POWER-METERSPOWER - ACCURACY, QUALITY, BUDGET

THE POWER HOUSE

15 years of experience, your specialist in power meters BVBA WEST-CONSULTANCY

SHOWROOM KORTRIJKSESTEENWEG 205 B4 SINT MARTENS-LATEM 9830 BELGIUM

POWER-METERS SALES,RENTALS, TRAINING PACKAGES/MODULES, TEL: +32 (0) 486460484 EMAIL:WESTCONSULTANCY@GMAIL.COM

POWERACCURACY

CHOOSING A POWER-METER FOR YOUR NEEDS

Training using power has become the gold standard in training data analysis over the last 15 years.

Accuracy using power data is knowledge that this data received is measuring the bicycle’s output within a range of different %variables. Power data is constant and although the type of power training tool you choose will determine how accurate your data you see on your bicycle computer. This training data correlates to your energy system and is directly related to you training zones. Individual training zones using a power-meter are an important indicator for your training program.

The accuracy of direct power measurement has put to one side the heart-rate as a medium of training analysis. Heart rate has too many variables (weather, emotions) and has a low response time between your efforts and registering your output.

The power-meter is an accurate direct indicator of your physiological means to power your bicycle accurately. Designing your training program has become easier using the power-meter. Whether your training your system to improve its fat metabolism, increase its aerobic capacity, sustain its aerobic power or increase your anaerobic power. All these types of training intensities are valid in developing an individual profile.

The more accurate you wish to train the more precise your power-meter measurement needs to be.

Currently the saturation of power-meter technology on the commercial market has opened up opportunities for the beginner to the professional athlete to work with different types of power-meters.

The more expensive power-meters are all using strain gauge technology. This means that the power-output is measuring to its most accurate through indicating the strain on the metal components or structure at the point of attachment. (For example on the spider (SRM), or crank arm (info-crank)) Majority of systems are using algorithm, which is data calculations based upon a process to give an output. Here the accuracy is then lesser.

Accuracy

QUALITY

BRANDING - POPULARITYThe saturation of power-meters on the commercial market is creating differences in understanding manufacturer demands over quality and cost control.

SRM have been producing top quality science for more than 25years, science which is integrated in to quality cycling components from Shimano, Campagnolo, SRAM, FSA,Cannondale.

Info-crank for example are producing their own scientifically backed measurement using strain gauge technology and implementing this left and right technology into their own manufactured crank. Here is a prime example of how the customer has to choose quality of measurement understanding over bike cosmetics.

Stages and other systems using algorithm technology are then integrating their systems into established cycling component manufacturers such as Shimano. Looks over accuracy.

ACCURACY- CHARACTERISTICS CYCLINGPOWERHOUSE.COM  1. CycleOps

G3 2. Info-Crank 3. Power2Max 4. 4iiii Precision

5. Rotor Power 6. Garmin 7. SRM 8. Pioneer 9.Stages

Transmission - Relay communication

between powermeter and bike computer

ANT+ ANT+ ANT+ ANT+ ANT+ ANT+ ANT+ ANT+ ANT+

Battery Life 300 500 hours 300-400 hours  500 hours  400 hours 175 hours 1,900 hours 180hours 200hours

Software - analysis software

compatibilityPower Agent

O-Synce - WKO+,

training-peaksWKO+, training-

peaksWKO+, training-peaks

WKO+, training-peaks

SRM Software, WKO+,

training-peaks

SRM Software, WKO+, training-

peaksPIONEER, WKO+,

training-peaksStages, WKO+, training-peaks

Compatibility - Type bike

component Wheel, pedals Info-crank Diverse options Diverse

options Rotor Vectra Pedals Diverse Options Shimano Shimano

Measuring sides RIGHT Left&right Right Left Left Right&left Right Left Left

Measuring application Algorithm Strain gauges Strain gauges Algorithm Algorithm Algorithm Strain gauges Algorithm,wire

strains Algorithm

Weight 325g 405g 720g 9g 515g 213g 500-780g 62g+crank arm 20g+crank arm

Accuracy Avg n/a* 0,5% -2% 2% 6% 1% -1% +2% +2%

Max Accuracy Varience +4% 0,5-1% 6% 1% 10% 2-3,9% <1% +2% +2%

BUDGET excl.VAT €700-1300 1300 € €890-€1600 599 € 845 € 1099 € €2100-2600 €700-1329 €620-799

