Chain length

slc123

So, I've fitted quite a few new chains and never had an issue (mainly on SRAM derailleurs). I've been helping a mate out on his bike and i've converted it from 3x9 to 1x11 and all working well. It's using the new Shimano SLX kit. I measured the chain as per my usual method (largest to largest cog then add 2 x rivets) but it seems to be too short and really pulling the derailleur forward when I feel like there should be some slack. I know with the SRAM 11 speeds you add 4 x rivets and that's what I've always done but wasn't aware Shimano setup was the same.

Can anyone advise if this is the case?

Thanks

Chunkers1980

Check it in small - is there slack or does the mech soak it up? The chain needs to be short enough so it pulls round the arm enough to give it extra clearance on the cogs as the pivot sits under on 11 spd. Not sure on the measurement specifics but I've gone with long enough for small cog soak up and short enough to whip the arm round - note the bigger your biggest rear cog the more the mech needs to pivot to give itself clearance if that helps?

swod1

thats the way i normally do the chain sizing, its needs to be a little longer if the bike is full suspension to take account of rear shock travel etc.

It is hard to shift on to the two lowest gears as there you will notice if the chain is really too short, it will be hard to shift on to the two lowest gears.

slc123

Thanks guys, The arm just seemed really extended in the largest cog, almost straight if that makes sense, which is nothing like any of my bikes. There is always some bend in the arm so the chain is contacting both the pulley wheels where as on the largest cog it looked like the arm was over extended. If that makes any sense.

I am going to have another go with a different chain and make it longer as I've got a spare. I'll post some pics up if still having problems.

Cheers

Chunkers1980

Just buy a couple reusable quick links and put in the middle the bit you take out to lengthen it by a full link. It'll be much cheaper and useful. Also - the 11spd mech is fixed around the frame pivot which is different to Shimano ones before - that's why it perhaps looks different as it's only the cage which pivots on these.

02gf74

If you have increased the size of the largest cassette sprocket , then you may need a hanger extender for the jockey wheel to clear it.

Chunkers1980

02GF74 wrote:

If you have increased the size of the largest cassette sprocket , then you may need a hanger extender for the jockey wheel to clear it.

Not with proper 11spd cassettes and mech. The top jockey pivots lower to give the clearance as the chain shortens.