power meter Q again, compatibility

Discuss light weight issues concerning road bikes & parts.
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Boshk
Posts: 311
Joined: Wed Jul 19, 2017 2:59 am

by Boshk

New here but it seems you guys talk a fair bit about power meters.

I'm 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 arm.

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 (for the price) 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 model which is 24mm, so I'm thinking great!, pull my ultegra out and slot it straight in but it's 5bolts which means I can only use praxis chainrings and not my ultegra rings.

Quarq makes Dfour model, 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?
thoughts?
Colnago C60

by Weenie


wingguy
Posts: 4194
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

It's a "how many different versions of the same product can we afford to design, tool for and hold stock of". It's not a powermeter issue per se, it's an issue of how many BB standards and chainring standards already exist.

For spider or axle based PMs sold as complete cranks if you produced compatibility for every possible combination of bolt spacing and axle size you could be looking at 15+ products for what is fundamentally one type of powermeter. That gets very complicated and very expensive very quickly.

And as far as Quarq goes specifically, they're certainly not going to make a hollowtech 24mm spindle. Sram/quarq make GXP BBs. When they sell you a powermeter or chainset they want you to buy their BBs for it now and in future. They don't want you to go off and buy BBs from Shimano instead :wink:

Boshk
Posts: 311
Joined: Wed Jul 19, 2017 2:59 am

by Boshk

wingguy wrote:It's a "how many different versions of the same product can we afford to design, tool for and hold stock of". It's not a powermeter issue per se, it's an issue of how many BB standards and chainring standards already exist.

For spider or axle based PMs sold as complete cranks if you produced compatibility for every possible combination of bolt spacing and axle size you could be looking at 15+ products for what is fundamentally one type of powermeter. That gets very complicated and very expensive very quickly.

And as far as Quarq goes specifically, they're certainly not going to make a hollowtech 24mm spindle. Sram/quarq make GXP BBs. When they sell you a powermeter or chainset they want you to buy their BBs for it now and in future. They don't want you to go off and buy BBs from Shimano instead :wink:


Hi, thanks. So taking example of Quarq, they make a Shimano version DFour but only for their GXP BBs or BB30s.
So unless my bike is a BB30 or GXP 24/22, is it worth switching out my current BB for theirs?
Will it create more problem than its worth?
Or is it just a straight swap of the BB from a Shimano Pressfit on a Canyon bike to a GXP 24/22 BB installed into the Canyon bike?
Colnago C60

wingguy
Posts: 4194
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

Straight swap. GXP is equally compatible with the Canyon BB shell as Shimano Hollowtech is. Both designed to be a native fit in the same frames.

sp3000
Posts: 174
Joined: Thu Aug 21, 2014 7:12 am
Location: Sydney

by sp3000

GXP will fit Shimano

TobinHatesYou
Posts: 1776
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

sp3000 wrote:GXP will fit Shimano


This is cryptic. GXP will fit GXP. Shimano will fit Shimano. With a Shimano BB you would need a shim on the NDS side of the BB because GXP spindles are stepped 22/24mm.

pdlpsher1
Posts: 1689
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

If you are not in a hurry you can always wait for the Shimano DA powermeter. That powermeter will be a direct swap with your Ultegra crankset. Price wise it will be similar to a Quarq Dfour, I imagine.

by Weenie


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