New powermeter rumours

Discuss light weight issues concerning road bikes & parts.
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by HammerTime2

Is that a crank (Quark?) powermeter, as well as the Garmin Vector pedal-based powermeter?

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by jmilliron

Yup. Hence the two Garmins.
2013 Wilier Cento1 SR || 2009 Ridley Crossbow || 2011 Yeti AS-R 5 Carbon

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by eric

That's my friend's bike.

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by djconnel

I was impressed to see testing set-ups like this @ Berkeley Hills RR. Since that race is decided on climbs, a decision which didn't go in my favor in my race (I was popped right at the top of Papa Bear with a (I am told) 6.5 W/kg surge I couldn't follow), the added mass of an extra head unit seems completely unacceptable to me. Garmin has a dedicated local test crew...

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by MarkThailand

Currently, I am using the Cannondale SISL2 Spiderring crankset with my Shimano DA set-up.

I was wondering if there any power meters compatible with the Shimano 11-speed system available soon?

I suppose I could use the SRM-Campagnolo crankset but I have been waiting, and waiting for any news on others.

2012 Lynskey R330 with SRAM Red Quarq
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by KWalker

You popped because you don't have the power, a head unit wouldn't have mattered either way. I love hearing excuses like this after races, but in reality the difference between making it and not making it is pretty big when outputs and surges are around that high.

Shimano 11 has the same chainline as far as I know. The front mech will work with it and SRM has a 9000 unit.
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by nathanong87

friend uses red quarq with 9000. dunno how this works but it does. 9000 chain on old sram rings, unless the new rings got thinner too? ... 132d_h.jpg

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by asv

My stages SISL2 arm arrived yesterday. Only 13 additional grams even with the battery installed.


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by djconnel

KWalker wrote:You popped because you don't have the power, a head unit wouldn't have mattered either way.

Head unit + additional power meter adds around 120 grams. Haul that up 100 meters and that's 100 joules. That's around 1/3 second @ 300 watts. Does 1/3 of a second matter per 100 vertical meters? Probably not, but when that gap opens, it's hard to close it. At some point it's straw-that-breaks-the-camel's back.

The "you have it or you don't" thinking is really sloppy. It leads people to stop focusing on the details, details which may not be the #1 factor, but every bit helps.

On the Stages, asked a guy @ Palo Alto Bikes how customers are finding it. He said they like it, despite (my comment) the obvious flaw.

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by mentok

so DCrainmaker says that the stages with the new firmware is the business: ... pdate.html

thoughts, discussion?

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by mca56

DC Rainmaker's review proves that accelerometer based cadence can be accurate and reliable. This make me hopeful that Garmin can bring their accelerometer based Vector pedal to production.

I was stunned to see the amount of temperature based drift in the Quarg and to a lesser extent in the Powertap. I do hillclimb time trials like Mt. Washington with significant bottom to top temperature differentials. Pacing with a non-temperature compensated power meter could present significant problems. I think in the future we will be seeing automated temperature compensation in other power meters.

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by djconnel

Well, I wouldn't say the Stages is "the business". You're not going to use it to claim you're 2% better this year than last, or even now versus off-season, because it's fundamentally limited by consistency in L-R balance. But it appears you can use if for pacing, or for riding intervals, or post-race analysis of if you went too hard at the beginning of a climb, etc, so it's quite useful. It's nice they got the firmware glitches under control.

Big loser in the test is Quarq, which shows appalling drift when it's not been zeroed lately in changing temperature. Zeroing was forced at the yellow lines. Power is orange for Stages, grey for Powertap, and blue for Quarq:


But he asserts that the Powertap also has drift problems. I'm not sure. Look at the second yellow line. The Powertap doesn't move relative to Stages here. Rather my guess is he's getting tired, and his L-R balance has drifted, and that results in a systematic shift in the Stages versus the Powertap.

One thing I get from this is I'm pleased with my early decision to get a Powertap. That doesn't address the Powertap's aging behavior. Mine has issues relative to another I've tested in static torque load testing, for example. But those drifts on the Quarq are super-ugly.

I think the proof in the Stages accuracy will come only with tests done in conjunction with L-R balance data.

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by rchung

I'm glad that Stages responded to our analysis/criticism with updates. That speaks well of them -- and also of our analysis.

That said, the most important characteristic of a power meter is the quality of data it produces. In many ways, the least important use of a power meter is tracking changes in fitness.

I've occasionally wondered whether the Quarq has suffered since its acquisition by SRAM.

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by djconnel

The question was raised on the forum whether the Quarq used had Omnical. I don't think so: Ray described his ride in the Angeles forest where he collected these data in this blog post:


That looks to me like an older Quarq. But here's an Omnical Quarq ("1.5% accuracy": Chortle). I don't see any mention of temperature compensation here. AFAIK, "Omnical" is just a change in the mechanical design to reduce sensitivity to chainring flex.

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by airwise

Not surprised with the Quarq drift. I found it to be "not fit for the purpose" and got a refund on mine. Waste of time in the mountains.

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