Jeez, I know the SRM Hollowgram only lasts 700 hours but mine is dropping out twice now on rides and I only add up 480 hours. Any one else experience less that stated hours? Anyone want to trade for a quarq? I knew I had to ship it back to SRM when I bought it but I'm just really grumpy about it now..

That doesn't sound right. I know it's unusual but I got my first srm in the beginning of 2011 and still haven't changed the battery.

My compact lasted right around 450 hours before it died completely. This was in the span of 15 months. I was told time is also a factor.

My Specialized SRM with one battery in it only lasts ~400 hours instead of the stated 700. If you can solder, putting a new battery in isn't too difficult

How stable has the zero-offset been before each ride? Data dropouts are not always indicative of the batteries going flat but if the zero-offset starts varying by +/- 15-20 on a daily basis, then that would be an indicator of a battery issue. As already mentioned, if mechanically inclined and handy with a soldering iron - note battery leads are short and small, 22-gauge wire - then once you have replacement batteries, changing them can typically be completed in under an hour.

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Michael - The Anaerobic Threshold is neither...

I'm not mechanically inclined so I'll have to send it in. Not sure about the zero offset.

So did the power dropout completely for the balance of the ride or was it intermittent? If it dropped for the balance of the ride, and you can no longer pair or set the zero-offset then send it in.

Really a good idea to perform a zero-offset prior to each ride as well as make a mental note of the value returned as this typically is a pretty good indicator of whether or not the battery is going flat based on how much drift is experienced after setting zero-offset. For example, the SRM on my road bike which has been mounted on a stationary trainer for the past few weeks, typically returns a zero-offset of 631 with a high of 635-637 when outdoors iin warm weather and 625-628 when its cold. With the bike inside in a climate controlled environment, I would start to worry about the battery if I saw a zero-offset numbers that were +/-15-30 at the start the next several times on the bike.

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Michael - The Anaerobic Threshold is neither...

It's almost comforting to hear that the offsets on SRMs are affected by the temperature, as I've had that some issue with Powertaps and needing having to zero out when the temperature changes.

the SRM (like the quarq) uses strain gauges to measure the deformation in metal as a factor in the calculation of power. metal is affected by temperature and can affect zero offset if temperature changes during a ride (or, for example, if your bike is stored in a warm (cold) place and you take it outside to ride in cool (warm) temps).

it is important to note that while all systems are affected to a degree, the amount they are affected is quite important.

as a rule of thumb, for the SRM or quarq a 3-unit change in zero offset reflects ~1W @ 90 rpm. so, if you see the ZO changes by 5 before and after a ride, that is below the resolution of these units. on the other hand, if there is a 60-unit change (as can happen with some brands/types of power meters) that is a different matter and can cause problems with your data.

the real problem when you have a unit like that is you don't know if there is a steady drift throughout a session, or if it was +100 30 minutes in, -100 60 minutes in, then +60 at the end, for example.

Does anybody know how you can see your total riding time in Golden Cheetah? Let's say for a year.
Would like to know when I have to send in my SRM and avoid that it dies mid-race or mid-holiday

the latest SRM software (windows version only) can tell you the reported battery usage, but this may be or newer devices only.

it is easy to download and test, though. if you haven't tried it, i recommend that first. your PM may require a firmware update. the battery life is displayed after download of activities is complete.

The SRM dropped about an 1hour into a rainy ride. I tried to 'rescan' with the 500 and couldn't get anything. Later in the ride, I was still fussing with it and the 500 ended up pairing with my buddies quarq.

The next day I went out alone and it lasted an hour before shutting down. Then nothing at all on the 3rd day.

I've thought I have had strange wattage numbers before and have stopped mid ride to hit 'calibrate'. The rest of the ride never seemed right. I'm guessing one isn't supposed to do that- try and calibrate after a ride has started?

And now my Garmin is having issues powering up and down. Feels like the button isn't working right. Man, everything is just going to crap.

Hey just wanted to chime in and say that something definitely doesn't sound right. I have had great luck with all my SRM's as well as SRM service. I used my wireless Cannondale SRM for an entire year before sending it off. Definitely give SRM a shout and get things straightened out.

Things that can help things be wonky sometimes are a magnet not close enough to the sensor plate or even some garmin head units.

Hope you get it sorted out though.

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Just ride ..

Yeah, I called SRM and the lady said that it must be the battery. I fiddled with the magnet to no avail. On another note I am seriously considering a quarq instead. Since I have 11sp I need to order stronlight rings. I've heard that I would need 50/36 because for some reason 34's don't calibrate well on the Hollowgram quarq.? anyone on that?

Can I just get a sram bb30 compact quarq?

How about a Power2Max with Praxis Works chainrings? Shifting is spot on with campy 11s.
I just installed one on my Canyon Ultimate CF and I love it.

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Pfeiffer's Rennrad Camp and Cycling Coach
Independent HED Wheels/Powertap Dealer