The word “powermeter” is notorious for conjuring up mixed emotions. If you use one, you probably feel a phantom pain in your legs right now from a subconscious recollection of interval training and racing at your threshold. If you’re uninitiated, you either feel intimated, confused, overwhelmed, or all of the above. Both control groups have a right to these feelings because, frankly, powermeters are pretty damn confusing for all of us.
The application of a powermeter makes enough sense. After all, you only need to watch a couple of races with Team Sky at the front to appreciate their effectiveness. No, the real confusion lies in the tangled web of marketing jargon, complicated technologies, and what kind of powermeter that you should even purchase in the first place. Thankfully, though, this game has a pretty limited number of players on the field, namely PowerTap, SRM, Quarq, and Garmin. And until recently, you only had two options for powermeter placement. However, with Garmin now in play, this process has added another layer of confusion by opening up power at the pedals. So you’re left asking, should you invest at the crank, at the rear wheel, or at the pedal? Let’s find out.
Convenience is king when dealing with powermeters at the rear wheel, especially in terms of training. With a PowerTap rear hub, it’s simple to move your powermeter from bike to bike as you’re training — one day on the TT rig, on the road bike the next. You’ll also find that PowerTap provides one of the lowest overall powermeter weights, tipping the scales around 325 grams for a G3. However, it’s important to view the weights of powermeters in terms of the total product weight minus the unaltered product. So, if we were to compare the G3 to a DT Swiss 240, the net 85 grams is a very rough estimate of the powermeter’s actual weight.
There are drawbacks, however, namely that wheel-based powermeters aren’t ideal for racing. This isn’t because of performance; rather, it’s because of location. In the event of a flat, you’ll need multiple wheels at the ready. Multiples wheels, however, equate to multiple powermeters. In other words, you’ll be looking at a hefty investment. For training, though, this option is pretty hard to beat.
You’ll find that this option is the most heavily adopted system of the professional peloton. Typically, these aren’t as a lightweight as a wheel-based system, but it opens up the possibility for wheel changes — pro teams are on a budget, too. All in all, these systems add 120 to 180 grams to a typical crankset. However, there’s zero compromise in performance expectations, which makes these powermeters perfect for those who’re obsessive about their component selection. So, if you’re in love with the flange rigidity and engagement of your Chris King R45, you don’t have to risk sacrificing anything in order to obtain your readings.
It’s important to note that cranksets are obviously not as easy to swap out as a rear wheel, which complicates training with power on different bikes. This is further complicated with the higher cost of crank-based powermeters. Servicing these powermeters is also a little more complicated, especially considering that SRM requires you to send in your unit in order to replace the battery. But given that Quarq doesn’t require this, I wouldn’t be surprised to see this tedious practice redacted from future SRM units.
In a sense, these powermeters provide the best of both worlds. Its location means that wheel changes will have no impact on your readings come race day, and by being at the pedal, swapping between bikes is a simple affair. The location also enables independent power readings for both the left and right legs throughout the entirety of the pedal stroke. And lastly, battery service and installation don’t require anything more than an Allen key.
There are some drawbacks, however, namely that no system currently supports Speedplay. More broadly, though, you’re limited to a cleat system that’s specific to your powermeter, and the current pedal options are pretty hefty compared to the numerous sub-200 gram offerings on the market. For obvious reasons, the pedal isn’t somewhere that everyone is happy to stack on grams. But given that pedal-based powermeters are still in their infancy, I expect the issue of weight to be addressed in the near future.
Thus far, there isn’t a clear winner for placement, as perks and drawbacks accompany every system. Regardless of where you decide to place a powermeter, though, your training and racing will benefit from it.
Photos: Ben Kuhns