Serotta Meivici/HSG Rear Stay Bolts- Fix

[sandmonstersand]

A few months back, I decided to take out and grease the small bolts holding the seat stay to the rear dropout on my HSG. Unfortunately both sheared off as I was unscrewing them. For some reason they were aluminium, and appeared to have been custom made...

After a lot of searching for bolts that would work, I eventually found these (M10, 1mm thread pitch, 14 mm head diameter):

https://www.accu.co.uk/flat-head-soc...-HPPF-M10-1-A4

Unfortunately the head diameter is not actually 14mm but 16 mm, so I had to put the bolt on the end of a an allen key in a drill, and run the edge of the head against a file to reduce it down to 14mm. Hallelujah, they work!

Thought I would share here in case any one else hits the same issue.

[Brian Smith]

We made those custom Alu stay bolts in house. They were installed with medium strength removable loctite, and almost never came loose in use. We replaced plenty of them, any time we did any refinish type work if they were at all marred...generally they came out without issue, too bad yours didn't.
Why a design solution was chosen that required a custom fastener when all the parts being mated were also produced in house...I won't hasten to share an opinion.

Nice find with the close replacement item, and stainless steel for fasteners, while weightier, isn't a bad choice in my mind for that location.

[coolplanetbikes]

Cool solution, glad you got it figured out. Part of the issue you probably had there is that AL doesn't play well with Ti and you probably got some galvanic corrosion locking everything in place.

Originally Posted by sandmonstersand

A few months back, I decided to take out and grease the small bolts holding the seat stay to the rear dropout on my HSG. Unfortunately both sheared off as I was unscrewing them. For some reason they were aluminium, and appeared to have been custom made...

After a lot of searching for bolts that would work, I eventually found these (M10, 1mm thread pitch, 14 mm head diameter):

https://www.accu.co.uk/flat-head-soc...-HPPF-M10-1-A4

Unfortunately the head diameter is not actually 14mm but 16 mm, so I had to put the bolt on the end of a an allen key in a drill, and run the edge of the head against a file to reduce it down to 14mm. Hallelujah, they work!

Thought I would share here in case any one else hits the same issue.

[sandmonstersand]

Originally Posted by Brian Smith

We made those custom Alu stay bolts in house. They were installed with medium strength removable loctite, and almost never came loose in use. We replaced plenty of them, any time we did any refinish type work if they were at all marred...generally they came out without issue, too bad yours didn't.
Why a design solution was chosen that required a custom fastener when all the parts being mated were also produced in house...I won't hasten to share an opinion.

Nice find with the close replacement item, and stainless steel for fasteners, while weightier, isn't a bad choice in my mind for that location.

Ahh interesting- thanks for sharing. Tbh I think I could have left them and they would have been fine, but once I started i couldn't go back. It was 13 years old and heavily used.