open topic, for anything cycling related.
Because the Stages does not measure the forces applied to the right hand crank. It's strain gauge is located on the left crank arm.
The SRM (and Quarq and Power2max) are power meters located in the crank's spider, and hence they measure the total forces being applied to/from both cranks, forces which are transmitted to the rear wheel via the spider (then chainrings, chain and cogs).
And for reference to the left-right balance issue that was previously asked, I note this from the Bike Radar initial review of the Vector:
and a few references since it will no doubt come up (i.e. pedalling / power asymmetry is both normal and has been known about in the scientific literature for decades):
(AT) Alex , can you do us a favour then and for those that are in the same position as me (i.e, looking to get into the power meter market & therefore considering a stages) Provide 1 Pro & 1 Con for each of the well known power meters, Putting cost aside because I can always save for a little longer.
A no B/S pro & con list would be useful if possible
That then requires a priority or a value judgement on the individual features highlighted which may or may not reflect what's important to the user.
I did at one stage have a matrix I used in presentations about training with power, but I dont propose publishing it here.
So, for example, I'd propose listing all the relevant considerations when choosing a power meter, and then ranking a meter's performance against each, or providing the relevant data if not a ranking, e.g.:
Accuracy (this is multi-factoral, and the devil is in the detail and depends on purpose)
Precision (and/or repeatability/consistency)
Ease of use (various elements to this, and will depend on head unit choice as well)
Flexibility in usage
Compatibility (with bikes, with head units, with software)
Reliability and service life
Cost, initial and ongoing
Warranty and Service Support
Viability of company (e.g. will they be around to support in 3-5 years from now?)
2nd hand value
Then we have at least 15 on-bike power meter brands (or products that report a power number) and I've probably forgotten one or two, and many have various models that may perform differently, let alone different have price points and features:
Polar Look Keo
I'd put them in following broad categories, and recognise that each falls on a spectrum:
Known, reliable track record, accuracy to a very good level for most uses, long term back up and support:
Need more time to prove themselves before moving into above category:
probably another year or so and with some more rigourous examination it may move up*
- Garmin Vector
early days, promising start after a long wait for many, but new technology.
again early days, and with permanent accuracy caveat due to single leg measurement that means some restriction on high end useability of data, but for general training progression and overall workload tracking, and guidance on level of effort, it is likely to be fine, subject to reliability/durability. Keep in mind that proper local availability and back up not quite in place yet
Currently not meeting standard, but may still serve as a useful training tool provided one understands its limitations:
still reporting far too many issues, and not sure if available in Australia yet
- Polar Look Keo
too many issues, and restricted to Polar head units
- iBike, Powercal
these two non-strain gauge based power estimation devices may be helpful training aids, provided one recognises their limitations
- Polar WIND, ergomo
generally only available 2nd hand now, installation and accuracy issues for both, as well as non-existent service/support
Generally unavailable as yet (various reasons):
Pioneer, Brim Bros
Insufficient data to properly categorise:
* note I applied the same to Quarqs when they first arrived on the scene. It took some time before I felt they were ready to be in that category.
Thanks Alex, appreciate the time that went into that...
In your professional opinion, and i apologize if you have already answered this, would the stages not be suitable for a "Club Level B Grade" racer to use to get a total power number, then proceed to adapt training to improve this said number?
He said this right there in the large post:
but for general training progression and overall workload tracking, and guidance on level of effort, it is likely to be fine, subject to reliability/durability. Keep in mind that proper local availability and back up not quite in place yet
Haha thanks for that.... may have mis read that!
There are a couple of US dealers that will still ship to Oz but not sure how you'd go with any issues pending an Aussie agent being announced. Those that I spoke to also had 6-8 waits on units (Sram).
Some interesting info in there... a difference of less than 3% in avg power for the combined power number
Acceptable in my opinion when the price is considered!... bring on the Aussie Distributor!!
awesome... online shop with no address listed and a mobile number.. seems like a logical choice..
FYI at .95c exchange rate, paypal fees, shipping etc the ultegra arm was $923..
I got this in a newsletter frim WWW.wattagecycles.com.au
· Given the incredibly high interest we have been receiving with regard to the Stages Cycling products, we have begun accepting refundable pre-order deposits of $400. Place one today to ensure the earliest possible delivery of a Stages unit. The earliest pre-orders will be fulfilled first when stock arrives. Australian stock is expected by the end of 2013/early 2014.
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