I know very little about freewheel changing and replacement. I have a five gear freewheel now and I'm assuming I can only replace it with another 5 gear freewheel. I have a couple of questions

1. Can I only replace a 5 gear freewheel with another 5 gear?

2. Is it possible to destructively remove a freewheel without destroying the thread?

3. Are there any special measurements I have to know before ordering a freewheel off Amazon, or is it as easy as choosing the same gear number?

1. You need to measure the bicycle's drop-out (AKA over lock nut) width. A 5 speed frame will probably be either 120mm or 126mm at the rear dropouts. If it's the former, you can only fit a 5 speed or a 6 speed with compact spacing, like a Suntour Ultra (no longer made, mainly reliant on eBay to find). If it's the latter, you should be able to go up to 7 speed freewheel, which is still being made by various companies, including Shimano. A work around, that will allow you to get more gears, is to cold set the frame.

2. Shouldn't be an issue with the proper freewheel removal tool. The best way to use is to place the tool in a vice, remove the QR skewer, set the wheel into the tool and turn it like the steering wheel on a bus.

3. See #1

This article will explain the issues in greater detail. https://www.sheldonbrown.com/frame-spacing.html

The above method can only be used for splined freewheels, not Suntour, Regina, etc. and in some cases the skewer or nut is needed until the freewheel breaks free even with a splined tool if it does not insert very far. To answer the question - yes, one can disassemble the freewheel, clamp the body in a vise, and then remove in the same fashion without damaging the threads. https://www.parktool.com/blog/repair-...uctive-removal

Thanks for the info, yeah I have an old school Regina corsa freewheel that's been known to be very hard to come off, so this is good information.

Fitting a standard spaced 6-speed or a 7-speed freewheel to a 120 mm frame will require more than cold setting from 120 to 126 mm. The hub's OLD (over locknut dimension) will also have to be increased to 126 mm by fitting a longer axle, adding spacers and redishing (centering) the rim.

In addition to the good advice offered above, I can think of one more thing that's relevant here...

When choosing a new freewheel, in addition to the number of gears, you also need to pay attention to the gears' size. If you pick a freewheel whose biggest cog is larger than your original, your derailleur might not be able to handle it (you'd need to confirm your derailleur's specs) and you'd likely need a longer chain.

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...^^^also, if you want to join the club of people who spend way too much time thinking about this stuff, you can go to an online gear calculator, input your chainwheels, wheel and tyre size, crank length, and potential replacement cog cluster numbers and derive a little chart that gives you the results. Thus you can search for your own personal ideal gearing.

Or if it's working well for you, just count what you got and try to replace with the same or similar.

[MENTION=463691]Helix Lamont[/MENTION] - be sure you get the right tool. Regina used at least two different tools to remove the freewheel