What was unusual about two of the bikes that made the podium in 2004’s biggest time trials?
The machines — ridden by Bobby Julich (bronze medal at the Olympics) and Alexander Vinokourov (bronze medal at the world championships) — had odd-looking out-of-round chainrings.
Neither Julich nor Vino are considered to be TT specialists, so their results, while not totally surprising, turned heads.
The Osymetric rings they used were designed by France’s Jean-Louis Talo and have created quite a buzz. I was intrigued because my main competitive outlet these days is time trialing. So I arranged to meet Talo at Interbike last October hoping to get a pair of his unique rings to test.
It was an interesting meeting. Talo is tall and intense. It soon became apparent that he Wasn’t going to hand over the chainrings to just any journalist. He wanted to know if I understood their advantages and if I’d ride them enough to feel the difference. And he was politely curious about my racing pedigree. Finally, after several meetings during the show’s three days, he handed me a set of 52/42-tooth rings.
In addition to their race results, the chainrings have done well in the lab. Talo shows the results of several tests and studies on the Osymetric website.
In one study, fit cyclists were able to maintain an average of 300 watts with round rings and 316 with the Osymetric rings while riding at the same heart rate. Researchers attributed the improved performance to increased pedaling efficiency.
In an on-road test, two Festina pro riders (Laurent Brochard and Christophe Moreau) did a 14.8-km (9.2-mile) time trial. Their times on the Osymetric rings were faster than when using round rings by 1 minute and 17 seconds and 1:21, respectively.
These are significant improvements. What time trialist wouldn’t want a 15-watt increase at 300 watts or be able to ride 1:20 faster over 9 miles? That’s a savings of 3:40 or so in a 40K TT.
Sign me up!
With the Osymetrics in hand, I visited Alan “Uncle Al” Ardizone, owner of Cascade Bicycles in Montrose, Colorado. The rings wouldn’t fit on my 1995 Litespeed Vortex because of its relatively fat titanium chainstays. But they installed fine on the Shimano Ultegra crankset of my Gunnar Roadie, a steel bike. The rings came with excellent instructions, although the English translation was a bit awkward.
Because of the rings’ out-of-round shape, the front derailleur had to be moved up the seat tube. This was a relatively easy adjustment for an experienced mechanic. On some bikes, the seat tube water bottle boss might interfere, but that Wasn’t a problem on the Gunnar.
Although the rings look oval, They’re not. Instead They’re identically shaped with two different curves that have a central point of rotation. When a crankarm is straight up, the ring radius is small so it’s easier to pedal through this “dead spot.” But as the crankarm descends into the portion of the stroke where you can generate the most power, the radius gets bigger to take advantage of that power.
The first thing you notice when pedaling Osymetric rings is how awkward it feels. it’s like you’re galloping as the resistance changes due to the rings” shape.
But, remarkably, within 10 minutes the strange sensation vanishes and it feels like you’re on round rings again. I had no trouble adapting to the Osymetric rings or switching back to my normal chainrings. The short adjustment period remained when I rode the non-round rings only once or twice a week. They’d probably feel normal if they were ridden exclusively.
I also had to get accustomed to shifting more carefully. This was true with the Shimano STI levers on the Gunnar and later with the bar-ends on my Specialized time trial bike. Otherwise, the chain was apt to come off the inner ring and fall to the bottom bracket despite a perfectly adjusted front derailleur. Shifts back to the big ring have been trouble free.
I did a few time trials of my own to see if I could duplicate the results on Talo’s website. My tests certainly weren’t “scientific” and were affected indoors by the questionable accuracy of my old CompuTrainer. On the road, there were uncontrollable variables such as wind, temperature changes and air resistance caused by the amount of early-winter clothing I had to wear.
The improvement noted during my homemade tests wasn’t as much as in the studies on the Osymetric site, but it was enough to measure. At a given power output on my calibrated CompuTrainer, my heart rate would be about 3-5 beats lower with the Osymetric rings compared to round rings. And outside, times on my test courses improved about 2-3 percent with Talo’s rings.
I noticed that they made a difference climbing, too. Talo claims that riders will be able to use one gear higher (at the same cadence) on climbs as well as on the flats. I don’t know of a good way to test this but it seemed to be true. I nearly always used the same cassette cog on hills with the Osymetric 42-tooth ring that I’d use with a 39T conventional ring.
This is a preliminary report because I haven’t had time (or weather conditions) to test the rings more extensively or to race on them. Just before this writing, Uncle Al mounted the rings on my time trial bike. I’ll do more testing as the weather improves, and I plan to use them in early-season time trials. If the results are promising, I’ll keep them on for my state’s TT championship in June.
Coach Fred Matheny is an RBR co-founder who has four decades of road cycling and coaching experience. He has written 14 eBooks and eArticles on cycling training, available in RBR’s eBookstore at Coach Fred Matheny, including the classic Complete Book of Road Bike Training, which includes 4 eBooks comprising 250 pages of timeless, detailed advice and training plans. The Complete Book is one of the many perks of an RBR Premium Membership. Click to read Fred’s full bio.