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I acquired a vintage 10 speed Healing Commuter made in New Zealand, rode it everyday and treated it pretty poorly. No regular maintenance, chained it on the street come rain or shine. Having grown fond of it I decided I would do a complete over haul.

Fast forward 6 months, it’s a new colour and all the mech is working well... independently.

The bike has all its original parts except:

  • The derailleur now a Shimano Tourney 6 speed SIS
  • Both wheels now Shimano specialised pro mondo with a 6 speed cassette and
  • A new chain now a 7mm SRAM chain with a quicklink.

The crankset is a Shimano Front Freewheel System - from what I can tell, the FFS was pretty low end and a solution in search of a problem, to quote Sheldon.

Sadly my first ride was lack-luster thanks to a knock. When pedaling with gusto, something in the crank system is slipping so the rider experiences the pedal engaging normally followed by no opposite force from the pedal followed by the pedal engaging normally again. This occurs rhythmically and on both sides, when left foot is leading then right then left etc.

I’m wondering if it’s something to do with the crankset being a freewheel system plus the free hub system in the considerably newer wheels?

Maybe it’s an error I made in the rebuild of the crank?

Any crank troubleshooting tips would be much appreciated.

Ta

The Bike, have re-routed the cabling along the toptube[![][1]][1] close up of the Shimano Front Freewheel System

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    Did you replace the chain too? – Walto Salonen Feb 6 at 5:27
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    Yes I did, with a 7mm SRAM chain with a quicklink. – Mech_smith Feb 6 at 5:43
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    So you cleaned and refitted the original front chainring and cranks? Or is the "Shimano Front Freewheel System" something you added? From memory that was a way of allowing the chainrings to rotate forward with the crank arms stationary. I've never seen one in the wild, a photo might help. This sounds fixable, so do persevere! – Criggie Feb 6 at 8:56
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    Did you replace the cassette with a new one? Its possible the new chain is slipping on an old worn cassette. If the cassette has individual cogs you might get away with flipping each cog, but the splines don't quite line up and some filing is needed. Does it happen in all gears? Basically need to identify what is slipping. – Criggie Feb 6 at 8:58
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    @Criggie I suspect that the front freewheel is slipping. If so it should be reproducible standing still. Chain slip is difficult to reproduce. – David D Feb 8 at 16:08
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I had a Schwinn World Tourist and those had the freewheel system, too. It might... might be because you have two freewheels. The bikes that had those, had fixed gears on the wheel, since it was the crank that coasted. And yes, the whole point of the system was so you could change gears by coasting.

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I've finally gotten to the bottom of the bottom bracket problem.

The thread inside the spindle was worn and the NDS crank arm was moving independently from the DS crank arm.

Have replaced the FFS with a cup and cone BB with a retro chain guard, which is now engaging nicely.

Still have, what I now know is chain slip, just got to sus out whether its the chainrings or the free hub.

Thanks for all your troubleshooting.

BB with retro chainguard

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