How good are the power meters that are in the pedals or attached to the cranks? They seem to add minimal weight...
There are quite an array of power meters that are pedal/crank based (basically everything bar Powertap!).
Some are heavy, some aren't.
- SRM are the gold standard, big money, fairly light
- Power2Max look very interesting and sensibly priced, adds a reasonable chunk of weight
- Quarq are owned by SRAM, lighter than Power2Max, you have to glue a magnet to your frame for the cadence reed switch, in between P2M and SRM price
- Pioneer are messing around with a new system which is hideously expensive, bit of an unknown
- Polar/Look do some pedals, not ANT+, so you have to use the Polar head unit
- Garmin Vector pedals are very light, pretty expensive, reliant on accurate set up of 'pods' on the cranks
- Stages do a LH only crank unit, cheapest solution, works on assuming your power is 50:50 distribution and doubling the output from the LH side, perfectly good for most, lightest solution - only adds 20g
- Xpedo have just announced some Keo compatible pedals with all the gubbins in the pedal. Looks a little heath robinson, but they're meant to be pretty good value.
Personally if I was starting out now I'd get either P2M or Stages. Neither require any hardware on the bike, other than the unit itself, so you can move it around if you want.