Campagnolo SR WRL Powermeter Released

[Clean39T]

https://bikerumor.com/campagnolo-sup...eter-crankset/

Beautiful. Advanced tech. And a premium price.

The want is strong.

[edgerat]

no more red accents on SR? Kinda love the red.

[Likes2ridefar]

I expected a high cost but it’s even greater than I thought it’d be at 2450! $6900 for the group

Looks like some quality tech for those that want not.

[Zackus]

in 2024 you can spend $2500 on a new super record power meter crankset. or $2500 on a used hand-made steel frame rim-brake road bike built up with 11spd Super Record.

[Likes2ridefar]

Originally Posted by Zackus

in 2024 you can spend $2500 on a new super record power meter crankset. or $2500 on a used hand-made steel frame rim-brake road bike built up with 11spd Super Record.

The exact same thought went through my head as I’m trying to find a new all road frame set. Most of them are around that retail!

[StruggleClimber]

Campy is definitely leaning into the "luxury" market. looks great though

[Mark McM]

Seems like a nice unit, but Campagnolo seems a bit late to the table with this. I don't mean just late to the table with a power meter crank, but actually late to the table with a Campagnolo OEM power meter crank. SRM and Power2Max have been building power spider based power meter cranks with original OEM Campagnolo arms for years. Campagnolo's SR WRL crank appears to be using the same Campagnolo arms that they've been supplying to SRM and Power2Max. The only thing new here is that this cranks uses the SW WRL sub-compact BCD.

Here's the SRM and Power2Max units (notice the Campagnolo logos on the arms, and Campagnolo serial number sticker on the back of the Power2Max NDS arm):





Further reason to think the SR WRL power meter cranks use the same arms as already used by SRM and Power2Max is that the SW WRL cranks have the same limited range of arm lengths as SRM and Power2Max - just 170mm, 172.5mm, and 175mm. This, despite the fact that the non-power meter SW WRL cranks are also available in 165mm. Although I use Campagnolo drivetrains, my preference for 165mm cranks has prevented me from using the SRM or Power2Max Campagnolo cranks, and it looks like I won't be using the SW WRL power meter cranks either.

I wonder though, if Campagnolo will stop supplying arms to other power meter makers, now that they have their own (more expensive) power meter cranks. But European trade laws may prevent that.

[Clean39T]

Originally Posted by Mark McM

Seems like a nice unit, but Campagnolo seems a bit late to the table with this. I don't mean just late to the table with a power meter crank, but actually late to the table with a Campagnolo OEM power meter crank. SRM and Power2Max have been building power spider based power meter cranks with original OEM Campagnolo arms for years. Campagnolo's SR WRL crank appears to be using the same Campagnolo arms that they've been supplying to SRM and Power2Max. The only thing new here is that this cranks uses the SW WRL sub-compact BCD.

Here's the SRM and Power2Max units (notice the Campagnolo logos on the arms, and Campagnolo serial number sticker on the back of the Power2Max NDS arm):





Further reason to think the SR WRL power meter cranks use the same arms as already used by SRM and Power2Max is that the SW WRL cranks have the same limited range of arm lengths as SRM and Power2Max - just 170mm, 172.5mm, and 175mm. This, despite the fact that the non-power meter SW WRL cranks are also available in 165mm. Although I use Campagnolo drivetrains, my preference for 165mm cranks has prevented me from using the SRM or Power2Max Campagnolo cranks, and it looks like I won't be using the SW WRL power meter cranks either.

I wonder though, if Campagnolo will stop supplying arms to other power meter makers, now that they have their own (more expensive) power meter cranks. But European trade laws may prevent that.

The new arms are shaped differently and the new PM appears to basically be an SRM PM-10 .. a more advanced version with more strain gauges .. necessary? Of course not .. cool tech? Yep. And maybe it trickles down over time - alongside more crank lengths for those that want such things.

[Clean39T]

Originally Posted by Zackus

in 2024 you can spend $2500 on a new super record power meter crankset. or $2500 on a used hand-made steel frame rim-brake road bike built up with 11spd Super Record.

Really? SR11 groups are trading above $1k now.. where do I get a hand-made steel frameset, wheels, and finishing kit for $1500?

I get the point, but Campy SRMs when released have been wildly expensive going back to the 11-spd era.

[Mark McM]

Originally Posted by Clean39T

The new arms are shaped differently and the new PM appears to basically be an SRM PM-10 .. a more advanced version with more strain gauges .. necessary? Of course not .. cool tech? Yep. And maybe it trickles down over time - alongside more crank lengths for those that want such things.

Oddly, only the new left (NDS) SR WRL power meter crank appears to be shaped differently, the right (DS) crank appears to have the shape as previously used by other power meters. And that actually makes sense, as only the right crank needs to be special to accommodate the power meter spider. This points to the SR WRL power meter cranks being a bit of a hodge-podge, with a left crank specific to the SR WRL cranksets, but borrowing a right arm from an older OEM product.

As far as more strain gauges? That's not clear either. From the Bike Rumor article:

Those Wheatstone bridges are a bit unique in that the most accurate in-arm power meters (E.g. Infocrank) tend to use 1 Wheatstone bridge per arm with 4 strain gauges to ensure accuracy & temperature compensation. The most accurate spider power meters (E.g. SRM) tend to have 1 or 2 Wheatstone bridges per arm with 4 strain gauges each to ensure accuracy. Campy has 4 Wheatstone bridges placed around the spider (presumably at each arm connecting to the chainrings) with 16 strain gauges in total.

