93.0KMH on a road bike, but is it true?

[RedBike]

Surely then. some software inclusion can be accomodated by the cycle computer to take that into account, esp. with the technology thats knocking round today.

Your computer works by counting how many times the magnet passes the sensor. Your wheel is roughly 2.1m in circumfrence so the computer knows that if the magnet has passed the sensor say 50 times you've travel 50 x 2.1m, 105m.

It doesn't take into account the fact that you might have actually travelled nearly a complete wheel revolution before the magnet passed the sensor for the first time; or the fact that the magnet might now be half way around again.

A few metres error doesn't really matter when you're talking in terms of miles. Besides, the whole system is based an incurate appoximation of your wheel circumfrence. After 100+ miles you'll be luky if your computer is still accurate to within a mile nevermind a metre.

 

[yenrod]

Your computer works by counting how many times the magnet passes the sensor. Your wheel is roughly 2.1m in circumfrence so the computer knows that if the magnet has passed the sensor say 50 times you've travel 50 x 2.1m, 105m.

It doesn't take into account the fact that you might have actually travelled nearly a complete wheel revolution before the magnet passed the sensor for the first time; or the fact that the magnet might now be half way around again.

A few metres error doesn't really matter when you're talking in terms of miles. Besides, the whole system is based an incurate appoximation of your wheel circumfrence. After 100+ miles you'll be luky if your computer is still accurate to within a mile nevermind a metre.

IF that is the case: then, technology isnt good enough!

 

[Jaded]

After 100+ miles you'll be luky if your computer is still accurate to within a mile nevermind a metre.

My computer is within .5% after 100 miles. I've checked it many times against an Ordnance Survey map

 

[Over The Hill]

or look in the instructions - it comes with a table of size tyres to set.

If you do the Longers way make sure you are on the bike as it will come up a bit less. (deformation of tyre x pi)

 

[yenrod]

So:

..to do it the Longers way

Mark the road

Then wheel the bike backwards...

Get on the bike...

Ride...(at a slow speed - enough to dead stop)

When your valve is at the bottom of the wheel !!!

STOP



And measure!

 

[joebe]

I once got 47mph out of my Brompton with wireless cateye.



I was waiting for the train doors to open at Isleworth station.

 

[asterix]

While watching the 1st stage of the TdF this afternoon I heard the commentator announce as they were descending an ordinary hill into a village that they were travelling at 50mph (80kph). They were in a large bunch just trundling along, it didn't look fast at all..

 

[HJ]

An old drinking buddy of mine, Chris Yates, said his brother, Shaun could do up to 70 mph on a road bike, and I have no reason to doubt him...

 

[Smokin Joe]

An old drinking buddy of mine, Chris Yates, said his brother, Shaun could do up to 70 mph on a road bike, and I have no reason to doubt him...

Sean would give you a slap in the mouth if he saw you spelling his name like that

 

[doyler78]

Sean would give you a slap in the mouth if he saw you spelling his name like that

No fada then? Séan or Seán

 

[ejls2]

It sounds like the setting is wrong but that's certainly an attainable speed as long as you've got some long enough straight enough roads.

I've managed 88kph on closed roads (garmin and polar magnetic matched), admittedly it was ~25% and I was terrified!

I thought the pros could get pretty close to triple digits coming down the alps?