Jim’s Tech Talk
By Jim Langley
This week’s Tech Talk is self-explanatory, so let’s get right to it! As always, if you have experience with today’s question and have additional tips please share them in a comment. Thanks!
Arizona roadie, Wayne Riley asked,
[Note: Wayne’s talking about Dave’s stuck bottle cage bolt, which we covered in two parts starting here https://www.roadbikerider.com/stuck-bottle-cage-bolt/]
Wayne continues, “When I took off my bottle bolt, the whole female part of the frame’s screw came off and now the bolt hole won’t take a bolt – it’s just a hole in the frame. You can see from the attached picture what I’m talking about – see the top water bottle cage bolt hole.
How do I fix this problem so I can properly attach a water bottle cage?”
“I can’t really see that top hole in the photo very well, Wayne. It’s not in focus. But it looks from what I can see like it’s the same outside diameter as the one below. If so, then I believe the threads must have stripped completely (no threads left) in the top one.
But both inserts are still in the frame I think. So it’s not just a hole, it’s a hole with an insert in it but the insert’s threads are stripped.
To fix it, you probably need to remove and replace that top insert. Because I don’t think there’s any easy way to add threads to it. The inserts are usually M5 “rivnut” inserts, which you can buy online, try https://www.mcmaster.com/. You need to buy one that is made to fit your frame tube thickness so you’ll want to measure that once you get the rivnut that’s stripped out of the frame.
To remove the rivnut in the frame, understand that it’s mushroomed over on the inside of the frame. So you need to break free its grip on the top of the frame. Once you do that, you can push it down inside the frame to then get it out where it lands inside the bottom bracket of the frame.
To get it to the point where you can push it inside the tube, you could try drilling it but you don’t want to damage the frame tubing. So be careful and don’t use too large a bit or force the drill or bit in any way. If you’re afraid you can’t control the drill, don’t use the drill at all.
Instead carefully file the insert away until it’s weak enough to squeeze together or break. That’ll be a delicate procedure. Protect the frame so you don’t harm it. A Dremel tool with a cutting/sanding disc can work but don’t slip and cut the frame. Taping cardboard or even metal to the frame to protect it would be wise (see part 2 of Dave’s story).
Once you’ve successfully removed the stripped rivnut, you’ll need to put your new one in. Since I have never had to replace a rivnut, I went looking for a video showing the tools and process recommended for both removal and installation and found one. Here it is:
I hope this helps you fix it. Let us know how it goes.
Jim Langley is RBR’s Technical Editor. He has been a pro mechanic and cycling writer for more than 40 years. He’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Check out his “cycling aficionado” website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim’s cycling streak ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.