Shimano R9100-P Powermeter

Discuss light weight issues concerning road bikes & parts.
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benjaminm3
Posts: 46
Joined: Mon Jul 17, 2017 10:17 pm

by benjaminm3

Yeah I used the magnet. I suppose there are two things that are going to help maximize battery life for the power meter:
1) Use of a magnet for cadence
2) Use of a wire between the two strain gauges so that the unit only needs to send one wireless signal.

avispa
Posts: 149
Joined: Tue Mar 11, 2008 2:36 am

by avispa

rasmusic wrote:Yeah, I bet the magnet is to measure cadence. I had the chance to inspect this power meter first hand on the bike of a Sunweb-rider last week, and he had the same magnet. But I can't see why a magnet is a downside.

One reason I think is that not every frame has the same space in that area. I already see that it could be an issue on the Pinarello F8/F10 as they have very tight clearance there. Maybe one could just use a magnet ala SRM below the BB?

Now guys, be easy on Shimano! LOL this is a first generation power meter and its gonna take them a few tries to (let us) work the kinks and satisfy (get rid of) most customer complains. Tho I must say, I do find that for a power house as Shimano, I should bash on them a bit too...

I believe one will always have to calibrate these things before a ride for the foreseeable future no matter who makes a power meter. These things are affected by environmental issues that will affect the performance of the units, thus the daily calibration.
Last edited by avispa on Mon Oct 30, 2017 8:59 pm, edited 2 times in total.

avispa
Posts: 149
Joined: Tue Mar 11, 2008 2:36 am

by avispa

benjaminm3 wrote:2) Use of a wire between the two strain gauges so that the unit only needs to send one wireless signal.

I have always wondered what is the deal with having strain gauges for both legs! The main principle of a power meter has been to measure the power of forward motion. What difference does it make to know one leg is being more lazy than the other. Unless of course, you are using this feature after injury and to improve the pedaling efficiency, then. But on a race!!!???

I could see Froome saying: Gee Dave, I got kicked in the arse today by Quintana because my left leg was only doing 220 watts, while my right one only 310!

:P :P

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TonyM
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Joined: Thu Jan 22, 2015 4:11 pm

by TonyM

It might be easier to improve the "lazier" leg instead of improving the "stronger" leg. Just a though.

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micky
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by micky

If you focus on improving the wearker one, you aren't training the other one and missing the training for the "whole package".
But this is a subject for another topic, not here.

ccparkhill
Posts: 8
Joined: Fri Oct 04, 2013 1:56 pm

by ccparkhill

avispa wrote:
benjaminm3 wrote:2) Use of a wire between the two strain gauges so that the unit only needs to send one wireless signal.

I have always wondered what is the deal with having strain gauges for both legs! The main principle of a power meter has been to measure the power of forward motion. What difference does it make to know one leg is being more lazy than the other. Unless of course, you are using this feature after injury and to improve the pedaling efficiency, then. But on a race!!!???

I could see Froome saying: Gee Dave, I got kicked in the arse today by Quintana because my left leg was only doing 220 watts, while my right one only 310!

:P :P

Don’t single-sided soloutions just double what they measure? So in your example you’d either see 440 or 620 instead of 530.

avispa
Posts: 149
Joined: Tue Mar 11, 2008 2:36 am

by avispa

ccparkhill wrote:
avispa wrote:
benjaminm3 wrote:2) Use of a wire between the two strain gauges so that the unit only needs to send one wireless signal.

I have always wondered what is the deal with having strain gauges for both legs! The main principle of a power meter has been to measure the power of forward motion. What difference does it make to know one leg is being more lazy than the other. Unless of course, you are using this feature after injury and to improve the pedaling efficiency, then. But on a race!!!???

I could see Froome saying: Gee Dave, I got kicked in the arse today by Quintana because my left leg was only doing 220 watts, while my right one only 310!

:P :P

Don’t single-sided soloutions just double what they measure? So in your example you’d either see 440 or 620 instead of 530.


No.... not all power meters do this and not even SRM.

And what about 440 and 620? That’s the average/peak wattage these guys are claiming they do, especially on mountain stages.

avispa
Posts: 149
Joined: Tue Mar 11, 2008 2:36 am

by avispa

toiyuet wrote:
TonyM wrote:
toiyuet wrote:I find an second-hand brand new for sale here, Hong Kong.

Why would someone sell it ? :shock:

Don't know.
When someone asked where did the seller get it, he just said "business secret"

And that price? Japanese Yen? $9700 seems to be too high for any power meter!

avispa
Posts: 149
Joined: Tue Mar 11, 2008 2:36 am

by avispa

micky wrote:If you focus on improving the wearker one, you aren't training the other one and missing the training for the "whole package".
But this is a subject for another topic, not here.


WORD!!! :mrgreen:

climber8
Posts: 107
Joined: Fri Oct 29, 2010 6:10 am

by climber8

micky wrote:If you focus on improving the wearker one, you aren't training the other one and missing the training for the "whole package".
But this is a subject for another topic, not here.


Power imbalances are normal and not a sign that anything is 'wrong' with a rider. Further, they have shown to be non-linear, meaning one could be balanced at easy pace (e.g. endurance) and imbalanced at VO2max efforts.

Other than recovery from injury, there has been no proof that there is anything *actionable* to do when one discovers an imbalance.

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toiyuet
Posts: 169
Joined: Wed Dec 14, 2011 2:47 pm
Location: Hong Kong

by toiyuet

avispa wrote:
toiyuet wrote:
TonyM wrote:
toiyuet wrote:I find an second-hand brand new for sale here, Hong Kong.

Why would someone sell it ? :shock:

Don't know.
When someone asked where did the seller get it, he just said "business secret"

And that price? Japanese Yen? $9700 seems to be too high for any power meter!

$ 9700HKD / 7.79 = $ 1245USD

TurboKoo
Posts: 427
Joined: Wed Oct 29, 2008 7:55 pm

by TurboKoo

Image
Everything included 570g without chainrings.
Scott Foil
Shimano 9150
Shimano FCR-9100-P
Shimano C60 tubulars

Delorre
Posts: 913
Joined: Sat May 24, 2014 12:09 pm

by Delorre

TurboKoo wrote:Image
Everything included 570g without chainrings.


Add 160gr for chainrings, and you are not significantly lower than a Power2max or Quarcq, for the same price. Seems 4iiii dual of Stages dual is a better WW deal.

TurboKoo
Posts: 427
Joined: Wed Oct 29, 2008 7:55 pm

by TurboKoo

It's 80g heavier than without powermeter.
Scott Foil
Shimano 9150
Shimano FCR-9100-P
Shimano C60 tubulars

mds
Posts: 199
Joined: Sat Dec 13, 2008 6:28 pm
Location: California

by mds

I received my R9100-P today, express from alex's cycles. It has mid compact chainrings and replaces my 6 year old SRM 7900 standard. I upgraded my SRM PC7 head to PC8 GPS, hopefully the Shimano will work OK with it. The Shimano looks good. The control box door and hinge seems lightweight, hopefully not too fragile. I am glad the connector is magnetic and not USB.
Attachments
R9100-P recharge.jpg
2009 Look 595

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