Elliptical Chainrings. Thoughts?

[tripleDot]

The second ride was a 12 mile race that I did last week.  Again, I didn't really notice much difference in feel.  So my current evaluation is that going from the 32 round to 34 Oval seems to feel pretty much the same to me.  What I'm hoping after I ride a little more is that is still feels like pushing the 32, but I carry more speed because I'm actually pushing the 34.

Shouldn't that already be a significant change?  You're pushing the 34T like it's a 32T.  Technically, you're exerting efforts of a 32T but going at 34T speed.  That's 1 step better output.

[voodoo320]

I have a Deckas 32T elliptical pair with XT 11-34. It works great. It gives you more power to accelerate.

[ottoreni]

VooDoo 320 did you have to do any sanding to the tabs of your Deckas ring?
Just asking, as I had to do some sanding to get it to fit my SRAM XO crankset.

Thanks!

[voodoo320]

ottoreni. I just ordered a nice set of bolts.... It is quite cheap here in China.... you don't need to do any additional effort...

[ottoreni]

Unfortunately, both China elliptical rings I have bought required a fair amount of filing to fit SRAM cranks.  The first one was a the least expensive labeled "SNAIL" I had to file the tabs to fit the crank.

The second one I  bought labeled "DECKAS" cost almost twice as much, but still required a fair amount of filing to fit the crank. It came with a set of inexpensive chainring bolts.  I used Wolf Tooth bolts to mount both. 

Both had 104BCD holes but the tabs were too long and would not let the ring sit on the crank.

Looking at both rings, they are identical besides the "names" painted on them.

Lesson to be learned from my experience, buy the cheapest elliptical ring you can find because you will have to file the tabs regardless of the price if you are using SRAM cranks.

I will post pictures later.

[carbonazza]

@ottoreni, these rings are a cheaper option, and filing a little is free

[voodoo320]

ottoreni.... I thought you were asking about the bolt.... my deckas just fit well with XT crank. Atleast you customized yours to fit. saved a lot of bucks compared to absolute black $$$.

[xcbarny]

The clocking on the Snail rings looks to be around 90 degrees, i.e. when the major axis of the oval is pointing straight up, your cranks are horrizontal. This isn't great.

Ideally it should come at around 110 degrees, so that your leg / foot is in the stongest position. I think rotor uses 108 degress, but allows you to change this with the OCP. Fairly sure that Absolute black ones are fixed at 110 - 116 depending on size.

The clocking being too early (90 degrees) will slow your leg down, since the major axis comes at a point when your leg isn't in its strongest position.

If anyone is looking for an innexpenive 'non round' chainring, I suggest checking out Doval on Ebay.  Can be had for about $30 and the shape of these rings is very natural - i.e. feels nicer than Q-Rings and all the other oval clones.

[325racer]

After some more time on the Absolute Black Oval 34t, here are some more thoughts.

Maybe, I'm not strong enough to push the 34.....  I haven't gone back to the round 32, but there are times I wonder if I'd be faster with the 32 as I find I just can't push as hard as I'd like.  Now, I'm not running out of gear, and I'm keeping my cadence averages 76rpm on a 10 mile, 12.7 mph race.  I haven't trained much, so maybe if I could spin closer to 85rpm with a smaller gear I'd actually be faster overall???

Also, I am noticing some Oval effect now, in that I get clunking as I spin because my pedal speed can't keep up with the cassette speed.  Again, not sure if this would or wouldn't happen with a round ring, or a smaller ring.

But that's my input to date.  On the plus side, as would be expected, no dropped chains or anything....

[RS VR6]

You would usually go with the same teeth you're currently running now. I use a 30T, so I stayed with a 30T. The ovals are typically + and - two teeth at the high and low parts of the ring. Going from a round 32 to a oval 34...you kinda went up four teeth from your round 32. At least that's how I understand it works. 

[325racer]

Yes and no.  I did go up to the 34 on purpose, as I wanted more gear.  Overall going to a 32 oval is still going to be a 32.  It allows you to put more power down in the strong part of the stroke.

Either way, yes I knew I was going to a bigger gear.  Some of my reasoning came after I had been riding my road bike in the dirt, which only has a low gear or 38 front 32 rear.....  so I figured 34 front 42 rear would be fine.

[VisionTim]

I tried one for a little while and didn't notice any benefits.

[cmh]

So, update on my Absolute Black. As I'm riding more this year and getting stronger, I'm tending towards riding bigger gears. My fitness and my preferred cadence have always been inversely related. When I'm weak, I spin like a top. When I'm strong, it's all big gear bashing. Dunno.

Either way, the 30t on the Epic has been a bit short lately. Did a ride on local trails where we averaged about 120 feet per mile of climbing over a 13 mile ride and realized that most of the time I was on the high end of the cassette. Have a bunch of chainrings in bigger sizes, but they're all 4x104 or Race Face Cinch spiderless. No use to me since I've got the 4x94 BCD on the SRAM cranks. So, I decided I'd bust out the 32t AB oval ring as it's a little bit larger. Plus, it'd be good to revisit the oval and see what I thought.

Commuted home the other day, and had the Epic waiting, so before I got changed, switched from the road bike to the Epic with the AB oval ring. Holy crap, that was weird. Switching from a 34t round ring on the road bike where I had been spinning along merrily on my easy cruise home, the oval felt REALLY strange. Like, lumpy. Interesting if inadvertent back to back comparison. The feeling went away quickly, though, and I imagine if I switched back after my quick cruise on the Epic, the road bike would feel strange the same way.

Did a proper ride with the oval again, and honestly, I still can't say as I notice the ring.So for me, it's really neither good nor bad. It's something different that you notice at first and then adjust to and it disappears.

[SportingGoods]

I was reading a French MTB magazine last week end. There is an article related to a research center doing advanced studies related to XCO racing, supporting a specific local team. They mentioned non-round rings and their short conclusion is that it only makes a difference if you have a VERY good pedaling technique. Otherwise you should just stick to round ring.

[Viperdriver]

I have one on my SS and 1x11 bikes.  I really like the oval rings, get one!