Driving his uncooperative truck about 30 miles per hour on a highway shoulder, Bob Balk kept his spirits up. Sure, he had just spent about $900 to fix the vehicle, only to have the mechanics return it scratching their heads. Maybe it was bad gas; they couldn’t tell. But the seven-time Paralympian was used to challenges, so driving three hours roundtrip from his hometown in Moravia, N.Y., to Rochester didn’t phase him. Balk could empty...