When I first got my Quarq CinQo I was often asked, “Why didn’t you go with SRM?” The primary reason at that point was cost. The next reason was the ANT+ protocol that promised more freedom with head choices. Having never used a SRM, I’ve hesitated to write about the two in comparison. Well, it turns out a reader has done it for me.
The below posting of a comment from John does cover most of the comments I have heard over and again. Again, I have not compared the two, so if there are any SRM defenders who wish to counter — have at it. Thanks John for the comment.
I’ve used an SRM for the past 9 years and just 1 month ago moved to a Quark + Garmin 500. I did this mainly because the SRM I have is a wired system, and the software is really Windows only (SRM software and CyclingPeaks are both Windows-only, and Golden Cheetah is a piece of crap). Using a Mac, I really wanted to use some nice software, e.g. rubiTrack, and using a Garmin 500 as a head unit gives me that option. I can also analyze the data in CyclingPeaks in a VM until they update it.
So that said, I’ll say that after using the SRM for 9+ years, I really don’t notice a lag in moving to the Quark + Garmin. Is there a 1 revolution lag? Probably. But I don’t really understand what “instantaneous” power would measure anyway? Power is force*distance (torque * rpm) so you need to get a rotation or two to measure it anyway. The SRM may be marginally quicker but not appreciably so.
Also, note that the default of the SRM is to average power over 3-4 seconds, continuously. You can set this in the SRM software. I actually changed my Garmin to show “Power 3 seconds” instead of “Power” to more accurately reflect this, because otherwise it jumps around a little too much to give a reading that’s sufficiently consistent to gauge your pace. If I’m accelerating, I don’t want to see 750w 400w 800w 350w 600w because it’s really more useful to know if it’s closer to 500-550w on average… I know how many seconds I can go at that pace before I’m going to exceed my LT.
One other thing, and a big advantage to me: As an SRM user for 9 years, I’ve sent units back to SRM 4 times over that time period. The batteries in the crank are claimed to last about 2 years, but if you ride 200 miles/week year-round it’s actually more like 1.5 years. So you pack it up, ship it off to CO Springs (used to be to Germany!) and have them change the battery. So $100 and 1.5-2 weeks later you’re back going again. What do you do in that 2 weeks you have no cranks? OK, so you buy a spare set of Dura-Ace cranks at $400 so you can train while you swap out your battery… ugh. Replaceable batteries = win.
I’d also like to say “Thanks” to Jim and Mieke at Quarq for their help over the last year. The Quarq logo has shown in our sponsors area since last April. Tomorrow there will be a space for another sponsor as Quarq comes down. Still, I’m a big fan of Quarq and the CinQo.