Oval chainrings are without question, one of the most hotly debated topics in cycling.
Do they work? Do they make you faster? Is it just ‘marketing’?
Surely if they were better than normal round chainrings, every bike would have them… right?
It’s a debate that will likely rage forever more, but a quick informal poll in the office, a look at some footage of Wiggins at the 2012 Tour de France and some of our own real world testing means we have some conclusive opinions for battling Internet forumites.
Here’s why we use them and why you should give them a go too!
The Science Behind Oval Chainrings
Thankfully, modern oval chainrings are far removed from their origins that go back to Shimano’s BioPace rings. These were oval but worked the opposite way to how oval rings work now.
A modern oval chainring works by providing what is effectively a “smaller” chainring at the part of your pedal stroke where your legs produce the least power, and a “bigger” chainring for where they are at their most powerful. As our legs cannot naturally produce a completely even and smooth power output, oval chainrings use this mechanical advantage to make more efficient use of the power that you produce.
BioPace worked the opposite of this… you can see why they never caught on!
If anything, having an oval chainring actually makes your pedal stroke rounder due its shape and how leg muscles engage through a crank rotation!
What does this mean for you on your local loops? More efficient pedaling = ride for longer.
Are Oval Chainrings Better on Climbs?
The efficiency of the oval chainring seems to really shine on climbs. In the world of mountain and gravel bikes, loose or technical climbs are a common feature and with a round ring small spikes of power in the crank rotation can easily lead to the rear wheel breaking traction and spinning out.
The smoother pedal stroke and more consistent power delivery that an oval delivers might just be the difference that gets you over that tricky climb without a dab.
What are the downsides of Oval Chainrings?
Are there downsides to oval chainrings? Well, yes. Let’s talk about shifting!
On bikes with double or even triple chainrings, the oval shape presents a massive challenge. Front derailleurs are designed to work with round rings and can’t alter their position to match the shape of an oval as it rotates. The result is a set-up headache and a shift that is less smooth than with a round ring. All those efficiency gains could easily be thrown away with an interrupted cadence from a poor shift or jammed chain.
What about mountain bikers with a 1x drivetrain? The perfect platform for our oval overlords (ovallords?)!
Yes and no… Watch out if you have a full suspension bike, as in theory, the altering size of the ring and differing forces that are acting on the chain and cassette are another factor (in a very long list of factors) that may change how a rear shock performs (often referred to as “pedal induced suspension bobbing”). We recommend reading some of the interesting and polite discussions on forums about this if you have a spare 5 or 6 hours…
Our Experience with Oval Chainrings
In our experience though, we’ve found the benefits of oval rings to outweigh the negatives. Our resident MTBer Tom and Road aficionado Peter both use oval rings exclusively on their bikes. Tom is a firm believer that oval rings make a big difference to climbing when out on the trail, feeling he can not only push a gear harder than he normally would with an oval ring, but that he can feel the improvement in traction on the loose, technical climbs that he loves. He notices it less on the flat and not all when descending, so for him, it’s all about making those climbs that little bit easier. Peter always looks for marginal gains to shave precious seconds off his TT times and in his hunt for Strava PRs he finds that oval rings just feel plain faster to him and he notices his legs feel a little wearier if he has to ride normal round rings.
They may not be ubiquitous on bikes, but oval chainrings have their benefits for riders looking for a little extra performance from their bike. Check out our range of absoluteBLACK oval chainrings online now and find out for yourself!
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