Funktopus

So I'm riding a brand new build. The first chain I put on this thing was getting bad chain suck on a ride out and about. Before I could get home and diagnose the problem the chain broke. I put this down to the chain having been moved from one bike to another using a chain breaker rather than a master link. I thought maybe the link that had been broken was stiff.

Now I have a brand new KMC x9 on it, and while I haven't been able to visually confirm the issue is chain suck again, I'm feeling the chain behave in a way that seems to be chain suck. A kind of jerky, popping feeling. It only seems to happen when I'm in the smallest cog on the front and back.

So I'm wondering if this is too much slack:


That's the bike in the smallest cogs. There's some droop there. Not much, but definitely some. Should I take a few links out?

Thanks

trailangel

Serious problem with your DR cable.
If you can take out a a link, do so... your DR looks like it's lost some of it's tension. Shortening as much as possible might help.
Show a ick of this setup in the Big/big gear.

woodcraft

That doesn't look like a 9 speed cluster, so You might be better off with an 8 speed chain.

I would make the chain shorter, by using the big/big + one link method. You wouldn't tend to be riding in that gear combo much, but there's no reason to have slack chain.

The cable housing needs a ferrule and longer loop so that the shift cable runs more straight.

Funktopus

OK, thanks. Here it is in big big.


Would the problem with the cable be that there isn't enough housing?

Funktopus

Its a 7 speed freewheel, but I've actually found a 9 speed chain works best with it. Possibly because I'm friction shifting, but possibly because its an old Aris freewheel with very bitey teeth. I found the wider seven speed chains would get caught on neighbouring teeth too easily.

I'll check out the big Big +1 method, thanks.

Funktopus

How much extra cable should I be adding? When I cut this cable I took a minimal approach, didn't realise there was more to take into account then the range of movement on the DR.

Bill Kapaun

See how much extra chain you have in BIG:BIG using this method.
You want at least 1" and less then 2".

Funktopus

Seems like a lot!

Bill Kapaun

It's hard to visualize, but removing 2" MIGHT be too much.
Remove 1" & repeat. You might end up in a scenario where you have 1-7/8" slack. DON'T go <1".
Pull the slack out, but don't force. You can feel when things "snug up" noticeably. Don't go tighter.

Funktopus

OK, will do. Need to wait for my masterlink pliers to arrive on Sunday, I'm not going to mess about trying to reuse cores that I've extracted with a chain breaker again. Thanks for the advice, feels like we're on to something here.

Bill Kapaun

On 9 speed (or more) chain, never reuse pins. The side plates aren't thick enough to hold.
I had a brain fart once and did so. I turned a RDER into a pretzel when the chain parted.
Quik Links or whatever brand are so much simpler.

I can't imagine a modern 6-8 speed chain causing interference issues with adjacent cogs on a 6 speed cluster. There has to be something else going on there.

Barry2 

I really like this method...

bikeme

I set my length so that in the big ring/biggest cog the RD cage is a little past vertical up to 45 degrees max towards the front of the bike. I then check when in the small chainring/small cog there is a bit of tension pulling the RD cage down a little with no sag in the chain. I find what length works for both parameters and break off the extra there, accounting for a quick-link.

jadocs

Yes that is too much slack in the small/small. Remove one and check again...there is a balance you need to achieve between the small/small and ensuring it is not too tight on the big/big.

Funktopus

One link seems to have done it! I've only tested cycling the length of my kitchen, as the weather outside leaves a lot to be desired, but the chain suck problem seems to have disappeared on a before and after roll around.

Thanks all.