QUESTION: On our group rides, one guy throws his bike back when he stands on a climb. It's miserable to ride behind him. How can we help him correct this dangerous problem? -- Shirley B.
COACH FRED: Making the bike kick back is a common technique flaw. The danger is to the rider behind because when a front wheel is struck, it's easy to lose control and fall. Meanwhile, the front guy will feel only a bump against his rear wheel.
His bike doesn't actually go backward, of course. It just seems to in relative terms because it slows abruptly.
When standing on a climb, the tendency is to pull back on the bar and lurch forward to get up from the saddle. This interrupts the pedaling action and, because of the grade, the bike decelerates.
You're right -- it's disconcerting and dangerous. But it's not hard to prevent or at least minimize. Suggest to your friend that he practice his timing so he stands as one pedal comes over the top. By making a smooth stroke this way, he'll keep more of his speed through the transition.
He can also push the bike forward a bit just as he stands, using his hands on the brake hoods. When timed right, this move offsets any speed loss on that key pedal stroke.
Some riders always say "Standing!" just before they do. This warning is helpful, but it isn't a substitute for proper technique and consideration of people behind.
When following any rider on a climb, it's a good idea to leave at least one foot of space or ride a few inches to the left or right of the rear wheel. This creates a safety margin no matter how good the rider is. Always stay aware by watching body language for signs that a rider is about to stand.