S-Works Power Cranks got me a little confused

Discuss light weight issues concerning road bikes & parts.
Post Reply
gurk700
Posts: 276
Joined: Fri Jan 20, 2017 7:40 pm

by gurk700

I LOVE how predictable S-Works Power Cranks have been. Never drops out, displays predictable numbers and very consistent day to day.

But the left / right balance makes me scratch my head a little.

In the past with dual sided units, I monitored my balance for a week or two and kind of stopped looking at it since I’ve always had 49/51 or 50/50.
With S-works, when I pedal with left only or right only, I still get ~40's%-~50's% readings from the pedal that’s unclipped.
I’m also getting 46%-54% readings consistently on my rides. Nothing has changed. No injuries, no different bike fit. I don’t know why the discrepancy.

Despite all of that though the final number that the unit displays seems very accurate, predictable and repeatable. My outside and inside FTP numbers etc all are similar.
When I average 3-5 watts more on a climb, I get predictably faster times in seconds etc.

So I’m a little puzzled. I wanna ask if anyone who has S-works Power cranks have similar issues.

CAAD8FRED
Posts: 197
Joined: Mon Jun 18, 2018 10:52 pm

by CAAD8FRED

Ben Delaney did a review of either the Tarmac or Venge that had power cranks and he had the same problem of power being displayed from the unclipped pedal while pedaling with only one foot.

by Weenie


gurk700
Posts: 276
Joined: Fri Jan 20, 2017 7:40 pm

by gurk700

I remember seeing that however it was a much lower number like 2% i believe. not that that’s not a problem. But yeah mine shows 40%+ on non pedaling side!

Stueys
Posts: 351
Joined: Sat Nov 22, 2014 1:12 pm

by Stueys

Think unless you've got dual sided (pedals or stages) then the power split is pretty much a guess. I look at my Vector numbers but pretty much ignore the P2M ones.

AZR3
Posts: 802
Joined: Wed Sep 12, 2012 9:00 pm
Location: Az USA

by AZR3

Stueys wrote:
Fri Aug 09, 2019 12:09 pm
Think unless you've got dual sided (pedals or stages) then the power split is pretty much a guess. I look at my Vector numbers but pretty much ignore the P2M ones.
The S-Works power cranks have sensors on both crank arms so they should give accurate L/R balance.

I haven’t read much about them so not sure how reliable they actually are. I’d be nice if GPLama were to test them but seeing as they’ve been out for a while now it doesn’t look likely.

sgtrobo
Posts: 63
Joined: Mon Dec 12, 2016 4:36 am

by sgtrobo

AZR3 wrote:
Fri Aug 09, 2019 12:47 pm
Stueys wrote:
Fri Aug 09, 2019 12:09 pm
Think unless you've got dual sided (pedals or stages) then the power split is pretty much a guess. I look at my Vector numbers but pretty much ignore the P2M ones.
The S-Works power cranks have sensors on both crank arms so they should give accurate L/R balance.

I haven’t read much about them so not sure how reliable they actually are. I’d be nice if GPLama were to test them but seeing as they’ve been out for a while now it doesn’t look likely.
DC Rainmaker reviewed them
https://www.dcrainmaker.com/2018/03/spe ... eview.html

AZR3
Posts: 802
Joined: Wed Sep 12, 2012 9:00 pm
Location: Az USA

by AZR3

sgtrobo wrote:
Fri Aug 09, 2019 1:37 pm
AZR3 wrote:
Fri Aug 09, 2019 12:47 pm
Stueys wrote:
Fri Aug 09, 2019 12:09 pm
Think unless you've got dual sided (pedals or stages) then the power split is pretty much a guess. I look at my Vector numbers but pretty much ignore the P2M ones.
The S-Works power cranks have sensors on both crank arms so they should give accurate L/R balance.

I haven’t read much about them so not sure how reliable they actually are. I’d be nice if GPLama were to test them but seeing as they’ve been out for a while now it doesn’t look likely.
DC Rainmaker reviewed them
https://www.dcrainmaker.com/2018/03/spe ... eview.html
Ive seen that review and while I trust DC, GPLama has been really digging deep into L/R power meters lately and found a fundinental flaw with shimano based dual sided power meters, so just given that it’d be nice to see him have a go with these and see what he finds

jfranci3
Posts: 679
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

How many watts are you pushing when you were testing L/R independently?

TobinHatesYou
Posts: 4023
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

CAAD8FRED wrote:
Thu Aug 08, 2019 4:04 am
Ben Delaney did a review of either the Tarmac or Venge that had power cranks and he had the same problem of power being displayed from the unclipped pedal while pedaling with only one foot.

This only applies to asymmetric drive-side Shimano crankarms, not S-Works power meter cranks.

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post