SRM ditching Shimano?

Discuss light weight issues concerning road bikes & parts.
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pritchet74
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by pritchet74

Great review on the new Shimano power meter. It looks like "Stages" tech which I have never really been a fan of - friends that have had Stages tell me that they don't get accurate data from sprints and accelerations.

http://www.cyclingnews.com/reviews/shim ... er-review/

I will be happily sticking with my SRMs for the foreseeable future.
Have you ever wondered if there was more to life, other than being really, really, ridiculously good looking?

avispa
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by avispa

pritchet74 wrote:
Sun Jan 28, 2018 6:36 pm
Great review on the new Shimano power meter. It looks like "Stages" tech which I have never really been a fan of - friends that have had Stages tell me that they don't get accurate data from sprints and accelerations.

http://www.cyclingnews.com/reviews/shim ... er-review/

I will be happily sticking with my SRMs for the foreseeable future.
Me too... On a separate thread we briefly discussed the value of power meters measuring both legs. After reading this review, I think this can be an issue of concern to anyone really thinking about a system that measures both legs.

by Weenie


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TonyM
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by TonyM

avispa wrote:
Mon Jan 29, 2018 1:41 am
pritchet74 wrote:
Sun Jan 28, 2018 6:36 pm
Great review on the new Shimano power meter. It looks like "Stages" tech which I have never really been a fan of - friends that have had Stages tell me that they don't get accurate data from sprints and accelerations.

http://www.cyclingnews.com/reviews/shim ... er-review/

I will be happily sticking with my SRMs for the foreseeable future.
Me too... On a separate thread we briefly discussed the value of power meters measuring both legs. After reading this review, I think this can be an issue of concern to anyone really thinking about a system that measures both legs.

As far as I understand the Dura Ace powermeter delivers correct values for the total power (L+R) but wrong values for the left and right, so therefore one being too low and the other one being too high which makes a L/R analysis not accurate.

So if someone has an imbalance L/R (most of us I suppose) they will get have an accurate and reliable value for the total power - but they could not check the L/R imbalance nor correct it (if they want to).

Delorre
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by Delorre

pritchet74 wrote:
Sun Jan 28, 2018 6:36 pm
Great review on the new Shimano power meter. It looks like "Stages" tech which I have never really been a fan of - friends that have had Stages tell me that they don't get accurate data from sprints and accelerations.

http://www.cyclingnews.com/reviews/shim ... er-review/

I will be happily sticking with my SRMs for the foreseeable future.
Besides incorrect L / R balance, what bothers me more, is the poor temp compensation. In Belgium, mornings can be really chill all year around, but around noon, you can have 20°c or more, so temp. compensation is an important feature. This also causes some headaches for clothing sometimes :?

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pritchet74
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by pritchet74

Delorre wrote:
Mon Jan 29, 2018 10:12 am
Besides incorrect L / R balance, what bothers me more, is the poor temp compensation. In Belgium, mornings can be really chill all year around, but around noon, you can have 20°c or more, so temp. compensation is an important feature.
This is my concern as well. The auto zero offset feature on the PC8 is fantastic for taking care of temperature compensation. Back in the old PCV days when I started a ride in the morning when it was cold out I would reset the zero offset during a ride as the temp increased to ensure accuracy. I still sometimes check it during those early rides and the PC8 has always taken care of it for me.
Have you ever wondered if there was more to life, other than being really, really, ridiculously good looking?

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TonyM
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by TonyM

pritchet74 wrote:
Mon Jan 29, 2018 4:45 pm
Delorre wrote:
Mon Jan 29, 2018 10:12 am
Besides incorrect L / R balance, what bothers me more, is the poor temp compensation. In Belgium, mornings can be really chill all year around, but around noon, you can have 20°c or more, so temp. compensation is an important feature.
This is my concern as well. The auto zero offset feature on the PC8 is fantastic for taking care of temperature compensation. Back in the old PCV days when I started a ride in the morning when it was cold out I would reset the zero offset during a ride as the temp increased to ensure accuracy. I still sometimes check it during those early rides and the PC8 has always taken care of it for me.
Sorry to ask but I am not sure I understood it correctly; Does the PC8 perform an automatic temperature compensation with the Dura Ace powermeter ?

