Elliptical Chainrings on MTB. Testing the Absolute Black Elliptical Ring.

In my family I’m the annoying guy that questions everything. I like science. I like proof. I like numbers. Everything black and white. Let’s just say when the dinner table conversation gets around to naturopathy, the atmosphere can get icy…

Thus, I like testing gear to see if there a real world advantage or not, based on real data from heart rate and power. Not how something feels. Enter elliptical chainrings and testage of said chainrings. I wondered if they work. So I bought one today and found out…

Heres my normal chainring. Its a 30T RaceFace Narrow Wide. It’s round and green.

 

Heres one I bought today. Its called an Absolute Black Oval 104BCD Narrow Wide Chainring 32T – it’s black and err, oval.

I bought it from Capital Cycles. It cost $140. Shhh don’t tell my wife…

IMG_3585

The theory about elliptical chainrings is that it increases the leverage of the pedal stroke where you have a muscular biomechanical advantage – i.e. the downstroke, and vice versa. But you already knew that. What you want to know is is it any faster?

Well, I was all ready to call 100% bullshit on this one. But then I went home and downloaded the data… Yikes…

Well, it looks like, umm, yes it probably is faster. Bugger..

I have power (Stages) and heart rate on my MTB, so I can have some basis for measuring output in both ways, which is handy because there is some debate about the accuracy of a stages with elliptical rings. Stages say power is skewed about 5% (up) with elliptical rings.

What I’ve done is kind of looked at times based more on heart rate. And when I think about it, that kind of makes more sense, because for the same power, I can’t see any reason why elliptical rings should be faster, I mean, physics says that right? But if we are talking about heart rate, we are talking about defining out a physiological output, so it makes more sense to use that surely. My understanding is that the purpose of the ring is to give you more lower effort for the same power by the aforementioned leverage principal thing. Sounds like complete bollocks doesn’t it? Well, I slapped down my dollars so you don’t have to, to find out once and for all… I paid for this thing FYI. No sponsorship or anything like that involved so I really don’t care what the outcome is. I just want to know if its better.

I have only done one ride so far, but I chose a good long climb that Ive got plenty of comparison data for. Its called ‘Aratihi’ up at Makara Peak.

Let’s get to the good bit. Now, don’t focus too much on the power numbers here but main takeaway is that the average HR is within only a few beats (3-4) of the comparison ring. Pretty close.

Absolute Black 32T 1: 10:09/ 299W/ 136BPM (‘Corrected’ wattage 285W)  

Round Ring 1: 10:10/ 133BPM

Round Ring 2: 10:44/ 139BPM

Round Ring 3: 10:38/ 135BPM

Round Ring 4: 11:40/ 250W/ 132BPM

But check out the comparison chart. The black base line is the Elliptical Ring. For the majority of the climb, you can see it making up time on the round ring rides. Now, of course this isn’t perfect, and you don’t know exactly how the power was applied and how good I rode the lines etc but just look at that trend. It’s not bad, and very consistent. Ignore the freaky dip in the middle. Its a weird little 90 degree corner half way up – I must have done it fast today. The wind isn’t really a factor in any of these either. I can also hear you saying that heart rate versus power fluctuates over time too, and thats true, but the evidence here is in the trend.

Screen Shot 2015-12-01 at 4.32.18 pm

The trend is pretty clear huh? – it looks like anywhere between 10 sec and maybe 40 sec or so faster over a 10min climb for about the same heart rate output. Say an XCO course contains maybe 10 – 20 min of climbing per lap, that might be worth a minute or more in a 6 lap race.

It doesn’t feel that different to a normal ring. You forget it’s there after 30 minutes.

Also, I did a wee sprint at the end to see what it was like. It felt really different in a good way. It was kind of like having a all these mini breaks in the pedal stroke, and subjectively felt nicer. I also set my best ever 10 second power in this little sprint test too, so I guess thats a thing.

Screen Shot 2015-12-01 at 4.40.18 pm

See that  bit there in the power curve at 10sec? – That was today.

OK, so after the test what do I reckon? Well, I think there is some evidence that the elliptical ring gives you a lower heart rate for the same power. Going by my records, It looks like about 5 – 7 BPM we are talking about. That’s quite a lot. If you want to buy one, please do it at Capital Cycles in Wellington. That would be nice.

I’ll do some more testing too and let you know how it goes…Watch this space…

 

 

 

 

 

 

 

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