapphireskates for low friction (we will discuss other brands & materials in another post).
I've mentioned before that friction has so many factors that go into play that it becomes difficult to make generalizations. Therefore, conclusions must be drawn experimentally. While this is still true, over the course of the past few months, we now have some more solid principles about friction when it comes to getting the best gaming glide.
We found several places in which you can reduce friction:
Principles & How We Test
You can learn a lot from measuring the angle in which the mouse falls, including the coefficient of friction. You can find the CoF by dividing the frictional force by the normal force (which is the perpendicular force to the surface). Let's say the mouse fell at 12 degrees instead of 6. Then, the frictional force would be greater and the normal force (perpendicular force) would be slightly smaller, thus resulting in a higher coefficient of friction at nearly double (0.21). You don't need to know all of this though, just that lower CoF = lower friction between two surfaces. Increasing an object's weight does not have an effect on the CoF because when weight increases, the frictional force and normal force will increase commensurately.
A lot of our findings are based on simple measurements of static friction. Put the mouse on an inclined plane and see at which angle it falls. So please note that this doesn't cover kinetic friction directly, the two are closely related. Once you know the CoF, you can take an applied force and multiply it by the CoF to determine the frictional force. Thus, the smaller value means lower friction. Let's say it's 0.1 CoF: you multiply by an applied force of let's say 10N, then the frictional force is just 1N. One-tenth of the weight of the object is required to overcome static friction.
With limitless combinations of surface pairings to test, doing a quick angle measurement is an efficient way to do things. (I currently have my Artisan Hien Mid sitting on top of a custom glass panel, so I can take a measurement anytime, such as while queuing for a ranked Apex match.)
OPTIMIZING SAPPHIRESKATES FOR LOWEST POSSIBLE FRICTION
Many things involving friction operate on a curve: If something reduces friction, more of something should reduce friction even further but once you do too much of it, friction increases. Consider something like a phone screen protector. Despite the surfaces having high uniformity with low asperities, these two surfaces can have a very strong bond.
Another example is when you are gripping an object and begin to sweat. In the very beginning, a little bit of added moisture can help to grip a shiny surface. But once it overcomes a certain threshold and gets sweatier than a 3-stack pred squad, you suddenly lose grip and friction is reduced.
Kim, D., Yun, D. A study on the effect of fingerprints in a wet system. Sci Rep 9, 16554 (2019). https://doi.org/10.1038/s41598-019-51694-9
Its all about identifying the sources of these various factors: in the sweat example, the initial grip is from surface tension between moisture of your hand and the object. This turns into more of a macro-level phenomenon if the sweat is excessive. These are the things that we aim to uncover when optimizing for low friction.
Selecting the Right Surface PairingFirst thing that we looked at is the hardness vs. softness of the mousepad. Our hypothesis is that hardness decreases friction up to a certain point. This is supported by our tests as the soft mousepad (Glorious) falls at 5.2 degrees:
So if we increase the hardness further, will that also further decrease friction? Theory says it might not, due to other factors coming into play when reaching extremes. Measurements support this, with glass having significantly more friction when paired with sapphire:
Why did the glass scratch here? The reason is in the lack of flexibility of the materials. When pairing a flexible material with a rigid one, the flexible one bends out of the way.. Two rigid surfaces? The softer one yields to the harder one, causing the softer material to shear and introduce scratches.
The rest of the results do support my theorycrafting: I tested for the CoF of sapphire on teflon (trade name of Polytetrafluoroethylene in the form of adhesive release-liner. It had very low friction:
|Angle In Degrees of Falling (Breaking Static Frtiction)
|Glorious Mousepad Soft
|Artisan Hien Mid
|Teflon Release Liner
|PTFE on Teflon Release Liner
Properly Cleaning Mousepad and Skates
UPDATE 4.28.2022: I re-tested using a very clean and very dry mousepad. Apparently, my mousepad wasn't clean or dry enough. This time, I thoroughly rinsed it, ensuring that I rubbed it to get out all the dust, dirt, oil, and residual soap. Then, I patted it dry with a towel and then blasted it with a steam cleaner to get the small debris out. Finally, I dried with a hair dryer and then allowed it to dry for a few minutes in the sun through a window. After that, re-tested it and got a very low angle of falling of just 3.6 degrees which is the lowest friction test so far.
No one likes a sticky-feeling mouse, and part of the inspiration for Sapphireskates was my smartphone display: glass material often felt sticky which would generate friction. We tout Sapphireskates as being more hydrophobic than glass, which is experimentally true: you can rest a drop of water on top of sapphire but try to do the same with water, and the water spreads.
