I’ve read the blurb on the website but still can’t get my head round it.
Can someone explain in simplified terms why I might need one to go with my Sunrace MX3 cassette?
Cheers.

I fitted one to my bike with a Praxis 11/40..
It allows the derailleur to sit in a more natural position where you can use the original B tension screw and you get a more of the chain sat on the cassette, so there should in theory be less wear to your new Sunrace.
I fitted mine ages ago and its worked so far.

It changes where the rear mech sits, depends on where your hanger is at the moment. The mech may not reach out and hack enough for the big cogs.

I fitted a sunrace 11-46 with a xt m8000 mech and the pulley arm on the mech caught the 2nd largest cog, wouldn’t work no matter what I did with the b screw, the goatlink 11 solved the issue by moving the mech and shifting is great.
I noticed the step down to the 2nd largest cog on the sunrace isn’t as great as a shimano cassette which makes the clearance issue worse on the sunrace.

I fitted a Sunrace 11-42 with an XT mech and it required so much b-screw on the 42 that it left very little chain-wrap on the 11 tooth ring. Goat link and similar fix that; I actually went for a Pilo S10 adaptor which also rotates the mech more clockwise round the wheel. YMMV and all that depending on the geometry of your mech mount.

I’ve just fitted one to mine, 10 speed drive train with the sunrace 11-42 cassette, before I fitted it the shifting was fine, (B-Screw pretty much as far in as it would go). However in the smaller couple of cogs, when any power was put through it would keep slipping. (It was a new drive train)

When you actually look at the mech in these gears the top jockey wheel with the B-Screw in was so far back the chain only wrapped round the top few teeth of the cassette. I fitted one and it allows you to have the adjustment on the B-Screw to bring the top Jockey wheel further forward, enabling some more chain wrap on the smaller cogs.

Which after one ride seems to have fixed my problem with the chain slipping. I wouldn’t say it has made any difference in performance of the actual changing gears up and down though.

pilo s10 here.

Works with it flawlessly. Doesnt play as nice without.

But a pain removing the rear wheel!

I’ve used them and they did help. I’m trying to move over to get he wolfcage though but it’s looking like expensive without a UK importer.

Does this depend on the mech hanger design/position? I’ve just fitted a Sunrace 11-46 to two bikes with M8000 mechs and they seem to be working fine.

On one it was a bit odd – set up in the stand and set b-tension but then after the first couple of runs something settled and I had to add a load more b-tension but still has a fair bit of thread showing.

I think a lot of it does depend on the design, but I think it is more to do with getting the aftermarket 10 speed wide range parts to work. Whereas the 11 speed stuff was already designed to work with it. My m8000 mech works fine on my other bike without one.

Am I correct in thinking the goat link is similar to a direct mount mech hanger?