I am at a bit of a loss, normally pretty good at diagnosing drivetrain issues.

11 speed setup. All shimano 105 and 11 speed kmc chain.

Indexed fine and shifts lovely.

Under power / heavy load everything is all good.

No stiff links

However When In High gear (smallest 3 sprockets) and going fast under light load… The chain seems to skip a tiny bit with a clunk.

I am trying to find a new freehub (I did ride through a ford a few days ago which has probably caused this issue)

Any ideas?

Should add drivetrain is on 1700 pretty rubbish weather miles on my croix commuter. Bit early I would have thought for chain / cassette death? There does seem to be lots of play in the rollers on the pins (not checked chain wear yet)

So far I’ve had:

1: chain stretch/cog wear. Solution = new chain and cog. Usually skips on the cogs taking the most wear. I.e cogs with less teeth for me.
2: cassette bearing wear. Solution = new cassette. Slop in cassette means the cogs aren’t where they should be. Tends to skip and miss changes in cogs with more teeth.
3: bent hanger and or frame. Solution = new hanger and pay the lbs. generally screws up changes and reaching the smallest cog despite hours of fiddling with adjustments.
4: adjustments out. Solution = watch lots of YouTube videos. Tend to show as inability to select extreme gears, mech through spokes, skipping gears, rough changes, changes when not expecting them.
5: work jockey bearings: solution = new jockey wheels and bearings. Shows as similar gear selection issues to 4.
6: b screw not in far enough. Solution= screw it in more. Shows as chain sandwich between smallest cog and jockey combined with nasty grinding noises.
7: worn chainring: solution= new drive chain. Shows as big skips when you put the power on which feel to me like the chain slipping on the rear.

No way is it the freehub.

1700 miles, 0.75% worn I bet but I doubt its causing this.

Unable to suggest a cause, sorry.

Cheers for that. Pretty much had all those in the past too!

Was not skipping before I submerged the hub so that’s probably the main culprit (nothing else changed) . Weird thing is with all freehubs I have had that failed, they would skip on high load….its light load and when wheel is spinning very fast it skips. Wondering if there is still water in there… Hmmmm

Or maybe the chain is worn (not sure if play in the rollers is usual or not. I suspect not as my other bikes running 10 speed chains rollers solid).

Shift ramps on the inside of the big ring picking the chain occasionally (Usually worse on compact combined with short chainstays).
.
Edit….1700 miles on commuter….Drivetrain shot.

Why would it be the freehub when it only happen in certain gears?

Al good point but I cannot think of anything else… Was fine before I rode through a ford…. And by rode through… I mean water up to the top tube kind of deep.

Had to pour water out the seat tube 🙂

Then the skipping started…. At speed…. Even after lubing up chain.

I guess I could have killed chain by riding for 5 miles home after soaking it in water and washing app lube off.

But all is well in all gears under heavy load…. And I mean all 13 stone hulking and stomping on pedals.

Tis a weird one

I forgot one – grit, mud or caked dry lube between cogs, but that tends to make it skip all the time. It would fit in with the immersion being the cause.

Cynic-al, if there is play in the freehub, and you rock the freehub, then the teeth of the larger cogs move more than those of the small cogs due to the different radius, meaning the alignment is further out on the big cogs.

The fact it does this with little pressure but not big stomping points to something getting aligned or being stopped from moving by the higher loads rather than chain/cog/chainring wear.

Having said all that I’d say it’s probably chain wear – buy a chain wear tool and be prepared to replace the chain (probably), cassette (probably) and the chainring that gets the most use ( probably not). 1500 miles is about 3 chains for me but my bikes do like mud.

Is both chain and cassette only 1700 miles old? If both same age, next thing I’d check is the gear hanger.
One last thing, you say 11 speed 105, the pull of the rear derailleur is different between long and short cage versions so the cable clamps differently, might be worth double checking that. Short cage is over the top of the bolt, long cage is on the lower side.

Right, chains at 1% stretch so maybe this is ze problem.

KMC chain & 105 cassette ordered from ze germans so hope this sorts it.

ta all

I found my last similar skip was caused by the KMC link not fully locked home by fraction of a mm!