Compatibility With Bike Model
Another crucial aspect to consider when buying a power meter for your mountain bike is to make sure it is compatible with your type of bike. Power meters come in multiple forms, meaning they attach to different points such as the crank, hub or pedal. If you are riding a Specialized Stumpjumper with a crankset with a non-standard design, you will have to find a power meters that fits this crankset design without causing any clearance issues or affecting the crank arm itself.
Compatibility> A pedal-based power meter such as the Garmin Vector or Favero Assioma could be a good option. These are single-platform units which will swap between any bike that is using a standard pedal thread. This means the devices can be swapped easily from bike to bike, which can be very useful if you have several bikes. A Garmin Vector is as simple as just unscrewing it from one bike and attaching it to a new one, with recalibration in less than five minutes.
Crank-based power-meters like SRM or Stages need more thought. Here you will have to be sure that all BBSHD devices are suited to the dimensions and chainring setup specific to your mountain bike. A Stages power meter manufactured for use with a Shimano XT crank won’t install on a SRM model specifically designed for Cannondale. Before purchase, the crank area will need to be accurately measured and the crankset geometry understood in detail. Chartreuse was created in part based in a Cycling Dynamics study which found that 10% of compatibility concerns with crank-based power meters could be addressed by potentially more in depth compatibility forces-hull data provided by manufacturers.
Hub-based power meters such as the PowerTap are less finicky about bike compatibility but are dependent on particular sizes and types of hubs It also makes them perfect for a rider who needs to be logging consistent training across a few bikes and does not want to spend the numerous minutes each morning setting up a rear light. Professional mountain biker and Life Time Fitness ambassador Emily Batty runs a hub-based PowerTap on both her training and race bikes, which allows for uniform data collection regardless of the riding conditions.
Measurement Accuracy
The most important part of selecting a power meter for MTB is the accuracy. With an accuracy range of around +/- 1 to 2 percent, relatively high price, accuracy is another key point here as it’s super important when trying to get a thorough workout analysis (manufacturers like Quarq and SRM also often gloat about having such a range in their power meters). More extensive error can actually allow you to trick your training zones and perceived exertion metric (e. g. A 2% error in a 300W effort could actually represent a 294 or 306 watt effort).
Mountain biking comprises rough terrains which often shake the equipment. A test by Cycling Analytics also showed that power meters built into the crank – such as the Quarq DZero – delivered similar results even over a rough trail, whereas the pedal-based meters (PM) exhibited significatly different behaviour, which is probably due to mud and impacts which have an impact on the signal between the pedal body and the sensor.
In professional sport we just have to look at the likes of Nino Schurter who tailors his interval training around very precise wattage targets and requires consistent accurate power data from his power meter to allow him to achieve that. Take, for experiment, pre-season training block, Schurter will focus on hitting specific wattage target up the main climb, and with the power meter accuracy, making certain that the right amount of effort happens.
When you take into consideration mountain biking, where external factors like temperature changes and mechanical shocks are common, having the weight and hassle of adding calibration equipment every few weeks can quickly make you change your mind. Calibration is key to a power meter’s ability to deliver the same level of accuracy year after year. This could be a few seconds of your day, like a fast zero-offset before each ride, but if it gives you clean data then it is worth doing.
Installation Ease
Installation is one of the most important things for a mountain biker considering a power meter, because it is not only relates to the initial install process, but also the power meter portability when switching the device from one bike to another. Pedal-based power meters like the Favero Assioma, are the easiest to install and use only require the ability to screw in a pedal. A prime example is installation, it usually takes fewer than five minutes; you just have to thread the pedal into the crankarm, secure it with a hex wrench, and perhaps the other way around as well, and you are ready to go.
Crank-based power meters give great accuracy but can be a bit fussy to install. For example, you have to take off your existing left crankarm and pedal, make sure that your bottom bracket is compatible with the crankset, and that you tighten all the bolts to spec. The process, outlined in a Shimano installation manual, its around 15 steps and might best be served by using some type of special, proprietary tool, a torque wrench (literally every time you ever have a crank on or off — thenanti-seize is a must); or an ISIS drive cap removal device. However, this complexity was a one-time upfront effort and the tradeoff was that you got accurate data that could stand up to the rigors of mountain biking.
