Power Meters
- Thread starter Zofo
- Start date
Page may contain affiliate links. Please see terms for details.
Ningishzidda
Senior Member
Look at any turbo with power output, making sure it has REPEATABILITY, not necessarily accuracy.
You could, like some others, measure yourself, bike and road to the n th degree, to get a prediction tool.
As long as the apparatus has repeatability and you get a reasonable measure of your W for kmh by doing a simple hill test, you can use the apparatus as a comparator to compare this week's result with last.
With any laboratory experiment, there will be factors which cause it to be different from reality. Try to make these factors constants.
For example if rolling down a hill results in a figure of 200 W for 22 mph, tune the Bushido using its gradient adjustment so it is absorbing 200 W when its doing 22 mph.
Then you can do CP20s every week on the same set point to see any improvement.
You could, like some others, measure yourself, bike and road to the n th degree, to get a prediction tool.
As long as the apparatus has repeatability and you get a reasonable measure of your W for kmh by doing a simple hill test, you can use the apparatus as a comparator to compare this week's result with last.
With any laboratory experiment, there will be factors which cause it to be different from reality. Try to make these factors constants.
For example if rolling down a hill results in a figure of 200 W for 22 mph, tune the Bushido using its gradient adjustment so it is absorbing 200 W when its doing 22 mph.
Then you can do CP20s every week on the same set point to see any improvement.
jdtate101
Ex-Fatman
- Location
- Boring Birmingham
I own both a P2M (Mk2 varient) and a powertap, and of the two I'd recommend the P2M any day. My powertap has given me nothing but trouble and I wish I'd never bought it. Some things that have gone wrong:
1) Wheel going out of true constantly (despite being built twice by the best wheel builder in the Midlands)
2) Bearings shot after a nasty rain shower (within warranty so repair FOC)
It seems reasonably stable right now and I'm going to use it in my TT bike. The truing issue only happened under very high torque loads (ie sprinting and attacking on climbs), so it should be ok in a TT bike where the torque load is more even and less "jumpy".
Never had a single issue with the P2M...it's faultless so far.
1) Wheel going out of true constantly (despite being built twice by the best wheel builder in the Midlands)
2) Bearings shot after a nasty rain shower (within warranty so repair FOC)
It seems reasonably stable right now and I'm going to use it in my TT bike. The truing issue only happened under very high torque loads (ie sprinting and attacking on climbs), so it should be ok in a TT bike where the torque load is more even and less "jumpy".
Never had a single issue with the P2M...it's faultless so far.
Did you fit P2M yourself? It's not very clear on their website if its compatible with Ultegra system
Rob3rt
Man or Moose!
- Location
- Manchester
There are many different versions of the P2M much like with the other crank based PM's, which one are you looking at? At least one is bound to work, if not half a dozen of the various versions. You will need to buy the right bottom bracket of course.
Rob3rt---I'm totally confused by their website I'm afraid! Don't think I'd have much confidence to mail order and that the right unit would turn up, so think I'll pass on that one.
It looks like Power is the right way for me to go as I need to get as much training benefit out of as little time as possible. I reckon that, eventuall,y the pedal based system is the way to go in terms of flexibility--can swop from bike to bike- and functionality--ability to split L/R foot power profile + abilty to monitor correct pedalling technique etc. So reckon I'll hang on for Garmin to bring their Vector system to market , hopefully sometime later this year
Rob3rt
Man or Moose!
- Location
- Manchester
It takes 5 minutes or less to swap a crank based PM.
View: http://www.youtube.com/watch?v=ibycOXD-Mw0
Brave man buying the 1st gen of a power meter! Doubly brave buying such a product from Garmin, you will be a beta tester, but paying >£1000 for the privilege.
View: http://www.youtube.com/watch?v=ibycOXD-Mw0
Brave man buying the 1st gen of a power meter! Doubly brave buying such a product from Garmin, you will be a beta tester, but paying >£1000 for the privilege.
jdtate101
Ex-Fatman
- Location
- Boring Birmingham
The P2M is a crank and I chose the Rotor 3D system as it uses the same 24mm axel as all shimano cranks, therefore you can directly swap the Rotor based P2M into existing shimano BB's.
I'd second what rob3rt said about the vector, by all accounts it has suffered badly from quality control issues and will probably only see the light of day in 2014, even then it's going to be expensive.
T.M.H.N.E.T
Rainbows aren't just for world champions
- Location
- Northern Ireland
FSA Gossamer is Hollowtech 2 compatible (hollowtech 2 being 24mm Axle with outboard bearings.)It looks like Power is the right way for me to go as I need to get as much training benefit out of as little time as possible. I reckon that, eventuall,y the pedal based system is the way to go in terms of flexibility--can swop from bike to bike- and functionality--ability to split L/R foot power profile + abilty to monitor correct pedalling technique etc. So reckon I'll hang on for Garmin to bring their Vector system to market , hopefully sometime later this year
I agree with everyone else. Crank based is the way forward at the moment. Pedal based systems may never really take off, and their advantages are dubious anyway.
My next PM will be a P2M or SRM depending on fund situation. And that's despite being very happy with the Powertap so far. It also somehow seems that one power meter just isn't enough
My next PM will be a P2M or SRM depending on fund situation. And that's despite being very happy with the Powertap so far. It also somehow seems that one power meter just isn't enough
Ningishzidda
Senior Member
I agree with everyone else. Crank based is the way forward at the moment. Pedal based systems may never really take off, and their advantages are dubious anyway.
My next PM will be a P2M or SRM depending on fund situation. And that's despite being very happy with the Powertap so far. It also somehow seems that one power meter just isn't enough
This is true. A half decent engine tester will have a torque meter on the flywheel between engine and driveshaft, and an 'S' strainguage on the dynamometer between brake and frame.
I've got a Dura-Ace press fit BB, do you think this would be easy enough to fit myself?
jdtate101
Ex-Fatman
- Location
- Boring Birmingham
