Maximum Speed

[phil120867]

I set my speedo to km by accident and when i got home my top speed registered at 99.9kmh, I only realised afterwards that somewhere along the route I was travelling (downhill) at over 100kmh, but the computer only goes to 99.9kmh. There are loads of hills round here (between 7oaks and Edenbridge in kent) so I haven't worked out which one is the fastest yet. I will get round to setting my speedo to MPH and do the route again just to see but I'll wait until its dryer and when I find more Diazepam down the back of the sofa(joke)

 

[Randochap]

I set my speedo to km by accident and when i got home my top speed registered at 99.9kmh, I only realised afterwards that somewhere along the route I was travelling (downhill) at over 100kmh, but the computer only goes to 99.9kmh.

Ah, I think you might want to check your wheel/tyre circumference/computer calibration, as well.

 

[Dave5N]

To put the record straight.

There are three forces acting on a rolling vehicle which impede its motion.

1/ Rolling resistance of the tyres. - Energy to deform the rubber and absorb heat due friction with the roadsurface.

2/ Aerodynamic Drag. - The energy it takes to move the volume of air the vehicle intends to occupy and the reduction in pressure following the vehicle causing a rearward movement.

3/ Gravity. - The mass of the vehicle and the position of its 'centre of gravity' relative to its 'plan centre'. ie Angle of inclination.


All downhill velocities will be assisted by 3/, therefore elliminated from any 'speed boasting'.

Smooth clothing and 'tuck' positioning are an assistance, but valid for 'speed boasting'.
2/ is non - linear. The faster the velocity, the greater the force, and therefore the greater power is required to increase velocity. It requires more power to increase from 28 to 30 mph than it does to increase from 8 to 10 mph.

1/ is linear. If 10 Newtons are required at 10 mph, 20 N will be required at 20 mph and 30 N required at 30 mph. ( Do not take these figures at reality. They are merely to serve as an example )


I don't deal in Newtons. There is an equation to directly calculate HorsePower from Coefficient of Rolling Resistance and Coefficient of Drag.

Pf = ( Crr x (W/375) x V ) + ( CdA x (V^2/391) * (V/375) )


This is the 'Holy grail'

Crap physics. You forgot spacetime.

 

[jimboalee]

Newton realised gravity when an apple fell on his head. ( true ? )

Dave5N realised gravity when he heared a splash in the lavatory pan.

Newton said "For every action, there is an equal and opposite reaction".
Just before the splash, both Dave5N's brain cells moved apart.


Sorry Dave5N.
That's an old University joke. Very apt after your "Crap physics" joke.

 

[classic33]

Fast enough to set the speed camera off, on a Brox. A629 from junction 24, M62, Ainley Top down into Elland.

All this talk of gearing what do you think you could manage with a gear of 229 inches?

 

[MacB]

All this talk of gearing what do you think you could manage with a gear of 229 inches?

a hernia?

 

[Flying_Monkey]

I set my speedo to km by accident and when i got home my top speed registered at 99.9kmh

I suspect that this was caused by a malfunction going under electricity pylons or similar. There are other things that can cause this too. I've seen is happen on mine.

 

[Randochap]

a hernia?

I think Jose Meiffret was towed up to speed.

 

[jimboalee]

http://www.canosoarus.com/08LSRbicycle/LSR Bike01.htm

Jose has been superseded.

Note the two stage geartrain.

 

[jimboalee]

Wait a minute,,,,

http://www.fredrompelberg.com/en/html/algemeen/fredrompelberg/record.asp

Fred's the man.

 

[stumpy]

Wait a minute,,,,

http://www.fredrompelberg.com/en/html/algemeen/fredrompelberg/record.asp

Fred's the man.

Well in that case if you look at the chart on this link. I'd be the world record holder in 1937....all I need now is a time machine

 

[HLaB]

I hope that comma should be a decimal point .

Fred Rompelberg,
Maastricht, the Netherlands,
eldest professional cyclist in the world,
current holder of the Absolute Speed World Record Cycling
with 268,831 km/h.

 

[Goffins]

28.5mph is my maximum so far on a flat, it was quite a short distance mind you and riding in roughly the same direction as the wind.

This was some weeks back so I may have another crack soon.

 

[Will1985]

I hope that comma should be a decimal point .

It'll be European style - they use commas instead of points.

 

[jimboalee]

"Fred Rompelberg,
Maastricht, the Netherlands,
eldest professional cyclist in the world,
current holder of the Absolute Speed World Record Cycling
with 268,831 km/h."

Which by strange coincidence is the Geostationary Orbit velocity of Saturn.

He must have been on the 'Big ring',