Keeping a bike upright while stopping

posted: June 25, 2022

tl;dr: Some tips on how to avoid the most common type of fall from a bicycle or motorcycle...

As someone who is both a bicyclist and a motorcyclist, I spend a lot of time on two wheels. I empathize with what President Biden experienced last weekend, when he fell from his bicycle while coming to a stop in heavy traffic, in a crowd of fellow bicyclists and stationary onlookers. This is the most common type of fall from a bike: when the bike is barely moving or even stopped. Although the President said he was fine, if he was unable to break his fall with his gloved hands and his body hit the pavement full force, I’m sure he has been feeling the aftereffects for days.

Physics can explain why this is a common type of fall. When the bike is moving, the spinning wheels have a lot of angular momentum: the faster the wheels are spinning, the more angular momentum. If you’ve ever held an upright spinning wheel by its axle, you know that it takes a fair bit of force to tip the wheel to the side. Stop the wheel, or slow it down to a crawl, and it becomes very easy to tip the wheel over. Everyone who has ridden a bicycle knows that they are rather tippy at low speed, and more stable at higher speeds; motorcycles are the same. Angular momentum is the reason.

So one of the challenges of riding a bicycle or motorcycle is keeping it upright when coming to a stop, and at a stop. It is actually a much bigger challenge for a motorcycle, simply because motorcycles weigh a lot more than bicycles. A bicycle that weighs 20 to 30 pounds can be tipped over very far, and if the bicyclist is in a wide stance, the bike is not going to push the rider to the ground. Not so with a motorcycle, especially a heavyweight bike like a Harley-Davidson touring bike, which can weigh over 900 pounds. If you get a motorcycle a bit too far from upright, it will tip over and take the rider with it.

A bicyclist, wearing a bike helmet, shorts, and gloves, starting to get up from the pavement after a fall

The President's fall from his bicycle was preventable

With that as background, here are my tips for casual bikers, such as the President, to keep a bike upright while stopping.

Lose the toe clips and toe cages when in traffic

The President hopefully realizes, in retrospect, that he should not have been using toe clips or toe cages for a casual bike ride on a crowded trail. The only reason for toe clips or toe cages is to connect the bicyclist’s feet to the pedals so that the bicyclist can simultaneously push down with one foot and pull upwards with the other foot, thereby delivering additional force to the crank which can increase speed. Speed matters for racers, but there’s a safety tradeoff, as the bicyclist is now attached to the bike.

The bike I ride on trails, a Specialized Crosstrail, doesn’t have toe clips or toe cages. I would never put them on such a bike, because it is more important to be able to stop quickly to avoid the many obstacles on a bike trail: other people, dogs, animals, and debris. My carbon fiber road bike does have toe clips, and I use them when I am bicycling on a clear road without much other traffic. The pedals have clips on one side and a flat surface on the other side, so the bike can also easily be ridden without being clipped in, should conditions warrant.

Motorcycles don’t have toe clips or cages, for obvious reasons, so this tip doesn’t apply.

Learn how to stop by putting just one foot down

This takes practice, but after a while it becomes automatic. It is easier to do on a bicycle, but it can also be done on a motorcycle.

On a bicycle, I like to remove my right foot from the pedal while slowing, and lean the bike to the right while coming to a stop. I typically leave my left foot clipped in, to get ready to take off. A lightweight bicycle is super easy to keep upright with just one foot down: there’s no real need to remove the second foot from the toe clip, in most situations. The reason I lean to the right is that, in the U.S., bikes typically travel on the right side of the road, so leaning right leans away from traffic.

If you watch the video of the President’s fall, he actually does get a foot out while the bike is slowing, his left foot, and he gets his left foot to the ground. Using the left foot is not ideal, but if he had leaned the bike sufficiently left, he would not have fallen. He falls because he has trouble getting his right foot out, and leans his bike right. I’d recommend more practice, if he is going to insist upon using toe clips or toe cages.

The one-footed stop maneuver is much more difficult on a motorcycle, but worth it if you can master it. It’s the way that motorcycle cops are taught to stop, and other motorcycle safety fanatics swear by it. It’s definitely not for beginners: riders first need to be very comfortable coming to a two-footed stop.

For a motorcycle one-footed stop, you want to lean the bike slightly left and put your left foot down, keeping the right foot on the rear brake. The primary benefit is that, once stopped, your right foot is on the brake, right hand is on the throttle, and left hand is on the clutch, so that you can rapidly get the bike moving should a problem develop, such as a crazy driver approaching from the rear who may not stop in time.

The secondary benefit is that it teaches the rider precision bike balancing. To do the maneuver successfully, such that it becomes second nature, you will be forced to pay close attention to the position of the bike and the road. It can be challenging when the road has a strong rightward tilt, for rain runoff, which pushes the bike right. It’s also tricky when stopped before a right hand turn, as you’ll need to quickly lean the bike right when moving in order to execute the turn. The good news is that if you feel yourself getting in trouble because the bike is leaning a bit right, you just put your right foot down and do the two-footed stop that most motorcyclists do. You’ll still be much better balanced than the majority of bikers.

Know your limitations; maybe it’s time for a third wheel

Father Time takes his toll, and the Grim Reaper comes for all of us. Balance is often something that degrades with age. That’s one reason to continue biking, to practice balancing, but eventually it may become too much. A common reason old motorcyclists give up the sport is because they drop their bikes one too many times and struggle to get and keep them upright. The President might be at this stage of life, too.

Fortunately there are tricycles, with and without motors, for ex-bicyclists and motorcyclists. Harley-Davidson, to its credit, offers several models. I’ve heard some bikers derisively call these “wheelchair bikes”, but I give the riders of these trikes a lot of credit: they still are getting out and enjoying the open road. Not everyone has the balance needed to ride a two-wheeled vehicle, whether because of age or infirmity. Some of the trikes that Harley sells are to servicemen and servicewomen who suffered injuries while defending our country’s interests; these people deserve our respect. The President may not need a trike yet, but the day may soon come when he does.