By Rick Schultz
Over a decade ago, bicycle component manufacturers started moving from steel to titanium. At the time, they didn’t understand that titanium is a notch sensitive metal. The first pedals to use titanium for the spindles (axles) snapped and several cyclists were seriously injured. Several years ago, a friend who was a bike shop owner got a pair of titanium skewers to test. During a 40mph descent on a group ride, he hit a small rock in the road and the front skewer snapped, he crashed and again, he was seriously injured. So what do these two incidents have in common?
- If these parts would have been made from steel, this would not have happened
- In both cases, the threads were cut and not rolled.
Background: In my previous career, I started a titanium fabrication business and it just happened that my first client was the US Navy Special Warfare Group (NSWG). The project was a non-magnetic, indestructible titanium knife for the US Special Forces that eventually went to all of our allies. I joined forces with an engineer who worked at one of the worlds leading titanium plants and the first thing he taught me is that titanium is a notch sensitive material. Always use gradual curves, round over and smooth out everything, every curve and never, ever use a sharp point (i.e., notch). I built the knives and over the last 20 years, there have only been a handful of broken blades. My next project for NSWG was building threaded titanium rods used as EOD demining probes. Not one has broken, why? Because I rolled the threads instead of cutting the threads. It was more expensive to manufacture, but the only way to fabricate threaded titanium parts.
Going back to the titanium skewers and pedal axles. Both were cases of the manufacturers not understanding the nuances nor the differences in fabricating titanium vs steel.
So, the decision you need to make is “How much weight savings am I gaining vs. the safety / integrity of the product?”
As an example, is 1.53 ounces saved in non-rotating weight worth the cost of this part failing at high speeds?
|QUICK RELEASE SKEWER||STEEL||TITANIUM|
|WEIGHT / PAIR (claimed)||3.2 oz||1.67 oz|
Coach Rick Schultz is an avid cyclist who trains, races and coaches in Southern California. Rick is an engineer by trade, and in addition to being a coach, he’s a bike fitter and prolific product reviewer. He’s the author of Stretching & Core Strengthening for the Cyclist in the RBR eBookstore. Check his product reviews website, www.biketestreviews.com, and his coaching site, www.bikefitnesscoaching.com. Click to read Rick’s full bio.