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Tech Q & A: Dave’s Stuck Bottle Bolt

Jun 14, 2023

Jim's Tech Talk

By Jim Langley

Before we tackle today's question, thanks for all the fine feedback on our tube installation tips last week: Fixing flats is always a popular subject and you provided many excellent additional tips sure to help.

This week, we’re offering help for an RBR fan named Dave, who has a stuck bolt. Read his question and our advice and chime in if you have other suggestions,

"I read and enjoy your weekly column, Jim, and hope you can provide some experience.

Back in my college days, I worked in two bike shops and dealt with a lot of poorly maintained bikes. From my previous professional life (now retired – more time to ride!) I have been sensitive to corrosion / dissimilar metals issues. That has carried over to my bike maintenance and I usually apply anti-seize when reinstalling fasteners (pedals, thru axles, etc, etc).

I recently bought a new high end bike from a large name manufacturer. I was surprised that most of the fasteners appear to be steel with only black oxide coatings. I have been slowly replacing them and/or applying anti-seize. Unfortunately, one of these is now a problem.

The bike came with preinstalled bolts for bottle cages and I used them at initial installation. This week, I decided to replace them with Silca titanium bolts (not for the negligible weight saving but for the better appearance and corrosion resistance) Three of the existing bolts on the bike were easily replaced. However, the 4th is totally seized.

So first, I hope this is a warning for others to pay attention to this issue in advance and remove and treat bolts and other fasteners before they can become stuck.

Then, I’d like to ask for some guidance, suggestions on getting this bolt out – as it will only get worse over time. I have soaked it with penetrating oil, no benefit. The recessed hex is still intact (I’m very careful with tools).

How much torque will the existing frame insert withstand? Say I can get access to the bolt head outside diameter and could put much more torque than an internal hex key?" …

At this point, Dave's email text ended. It's possible he wasn't finished explaining. I went ahead and replied and haven't heard any more from him yet. So, I’m going to share my reply here because seized bottle bolts in inserts are something anyone with frame inserts might run into.

Nice to hear from you, Dave. On those bottle screws you should be able to get the seized one out. You might try warming it with a heat gun for a while before trying to get it loose with the wrench. Of course don't heat any paint or carbon or you could ruin it. Wrapping damp rags around anything you don't want to heat will usually work but don't take any chances.

Since the bolt head recess is still intact, the bolt should come free because you can get a good grip with the wrench. Usually the hex recess will strip before you could put enough force on it to loosen the insert.

You said you could grip the outside of the bolt and that makes it even more likely you can get the bolt out. The button head bolts, which have thin, round and difficult to grip edges are the ones that usually cause problems (photo). I’m including tips for those, too, since a lot are out there. I’m also going to offer some insert tips just in case.

It's a great question, but I actually have no idea what torque it would take to loosen an insert and it would likely vary based on the insert type and frame construction. But if you did loosen the insert – depending on its design it might tighten up as soon as you install a cage and put the new ti screw back in.

Note that when inserts first came on the scene (1980s) I was told by a bike company spokesperson, that one of the no-nos with them is tightening the bolt without a cage under the bolt. Ever since I have avoided tightening bottle cage bolts unless there's a cage to tighten.

Now, if the hole for the wrench in the hex bolt is stripped, you might try a slightly oversize torx wrench to see if you can tap it in with a hammer (go easy) and get it to "bite" enough to turn the bolt. By tapping the right tool in it might press its own shape into the bolt and give you the purchase to get it out.

A blow from a small pointed tip cold chisel hit by a ballpeen hammer in a counterclockwise direction can sometimes break button bolts free. But be careful not to slip or miss with the tools if you try this or you could damage your paint or worse, your frame.

To prevent the punch slipping, tap the punch on the bolt head until you make a divot in the bolt for the punch tip to go in. Just tapping on the bolt might loosen the bolt if you’re lucky. If not, once you have the divot, you put the punch point in it at an angle that lets you gently hit the punch with the hammer trying to turn the bolt to loosen it. Again, work carefully and don't do any damage.

If no wrench will fit in the bolt any more, you might be able to drill a hole through the center of the bolt. As you drill, the bolt will heat and the insert will get hot, too and the bolt might loosen as you work as a result. If the bit gets stuck in the bolt as you center drill it, you can reverse the drill and sometimes the bolt will come right out with the drill bit.

If none of this works but you do get a hole in the bolt, you could try an easy-out tool to remove it. These look a little like drill bits but they have reverse blades that dig in and bite more as you turn them counterclockwise. Here's an example so you can see what they look like (don't buy this set unless it's the right size for what you’re working on):

Lastly, if the insert were to somehow get ruined, you could do a little research with the company that made the bike to see if they have inserts and installation kits available for their frames. Usually they work sort of like rivets and if the inserts and installation tool are available it should be repairable though maybe best sourced and done by a dealer of your bike.

I hope one of these suggestions helps you get it out and finish installing those nice new bolts, Dave!

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, 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.

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