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Getting to the Bottom of Spring Weight

Springs. There’s countless instances of these simple machines all over the place in our daily lives, and even in the nightmares of those who have braved physics courses in their times. Unlike some of the more obvious day to day appearances of springs, I think that many people newer to the mechanical keyboard hobby would be shocked to hear just how important of a role springs play in their custom builds. While switch springs are capable of affecting all sorts of characteristics such as stem wobble, switch sound, and even the tactility in some switches, at the most fundamental level springs are what are responsible for giving each keystroke its weight and heft. You can radically change your keyboard’s feeling just by swapping to springs just a few grams lighter or heavier. 
Image Credit: @Miroboru Typically, switch springs are sold already pre-installed with only a few numbers to denote them on a switch’s sales page. While it is fairly common to find switch springs sold separately as add-ons which can be swapped into existing switches of your choice, the numbers used in marketing these are the same as those already preinstalled. Regardless of the type of spring that you’re looking into (extra-long, multi-stage, progressive, etc.) the vast majority of them are marketed with a “bottom out” weight and/or an ”actuation” weight. Completely disregarding the type of metal used to make the springs since it is just a fancy extra to help market mechanical keyboard switches, these two numbers (and arguably only one of them) are all you will need to pay attention to. The first and least helpful of the two weight terms you will likely see is the “actuation” weight. Used to refer to the point at which a switch will actually register a keystroke in your keyboard, actuation weights are located somewhere in the middle of a keystroke and are incredibly switch-specific. Since actuation forces and distances change with any modification to your switches, unless you’re buying your switches stock and not planning to press them all the way in, this isn’t really the number to look out for. In fact, there are some packs of switch springs sold separately from prebuilt switches which market actuation weight/force with them, which if you think about it doesn’t make much sense at all. The real number which will give you the most universal descriptor of a spring is that of the ‘bottom out’ weight. ‘Bottoming out’ is the term used to refer to pressing one’s switch all the way in until the stem meets the bottom housing internally and it can’t be pressed in any further. Since this is the maximum force that can effectively be gotten out of a spring in a switch, this is definitely the number you should be keeping in mind as it is much more universal and less-switch dependent. It’s also worth noting that this may not be the absolute heaviest point of a switch either, as tactile switches often have bumps which are heavier than this bottoming out weight. With that in mind, however, up to this point we’ve only really talked about spring weights in an abstract sense. What is the range of weights that springs exist within? What are some examples of really light and really heavy switch springs? Knowing full well that these questions were likely already in your head when you clicked on this article, here is how I break down the three different categories of bottom out weights. Light Weights (<55g)
Light weight switches including Ajazz x Huano Banana, Kailh Box Red, Kailh Crystal Burgundy,
Akko Vintage White, and Clickiez (40g).
‘Light Weights’ are how I refer to any switch which effectively has a bottoming out less than 55g. In the normal MX switch footprint, it’s pretty uncommon to see stock switches go below that of 35g of bottoming out weight, as any lower and the switch stem has a hard time returning after pressing it in. Except in the instances of low-profile switches (e.g. Kailh Chocs), which can easily go as low as 20g of force at bottom out, most MX-style switches hover around 40-50g of bottom out force. Not often stocked by vendors explicitly due to their more ‘niche’ bottom out weight, factory assembled switches in this range are often linear switches and come around fairly infrequently. Typically, these types of low-weight switches are preferred by people like me who experience fatigue after long typing sessions and/or just have weaker fingers on the whole.  Middle Weights (55-75g)
Middle Weight switches including Obsidian Pro, KTT Strawberry, Tecsee Sky Blue, Drop Holy Panda X,
and Novelkeys Cream.
‘Middle Weights’ are how I refer to any switches which bottom out between 55 and 75 grams of force. This category by far is the most common weighting for switches and will constitute likely 90% or more of the switches you see sold through various vendors. Within this range it’s very common to see numbers such as 62 and 68g of bottom out force as these have been custom spring weights used as far back as 2016 and will likely be favorites for many years to come. While switch type (e.g. linear, tactile, or clicky) will likely play more of a role here in one’s typing experience than bottoming out weight, it’s still important to have an understanding of where the average spring weights lie as you go through the journey of finding your endgame switches. Heavy Weights (>75g)
Heavy weight switches including Kailh China Box Ancient Grey, Kailh Box Black, Novelkeys Cream Arc, Zealio V2 78g,
and Cherry MX 'New Nixie'.
In a similar sort of rarity to that of the ‘Light Weights’, the ‘Heavy Weights’ are any switches which have springs that bottom out beyond 75g of force. While it isn’t all that uncommon to see heavy weights between 75 and 90g of bottoming out force such as the Zealio V2 (78g) or the Cherry MX ‘New Nixie’ above, going above 100 grams is quite a rare experience to come across. Used by only the heaviest of typists with seemingly no ability whatsoever to fatigue when typing, the sky is the limit with heavy springs. Cherry MX Mega Blacks, for instance, come in very selective vintage keyboards with springs bottoming out at almost 250g of force. To even further blow your mind, some vendors sell springs separate from switches that go above 1000 g of force, which is akin to putting something beyond an average pen spring in a tiny mechanical keyboard switch!
In as poetic of a fashion as possible, you’ve reached the bottoming out of this discussion on spring weights. While this was far from a comprehensive range of all mechanical keyboard switch spring weights out there, and these categories I’ve set up are far from set in stone, this should give you some indication of what to look for in your next switch purchases. If you’ve not yet ventured outside of that middle weight spring range yet, I would definitely encourage you to go either direction to see what all switches have to offer. Maybe even pick up a switch tester so you can try a whole range of weights easily without breaking the bank!

Jan 15, 2023
I believe the click bar in Kailh springs help make the main spring easier to depress after the click. I used 100g springs in Box Navy and Box Royal switches, the Box Navy feel softer to bottom out.
Jan 12, 2023
I really appreciate this kind of publications, giving us more depth on keyboards understanding. Thanks!
Jan 11, 2023
Sorry to be nitpicky. The article is about MX mechanical switches, but the keyboard image used above is a Happy Hacking Keyboard(Topre switches) in Norbauer case.
Jan 12, 2023
SpacebarRattle(Does it ruin the subtle irony if I point out that this was intentional?)
MX Grey (both Light and Dark) have 120g bottom out weights. While rare, you could find a few select models with these switches in pre-made keyboards. Box Navies and MX Clears have a 90g weight, and there was a variant of Royals that had I think a 100g weight. I find about 125g is the heaviest you want to use with tactiles (or clickies), while 185g is about the heaviest spring you can find easily. I recommend only using such springs in Linears.
Jan 12, 2023
VandenhulAre you talking about the APC Green Alps clones for the 185g springs? Those things are hilarious.
ThereminGoatMKYou can find 185g MX springs. I have a 'board with 185g Cherry Silents. My lightest switches are MX Clears, though my 100g Inks feel lighter. Maybe it is the smoothness.
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