Installing GX Eagle Chain

Sorry for such a newbie question but never actually installed a new chain before.

Mine snapped yesterday after hitting a drop off a bridge. I have the chain and can’t 100% be sure if a link has gone or it has just snapped.

I have watched the YouTube guide from SRAM. Take air out of fork and then measure chain without going through derailleur.

I have a question on is the length. It says 2 extra links, does this mean 1 outside link and one inside link?

Also does the power lock count as a link or do I measure 2 extra links + the power link?

Does that make sense?

Take the guess work out and measure it against the old chain. It won’t have lost a link, it would need to break in two places for that to happen.

So,  to determine “a link” in this case; count three pins across (an outer and inner plate)

Also does the power lock count as a link or do I measure 2 extra links + the power link?

measure the chain on the bike, add two links (6 pins), break, install power link.

If you want to start from scratch it’s easier to unbolt the shock then move the suspension though its travel to find the point where the chain length would be longest, then use that as your base length – how much it varies will depend on your frame. Once you’ve done that do a sense check against the old chain.

This might be Chain School 101 but remember GX Eagle chains are directional so make sure it’s the right way round, make sure the power lock curves the right way and that you’ve threaded it through the rear mech properly too.

I always check the length in largest cogs (front and back) to make sure it won’t snap the derailleur when you change into the largest sprocket. Expensive mistake otherwise esp with modern derailleurs which cost £100s.

So, to determine “a link” in this case; count three pins across (an outer and inner plate)

That is 2 links.

This might be Chain School 101 but remember GX Eagle chains are directional so make sure it’s the right way round, make sure the power lock curves the right way and that you’ve threaded it through the rear mech properly too.

The chains are not directional, only the powerlink.

That is 2 links.

This

The chains are not directional, only the powerlink.

Gah – getting my GX and XT mixed up!

How old is the current chain? You could just put a new power link on that and re fit it if it’s not old or damaged.

Gah – getting my GX and XT mixed up!

Never understood what is asymmetric about Shimano chains and now much it really matters?

Pretty sure they didn’t used to be back in the day.

What smallspinsized said, at the price of new chains !!!

Depends on chain growth under full compression as to how many links you need, which is why I never trust ‘the rules’.
I just install the chain with the connecting link very lightly connected, but the bike in big / big chain ring and sprocket combos, unhook the shock from one mount and move the shock out of the way and then move the rear wheel to bottom out position. From there I roughly decide on the chain length but if in doubt go a link too long. Then roughly adjust the B-tension screw as that will also have a slight impact on chain length requirement. If you are not sure if you can take another link out, you can mimic removing a link by folding the chain over one link with needle nose pliers. Once the chain looks good, properly connect it and fine tune the B-tension after installing the shock (or pressuring if removing the shock bolt and pivoting the shock out of the way wasn’t an option).

Significantly more of a faff than following the rules but at least you will know that the chain length is 100% dialed. I’m sure that the rules are fine for road bikes and hardtails.

If the chain snapped, I wouldn’t trust that the old chain wasn’t too short. That may be the reason that it snapped!

If the chain snapped, I wouldn’t trust that the old chain wasn’t too short.

If it was too short your derailleur would be snapped in two before the chain snapped.

Eagle recommends 1 full link (inner + outer link) for a full suss bike at bottom out.

In my experience I prefer 2 full links – someone recommended it on mtbr and it sorted out some shifting issues in the mid-gears.

If it was too short your derailleur would be snapped in two before the chain snapped.

The weakest link (no pun intended) will fail. Sure it’ll be the derailleur if the chain is in good condition but I don’t know from several thousand KM away what the chain looks like 😉 Maybe a link had cracked previously, and bottoming out the suspension then snapped the chain. The OP mentioned going off a drop. Either way, the point was to not trust the length of the old chain unless you know for a fact that it was the correct length in the first place.

I’d start from scratch in case the old chain was the wrong length. Not unheard of even on a new bike. It is one inner and one outer with rear suspension fully compressed and chain not routed through the mech. Do not include the quick link as this is extra. The chain is not directional but the link is. The document linked below has some clear pictures of the setup. Eagle is very sensitive to chain length so stick with what is recommended.

Sram Document

Thank all. Great help thank you.

I lost four inches of chain powering through a bog on the Quantocks many moons ago so not always possible to just ‘measure wot u got’.