TABLE TERMINOLOGY▸ Transmission: This addresses how the power-meter communicates with bicycle computers, there are two standards currently

on the market with the most common being short range, low power, low maintenance networks ANT+, the other being bluetooth low energy

▸ Battery life: Battery life has been a problem with the more budget minded power-meters. Initially when SRM were the only power-meters working on the market after every season the system had to go in for a new battery, maintenance and calibration. With SRM you still have to send you system back when the battery fails. However in 2011 when the patent from SRM finished the market quickly became saturated with numerous different types of power-meters. Most of the brands to come out have given the option that a battery can be simply replaced by the customer and the slope and calibration of the power-meter is automatically carried out by the power-meter firmware. There have been a lot of start up problems with this type of user friendly devices, however over time the accuracy and user friendly reliability has proven to be good. Systems like Info-crank are giving a 500 hour energy lifespan of hearing aid type batteries in their systems, so this is really showing a strength in depth of their technology.

▸ Software: There are many different types of software on the market for analysing power data. The objective of software is to be able to create a history recording of your performances. This type of data reading creates a performance chart which will indicate where your best performances have been and where you have taken rest periods. These performance indicators are crucial in anticipating your seasonal planning and goals. Many of the bicycle computers are saving their file formats into a fit-file. This has opened up the opportunity for many systems that have their own software programs like SRM to be able now to also accept other types of power-meter files. Some software analysis programs are more detailed than others, for example WKO+ from www.trainingpeaks.com is one of the founders of data analysis and is a complete package for analysing with many charts of choice to study each parameter of your data. www.strava.com is also a very popular platform because of its ability to compare routes, data and give you challenges through GPS.

▸ Compatibility: 20years ago when SRM introduced the power-meter into cycling. It was a period of very simple application. Although the power-meter communicated through wired-technology in those days compared to the wireless systems today. The application was straight forward as there were just two compatible type of bottom bracket fitting. The octal ink from Shimano and the square taper from Campagnolo. These days there has been a tremendous amount of different crank arm and bottom bracket fittings on the market. This has made it more complicated for power-meter manufacturers. Consequently power-meter companies like SRM have made agreements with companies like Shimano, Campagnolo, FSA, SRAM, Cannonade to develop an integration of their power-meter technology into their respective cranks.

TEXT

▸ Measuring sides: For many years data analysis has only been measured one sided. SRM always measured on the drive side, logically where the main forces are delivered into the spider. However now there are some competitors on the market that are either cost productive like Stages that produce their measurements on the left crank, so enabling the customer just to purchase a left crank. One company in particular Verve cycling manufacture the Info-crank and have produced a very accurate left and right crank measuring instrument that proves to be more accurate than most. The left and right integration creates a whole new understanding of power measurement and lets the user understand balancing between strong and weak legs, in balance in positioning on the bike and specific development for time trailing and climbing specific.

▸ Measuring application: This is all about accuracy. The most accurate power-meters on the market are measuring using strain gauges placed at strategic points of metal stresses. Either at optimally at the spider like SRM or on the crank arms like Info-crank. The latter measuring the most accurate at 256Hrz. The lesser accurate models that are estimating through structured calculations or algorithm are then also producing lesser Hrz or measurements per second like Pioneer, Stages, power tap. The lesser accurate that the measurement becomes the lesser accurate you can start to make measurements in climbing profiles or time trialling efforts, especially track cycling disciplines.

▸ Weight: Weight always has been a stumbling block for many cyclists in the past. Now the systems are coming down in weight with using carbon, or creating their power meters as add ons in plastic housing. The heaviest will obviously always be the strain gauge models.

▸ Accuracy average: This is dictated by the amount of Hrz that the power-meters are recording per/second and if they are measured by strain gauge technology or algorithm.

▸ Max accuracy variance: The more specific you will want to work the more that the maximum data becomes important. For example standing starts in track cycling, maximum flying efforts on the track where fractions of seconds are needed to analyse data.

▸ Budget: The model of power-meter you chose will of course have some specific boxes to tick before you make your choice. Do you need maximum accuracy, do you need lightness, do you need left and right technology, do you need a specific crank component to be compatible with your bike? Once you have this it is quite easy to single down the specific power-meter for your needs.