Campagnolo SR WRL Powermeter Released

[drgonzo]

So does anyone have an idea what the heck are those covered up cut-outs on the inside of the non-power meter crank arms?? I thought those were supposed to be for the power meter strain gauges.

[Mark McM]

Originally Posted by drgonzo

So does anyone have an idea what the heck are those covered up cut-outs on the inside of the non-power meter crank arms?? I thought those were supposed to be for the power meter strain gauges.

The understanding is that Campagnolo protoyped a crankarm based power meter, but were unhappy with the accuracy and went with a spider based power meter instead. Strain gauges don't give as consistent a result on iso-tropic materials like carbon fiber, which is why most power meters apply their strain gauges to metal (aluminum) surfaces.

[robertbb]

Originally Posted by Mark McM

The folks over at Weight Weenies think that the SR WRL power meter was made in partnership with SRM, based on the description of the status LEDs. Looking at the manuals for each, I have to agree that the status LED operation appears to be identical, which certainly implies similar firmware:

I would have thought this was obvious just by looking at the thing without the flashy LED's.

No need for Campy to start from ground up here if they can partner up. They'd have learned from Shimano's repeat stuff ups too in the PM space.

My curiosity is around the commercials between the two companies, seeing as though Campy branded PM may eat into SRM's own sales. Clearly a compromise was struck that is of benefit to both parties.

[bicycletricycle]

I don’t really know how accurate the average power meter is but this seems like it might be deep into diminishing returns.

Can anyone point me to a good read on comparative accuracies of different power meters? Do some drift over the time and need recalibration? Do manufacturers offer recalibration? I think I remember sending an early SRM back for calibration (square taper with that crazy SRM handlebar computer, was it wired??

For most people using these for training I would imagine consistency is more important than absolute accuracy?

Originally Posted by m_sasso

More Tech-for-tech sake, when people use technology simply because they can rather than because they should or need it. One percent accuracy precision in a road Power Meter is a complete waste of quality. Scientific testing different story. Like driving a two hundred plus mph automobile on public roads.

[gravelreformist]

Originally Posted by bicycletricycle

I don’t really know how accurate the average power meter is but this seems like it might be deep into diminishing returns.

Can anyone point me to a good read on comparative accuracies of different power meters? Do some drift over the time and need recalibration? Do manufacturers offer recalibration? I think I remember sending an early SRM back for calibration (square taper with that crazy SRM handlebar computer, was it wired??

For most people using these for training I would imagine consistency is more important than absolute accuracy?

Accuracy is pretty important as well because many people will use different power meters at times. In today's data-driven environment, a single ride with a different meter can negatively impact your data in a way that can be difficult to reconcile.

My current experience with 3 different power meters (pedal, crank arm, trainer) is that they are all accurate enough (minus some early issues with the pedals) that I can't tell a difference between them. I think 1% accuracy is a good target. 2% is on the edge. Anything over that is too much.

[bicycletricycle]

What does “negatively impact your data” mean practically? If 1% variance is enough to be a problem , well, isn’t that just a 2-3 watt difference most of the time? I am a total idiot with this stuff so I am genuinely curious.

I would imagine the same ride sone on the same equipment done a couple days apart would yield bigger differences so how can this small of a difference be noticeable?

Originally Posted by gravelreformist

Accuracy is pretty important as well because many people will use different power meters at times. In today's data-driven environment, a single ride with a different meter can negatively impact your data in a way that can be difficult to reconcile.

My current experience with 3 different power meters (pedal, crank arm, trainer) is that they are all accurate enough (minus some early issues with the pedals) that I can't tell a difference between them. I think 1% accuracy is a good target. 2% is on the edge. Anything over that is too much.

[gravelreformist]

Originally Posted by bicycletricycle

What does “negatively impact your data” mean practically? If 1% variance is enough to be a problem , well, isn’t that just a 2-3 watt difference most of the time? I am a total idiot with this stuff so I am genuinely curious.

I would imagine the same ride sone on the same equipment done a couple days apart would yield bigger differences so how can this small of a difference be noticeable?

1% is good. 2% is ok-ish. Above that is a problem. At 3% that's 9w at 300w output. That's enough to materially change my FTP which is what all my zones are based on. 10w over/under FTP is a big difference.

Edit - Also, those values are +/-. So worst-case, the differences between two different meters are double the above values.

