boshk

Wondering why there isn't more compatibility within crank based powermeter.

I did a lot of reading and research on most of the pm available now but still confused.

Pedal based like Powetap P1 are universal, they fit every crank.

Cranks like 4iiii and Stages fit all their respective brands... Stages shimano 105 fits shimano 105 crankset.

Now when it gets to crank based ones like Quarq, power2max, Rotor, it's very different.

I was set on power2max or Quarq but they don't make their specs to fit a 'standard shimano'

I may have misread the info, but I always thought for example a standard shimano ultegra crankset is 4 bolts and 24mm axles.

Power2max offer the 3d24 which is 24mm, great, pull my ultegra out and slot it straight in but it's 5bolts which means I can only use praxis chainring and not my ultegra rings.

Quarq makes a Shimano pm, Dfour, specifically made for Shimano according to their website... Great! so I can use my ultegra chain rings BUT it's 30mm axles or a sram 22-24mm gxp axle.

Is it a licencing issue, patent issue?