[Closed] Chain suck on a road triple help plz

It is normally something worn on the drive chain (since I'm assuming there is no claggy mud involved). There is no answer but you could check:

Chain length - as you say. Needs to be a couple of links longer than worst case big sprocket to big sprocket.

Sloppy rear mech - springs/pivots not as good as they were. Jockey wheels knackered.

worn cassette (I assume you changed this when you did the front and chain?)

Knackered freehub - does it work and move freely when you back pedal

Stiff link.

Chain line - if it was really off it could be a problem.

If it's only happening when shifting, it's not "classic" chainsuck and is thus harder to diagnose. If it's an old chain on a new chainset that will cause "classic" chainsuck though. It could be chain length, download the service manual from the Shimano website to check how long it should be.
Basically because an older chain will have a longer pitch, the chainring teeth at the bottom of the chainring will be transmitting all the force and the chain won't slip off them so easily, compared with a matched chainring/chain pitch where the top few teeth will take all the load and the chain will be relatively slack by the bottom of the chainring.

Chain length - as you say. Needs to be a couple of links longer than worst case big sprocket to big sprocket.

I think this is correct, but depending on the range/rear mech you're using there are now 2 alternative ways to set it up - as I said I think you'll be right with this one for a "big cassette" option but I'd double check before setting chain length

You cleaned the sticky goo off the outside of the chain?

If your mech is a bit old and tired it might not be able to break the stickiness.

All drive train parts are nearly ndw and all bought for this build so no one part older than the rest and have not done many miles.

No mud involved.

It has happend back pedaling also.

its a [b]new [/b]Tiagra crankset [b]new[/b] 10 spd chain, rear derailer is a Deore mtb unit non clutch, and cassete [b]new [/b]sram 11/36

All drive train parts are [b]nearly ndw[/b] and all bought for this build so no one part older than the rest and have not done [b]many miles[/b].

So are they 'new' or 'nearly new' and what constitutes 'many miles'

Only being so picky as chainsuck with new components should never happen unless you have fitted incorrectly (chainline out, stiff link etc).

but nearly new/done a few miles on the other hand could cause issues as chainsuck is [i]normally [/i]wear related

Ok nearly new its not my main bike and i would rate the componets as excellent condition.

If it's only happening on the front upon shifting, I'd suspect that your front mech isn't in the right position.

ahh to high or to low perhaps ill double check that

The front derailer is a sora unit could that be the problem I have read that 9 and 10 speed derailers have a slightly different shift width ?

Could be that. Have you tried re-positioning it? Not made a difference?

I looked at repositioning it but if I move it lower then when I change to the middle ring it would touch the outer ring with the outside of the cage.

so when in the midle position it only just clears the big ring if that makes sense.

From what I read (and set up a few), the outer face of the cage should be about 3mm from the biggest ring (gap under the outer part of cage).

If that doesn't solve it, I would look into the differences between the 9 and 10 speed.

I'm not especially liking the inside shape of the Tiagra 10sp front mech, mine seems [i]especially[/i] sensitive to how the angle of the cage is set, relative to the chainset, so that might be worth a quick look too?

(The mix of road and MTB in this context shouldn't be the issue in and of itself - I typically use XT on the back of my road bikes).

Changed the Sora front mech for a Tiagra all good so far.