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I just got a Colnago Master Arabesque single speed conversion from a friend who moved abroad.

It's set up as a fixie on a flip flop Hub. I flipped the wheel and installed a new single speed 1/8 freewheel, loaded up the chain but it's skipping under pressure, wondering if anyone had any ideas why along with the below?

  1. New chain? - will be getting a new 1/8 chain today
  2. Misalignment, I noticed he'd probably bodged a cold set to get it to single speed, may be that the freewheel is out of alignment with the crank? - But then the fixie set up he had works fine when I flip it back.

Does anyone have any other suggestions as to why it skips so badly under even a little pressure?

  • Presumably you are running a chain tensioner as this is a single speed conversion? Is the chain tension set correctly? – Argenti Apparatus Sep 19 '18 at 12:01
  • Are the teeth of the chain-ring or cog worn? – David Richerby Sep 19 '18 at 12:19
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    If the chain is able to skip over the teeth of the sprocket, your sprocket is not made for single speed. Single speed sprockets have long teeth that go all the way into the chain links, making it physically impossible for the chain to skip. A single speed sprocket will retain its no-skip performance even when it is so drastically worn that it got several teeth missing. Failure will only come in the form of the chain jumping off the sprocket when you have more than one tooth missing in sequence, but it will never skip. Same for the chain-wheel: Made for single speed => no skip ever. – cmaster Sep 19 '18 at 12:30
  • @cmaster OP said new SS freewheel installed. Those come with a sprocket, right? If so the sprocket must be a SS type. – Argenti Apparatus Sep 19 '18 at 13:58
  • Yup new SS freewheel hence new sprocket on it, – Edd Gray Sep 19 '18 at 14:44
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One two options given that your freewheel is new:

  1. The chain is too loose. A chain tensioner might help. Alternatively, if you have semi horizontal dropouts just pull the rear wheel back and tighten.

  2. The front chainring is worn. This has happened to me before. Replacing the chainring solved the problem.

  • Sweet, I'll fit the chain this eve tight as possible, I'd rather not fit the chain tensioner, yup it has semi horizontal drop outs so when fitting the new chain will fit with them forward then move back to add tension. I'll check out the front chain ring, seemed fine with the other chain on fixie though – Edd Gray Sep 19 '18 at 14:47
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    @EddGray re 'I'll fit the chain this eve tight as possible' noooooooooo!!!!!! Chain tension must be set properly, see my answer. – Argenti Apparatus Sep 19 '18 at 15:06
  • @EddGray as mentioned above, you probably don’t want to set the chain as tight as possible. This can have adverse consequences. – Daniel Sep 19 '18 at 15:12
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    Rear wheel needs to be further back, its sat a little forward from where it should be on horizontal drop outs, realised I miscounted a tooth so have swapped on a 16T when the chain is for a 17T, dont mind the extra work on the 16T. Will fit the current and move it back, remove a link if the problem reoccurs, will see if that works, will update! – Edd Gray Sep 20 '18 at 14:44
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From comments after question it seems lack of chain tension could be the problem.

If the bike does not have slot dropouts to tension the chain (which it might not have as it's a SS conversion) you need a separate chain tensioner device.

When properly tensioned chain should move up or down about 12mm / 0.5 inch at the midpoint between sprockets.

Park Tools excellent video which includes chain tensioning:

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