Bicycle Mechanics - 10 speed missing links

So I broke my chain today. Was wondering if I could use a 9 speed missing link till my shop can get some 10 speed ones, it will be about a week

If I wanted (or needed) to ride while waiting for the proper link, I'd just go ahead and purchase a new chain. Even if you trusted the sloppy fit of the 9s connector on a 10s chain, I doubt it will fit the tighter spacing of the 10s cassette.

So I broke my chain today. Was wondering if I could use a 9 speed missing link till my shop can get some 10 speed ones, it will be about a week

Not ideal, but it'll probably do in a pinch. The difference in width isn't so great and many 9s chains will work fine. I ride my 10s Campy system with old 9s Sram PC-81 chains, (because i still have an old stock set aside), and have zero issues. The only issue is that the wider chain is more trim sensitive, and in your case you might hear the link click as it comes around and touches a neighboring sprocket.

BTW- the width does become a factor when riding the inner ring with the outside of the cassette. My chain angle becomes critical and the chain touches the outer chainring when coming from both outer cassette sprockets. I suspect a 10s chain would only touch coming from the outermost. Not an issue as I use the inner almost exclusively for climbing and therefore not with the smaller cassette sprockets.

BTW- the width does become a factor when riding the inner ring with the outside of the cassette. My chain angle becomes critical and the chain touches the outer chainring when coming from both outer cassette sprockets. I suspect a 10s chain would only touch coming from the outermost. Not an issue as I use the inner almost exclusively for climbing and therefore not with the smaller cassette sprockets.

I have the same issue with my climbing bike when on the middle of a triple crankset.
It is a road frame with a 10s XT drivetrain.
It took me a while to figure what was causing that noise.

I'd just buy a second chain. It won't be money wasted - you can just rotate the chains and you'll get full use out of both eventually. I wouldn't hesitate to use a 9 speed link to get home in a pinch, or even for a little bit more, but for a week, I'd just go ahead and buy a new chain.

use it as an opportunity to try a different brand, then when you rotate the chains, you'll have first hand experience whether certain brands actually do work better than others.

I would not ride a chain that had broken while in use, except to get back home. You don't know how many links have been compromised by the initial incident.

There is a chance the link will come undone this will grab the derailer and break it or perhaps your frame.

I would not ride a chain that had broken while in use, except to get back home. You don't know how many links have been compromised by the initial incident.

+1

If it was a master link that broke, sure, replace it. But when a chain breaks I just throw it away. Chains break at the worst possible moment (when you're sprinting or standing up) and it always hurts when you come crashing down on the bike. If one link was bad enough to break chances are other ones are close too.

If you must ride the chain that broke do it carefully and don't stand up to pedal.

I would not ride a chain that had broken while in use, except to get back home. You don't know how many links have been compromised by the initial incident.

+1, and/or there may be other links may have the same manufacturing defect that caused the initial break..

Probably time for a new chain anyway, it will keep from wearing
down the cassette so quickly.

What kind of bike shop lets their supply of 10-speed missing links run out? I'd think about trying a different shop.

+1 new chain entirely.

What kind of bike shop lets their supply of 10-speed missing links run out? I'd think about trying a different shop.

The last time I stopped at my LBS for a SRAM 10s link, they had none.
Any wonder I only go in there once a year?