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I've just swapped my Sherpa to singlespeed using my old singlespeed set up (9sp steel ring and cog showing no wear) plus a new 9 sp chain and an XLC tensioner.
Under load it skips every few rotations which makes going up hill a bit scary. The skipping doesn't seem to have a rhythm suggestive of a crank or cog revolution issue and the chain never falls off.
I cannot for the life of me work out why and it is driving me up the wall. I want to blame the tensioner as all previous SS set-ups used EBBs......
Hub (pro2) pawls seem to engage fine (on bench, hard to know under load but all looks in good condition), axle is intact, chainring is secure and square with good teeth, sprocket is square and tight with good teeth, chain runs fine without stiff links and is as short as it can be, alignment seems good. Have swapped cranks/ring/cog with no improvement.
Any other ideas to test? I'm convinced (based on no evidence at all) that it is the tensioner, but I've no idea why it would do that under load......
The cog may not look worn, but it may not be playing well with the new chain - try a new cog?
Try checking chain line and maybe flip the cog the other way to see if that helps
Ive never had a tensioner that didn't skip like a ****t at some point, Paragon sliding dropouts or ebb everytime.
Thin/cheap ss cogs can also flex and get a bit skippy/drop tastic.
Can you play with the tensioner so its pushing up to give more chain wrap, in a surly singualtor styleee ( the only one i found that sort of works)
As above plus check sticky link in the chain? Chain alignment?
I think that I have checked all of those at some point! Cog is a king steel one or surly steel, both wide based, both tried both ways round (I know the king one had never been used in one orientation).
May try a half link chain to get as much wrap as possible before the tensioner gets involved. Failing that I'll put gears back on.
I miss my ebb swift......
NOt enough wrap on the rear cog? Can you set the tensioner to press up not down and get more wrap or take a link out?
SS setups with tensioners can work fine - I did ten of thousands of miles on a rohloff with tensioner which is the same setup without it slipping
New chain on old sprockets, exacerbated by possible lack of chain wrap with tensioner.
I had one of those Surly wide sprockets which looked fine but grumbled with a new chain, even when flipped (it was a frame with stiff chainstays and bolt in hub so couldn't actually skip but didn't feel or sound nice). New sprocket fixed it straight away.
Have you got a straight edge or metre rule? Put that against the chainring and use to check chain line of both sprocket and idler.
Chainline?
What chain? Surly cogs will work with up to a 10 speed chain. But Surly style chainrings only up to 9 speed.
Single speed chains can skip if there’s not enough tension due to side to side movement. Normally combined with poor chainline.
Photo is worth a hundred words 🙂
PS Push up tensioner. Shorten chain. Is the rear cog a 9/32 or 1/8th?
Is the chain the right inner width for both cogs?
Thanks all.
Chainline is as close to perfect as I can measure.
Chain is 9sp and same as previous chains used in same set-up.
I think it is chain wrap - will get a new 3/32 chain and a half link.
Ive never had a tensioner that didn’t skip like a ****t at some point
Paul Components Melvin is your friend, my friend! Mine has been on all kinds of bikes, from an Orange Patriot through to my Surly Cross-Check, and has been utterly faultless. Sorry OP, not really helping your predicament, although if it is the tensioner then the Paul one is definitely worth a look.
chain line and get the chain as tight round the rear sprocket as possible.
I've been running a similar set to yours for 10yrs and have experienced the same thing several times.
I've rarely had issues with rear sprung tensioners; when I have, they have tended to be to do with chainline issues, worn teeth, or the cassette lockring not done up quite tight enough.
More recently, I've been using a BB mounted tensioner, which both looks great (better) and gives more chain wrap.
Every time this has happened to me in the past it's a chain>cog problem that only happens under load. Get someone to sit on the bike and pedal it forward under load holding the brakes while you watch the chain/cog/rearwheel. I can almost guarantee that it's riding up the cog, will skip forward and then settle and repeat.
It's almost always been a tension/chaintype problem for me in the past.
More recently, I’ve been using a BB mounted tensioner, which both looks great (better) and gives more chain wrap.
It's been a while since I had a SS frame with either EBB or sliding dropouts. When I SS'd a normal frame I too found a BB-mounted tensioner worked much better than a rear-mounted sprung tensioner. And yes, looked better too IMO.
Only SS (drivetrain) issues I ever had were caused by a cheap rear sprung tensioner, but that was chain falling off rather than any sort of skipping - I've nothing to offer for that.
Blackspire Stinger as a BB-mounted tensioner:
As mentioned a few times, think you can cure it with slighter tighter chain and tensioner pushing up to wrap the rear cog better. I had exactly this issue on my Inbred even with a half link chain, and doing this sorted it out for good. Rear tensioners are a bit hit and miss though, the BB tensioner above is another good idea...
I also run a Blackspire on the front but swapped out the roller for a jockey wheel, runs far quieter & you can run different teeth numbers to really get the chain dialled. Tend to find getting the rear wheel in and out is far easier too.