New cycling speed record of more than 174mph

[Conor Dary]

Something different from the old music threads....




https://www.theguardian.com/lifeands...re-than-174mph

[guru]

Note that the article says he set the men's speed record. The world record is actually held by a woman - 183.9 MPH, set in 2018.

http://theprojectspeed.com/

[Atticus]

Note that the article says he set the men's speed record. The world record is actually held by a woman - 183.9 MPH, set in 2018.
http://theprojectspeed.com/

I'm not understanding the physics there. Is she being sucked along by some wind vortex? She is obviously not pedalling that fast.

[Conor Dary]

You don't have to pedal that fast....it's a HUGE gear....204x11!

Mueller used a 60-tooth front chainring going to a 13-tooth cog on a Jackshaft that was supplied by da Vinci. The Jackshaft transferred to another 60-tooth chainring going to a 12-tooth cog on the rear wheel. This combination yielded the equivalent of a 204x11 road gear without the need for a chainring that would have scraped the ground, which would have been the case with a traditional chainring-cog drivetrain! This top gear was more than four times larger than the 52x11, which is the biggest gear on a standard road bike.

https://www.bicycling.com/bikes-gear...breaking-bike/

[bambam1729]

I'm not understanding the physics there. Is she being sucked along by some wind vortex? She is obviously not pedalling that fast.

No. She doesn't have to pedal super fast because these land speeds have a dual set of big rings, unlike a regular bike with a single big ring. So a Tour de France rider may ride a big gear of 54 x 11. But the land speed bikes are something like (50x12)x(50x12) or effectively, something like 215x12. The gearing is so big that the rider can't actually get it started by himself, hence he must be towed by the car to get the wheels turning up to a certain speed. The rider is then released from the tow and pedals on his/her own at that point. The huge gearing lets them reach enormous speeds while still only having to rev at about 100 rev/minute.

[bambam1729]

Here's a picture of the bike ridden by the Dutch guy back in 1995. Note the double set of big rings.

[Conor Dary]

A 204x11 gearing means the rear wheel rotates 18.5 times for each turn of the crank .

[gh]

I remember first reading about these insane bicycle speeds in the '60s, and the article said the biggest problem they had was in finding a car that could reliably travel as fast as was required!

[lonewolf]

Do they draft a vehicle? How do you get off/stop a bike tavelling 189 mph?

[bambam1729]

Do they draft a vehicle? How do you get off/stop a bike tavelling 189 mph?

Yes, they draft a specially adapted car. It has a hood set up in the back of the car and the rider basically rides the bike in that hood for maximum protection from wind resistance.

The bike is towed by the car to start. After the bike is released it has to pass thru a timing trap and then ride 1 mile to pass thru another timing trap, all within the car's protective hood. After passing thru the second timing trap, the car pulls off to the side and the cyclist now slows down dramatically because of air resistance. That and brakes bring the bike to a stop gradually. Nothing fancy about the stopping, except I'm sure they all use disc brakes now.