Advice: Ergomo vs SRM

Bob Dopolina

Ok. Let's leave price out of it. There is a clear winner here.

What I'm looking for is personal experiences with both and the pros and cons of both.

I am an experienced certified coach/rider but am new to some of the jargon for wattage based training. If you are going to use abreviations please clarify.

daveryanwyoming

Easy, the Ergomo Pro has some great on screen features in its cycling computer like real time TSS(you're a coach, look it up in the acronyms stickies: http://www.cyclingforums.com/t386984.html) and NP. As well as real time and average power displayed simultaneously in interval mode, calories burned, altitude, temperature, etc.

But all in all the SRM would be my hands down winner assuming cost is no object. It's not finicky about installation and you can independantly verify it's accuracy and even calibrate the device in the field. Unless you have a calibrated cycling dynamometer or a known accurate PM you can't validate the accuracy of an Ergomo. Even then folk's report accuracy slew across the power range with good match to a validated PT or SRM at some power levels and not at others. Other's report great results with Ergomos, but again you need some other device to validate the readings. All you need is some fixed weights to validate the accuracy of an SRM or PT.

Good luck,
Dave

Woofer

I own and use a SRM and would disagree a bit or point out some issues at the least. Having to make a custom mount on most available aerobars is a major pain or having to live with a compromise position for the CPU - this hardly seems very acceptable for the most expensive powermeter. Folks with carbon bikes with large bottom brackets areas have had to resort to a lot of tinkering to get the sensor on correctly - hopefully that has been resolved in the past year. I find that the pickup sensor for the crank is extraordinarily sensitive to placement and mounting it solely with the elastic bands is a major pain, any adjustment is automagically resisted by the bands so they undo what you did if you are off by a bit on the initial placement. With the traditional cranks you guess where you need it to be, put the cranks on and test, and moving it while the crank is on and the elastic is on is problematic, as is putting the elastic on after the crank. I just end up putting lots of electrical tape to make it stick in one position. Some of this is only a concern if you have multiple bikes and do lots of switching of a single crank. I also wish I could customize the display more than one can do now.

POGATA

The new sensor might work well with a carbon frame but not with a Ti frame!

Bob Dopolina

Some useful stuff so far. Thanks for the sticky. That's a gem.

I have two team mates on SRM, so calibration will be pretty easy.

How about features? Display capabilities? Software? I have heard that there were some limitations with the ergogmo computer. have these been addressed?

daveryanwyoming

So your team mates are going to let you borrow their SRMs and then you're going to mount both the SRM and Ergomo on your bike simultaneously to verify the Ergomo? And you'll verify the Ergomo against the SRM across your useable power range say from 100 to 1200 watts or more? It's harder than you might think. It's easier to verify an Ergomo against a PowerTap but it's still not simple since folks have had trouble getting them to track at both high and lower power ranges simultaneously.

I used an Ergomo Pro for several months before switching to PT hubs. I do miss many of the computer features of the Ergomo relative to the PT. It has a much larger display and shows a lot of good information real time that I can only get from my PT(or an SRM) after getting home and loading the data into CyclingPeaks WKO+. I haven't used an SRM so I can't make that comparison, but the Ergomo computer has a lot of good features built right in and allows you to see several important things at the same time like real time as well as average power during intervals(really useful in time trials) as well as the stuff mentioned above. I wish the other PM manufacturers had put as much thought into the computer functions, my only peeve with the Ergomo is the difficulty in validating its accuracy.

-Dave

Bob Dopolina

This is not the first time I have heard this. By accuracy are we talking about a general +/- accuracy across the entire wattage spectrum or are the situations in which accuracy will fluctuate OR is it a matter of a deterioration in accuracy?

Some clarity here would be helpful.

Ergoman

My observation after over 5000 miles with an Ergomo Pro is that accuracy is good and results are consistent so long as the installation is done very carefully and totally in accordance with the manufacturer's instructions. It is also critical that offset tests be run frequently. SRM and PT appear to be more forgiving in regards to installation and calibration.

I like my Ergomo and I would buy one again but if money is no object for you, and your team mates all have SRM, then choosing an SRM would seem to be a no-brainer.

POGATA

I have both an Ergomo Pro an a SRM Pro, Dura-Ace version, so I can`t put them on the same bike, but the power numbers seem to be pretty much the same on both of them when I ride with the same bike, same perceived effort, same heart rate, same speed on specific courses etc.

beerco

So you've swapped DA BB to Ergomo BB several times back and forth?

beerco

How did you come to this conclusion?

Squint

My guess is wishful thinking.

daveryanwyoming

I doubt whether many folks have run multiple PMs on the same bike long enough to track deterioration over time. I'm just talking about the difficulties of first validating a single point on the power curve against a known good reference standard and then getting multiple widely spaced points on the power curve to correlate well. Check out the comparison graphs and subsequent analysis in this thread: http://www.cyclingforums.com/t387259.html

Folks can argue the methodology and accuracy in this comparison, but that's just my point. A comparison between multiple PMs across a representative power range is not as simple as it may sound. That to me is the big advantage of a SRM or PT, you can directly test static torque which is the basis of power measurements. You can even test various high and low static torques by varying weight or gearing(in the case of the PT) to check the strain gauge linearity. It's a much simpler test of accuracy than dynamic power comparisons across a wide range particularly if you take into consideration sampling rate differences and synchronization issues for the invariably dynamic power data. It's not impossible with carefully structured tests, but not simple either.

Remember you started this thread with the statement "Ok. Let's leave price out of it." from that standpoint and comparing an Ergomo to an SRM it really seems like a no brainer.

-Dave

Bob Dopolina

Perhaps I was misleading you all when I said "lets leave price out of it". what I meant was, I don't need to hear 42 times that the SRM is more expensive...I was looking for information regarding function, quality, reliability, ease of use/installation and what ever else I hadn't considered.

Price is an issue but that one was pretty easy for me to figure out on my own.

Thanks for the feedback thus far.