Long Term Review – Absolute Black Oval Chainring
Remember Biopace chain rings? They are back… kind of. Single chainring drive trains have resurrected a concept from the 90’s- that didn’t work with multiple chainrings. In concept oval rings should smooth out the torque transfer from the cranks to the back wheel. No matter how much work you have put into your pedal stroke, you do not produce power evenly through a pedal stroke. The idea is that an oval ring can make the most of the stroke where power is produced by giving you a slightly higher gear, and minimize resistance where it isn’t by lowering your gear.
Here’s what Absolute Black has to say about Biopace
Word on BIOPACE – Please understand that this is not Biopace technology. Shimano created Biopace with the completely wrong orientation of the biggest radius of the oval. Instead of positioning it in power zone which is slightly below the level of the crank, they clocked it to the dead zone where human generates least power. The result was that in power zone pedaling was too easy and in dead zone very difficult. Exactly opposite to how it should be.
Absolute Black said that I would feel a smoother pedal stroke and the oval would be easier on legs while climbing. In fact they go so far to offer,”with oval rings rear tire traction improves greatly on loose and slippery terrain. Your legs will be less tired and your speed improved. Climbing will become easier than ever before. It is world’s best oval chainring.” That’s a big promise. Could a simple chain ring really make me a fast as Nino Schurter?
Well no it can’t, but after years on round chain rings were there any big noticeable difference that I could feel?
I have spent some time on skinny tires and countless hours on a trainer over the winters smoothing out my pedal stroke. In fact I own a trainer that measures my torque output while analyzing my pedal stroke. I know that my pedal stroke is pretty good. Sure it’s oval shaped, but it is smooth.
Traction isn’t something I particularly struggle with either. Part of the learning process of riding a mountain bike is to understand when you can lay down the power and when traction won’t allow it. Shifting weight and being judicious about when to apply juice; these are essential skills to any rider who wants to climb challenging terrain.
Skepticism in place, I fitted the chain ring. I took it for a quick spin around the block and I immediately noticed something was weird. The pedal stroke just felt strange. There is a sense that your drive train is full of treacle at certain points of the pedal stroke and then it changes to being perfectly lubed. Well a spin around the block does not constitute a test, so here I am 6 months on.
Oval rings do make your pedal stroke smoother. After getting used to the feeling of the oval ring I stopped noticing it. I actually threw my mountain bike on to my trainer and compared the profile of my pedal stroke with the oval ring to a regular circular ring (yes, I did that for you). The profile is much more ’round.’ I can’t say that I noticed that as much on the trail, and it seems there are too many variables in play to make that measurement. The science dictates that maybe there is a benefit there and who am I to argue with science?
There’s so much I can’t confirm about Absolute Black’s claims. I can’t hold up my hand and swear that my knees feel any better after a ride. I can’t say the traction was improved enough that I was able to clean a climb that I hadn’t before. But I didn’t feel that there were any negatives either. Since I’m an engineer I’m going to have to trust physics on this. The ring stays.
The Absolute Black Oval Ring comes in 26 to 34 tooth equivalents. The actual ring profile varies obviously. My 32-tooth ring, for example, goes from a 30 tooth to 34 tooth profile around the circumference. It is available in direct mount models for Race Face Cinch and SRAM cranks as well as bolt on models. Pricing varies but right now they retail for $66USD £45.99 and €56.99 for the SRAM direct mount model.
Absolute Black have recently announced an Ambassador Program for anyone that might be interested in checking out their rings and other components. Check out the details here.
Ready to step back in time and try an oval ring again (albeit a different oval)?