[glepore]

I'm going to get some heat from the Campy fans here, but I have multiple Campy bikes with powermeters and none run Campy cranks or SRM's. The Sigeyi pm's from China are $350, charge magneticly, and fit on pretty much any interface you want except Campy. I run mine on SRAM carbon arms that have been sanded to nude and cleared. Before they were available I ran Elsa's.
I've had SRM's and while I don't doubt that they remain a luxury good type purchase, the Sigeyi and Quarqs are as functionally accurate and precise.
The battery on the Sigeyi is not user replaceable but it costs effectively less to replace than a battery change on Campy, and not much more than SRM.

The shifting works just fine with these cranks and almost any ring. Again, I'm sure that Vincenza wouldn't approve, but real world it works.

Not bashing Campy, I get that some folks want "the best" regardless of a value proposition but not for me.

[bicycletricycle]

Makes sense , seems like even cheap power meters meet the 2% goal?

Also, I would just like to say that if you only had 1 meter or one type with matching errors across bikes nobody would notice these errors and I doubt it would impact training effectiveness.

I wonder how much a riders FTP changes day on day.

Originally Posted by gravelreformist

1% is good. 2% is ok-ish. Above that is a problem. At 3% that's 9w at 300w output. That's enough to materially change my FTP which is what all my zones are based on. 10w over/under FTP is a big difference.

Edit - Also, those values are +/-. So worst-case, the differences between two different meters are double the above values.

[gravelreformist]

Originally Posted by glepore

I'm going to get some heat from the Campy fans here, but I have multiple Campy bikes with powermeters and none run Campy cranks or SRM's. The Sigeyi pm's from China are $350, charge magneticly, and fit on pretty much any interface you want except Campy. I run mine on SRAM carbon arms that have been sanded to nude and cleared. Before they were available I ran Elsa's.
I've had SRM's and while I don't doubt that they remain a luxury good type purchase, the Sigeyi and Quarqs are as functionally accurate and precise.
The battery on the Sigeyi is not user replaceable but it costs effectively less to replace than a battery change on Campy, and not much more than SRM.

The shifting works just fine with these cranks and almost any ring. Again, I'm sure that Vincenza wouldn't approve, but real world it works.

Not bashing Campy, I get that some folks want "the best" regardless of a value proposition but not for me.

I looked at those and other spider-based options because people quote those low prices, but by the time you add a compatible crankset and chainrings, you're at $900-1000 all-in. At that point I decided I'd rather have the flexibility of pedals.

[glepore]

Originally Posted by gravelreformist

I looked at those and other spider-based options because people quote those low prices, but by the time you add a compatible crankset and chainrings, you're at $900-1000 all-in. At that point I decided I'd rather have the flexibility of pedals.

I don't dispute that. Unfortunately I'm acclimated to Time pedals, and at this point in my life don't want to change over to another interface, so no pedal based option...

[gravelreformist]

Originally Posted by glepore

I don't dispute that. Unfortunately I'm acclimated to Time pedals, and at this point in my life don't want to change over to another interface, so no pedal based option...

Grrr. I hear that. I have been riding Time pedals for 25 years and REALLY did not want to change....

[oldpotatoe]

Originally Posted by huck*this

SRM offers a PowerMeter Comprehensive Service for $200, which includes battery replacement, recalibration, and QC test at least this is for the SRM 9

You can also upgrade other, select SRM to rechargeable USB based SRM 9 boards for $850

I guessed you missed the sarcasm part. Getting a new battery isn't $1000 or even $850....Gad Zooks...

[Mark McM]

Originally Posted by gravelreformist

I looked at those and other spider-based options because people quote those low prices, but by the time you add a compatible crankset and chainrings, you're at $900-1000 all-in. At that point I decided I'd rather have the flexibility of pedals.

I guess if you needed to get fancy matchy-matchy cranks a spider based power meter might be that expensive, but you can get a one for about half that. If you've already got an interchangeable spider crankset, then a Sigeyi power meter spider is only about $380. If you don't have a compatible crankset, then you can currently get an SRAM Rival 22 crankset (3 bolt spider interface, with chainrings) for about $100, for a cost of $480 all-in. If you want carbon crank arms, then get an SRAM Force 22 crankset for about $230, or about $610 all-in.

[glepore]

I can usually find used Force carbon arms for half new, if patient. Last set I did have to buy new as needed gxp 165's and they're rareish. 172.5's easy, bb30 easy, just a difficult combo.