If it’s relevant this is a carbon fs bike with boost spacing and a rear through axle
The back wheel is a DT Swiss 1900 with an xd driver
A few months back i noticed the freehub seemed a touch draggy. With the xd driver it’s easy enough to pull the block off and then look inside freehub. My initial diagnosis was a slight dent in the hub body where it touches the seal of the free hub body. I continued riding for a few months with no issues.
But it’s now got much worse. If i stop pedaling in a high gear the chain goes slack and can drop off. With the wheel in place there is noticeable resistance turning the block. However with the wheel out and horizontal i can hold the block and the wheel will spin for ages. So it seems like tightening the rear axle is pushing the free hub body again the hub. But no idea why this has started happening. Could it be the wheel bearings have worn? I don’t have a clear idea of what’s in the rear hub
It’ll probably go to the LBS at the weekend but I’d like to understand what’s going on
Hard to diagnose without having the wheel here but bearings, a freehub service or damaged hub seal are the most likely culprits.
Is it an old 3-pawl model one or one of the newer Ratchet LN ones?
As a first step if you're dismantling everything, replace bearings in hub and freehub, and clean and regrease the pawl's and clean the ratchet teeth and then see how you get on.
I got caught out with a circlip between two freehub bearings.
This might be a total facepalm moment, but freehub/drivetrain things sometimes fox me when I try to think about them without actually having a bike in front of me. So...
Have you given your jockey wheels a spin and once-over?
The reasons for me saying this is I had some rub/squeak/seize symptoms when pushing the bike backwards and back-pedalling. It came and went, then last night it got really bad. In the end I traced it to the top jockey wheel. I didn't have any oil with me, but luckily some cordial from my camelbak mixed with saliva free'd it up enough to get through to the end.
The onset of slightly wet conditions had caught me by surprise with things like jockey wheels, TBH.
Worth a check?
Thanks for the replies. The jockey wheels are reasonably new and i can feel the resistance on turning the cassette. As you have said it’s hard to diagnose via an online description so off to the LBS . Wheel bearing are still the last frontier for me