Hi This my first post here.
Today I serviced the rear shock on my Blur XC and managed to shear the lower Ti bolt. I notice that there has been some discussion re the quality of these bolts over the years on this forum. Being an engineer I looked around for some guidance on torquing Ti bolts.
I thought the following might be of interest to SC owners.
SC's torque rating is 160 ins-lbs for these bolts, however on the site of a manufacturer of Ti bolts ( Mettec Makers of Quality Titanium Fasteners, Motorsports Products, and Motorcycle Accessories.) I find that the min/max recommended torque for an M8 Ti bolt is 120/145 ins-lbs non-lubricated and 108/130 ins-lbs lubricated. Additionally they note: 'for bolts in shear reduce the values by 30-40%'.
These numbers are significantly different from SC's spec and might account for the high number of failures. Certainly from my point of view 160 in-lbs is significantly higher than the bolts were originally tightened. In fact if I had not specifically bought a new torque wrench (with calibration cert.) I would have not gone anywhere near this value, it felt overtight - should have relied on my experience.
I also looked at the failed bolt with a watchmakers loop and could not see any obvious flaws in the metal. The thread cutting was a bit iffy with some cracks but otherwise a classic failure pattern.
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Thread: SC Titanium Bolts