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My 7-speed freewheel (13-21t) needs replacing as it is very worn, yet it won't come off the wheel (it's stuck, the bike shop could not get it off). Since the rear wheel is old, for tubular tyres, and has a missing spoke, I wouldn't mind replacing it anyway.

I am not sure which parts are compatible with which. The way I understand it is that I need a rear wheel compatible with a 7 speed cassette (I can switch to a cassette, if I get a new wheel?), and a 7 speed cassette. (Does it have to be 7 speed? or can I go 8-9-10 and just not use the outermost gears?) And if the new cassette has a bigger largest chainring, I need to make sure my derailleur can handle it.

My cranks are 2-speed 42-52t but I don't know if that's relevant.

Is my thinking here correct? Or am I overlooking something?

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  • It's difficult to answer this question without knowing how open you are to reworking the bike and also what quality level you want to keep things to (since a bike with tubulars from the 7-speed era suggests some level of fanciness). And if you want to know your options for changing components, the single most important factor is what kind of gearing range you want to wind up with. Also what frame is this? Oct 21, 2021 at 19:44
  • Can you measure the Over Locknut Dimension of the rear triangle? I suspect its 126mm between the insides.
    – Criggie
    Oct 21, 2021 at 22:30

2 Answers 2

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If you don't have indexed shifting, it doesn't matter. You may need to adjust your derailleur's limit screws.

If you have indexed shifting, you cannot use a cassette or freewheel with a different number of speeds, as the sprocket width and spacing between sprockets are different, so the derailleur won't index to where the gears are. You cannot even use a cassette with the same number of sprockets. This page has more info. This has still more. 7-speed freewheels and cassettes were made to different standards, and 7-speed Dura Ace was different yet again.

So either be prepared to upgrade your shifting or stick with a 7-speed freewheel. Or, if you can switch off indexed shifting on your shift lever, you can use friction shifting. In any case, it would be a good idea to get a new chain as well. And the chain should be the right width for the rest of your drivetrain.

If you're changing the size of your big sprocket in back, you should research the maximum sprocket size your derailleur can handle, and its maximum wrap capacity.

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Adam's answer is not quite right.

This table is from one of his links: enter image description here

You can use a 7sp cassette (and wheel) to replace any 7sp freewheel.

The biggest problem you are likely to face is finding or modifying a cassette wheel if your frame spacing is less than 130mm. there are solutions but best to measure first to assess the best options.

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  • Confirmed - I have a bike with two wheelsets, both 7 speed. One's a freewheel+tubulars, and the others a freehub+cassette+clinchers.
    – Criggie
    Oct 21, 2021 at 22:29

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