I’m thinking about installing an oval chainring on my MTB bikepacking/ touring bike and would love to hear real-world experiences.How does it feel over multiple days,
especially:
a) during long, fast riding on flat asphalt
b) slow climbing in the lowest gear, fully loaded?
Happy to hear experiences, especially with flat pedals and 1x drivetrains. My system weight ist up to 120kg/ 265lb
by EfficientHornet2170
11 Comments
If I remember correctly, there was found to be little to no difference with oval rings. They were a thing briefly a while back.
Some form of these get invented every decade of so, then disappear again. Shimano had Biopace in the late 80s. I had a bike with it which I used a a courier. It felt slightly different from round chainrings, but I don’t miss it.
There are plenty of believers but there is no published proof. They come and go in popularity and have been around a long time.
Certainly they aren’t a terrible idea, but there is nothing other than anecdotes to support their use. If you like them, go for it. I have never tried one but am also not tempted. Also if you have a front mech you might suffer more chain drops and/or wonky shifting. 1x seems more sensical if you’re going to try them.
I like them, used biopace on my 80s tourer for the past 15 years. It does feel like a slight ergonomics boost more than anything else. Maybe tautologically, ergonomic gains=power gains. I like having a varied gait, it feels like it exists for a reason, under my feet
There are no large-scale studies but a handful f small ones [like this one](https://pmc.ncbi.nlm.nih.gov/articles/PMC3990898/). The broad consensus is that, properly oriented, an aggressive oval/nonround chainring can provide a small boost to your efficiency, somewhere around 1-2%. If this holds true in larger studies, it would be roughly equivalent to ceramic pulley wheels. Adding in that smaller chainrings seem to benefit less from shaping than larger ones, I don’t think they’re worth the money for touring. Their ideal use is during a time trial where huge chainrings, consistent cadence, and high power are key elements and literally every second counts.
Shimano’s biopace weren’t oval but kind of flappy square and were claimed to be designed for efficiency over power. Unfortunately I don’t believe they’ve ever released their data but old school riders like Sheldon Brown comprised a small but loyal following.
I did Chicago to Niagara Falls with an oval chain ring 10 days 840 miles. And I will continue by touring with an oval chain ring. I don’t know if it really helps but the placebo effect is all I need.
Some people swear that biopace is more efficient others say it’s a gimmick. I have biopace chain rings on my 80s era Panasonic road bike and I don’t think there’s a noticeable difference, if any.
More prone to failure. Circles circle good. Ovals don’t circle good. Torque is equal on every part of a circle. No so much on a oval.
Leads to gradual fatigue, especially if it’s aluminum.
Never seen on the TdF so must be snake oil
It’s elliptical (two center points) as compared to an oval.
Its neither a gimmick or a game changer. It’s a preference. I have ovals on one my of my bikes, I love getting on it after I have been riding my standard bikes for a while. Ultimately it makes no difference, but to me it feels nicer.