If you use wet PTFE skates, you may not notice a problem. Why is this? It's because the mechanism for which PTFE reduces friction is different from the way glass, sapphire, or ceramic mouse feet do. The self-lubricating PTFE utilizes lubricated sliding rather than non-lubricated sliding. Lubrication separates the two surfaces from interacting. PTFE's non-reactivity makes it resistant to most things, including water. But the downside is that PTFE is not going to hold its shape. An interesting fact for those into mechanical keyboards: your keyboard lube like Krytox GPL 205 is made of none other than: PTFE.
Going back to the topic of the impact of water or oil on sapphire's glide: the results of the test showed surprisingly less of an impact than I would have guessed. Based on the way that sapphire reduces friction by minimizing asperities from its high polish, dry performs the best as it doesn't introduce other factors like surface tension into the mix.
Adding a bit of oil directly to the skates ended up slowing them down even more than water. Fingerprints had a small but noticeable impact in increasing friction. If you want to maximize your glide, give the Sapphireskates a nice wipe with a microfiber cloth after you've touched them.
This time, I did not test the affect of a moist mousepad, but from my experience, it is critical to fully dry your mousepad to get the maximum friction reduction. I wash my Artisan mousepad according to Artisan's instructions: hand wash with soap and water. Ensure you fully rinse out the soap from the pad too as soap acts like an oil since it is also a lipid. Then, I dry my mousepad in front of a floorstanding heater. Warning: be extremely careful here, I don't want to be the inspiration for any accidents due to someone forgetting they left their mousepad in front of a heater. Keep the mousepad a reasonably safe distance from the heater, or take a safer approach and use a hair dryer.
However, the best pro-tip I have for drying your mousepad: put it on top of your car's dashboard, leave your car, and wait 10-20 minutes: you can let the greenhouse effect and direct UV light do the work for you!
|Angle In Degrees of Falling (Breaking Static Friction)
|Dry and clean mousepad
|3.6 (measurement added 4/26/22)
|Wet with Water
Using a trick when setting the mousepad on the table
Are you using a cloth mousepad and want to decrease friction even further? You can use this simple trick to do just that. Take your mousepad and grab just one corner of it. Place that corner on the surface as you normally would. Then, take another corner and stretch it out a bit. Then, place that corner on the table while continuing to hold on the previous corner.
Next, lift up the other side of the mousepad opposite of the corners you are gripping and adhere and slowly go back down while applying downward pressure with the opposite hand.
The idea here is that you adhere one side of the mousepad to the table, bit by bit, and reduce any air bubbles. Think of this process as if you are applying a screen protector to your phone.
The end result is that you want a little bit of stretch on the mousepad and no gaps between the mousepad and surface. You can take a piece of plastic (or even your mouse) and rub it methodically on the mousepad as a final step (think of it like a squeegee.)
Testing results show that this method gives a nice reduction in friction for cloth pad users using Sapphireskates:
|Angle In Degrees of Falling (Breaking Static Friction)
|Cloth pad without stretching
|Cloth pad with stretching
The effect of using more than 1 set of Sapphireskates
Many of our customers have purchased more than 1 set of Sapphireskates. We wanted this to be both optional, as well as something that is supported. That's part of the reason why we chose the 7mm diameter for the skates: it allows you to fit 2 pieces in the channel of a Finalmouse Ultralight 2 or any mouse with a similarly-sized cutout.
The reason why we include 5 pieces is because 1) we don't want to make the cost prohibitively expensive for new users and 2) the performance of 5 pieces ends up being quite similar to a greater number of skates.
The results support this as adding additional skates only leads to a minor reduction in the angle of falling:
|Angle In Degrees of Falling (Breaking Static Friction)
Of course, there are other reasons you may want to consider adding an additional set as well. Primarily, users with a firm downward grip combined with a softer pad may experience more "dig" with a standard setup. This problem is fully resolved on a 10-piece configuration.
Now we have some solid recommendations on how you can further reduce friction using Sapphireskates. These principles absolutely apply to other types of mouse feet. But a reminder: this article is written from the perspective of Sapphireskates users, and we will be doing more testing of other materials in future posts.
Something to consider: you don't necessarily want friction to be too low. Personally, I would not go any lower than the way my setup is currently (falling at around 4.5 degrees on an inclined plane). At that point, you are going to start to introduce graphical errors in many games. The effect is essentially like micro-stuttering, plus you will have trouble keeping the crosshair stationary.
Lastly, the true prime benefit of Sapphireskates is in their ability to maintain that same level of friction from the beginning until years afterwards. Try measuring PTFE on day 1 versus day 2 and you will see a difference. I have heard that even Pulsar glass skates contain a coating that wears off quite easily, thus changing the glide sooner than one might expect.
Hopefully, this article is a good starting place for your own testing and discoveries on friction.