Crank based power meter questions

Discuss light weight issues concerning road bikes & parts.
cbrshadow
Posts: 35
Joined: Tue Jun 03, 2014 8:12 pm

by cbrshadow

If someone could help me figure this out I would really appreciate it. I need a crankset education. :-)
I'm building up a 2018 Venge with OSBB (basically BB30) bottom bracket. I want to get a crank-based power meter through CleverTraining.com like this:
https://www.clevertraining.com/quarq-dz ... meter-alum

If I purchased this in BB30, would I just need to buy "rings" and attach them? What rings would I be limited to?

What does it mean to have "hidden bolt" vs. "Non-hidden bolt"?

There are a ton of options on their site for Quark power meters but I'm stuck on which to go with. Through DC-Rainmaker there's a 20% off deal so I'd like to get it through CT.com

Thanks for any help!

by Weenie


alcatraz
Posts: 2057
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Bb30 cranks lose a lot of value because less manufacturers use the standard. (Personally I like bb30. Just feel I should tell you.)

Make sure you are going to use this bike for a few years at least so you don't get buyers remorse.

Hidden bolt is a standard sram uses on some of their cranks and chainrings (bolt mounts are shifted). Only some chainrings are compatible with both.

If you prefer to use sram chainrings or certain hidden bolt compatible ones you're ok to go with the hidden bolt standard. If not then go with standard mount. The few hidden bolt only chainrings there are will not be compatible.

I would imagine the resell value of hidden bolt cranks would be lower.

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Lewn777
Posts: 725
Joined: Thu Mar 09, 2017 5:35 am

by Lewn777

Yes as Alcatraz says this is basically similar to a SRAM Red power meter and crank for BB30 or GXP bottom bracket. I prefer GXP becuase I think it's less prone to creaking (but heavier). I'd run it with a Praxis conversion BB https://praxiscycles.com/product/conv-bb-sram-gxp-road/. You'll probably need the Specialized version.

I would prefer to call it 'chain ring spider based' power meter rather than 'crank based'.
Use it with SRAM rings or you can run many others.

It should work well with any groupset.
Last edited by Lewn777 on Sun Nov 25, 2018 2:08 am, edited 1 time in total.

TobinHatesYou
Posts: 3611
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

In simplest terms, there is zero benefit to owning a hidden-bolt Quarq vs non-hidden-bolt.

kb1iub
Posts: 8
Joined: Wed Sep 12, 2018 12:50 pm

by kb1iub

Not crank based and this measures both legs. Important to note that most cranks double left leg power. This is more accurate.

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commendatore
Posts: 224
Joined: Mon Dec 30, 2013 1:51 am
Location: North Carolina

by commendatore

kb1iub wrote:Important to note that most cranks double left leg power.
Not sure where you pulled that nonsense from but it is false.

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cveks
Posts: 86
Joined: Mon Aug 21, 2017 8:15 pm
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by cveks

commendatore wrote:
Tue Nov 27, 2018 1:47 am
kb1iub wrote:Important to note that most cranks double left leg power.
Not sure where you pulled that nonsense from but it is false.
same...

kb1iub
Posts: 8
Joined: Wed Sep 12, 2018 12:50 pm

by kb1iub

Do you know what a crank applied unit reads? One side.

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sennder
Posts: 106
Joined: Mon Aug 08, 2016 12:13 pm

by sennder

kb1iub wrote:
Mon Dec 03, 2018 3:35 am
Do you know what a crank applied unit reads? One side.

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I think it would be better to distinguish between crankarm based and crank spider based here. Crank spider based power meters transmit actual power. Many (perhaps even most) crankarm based power meters are single sided, though pretty much every crankarm pm manufacturer (4iiii, stages, pioneer, etc.) now also do double sided power.

Sennder

TobinHatesYou
Posts: 3611
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

kb1iub wrote:
Mon Dec 03, 2018 3:35 am
Do you know what a crank applied unit reads? One side.

Pioneer, Stages, 4iiii, etc. all make single-sided and dual-leg crank power meters, so you what is your point?

petromyzon
Posts: 377
Joined: Mon Apr 05, 2010 4:14 pm

by petromyzon

I run Praxis Buzz rings on my DZero. They can be run in a hidden bolt or a non-hidden bolt configuration. I highly recommend them.

HB just means that one of the 5 chainring bolts plugs in behind the crankarm. It's standard for SRAM Red but has minimal benefit. NHB is more common and will allow you to use the cranks with other, older 5 bolt compact chainrings. It is a discussion that will go away with the latest generation of groupsets (Shimano and SRAM have their own 4 bolt setup and new Red Etap looks to be going direct mount).

I can't imagine Quarq, even as part of SRAM, had a fun time having to offer HB and NHB versions of carbon and aluminium cranks. Just go NHB unless you are getting a discount on HB.

BdaGhisallo
Posts: 2262
Joined: Wed Mar 17, 2004 1:38 pm

by BdaGhisallo

kb1iub wrote:
Mon Dec 03, 2018 3:35 am
Do you know what a crank applied unit reads? One side.

Sent from my Moto E (4) using Tapatalk
Not true. A crank with the powermeter in the spider with an array of strain gauges , as is the case with SRM, Quarq and Power2Max, will read the actual torque applied throughout the pedal circle by both left and right legs.

TobinHatesYou
Posts: 3611
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

petromyzon wrote:
Mon Dec 03, 2018 8:07 am
I run Praxis Buzz rings on my DZero. They can be run in a hidden bolt or a non-hidden bolt configuration. I highly recommend them.

HB just means that one of the 5 chainring bolts plugs in behind the crankarm. It's standard for SRAM Red but has minimal benefit. NHB is more common and will allow you to use the cranks with other, older 5 bolt compact chainrings. It is a discussion that will go away with the latest generation of groupsets (Shimano and SRAM have their own 4 bolt setup and new Red Etap looks to be going direct mount).

I can't imagine Quarq, even as part of SRAM, had a fun time having to offer HB and NHB versions of carbon and aluminium cranks. Just go NHB unless you are getting a discount on HB.

In the case of DZero spiders there is zero benefit to HB and only inconvenience. The hidden bolt screws into a knurled insert rather than the crankarm itself. I highly advise against the HB option unless you want Red branding.

lazypete
Posts: 18
Joined: Fri May 25, 2018 7:00 pm

by lazypete

I've got a NHB carbon DZero. GXP for max compatibility as I swap it between frames and as far as I could work out everything can fit a GXP in, but not everything can fit a BB30 in (without using really skinny bearings). Also wasn't keen on being restricted to Shimano rings only with the DFour. Run SRAM Red chainrings - the same rings for NHB or HB, they just get mounted differently.

I love it, swaps between bikes in less than a minute, fit and forget simplicity, total (or r+l combined) power. Calibration free chainring changes.

Pete

by Weenie


kafreeman
Posts: 105
Joined: Thu Jul 23, 2015 8:46 pm

by kafreeman

BdaGhisallo wrote:
kb1iub wrote:
Mon Dec 03, 2018 3:35 am
Do you know what a crank applied unit reads? One side.

Sent from my Moto E (4) using Tapatalk
Not true. A crank with the powermeter in the spider with an array of strain gauges , as is the case with SRM, Quarq and Power2Max, will read the actual torque applied throughout the pedal circle by both left and right legs.
Better said... it's the sum of the torque.

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