Titanium Mountain Bike Bolts
Mountain Bike Titanium stem bolts are not reliable?
My stem is a raceface diablos stem.
It came with M6 bolts and the manufacturer says to not use “inferior bolts” such as titanium. The standard bolts are steel bolts.
Would titanium crack or break off somehow? How can Titanium bolts be considered “inferior?”
This is less a function of the Titanium bolts than it is the design of the Diabolus stem. The way the stem secures the bar has very little material overlap and relies heavily upon the securing bolts for structural support. In the original diabolus, the bar mounts from the front of the stem and has only about 8mm of material supporting it from the bottom. They’ve actually corrected this with the new D2 version of the stem, where the bar now essentially sits atop the bulk of the stem material and is secured from the top, down over the bar.
You can easily see what I mean from photos…
Old “D1″ version
http://i.s.shopwiki.com/i/data/__Race+Face+Diabolus+Stem/140×140/0/841/19/aHR0cDovL2VjeC5pbWFnZXMtYW1hem9uLmNvbS9pbWFnZXMvSS8zMVpXUmxDdlB1TC5qcGc===.jpg?flags=NO_CHK
New D2 version
http://i.s.shopwiki.com/i/data/__RaceFace+Diabolus2+50mm+31.8mm+Stem+80%2F100%2C+Black/140×140/9/824/25/aHR0cDovL2RpcmVjdGJpY3ljbGVwYXJ0cy5jb20vaW1hZ2VzL2xpYnJhcnkvY2F0YWxvZ3Mvc29jL3AzNTBYMzUwbS9TTTY4MDIuanBn==.jpg
Also, since the intended use of that stem is extreme FR and DH, they expect that it will be seeing some serious drops. Figure a 150lb rider on a WELL CONSTRUCTED 10 foot drop will easily exert over 300lbs of force into his handlebars and that many people are sending ten foot drops that arent very well contructed further increasing the force and you can see how the shearing strength of the bolts becomes critical in the old stem’s configuration… the bolts essentially have to support about 90% of that force. In the newer D2 stem, all that force goes into actual stem itself and the bolts simply have to secure the bar from rotational forces which are considerably less.
I should mention as well that, while the other posters are correct in saying Ti bolts will snap well before an M6 steel bolt, a well constructed DH or FR part can easily use Ti bolts and such. I ran a Point1 Limited Edition direct mount stem on my DH bike for over a year, that stem has ALL Ti hardware… and I go about 250-260lbs in gear so that sucker saw huge forces and never flinched. Sadly, they only make it for the Boxxer standard and I now ride Marzocchi. All of my rotor bolts are Ti, my seat clamp bolts are Ti, likewise on the shifters and brake lever bolts… but things like caliper bolts or pedal axles which see huge shearing forces in DH applications are to be avoided.
