What is FTP ?

[bruce]

BTW' date=' you can do this on an indoor trainer without a power meter, by using speed (if you have a sensor on your rear wheel)  bruce mentioned it the other day & he was spot on... the speed & power move almost perfect in sync... [/quote']

 

Yup, but there are some important things to note:

Only works on a magnetic trainer because the load vs. speed curve is linear (i.e. a straight line) as pointed out by windbreaker.

You must ensure the rolling resistance is always the same.  In order to do this, the tyre should always be pumped to the same pressure used for the TT, and the tightening knob should always be turned in the same amount.

If you change tyre types you may need to re-run the process.

[Guest Big H]

I suppose on a spin  bike the felt pad resistance kept even will also do??????

[bruce]

I suppose on a spin  bike the felt pad resistance kept even will also do??????

 

Yes, since the frictional force stays constant (kinetic coefficient of friction is fixed), power must increase linearly with velocity.

 

The trick will be getting the felt pad to be applied with the same pressure every time.

[Gumpole]

I suppose on a spin  bike the felt pad resistance kept even will also do??????

 

Yes' date=' since the frictional force stays constant (kinetic coefficient of friction is fixed), power must increase linearly with velocity.

 

The trick will be getting the felt pad to be applied with the same pressure every time.

[/quote']

 

and measuring speed... and measuring cadence..

unless you have a better spinning bike than the VA ones!

[Guest Big H]

I have Polar Speed and cadence sensors mounted to my bike and M has a Cateye Astrale 8 with speed and cadence on hers.