I recently needed to rebuild a 2016 FOX DPS mountain bike shock and FOX instructions recommend Loctite 277 threadlocker for the job at some point.

After a quick check around the workshop to confirm all my threadlockers were at least as old as this shock and had nothing to do with the 277, I was decided to get me some of the recommended product.

But toppreise.ch and galaxus.ch searches (my go-to websites to find something to buy in Switzerland) surprisingly didn’t show any results for this specific loctite 277…

Google search for loctite 277 shows that it actually exists tho. You can find the page with full description from Henkel here.

So after more googling and nerding about threadlocking I became totally confused about what to choose: loctite blue, green, red, 243, 263, 277, 270, 271,…

What’s the difference between all those threadlockers?
How to choose the correct Loctite for my application?

So here is How to choose the best Loctite Threadlocker for a job in 3 steps.

1. Strength (color)

In order to choose the best Loctite Threadlocker for you application, you need first to evaluate what strength you really need.
For this, Loctite categorize the strength of their thread lockers as colors:

Purple = Low strength
Blue = Medium strength
Green = Wicking (medium/high strength for preassembled fasteners)
Red = High strength

Note that you’ll normally need localized heat in order to remove Green and Red Loctite.
So think about the serviceability of the fasteners you’re working on. If you’ll need to unscrew a bolt every now and then there’s probably no need to use the strongest Loctite…

2. Fastener Size

For ease of use, you would normally use low viscosity threadlocker for small fasteners.
As for large fasteners, it will be easier to choose a higher viscosity or even thixotropic (like the paint you use on ceilings typically) product.

3. Application Methods

The majority of threadlockers are designed to be applied before assembly.
For this, you would use any of the Purple, Blue or Red Loctite.
But in the case you fastener is already assembled (set screws or electrical/electronic use), you would then preferably choose the Wicking Green stuff.

In conclusion, Henkel says you can do almost everything with 2 products: Blue Loctite 243 and Red Loctite 263.
Comparing the specs, I tend to agree with this but the 263 is unfortunately not available in Switzerland!
I contacted Henkel and they told to use Loctite 270 instead of 263.