So, "the most accurate spider power meters (E.g. SRM) tend to have 1 or 2 Wheatsone bridges per arm with 4 strain gauges each", which means that (4 arms) x (1 or 2 bridges per arm) x (4 strain gauges each) = 16 to 32 strain gauges. It further says, "Campy has 4 Wheatstone bridges placed around the spider (presumably at each arm connecting to the chainrings) with 16 strain gauges in total," or in other words, the same or fewer bridges and strain gauges as other power meter spiders. Campagnolo claims +/-1% accuracy, but so do SRM and Power2Max.

[jbrainin]

I'd prefer an Ekar powermeter crankset. Or, rather, I really want an Ekar powermeter crankset.

(I'm fine with the SRM/THM M3 and Power2Max/Lightning powermeter cranksets on my Crumpton road bikes.)

[Clean39T]

Originally Posted by Mark McM

Oddly, only the new left (NDS) SR WRL power meter crank appears to be shaped differently, the right (DS) crank appears to have the shape as previously used by other power meters. And that actually makes sense, as only the right crank needs to be special to accommodate the power meter spider. This points to the SR WRL power meter cranks being a bit of a hodge-podge, with a left crank specific to the SR WRL cranksets, but borrowing a right arm from an older OEM product.

As far as more strain gauges? That's not clear either. From the Bike Rumor article:



So, "the most accurate spider power meters (E.g. SRM) tend to have 1 or 2 Wheatsone bridges per arm with 4 strain gauges each", which means that (4 arms) x (1 or 2 bridges per arm) x (4 strain gauges each) = 16 to 32 strain gauges. It further says, "Campy has 4 Wheatstone bridges placed around the spider (presumably at each arm connecting to the chainrings) with 16 strain gauges in total," or in other words, the same or fewer bridges and strain gauges as other power meter spiders. Campagnolo claims +/-1% accuracy, but so do SRM and Power2Max.

The right one is shaped differently too - it doesn't sort of bulge and come back in - not that that matters..

Good point on the strain gauges. Thinking about these is straining my personal gauge.

Reality is I don't need a PM (or HRM) - but they are somewhat useful tools, so I'll probably keep using them. And if I ever go WRL, I'll get this one.

[Zackus]

Originally Posted by Clean39T

Really? SR11 groups are trading above $1k now.. where do I get a hand-made steel frameset, wheels, and finishing kit for $1500?

I get the point, but Campy SRMs when released have been wildly expensive going back to the 11-spd era.

I was looking at this, I believe also advertised in the classifieds.

https://www.ebay.com/itm/19605445188...Bk9SR7zr6Z7VYw

[gfk_velo]

Originally Posted by Mark McM

Oddly, only the new left (NDS) SR WRL power meter crank appears to be shaped differently, the right (DS) crank appears to have the shape as previously used by other power meters. And that actually makes sense, as only the right crank needs to be special to accommodate the power meter spider. This points to the SR WRL power meter cranks being a bit of a hodge-podge, with a left crank specific to the SR WRL cranksets, but borrowing a right arm from an older OEM product.

As far as more strain gauges? That's not clear either. From the Bike Rumor article:



So, "the most accurate spider power meters (E.g. SRM) tend to have 1 or 2 Wheatsone bridges per arm with 4 strain gauges each", which means that (4 arms) x (1 or 2 bridges per arm) x (4 strain gauges each) = 16 to 32 strain gauges. It further says, "Campy has 4 Wheatstone bridges placed around the spider (presumably at each arm connecting to the chainrings) with 16 strain gauges in total," or in other words, the same or fewer bridges and strain gauges as other power meter spiders. Campagnolo claims +/-1% accuracy, but so do SRM and Power2Max.

Bit of background to shed some light on the "if 10 is good, 11 must be better" type discussion ... ...

Wheatstone bridges are a method of measuring dynamic changes in electrical resistance in real time - they are used in this application primarily because they work very well in situations where temperature is a factor, because this is an additional real-time variable. In essence, the solution to the resistance calculation offered by a Wheatstone bridge placed across a stress gauge, because it relies on resolving an equation, one factor of which is tracked by a known shift in resistance with temperature, automatically compensates for temperature shifts.

The strain gauges used, as in most devices of this nature, vary in electrical resistance according to the elongation that they are subject to, hence using a bridge circuit. These gauges will also have temperature sensitivity.

4 strain gauges per bridge, each bridge will be measuring the average of four sets of resistance changes at any given moment and will automatically apply the temperature compensation. This happens at 5msec intervals in the Campagnolo design (no particular secret to this, it's in our dealer technical presentation). This output is monitored in real time and normalised to give a power reading ...

The number of strain gauges, or the number per bridge, only matters insofar as one of the problems in measuring applied power as a function of torque, is the orientation of the force that results in the torque being generated.

The application of power is not co-planar with the crankset spider or with the plane of the bearing, so any measure of torque transfer needs to take that into account. Also a factor is that the force application is not necessarily tangential to the axle - imagine a crank at bottom dead centre - you could apply as much force as you like vertically, but it wouldn't result in any application of torque at the chain.

Different makers have different strategies to cope with this lack of co-planarity / tangentiality and to compensate for the oblique application of torque. Some do it one way, others do it via a different method (usually part of the basis of their patent) but suffice to say that the number of strain gauges used is not itself a guarantee of accuracy - it's what they are measuring (and in what orientation, along with what assumptions are built into any algorythm) that matters ...

[Philster]

I wouldn’t draw any conclusions about the tech until I’ve read a longer term review from someone like DC Rainmaker. The accuracy of the meter being 1% versus 2% doesn’t matter to me at all. Where power meters tend to fall down is in what I’m going to call precision (I might be miss using the term). It’s the repeatability of this results without drop-outs and other anomalies. Power meter reliability is terrible. Campy certainly has not proven itself in this regard.