This is a plus for track riders or anyone that travels a lot, as the phantom-like P2s will move from one bike to the other with a minimum fuss or cost. This is perhaps best illustrated by amateur mountain bike racers who do not wish to wear out the same set of tires on both their practice bike and their race bike. The faster you can get set up the more time you have for working out and resting.
Their user-friendly designs also mean they are easy to maintain and re-install. Integration of power meters like this, with simple battery replacement and calibration process mean that a rider can handle the equipment themselves, and not require professional assistance. This independence improves the rider experience and guarantees that the performance measurement is maintained equally.
Durability For Rough Terrains
When it comes to durability, an absolute must for the wetness, mud, and pounding mountain bike power meters absorb, power meters designed for mountain biking must be able to withstand the elements and roughness of the trail. Mountain biking can be particularly brutal on power meters, as they must cope with impacts, dirt, and water ingress. This includes the SRM PowerMeter MTB, which has been designed to cope with the demanding nature of mountain biking with a tough casing and electronics sealed against mud and water ingress and shocks.
One Quarq XX1 Eagle DUB power meter was recently put through the ringer to show off how tough they were in irrefutably rough conditions. Using the power meter throughout six months of testing in a variety of different mountain biking conditions, from dry, dusty trails to wet, muddy ones, the power meter held up and gave consistent data. All this means that the Atlas Axon is an extremely hard-wearing insole, and its durability is only really challenged if you go wild with the step drills, burpees and slam balls. The key to that long life is the enclosed design that keeps the electronics and strain gauges from being battered by damp, debris-filled trainers.
Pedal-based power meters are incredibly convenient for swapping between bikes, but this does add an extra layer of complexity when it comes to long-term durability. While something like the Favero Assioma might have a robust construction, users are still expected to keep the pedal bodies relatively clean of muck and debris, which can interfere with pedal rotation and thus the recorded power itself. Riders like professional mountain biker Rebecca Rusch to clean and inspect their pedal-based power meters after every ride ensuring that their power meter is in optimal working order, even in the worst conditions.
Manufacturers are also protecting their product with features like Garmin’s new Vector pedals include metal protective caps meant to reduce the chance of rock strikes or crashes doing damage. The lifespan and reliability of the power meter under extreme mountain biking scenarios is helped by these minor enhancements.
Cost-Effectiveness
Cost-effectiveness considerations are extremely important for many, if not most, mountain bikers when it comes to evaluating the purchase of a power meter. While it is nice to pay as little gravel tax as possible, there is more to it than the initial purchase cost, weighing some combination of long-term maintenance needs, multi-bike compatibility, and possible upgrade wishes. Pedal-based power meters, such as the Favero Assioma Uno, come in at a relatively low introductory price, at about $450, but to upgrade to a two-sided system later you will pay almost twice as much.
Crank-based power meters are more expensive initially (usually between $600-$1200), though comparison among different studies has shown that they are probably a better value in the long run because they tend to last longer and have fewer maintenance costs. For instance, the Stages Power L and R is best known for its durability and accuracy that is good enough for the seasoned riders who are often training on bumpy roads.
How the hub-based PowerTap G3, a favorite among mountain bikers, can be found for as low as $400 used, and that’s just one of many comparably cost-effective options. Although this seems good on the wallet at first; if you then need to pay to have wheels building or compatibility work done when you change bikes, the overall cost may end up higher than purchasing a more expensive but adaptable crank based meter.
Certain features of the device play a large role in long-term savings, like battery life and how much maintenance the device needs. A power meter with a chargeable battery might save you hundreds of dollars in battery replacements as a few years go by, rather than those which rely on pricey coin-cell batteries.
When considering ROI for a mountain biker, the cost of usage and the incremental improvement in training may not make purchasing a power meter worth the money spent. A power meter which costs less but gives inaccurate data or breaks down frequently may actually turn out to cost more over the long them than the slightly more expensive option which is more reliable.
