Non-circular chainrings: by now you are either riding them yourself, or know somebody that does. With Osymetric and Rotor stepping up their product lines in the past few years, pro peloton riders such as Wiggins and Sanchez are using asymmetric rings as standard equipment on both their road and TT machines.

Why Asymmetric?

A number of studies have been done regarding these types of chainrings, with results of a nontrivial power gain of around 7-10% (as Osymmetric claims a typical rider will see) from eliminating the dead spots in pedal stroke where other studies have been unable to replicate the power gain, but do see a reduction in stress on the knee and hip. What it ultimately comes down to is that asymmetric chainrings are beneficial to a rider – as for what sort of advantage any given individual will see, that’s anyone’s guess at this point. But pro riders do not make equipment changes on a whim; in fact, it is notoriously difficult to get them to adopt unconventional kit, so when you see Wiggins and others on Osymetric chainrings, there must be tangible benefits.

First Rides

Because of the lack of a clear scientific consensus we wanted to test these out ourselves. Our goal was to find how quickly we could adapt to them, and see if we felt there was an increase in power. Like many of the pros we wanted to look at this subjectively versus making a judgment solely on the basis of competing scientific evidence. We had the guys at Alex’s Bicycle Pro Shop help us get our Osymetric 52-38 110BCD  rings installed on our CD0.1 test bike (with a Vision TriMax crank). The rings are known to be a little difficult to install so we wanted to have the guys at Alex’s help ensure we got the job done right. (But Osymetric has a great video walk-through for those that want to do it themselves – here.)

On our first ride, it took roughly 2-3 miles to get a hang of the new rings. At first your feet feel as though they float or glide at the top and bottom of the stroke. Almost as if you had accidentally shifted to a bigger rear cog just for those milliseconds you are at the top of the stroke. It is a bit weird for a moment, and then it becomes very natural. Five miles into the ride you completely forget that you are riding something different than the circular rings you had been so used to.

After adaptation the question becomes do we feel faster, and more importantly do we see numbers that are backing this up. The answers are yes and yes, we are easily able to hold an additional mph while cruising that we hadn’t previously. Our mates tell us the same thing; we have a bit more giddy-up in the saddle after making the switch.

What’s Next?

A few weeks of riding is not long enough for us to give a final opinion on non-circular chainrings, and thus our long term test will continue. On our list of tests is to climb with the chainrings. We already know how they feel while cruising at a steady pace; we want to see what happens when you stomp on them. Climbing (and maybe a little sprinting) is very much on the agenda. As usual let us know if you have any questions or want us to do anything special as part of the long term review.