On 4/13/2017 10:07 PM, Art Shapiro wrote:
I had a bit of an adventure when one of the two
handlebar-fixing bolts on my Deda Murex quilled stem decided
to snap with a rather impressive cracking noise. I somehow
didn't crash and happened to be only about seven miles from
home. I got slowly home holding the stem with one hand and
one of the brake levers on the dangling handlebars with the
other hand. (This is not recommended to the reader.)

I see that the bolt is a M6x18 tapered cone head Allen cap
screw with pressed-on washer.

The stem is two months shy of 15 years old, but I don't want
to have this happen again. Looking on eBay, I see quite a
few appropriate bolts, but I'm not sure what is optimal.
Can anyone help?

Everything seems to be Grade 5. Is that safe enough, or do
I really want to (somehow) find Grade 8?

Many are titanium. Is that a better choice than the
more-common steel? Or should I look for stainless steel? I
am always happy to save a few grams, but not if that's a
significant risk.

Advice welcome!

Original handlebar clamp bolts are Grade 8; readily
available and cheap. Grade 5 may be strong enough but for
pennies difference I suggest an 8. I wouldn't use Ti
fasteners in a stem but some guys do and many don't die.

Clean your handlebar, stem and and stem plate. Inspect for
damage/cracks. Clean threads in the stem, inspect for
damage, replace both bolts, lubricate at assembly, ensure
the gap of the handlebar plate is even on both ends. Deda
says torque to 10nm.

Stand in front of your bike and put your full weight on the
brake levers. Handlebar should not move. If it does or if
anything seems awry in any way, replace the stem.


--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971