BdaGhisallo
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by BdaGhisallo

Sorry to ask but I am not sure I understood it correctly; Does the PC8 perform an automatic temperature compensation with the Dura Ace powermeter ?




Yes, the PC8 has an 'auto zero offset' feature that will reset the slope automatically if it gets (I think) a 3 second period of no pedaling. This zero offset reset is how SRM accommodates temperature induced changes in the PM sensitivity.

goodboyr
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by goodboyr

BdaGhisallo wrote:Sorry to ask but I am not sure I understood it correctly; Does the PC8 perform an automatic temperature compensation with the Dura Ace powermeter ?




Yes, the PC8 has an 'auto zero offset' feature that will reset the slope automatically if it gets (I think) a 3 second period of no pedaling. This zero offset reset is how SRM accommodates temperature induced changes in the PM sensitivity.
That feature is what causes some problematic issues with SRM's. Under certain conditions it will give a bad offset which screws up your power readings. Much better to leave that off and only do a manual zero offset initiated by the rider. There's lots of discussion about this in forum threads.

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Calnago
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by Calnago

Yes, agreed. I actually prefer the Garmin head unit to the SRM unit even though I wouldn’t trade my SRM power meters for anything else. The Garmin head units have an autozero function which I experimented with a bit. I prefer to leave it off. If I’m out for a very long time and the temperature swings widely, and I care, I can manually reset the offset in a controlled manner, stopped and off the bike. But I rarely care that much to do it. Only did it to experiment a bit with the function after reading much about it as @goodboyr was referencing.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
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BdaGhisallo
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by BdaGhisallo

goodboyr wrote:
Mon Jan 29, 2018 7:33 pm
BdaGhisallo wrote:Sorry to ask but I am not sure I understood it correctly; Does the PC8 perform an automatic temperature compensation with the Dura Ace powermeter ?




Yes, the PC8 has an 'auto zero offset' feature that will reset the slope automatically if it gets (I think) a 3 second period of no pedaling. This zero offset reset is how SRM accommodates temperature induced changes in the PM sensitivity.
That feature is what causes some problematic issues with SRM's. Under certain conditions it will give a bad offset which screws up your power readings. Much better to leave that off and only do a manual zero offset initiated by the rider. There's lots of discussion about this in forum threads.

Sent from my SM-G950W using Tapatalk
I do agree with you. I have never used the auto zo myself, but some do.

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ms6073
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by ms6073

Calnago wrote:
Mon Jan 29, 2018 8:13 pm
The Garmin head units have an autozero function which I experimented with a bit. I prefer to leave it off.
Ditto. Garmin introduced that feature in a firmware update a couple year back and it was enabled by default. I noticed after a ride in rolling terrain my power numbers dropped off minuscule values right after a short descent and review of the power file showed that the zero-offset had reset right as I started pedaling up the start of the next roller - turned off the auto-zero function before the next ride!
Michael - The Anaerobic Threshold is neither...

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Calnago
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by Calnago

The way I noticed it was that before every ride I would use the "Calibrate" function in Garmin, which is really just a zero offset. It would show the previous calibration, which sometimes seemed to be different than what I remembered having seen it calibrate to the day before. That was puzzling to me... how was it changing on it's own I thought. Well, it was the damn "autocalibration" that was occurring on rides. So I turned it off. If I feel the weather conditions have changed enough during a ride (and I generally never feel that way), then I might reset the offset mid ride, but I just don't care that much to be honest. I like the consistent accuracy of the SRM, and I also like to know that if things change slightly weatherwise, it's only me that controls whether the offset needs to change or not.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
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ms6073
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by ms6073

Calnago wrote:
Mon Jan 29, 2018 9:34 pm
It would show the previous calibration, which sometimes seemed to be different than what I remembered having seen it calibrate to the day before.
That is kind of how I gauge our SRM's battery life, as I take notice when the zero-offset starts drifting consistently from offset to offset. While I have been an SRM customer since the days of the PC-V and wired SRM's, having found a new R9100-P on Ebay for a song, I am going to take the plunge. While I can change the batteries in our SRM's, I have never been a fan of having to ship the crank to SRM for firmware updates, and the Shimano model allows user updates and recharging, and while I use WKO 4, I rarely look at the left-right balance metrics.
Michael - The Anaerobic Threshold is neither...

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