So, update on this. Now new chain etc bedded it finally seems to have settled down and I've managed to do a few hundred miles and it hasn't needed the normal huge adjustment im tension for the first time ever in 2+yrs ownership and two (now on third) sets of chains and sprockets, thank god. I've been extra careful on snugging up adjusters and trying to compensate for movement as I torque the axle so maybe that or the new chain who knows, just hope it stays sorted, not hopeful though. Regarding "tight spots", something very odd is occurring still. Been experimenting, and as I rotate the wheel/chain I measured slack to the swinging arm with vernier at the masterlink, then brought chain all the way round to the masterlink again and remeasured. I did this 10 times and got different measurements every time, with a total variance of around 4mm (40.5mm to 45mm-ish slack). I then did the same measurement throughout the chains length, rotating 6 links and measuring, 6 links, measuring....Again similar wild variance with max to min slack of 4-5mm. Generally with 1 or 2 mm difference between adjacent measurements, but once or twice up to 3mm difference. This says to me that it's nothing to do with the chain? I don't have a proper run out guage but eyeballing and using a piece of rod in a clamp, both the sprockets seem to be running true (more sure of rear as its easier to see, but surely the counter shaft would be visably wiggly to cause such tension changes? ...its not). I don't see it can be the swinging arm moving with the wheels just being hand turned and the bearings feel rock solid anyway. So what on God's green earth is going on when the chain tension varies by 3mm when you turn the wheel by 6 links?!!!
A really basic question: Are you pressing the chain down at the measurement place (i.e. making sure it's unkinked) every time you make your measurements? Happy to pop round to confer....
Yep, I push it down then let go as I understand you're meant to do and put vernier on same spot at same angle each time to try and be consistent. If I look from rear sprocket towards front along the lower chain run as I turn back wheel (on paddock stand obs.) I see chain go up and down constantly as chain tension changes, yet nothing seems to be moving, just plain weird.
Yeah, if you fancy a look and a chin scratch some time, there's deffo a pint in it. "I'm not a gynecologist, but I'll take a look"
I’d say this is because a full rotation of the chain doesn’t bring any of the rotating parts back to the point they were at before you rotated the chain. If you’re confident about your measurements then I think the variance points to something(s) being out of line, out of shape or eccentric.
