Last week I wrote about my experience changing the headset on Miss Pop's Cannondale ST. It proved to be pretty straightforward. However, my Cannondale ST has proved to be a different story.
Having the same headset issues and needing to get the bikes ready for the season and our upcoming tour of Southern Utah, I intended to replace the headset also. Fine, except the alloy quill stem wouldn't budge. At all.
I spent many hours scouring the internet researching all the possible methods for extracting a corroded stem successfully. Over the course of a week I tried heat, cold, moderate force, twisting, hammering, vinegar and CNC Freeze-Off (which people swear by), to no avail.
Next up was these guys combination of clever engineering and brute force.The engineering part would require too many additional tools and materials to make it worth the while, but I did buy a rubber mallet in attempt to try the brute force method. I went at it pretty hard striking the underside of the handlebar clamp with the bike laid on the ground. The stem didn't budge a millimetre.
The last resort was to cut the stem off half an inch or so above the steerer column, hacksaw down the length of the remaining stem, and crush it inside the steerer with some vice grips. I'd read this approach never fails, save for sacrificing the stem.
I wasn't enamoured with the idea but, like my dental surgery I endured earlier that morning, I knew it had to be done. The stem cut off easily. I had purchased a handle grip hacksaw from Home Depot, it did help immensely. Hacksawing down its length required first fashioning a narrower saw blade but once started I progressed quickly. I had established that only three or four inches of stem were inside the steerer. I completed the first cut and started to clamp the vice grips from various positions. I could see the stem squeezing inwards and making a small space between the inside of the steerer. If I had a bench vice at this stage I would have applied some force to try and twist it off. I resigned to making a second, opposite cut, encouraged that it would be enough. Crimping the stem once again I could manipulate the two pieces in various directions, hoping to crack up the corrosion inside. But still the stem stuck. In the end it took placing a steel bar between the fork blades up inside the fork steerer and driving the stem pieces out with a hammer. It came out steadily by degrees but really didn't give up until the last few millimetres. It was a great relief as I thought it might take another two cuts to extract it.
This was an interesting exercise. There are lots of blogs form people wth seized stems asking for advice. No two stems are stuck the same amount, thus everyone's experience of extracting a seized stem is different. There is not one cure-all. The methods just escalate in extremity and difficulty. I would recommend the non-destructive methods first. Not knowing the history of my Cannondale I had no idea how corroded it was. There aren't many tell tale signs of the severity of corrosion from the outside. As it turned out I don't think any other method would have proved successful. I'm glad I cut my losses soon enough and got on with it, missing the first decent ride of the spring would really piss me off. In the end it wasn't that laborious, maybe 2 hours work. And I'm glad I took the chance, rather than leave it to someone else. Apologies for the awful footwear in the photo!
A word of note: Later, as I was installing the new headset I discovered that the steerer column had been forced "out of round" by the action of the vice grips on the alloy pieces pushing against the steerer walls. As a result the threaded cone and locknut would not catch the threads. Not good! After confirming this using a vernier caliper I carefully set about returning it to round using a rubber mallet set on a block of wood. It was a relatively simple process but it was definitely an unexpected consequence of the vice grips. Be careful!
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