US woman breaks cycling land speed record

[larrylamb]

Wow, 184mph on a pushbike. Credit where it's due, looks like an old bmx lol.

https://www.bbc.co.uk/news/world-us-canada-45572277

 

[Freeley]

The mind boggles.
I thought Guy Martin did something along these lines a couple of years ago? He obviously wasn't quick enough!

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[Gary&Heather]

Obviously had more than three gears then...

 

[Amarillo]

Obviously had more than three gears then...

I suspect she had just one gear. She was towed to about 100 mph then pedalled to 184 mph. I suspect that a huge chainring and tiny sprocket.is incompatible with derailleur gears. Wheel revolution speed makes hub gears unlikely, and a bottom bracket gear may very well add too much friction to be of benefit.

 

[Freeley]

Maybe she only had 3 gears and that's why she needed a tow until she got to 100!

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[Velma's Dad]

There was a really interesting piece on More Or Less (Radio 4) recently, about the physics of road race cycling. Can't remember all the stats but the point was that almost all the effort involved is about overcoming air resistance.

Recent research apparently shows the energy expended riding in the middle of the peloton is only about 5 to 10% of riding alone - an even bigger disparity than was previously thought.

Okay I thought it was interesting, anyway...

 

[Borris]

She must have had three Weetabix!

 

[soulstyledevon]

Brave, but she didn’t pedal to 184mph. She was towed.
It’s like saying, I cycled 30 miles in an hour uphill. However I used an electrical assist bike...
I don’t see the point of this record...?

 

[Amarillo]

Brave, but she didn’t pedal to 184mph. She was towed.
It’s like saying, I cycled 30 miles in an hour uphill. However I used an electrical assist bike...
I don’t see the point of this record...?

Much is about the team around her: the bicycle engineers, the way the wind shelter was constructed, the driver of the tow vehicle, etc.

 

[Amarillo]

Two 60 tooth chainrings and one 13 tooth sprocket and one 12 tooth sprocket make the rear wheel spin 23.077 times for every revolution of the pedals.

 

[owen_h]

An article I was reading said the whole design of the bike started with the tyres which were modified (and balanced) versions of ones used on dragster scooters. Who knew dragster scooters even were a thing! Tyres only available in the small size hence why the wheels are so much smaller than most bikes and the need to have the 2x 60 tooth chainrings.

 

[Amarillo]

Some more back of the envelope calculations:
- one revolution of the pedals drives the bike forward ~37 metres (wheels are 17", I'm assuming tyres are ~20")
- to reach 184 mph she would need a cadence of ~133 rpm spinning the wheels at ~51 times per second.

 

[flying banana]

I wonder if her fanny whistled

 

[soulstyledevon]

I wonder if her fanny whistled

That doesn’t sound very aerodynamic...?

 

[PudnBob]

Good lord. I thought I was going a bit quick on this ride. Was on accident by the way, definitely not on purpose!!

 

[Amarillo]

View attachment 38213 Good lord. I thought I was going a bit quick on this ride. Was on accident by the way, definitely not on purpose!!

Not so good when it goes horribly wrong.

Bet he was glad he had a helmet.

 

[Borris]

Not so good when it goes horribly wrong.

Bet he was glad he had a helmet.

The words Prize and Prat come to mind!