What to do with a busted freewheel on a vintage road bike?

Question

I have a 1986 Panasonic DX-3000 that I use to commute to work and for casual rides. The freewheel did not survive the winter and the bearing inside it is clearly shot and after changing the chain as part of early spring maintenance the chain started to skip on the smallest two cogs (the ones I use the most).

The bikes mounts a 14-28 6-speed freewheel: quite hard to find. However, because of other component breakdowns, I already have a modern derailleur and an eight speed shifter (it indexes the 6-speed freewheel just fine with the old alternate cable routing trick). It would not thus be hard to switch to an 8-speed freewheel or even to rebuild the wheel with a freehub and an 8-speed cassette. The 8-speed freewheel solution does not seem too difficult, but I am a bit lost when it comes to evaluating compatibility of the freewheel with the axle.

The goal would be to maintain the original "look" and "spirit" of the bike as much as possible but without necessarily sticking to vintage components.

What would you do?

There are a few new freewheels on the market and apparently they are mostly for E-bikes. Unfortunately the producers do not provide a lot in terms of specs, thus I do not really know what are the practical consequences. The SunRace MFM20 could be a drop-in replacement, if it were possible to find it in stock somewhere...

Does anyone feel like suggesting a solution?

Answer 1

Given the freewheel is toast already, there's no harm in disassembling it to attempt a refurb. If it breaks, it was already failed and you're no worse off.

1. Start by removing the freewheel and cleaning. It's going to be nicer to work on when clean.
2. Flush with solvent, soak it in an ultrasonic cleaner, or leave it in a tank of petrol for a while to dissolve all the grease. If that cleans it up, then dry and re-lubricate.
3. If that doesn't help, inspect for some way to disassemble further. There will likely be a ring of 40-100 tiny bearings inside, so try to not loose too many. Keep cleaning and inspecting. If the bearing surfaces are damaged, then give up, or if there are a lot of munched bearing balls it will also be unservicable.

Otherwise a 14-28 freewheel is still a common stock item new. If your LBS doesn't carry stock, then they should be able to order one. If they won't/can't then find another LBS.
Last resort is to order one from Aliexpress - they may not be fancy, but are fully workable.

Answer 2

The simplest solution by far is get one of the acceptable quality 6-speed 14-28 freewheels still made, such as Shimano. The challenge in recent years with keeping freewheel bikes going is that many of the repair type freewheels that are made now are bad quality and break under regular adult use, but the Shimano ones are still okay. There are no truly nice multi-speed freewheels in production now.

The bike is presumably 120 spaced. Hypothetically, to run an 8-speed freewheel on the wheel you've got, the steps would be respace the frame to 130 or 135 depending on how much resistance to bent axles you want, take away the axle and the spacers and locknuts, respace the hub so that the drive side locknut surface just barely clears past the small end of the freewheel, and space out the left side spacers and locknut to build it back up to your target of 130 or 135 (you could choose an arbitrary number too, but then once you get sick of having an 8-speed freewheel hub you would be left with a nonstandard spacing). Then you would re-dish the wheel and choose a different bottom bracket spindle length to match the new chainline, and then you would replace the front derailleur if it doesn't come out far enough anymore.

8-speed freewheels are bad because 8-speed freewheel hubs (which are their own category completely) bend and break axles chronically because of all the leverage on the axle. They shouldn't exist, and the reason they do was as a way of cheating the jump from 21 to 24 speed at a discount, whereas if what you're concerned about is selling a reliable bike, that jump requires a cassette hub, which is more expensive.

If you want to make the bike 8-speed in bike, just get a modern 8/9/10 130mm road cassette wheel for it, and spread the rear end and redo the front chainline as above.

Answer 3

This is a question of personal philosophy as much as anything else. I'd want to make the bike as "forward compatible" as possible, so I'd probably do this:

• Respace rear triangle to 130 mm
• Relace rim to modern Shimano freehub (like this, but check spoke count), or buy a new rear wheel
• Replace shifters with these
• Replace rear derailleur with this
• Use whatever 8-speed cassette and chain strikes your fancy.

Note that this is mixing parts from different component groups, but the cable actuation ratio is the same, so it should work.