“The cyclist was “dafting” off the car, using the pressure wave the car creates as it moves through the air to cheat a bit and go faster than he could pedal. I won’t say that when younger I’ve never done it but it is dangerous as all get out. Not only does a bicycle not accelerate as fast as a car they don’t decelerate as fast either without doing a front wheel stand.”
Have no idea what you just said. Only thing I understood was the word “Dangerous”.
” That means a cyclist can’t be looking for brake lights all the time.”
Don’t get that. Just like in a motor vehicle, one must figure the car/truck in front of you is going to slam the breaks on for anything at anytime...another car, cat/dog/deer, a child any reason under the sun. Does not mean “all the time” but it means one must be watching more so if they are going to be “dangerous” and tailgating.
See reply 23
As your automobile moves down the road it pushes air out of it’s path. This creates a bulge of high pressure around the front of the vehicle. There is also an area of low pressure behind the vehicle. The high pressure bulge then is drawn around to the rear of the vehicle and produces a pressure wave (Think of it as a fan blowing into a vacuum cleaner) traveling at the same speed as the vehicle about 5 feet behind the vehicle. Cyclist will try and get in the pressure wave because it both sucks them forward into the low pressure area and blows them forward with the tailwind making it easier to go faster. In big road races a rider can be disqualified for drafting a support car. If are drafting a large vehicle like a semi or cargo truck the effect can be dramatic and the land speed record for a bicycle used to be one that was set when drafting behind a train!
As to watching the front wheel remember that the more ergonomically efficient and comfortable position on a bicycle (At least one setup as a racing bike) has the rider with their head down.
Also remember many of the riders are on bikes with 21mm tire that run 120psi. Those are really only designed for use on smooth roads and a crack or small bump can cause a fall. When drafting you can’t see far enough to avoid such obstacles as easily.
Both of those things mean when you are drafting you can’t see far enough ahead to look at anything except the road in front of you.
I hope this helps