Is my chain now to short (pic)?

Mattcee

Amongst some other upgrades this weekend, I lost my 2 front rings (24/38) and replaced with a narrow/wide 38T single ring and Hope 40T expander ring. The front is like for like size but with the bigger rear sprocket, is my chain now to small?



Haven't riden it yet but It doesn't sound the smoothest in pictured gear on the bike stand.

Will Ingram

I would say yes it is too short?. Does it shift easily into that gear? Does it 'ping' and have you got to nugde the shifter when shifting?

The key thing is that you will probably be going uphill when you shift into that gear anyway, so chain will be under a lot of tension....might work but just means more wear & tear.

I had a chain that was short enough to work but as yours, extended the derailleur a lot... over time it fatigued the gear hanger (the block between the derailleur and frame) which snapped & the deraileur fouled the wheel.. I would put a few links on and see if the derailleur can cope at the top gear,
possibly a chain retention device may help.

nicklouse

Did you resize it? When you did did you check that it was ok through all the suspension travel?

If you have done none of the above and you are hoping that a picture with stop you ripping your rear mech off.

Mattcee

Nope, didn't resize it and thats how it was from new. I've just gone up on the rear from 36T to 40T now so its not a massive change.

rockmonkeysc

You need to let the air out of the shock to check what the tension is like on full compression. It does look a bit too short though.

Chunkers1980

If it was done right before then now it needs 2 full links, 4 pins

The Rookie

If it were a hardtail, that would be fine, but you need to check for chain growth through the travel.

Rightarmbad

I'd add three full links.
Chains run and shift best when they are as long as they can be without going slack or the chain rubbing the top pulley or cage.
Having said that, you have exceeded the maximum sprocket range of the derailleur that you are using, so all bets are off.
You need to assess exactly how the top pulley wheel swings in it's arc and how that combined with the B tension screw and chain length can be worked to keep the top pulley wheel in a close, but not too close to the cassette position, in all gears.

Do not forget to check it at all points of the suspension travel.

The Rookie

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19625614#p19625614]Rightarmbad[/url] wrote:

I'd add three full links.
Chains run and shift best when they are as long as they can be without going slack or the chain rubbing the top pulley or cage..

Ignore this, they should be as short as they can be (as long as they are safe), as specified by Shimano, SRAM and KMC as well as on Parktool.com, unless he really does know more than all of them......

Rightarmbad

Actually, SRAM and Campag clearly state that the chain should be as long as possible and that the indicator of correct length is that the pulleys just clear each other.
A short chain leads to the cage feeling high side forces and twisting when on the largest rear cog, this causes the chain to run onto the cluster crooked and makes indexing correctly impossible.
It also pulls the top pulley far away from the cluster resulting in slow shifts and the side forces wear pulleys prematurely.
There is nothing but very small weight loss to be gained by going short.

The Rookie

http://www.parktool.com/blog/repair-help/chain-length-sizing

And you are wrong about SRAM
https://sram-cdn-pull-zone-gsdesign.netdna-ssl.com/cdn/farfuture/T7YRSTHSNBjTvFzsLckvfK5CMekQ9hy6bt_n0bhTqM0/mtime:1412196372/sites/default/files/techdocs/95-2418-002-000_rev_b_2015_cassettes_and_chains.pdf
It says position rear suspension for the greatest chain length REQUIRED, clearly reading is not a strong point?

You also have less chain flapping around off road with less weight.