Don't know exactly how this happened but needs to be replaced. I didn't strip the threads but the entire insert spun. I'm told this is replaceable but an expensive job. Anyone know anything about this? FWIW it's on an AL frame Masi road bike.

Here is some info. https://www.parktool.com/blog/repair...ottle-fittings I don't think a shop would charge much.

they are called Riv nuts. Shop should be able to fix it. I know Newingtons shop has the tool for it.

That's pretty common. Take it to your LBS. They should be able to fix it.

What is your frame material, steel, aluminum, are carbon fiber? It's easy to do yourself however depending on the frame material requires a little caution when drilling out the old rivnut. You can pick up a rivnut tool kit for under $30. Rivnuts are are quite common in the avaition industry.

https://www.summitracing.com/parts/w...CABEgJ1KfD_BwE

How old is the frame? I'd go for a warranteed frame replacement if possible.

In almost all the cases I've encountered, the method suggested on the Park Tool site referenced by [MENTION=90165]shelbyfv[/MENTION] above is sufficient. Try that before you go to the bother of removing the old insert and installing a new one.

I've had the job done by a shop, and the cost was minimal, perhaps even trivial, as I don't even recall how much it was.

The bike is about 12 yrs old and is a Masi Gran Criterium S which is an AL frame with CF fork and rear stays. I'm going to pursue some of the leads people here have mentioned.

This is not an expensive fix.

It's a rivnut. They're not expensive at all. You just need to get someone (or yourself) that knows how to put a new one in. As its an aluminum bike this will be a piece of cake. It may come out quite easily or it may need to be drilled out either way its a matter of taking the old one out and putting a new rivnut it. It may need to be bored out slightly larger but it will still be straightforward.