Tag Archives: SRM

Why Quarq and not SRM?

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.

My final word on the Quarq CinQo & Garmin 705

I’ve had several different contacts recently concerning my Quarq CinQo and Garmin 705 combination.  It finally drove me down to the basement to do some testing to see if there is a lag in the processing of the data.  I also had to ask myself that if there is a lag… do I really care?

Quarq CinQo Saturn

My SRAM S900 Quarq CinQo Saturn

Some information about me so you understand where I am coming from as I write this.  I am a Category 4 racer.  I do not have a training plan or a coach.  I have a power meter because I love playing around with data.  I am also interested in building a power profile for future training.

Why this power meter?  I was drawn to the Quarq CinQo because of the price, Quarq’s innovative approach to application development, and the fact it would work with my Garmin 705.  Since I already owned my Garmin, it made the price point on the CinQo very attractive.

I do not regret getting my Garmin 705.  I know that there are people who down it as a power collection computer because of some of the algorithms used.  However, as a cycling computer it is pretty stout.  I’m not just talking about the GPS portions.  If I were to buy another cycling computer, it would be another Garmin.

So, what about the two of them together?  What about this lag that people are complaining about?  I went to discover what was up.

First, I have been riding with my new CinQo power meter and Garmin 705 computer with updated firmware for several rides now.  Second, I have gone into my “lab” to test and see if I could isolate a consistent delay in data making its way to my Garmin.  I’m now ready to give my opinion.

In real life, I have to admit that I just don’t notice it.  My approach to data is to go out and ride.  When I’m done, I move the data to my laptop and then analyze what I’ve collected.  I notice no lag at all in that case.

Yes, there have been times when I will bottom out at the end of a downhill and then kick up a new incline.  I will look down at the computer and then start pedaling.  I came to notice that I would not see the data appear on the screen until I had completed one full revolution with each crank arm.

So, I moved it into the lab.  I put the bike on my stand, held the Garmin in one hand, and then started turning the crank with the other.  Let’s see what happens.

I started the crank at dead top center.  On the Garmin I saw a blank line where the power would be displayed. I turned one revolution.  The Garmin registered a zero, but no number.  Hmmmm.  I tried it again and this time did two revolutions.  After the first revolution the zero appeared and after the second the power reading came up.

Wow.  That was a delay.  Now, that didn’t seem to be consistent with what I was seeing out on the road.  Then I stumbled on something.

After bringing the crank to a stop, I started the revolution more quickly.  This time the Garmin was registering a zero before I started to turn the crank.  No sooner had I finished one revolution than I saw the power data appear on the Garmin.  I repeated this several times and could not even time the delay with my stop watch.

What appeared to be happening is that the Garmin would “go to sleep” after a time of inactivity from the CinQo.  When this happened, there was a more substantial delay (we’re talking around 1.5 seconds).  However, when the Garmin was “awake” I couldn’t get the watch started and stopped fast enough.

Quarq tells me that the CinQo starts sending the data at the conclusion of the first revolution.  This will always be the case as long as they are using the ANT+ protocol.  So, if you want power data collection as soon as you move your foot a fraction, I guess the CinQo isn’t for you.

The Garmin 705 appears to take about a half second to display the data (when it is awake – as it would be in most cases when on a ride).  If you take that half second and a quarter second for the CinQo to calculate and transmit, you will be looking at the potential of three-fourths of a second delay.

So, what is my opinion?  If I were to go out to buy a power meter, I would do the same thing again.  The cost of the CinQo is a big factor to me, but so is the fact that they are building their system for growth.  If I don’t like the Garmin, there are other computers I can connect it with — even the iBike.  There will be even more to come.

I ride with friends who have Powertaps.  One particular riding buddy is a very similar rider to me (a much more experienced rider, but very close in build and riding style).  It is very interesting to see how similar our data is in WKO+ following a ride.  I am confident my system is doing as good of a job as the Powertap system.

What about the SRM?  Well, they aren’t letting me test their meter and I can’t afford it.  I do like the SRM for one of the same reasons I like the CinQo over the Powertap – it is crank mounted and not part of the rear hub.  However, I cannot say that I have compared the two in any way.

Here is the bottom line for me.  I have had absolutely zero problems with the construction or capabilities of my CinQo.  The Garmin is a known item that might do so many things well it isn’t necessarily the best for collecting data.  To me, its other positives outweigh that negative.  I have been given no reason not to be happy with my Quarq CinQo.

The apparent lag?  I know it might be important to some people, but I just don’t care.  Perhaps if I were a professional it might be a bigger deal to me.  However, for an amateur like me, I highly recommend this system.

The Quarq CinQo has given me consistent data for multiple months. I can say that the data I’ve analyzed has told me a lot about myself.  I have adjusted my riding to strengthen my weak points and been encouraged by the gains I’ve seen.

They say that ignorance is bliss.  Perhaps I am just ignorant of some major flaw in the product.  I have not experienced anything close to being what I could call a flaw or failure.  I am a very happy Quarq – and Garmin – customer.  Someone is going to have to have a pretty strong argument to make me otherwise.