power meter compatibility

vin31

I was hoping someone more knowledgable than me could shed some light on this, I currently have a specialized allez sport running 105 5800 as a winter/training bike, my good/race bike is a focus izalco team running SRAM force 22. I was wondering is it posible to get a crank based power meter which is interchangable between the two bikes, the allez runs BSA bottom bracket with external cups while the Focus is PF30 bottom bracket.

Any help will be much appreiciated.

dilatory

No*, pedal based power meter is your only hope outside of a powertap.



*You can get PF30 to BSA adapters etc but why would you want to and you'll end up spending more anyway.

StillGoing

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19727554#p19727554]vin31[/url] wrote:

I was hoping someone more knowledgable than me could shed some light on this, I currently have a specialized allez sport running 105 5800 as a winter/training bike, my good/race bike is a focus izalco team running SRAM force 22. I was wondering is it posible to get a crank based power meter which is interchangable between the two bikes, the allez runs BSA bottom bracket with external cups while the Focus is PF30 bottom bracket.

Any help will be much appreiciated.

If you want crank based then it is possible. A Power2max is crank based with left (estimated) and right power balance. You'd need to buy a system already mounted to a crank of your choice then simply switch it to whichever bike you want to use it on. I do exactly that with a Rotor 3D with a Power2max type S. One bike is PF BB386 EVO and uses FSA adapters to fit the crankset, but it works perfectly well. The other bike has no such problem being English threaded to take a Rotor BB. It's a quick enough job to swap cranks over and provided you're using the same big chain ring size, there's no need t be messing around with the front derailleur height.

amaferanga

A Power2max is crank based with left (estimated) and right power balance.

That's about as clear as mud...

P2M measures TOTAL power from both legs since the strain gauges are in the spider. L/R balance is estimated, but then it's a fairly pointless metric anyway so it's not even worth worrying about.

P2M are like SRM, Quarq, etc. which all measure total power, unlike the double-it-and-hope-for-the-best approach of Stages.

StillGoing

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19727910#p19727910]amaferanga[/url] wrote:

A Power2max is crank based with left (estimated) and right power balance.

That's about as clear as mud...

P2M measures TOTAL power from both legs since the strain gauges are in the spider. L/R balance is estimated, but then it's a fairly pointless metric anyway so it's not even worth worrying about.

P2M are like SRM, Quarq, etc. which all measure total power, unlike the double-it-and-hope-for-the-best approach of Stages.

I completely agree that L/R balance is not worth worrying about. Point I was trying to make though is that it is possible to have a crank based power meter and be able to swap it between bikes even if the BBs are different.

clogg

Buy a power2max sram compatible powermeter,
http://www.power2max.de/europe/en/Produkt/power-meters-en/power2max-type-s-sram-s900-and-force22-without-cranks-road/

You can even fit it on your current force 22 crankarms and change the rings over, its a 5 minute job . You just then need to get a bsa threaded Sram gxp bottom bracket for when you want to run it on the Allez.

vin31

Thanks folks, I had ideally been looking at the Power2max as they seem well regarded and competitively priced. It would mostly be used on the training bike but would be nice to have the option of racing with it if I chose to.

proto

Convert the PF30 bike to BSA with one of these:

http://www.chainreactioncycles.com/fsa-pf30-threaded-adapter-b3167-/rp-prod129936

then fit any BSA crank powermeter you like. I can recommend the Quark Elsa GXP.

vin31

Just as a follow up to my original query, i now have a power2max power meter mounted on rotor 3d30 crankset whihc i can use with my training bike in a rotor BSA 30 BB, this crankset is also compatibile with my PF30 BB in the focus and as a bonus I can run it in my TT bike as well just need to make sense of the numbers now.

Anonymous

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19729338#p19729338]proto[/url] wrote:

Convert the PF30 bike to BSA with one of these:

http://www.chainreactioncycles.com/fsa-pf30-threaded-adapter-b3167-/rp-prod129936

then fit any BSA crank powermeter you like. I can recommend the Quark Elsa GXP.

I fit one of these on one of my bikes to convert from bb30 to threaded. But in doing so you will invalidate your warranty if you have one still on your bike.