Titanium looks pretty good too. Alloys of titanium can be heat-treated to strengths equaling many high-strength steels, yet it’s light—only 58 percent of steel’s density. Then our hearts sink when we see that titanium has only half the Young’s Modulus of steel. This is why Formula 1 engines have swung back to steel connecting rods from titanium. When the piston decelerates at thousands of gs approaching top dead center, a titanium rod stretches twice as much as one made from maraging steel, and that requires the all-important squish clearance between parts of the piston and the head to be made larger to keep pistons from hitting the head. And that, in turn, makes squish less effective at bottom- and mid-range rpm, resulting in less engine torque. When a rider friend was given a titanium front axle for his Yamaha TZ750 roadrace bike, he tried it in a practice, then said, “Take it out.” It was certainly strong enough for the job but was only half as stiff, making the bike’s steering feel vague and imprecise.