Non Circular Chainrings

Please correct me if wrong, but can't find a thread about them in the forum, apart from this 7 years old.

I've been reading about them since I first got the chance to use a CX with Rotor Q Rings for two months years ago... But I'll finally try them in my last project

Yes, I know there is lots of articles and studies claiming that they let you deliver more power, and others that they really don't. Not here to start another holy-war / flame... just to talk about different models for those interested in trying them out.

As far as I know in the market you can find:

• Rotor Q Rings and QXL
  
• Osymetric
  
• Doval
  
• Ridea
  
• Wolftooth
  
• Dual Oval
  
  

Here's a nice article comparing Osymetrics vs Doval vs QRings (in Spanish, but google translates it well from the guy that did #2 on this year Trans American Race equipped with Doval. He's going to re-sell them (they are only sold via ebay and shipping takes more than a month).

Since the Doval ones are now the cheapest, and the design seems quite interesting, I'll give them a try and report if anyone wants to know how they perform with the chaindrops (yes they are ugly like the others, not looking for a salon bike here, just to avoid strains and pains on endurance rides)

Just found out another brand with many models:

http://www.rideabikes.com/pro_road_powering.html

I ride with doval inner chainring in 40 since ... 3 years. That's a paradise

Just got the Doval's, 110BCD, 52/36 and 16% of ovality. About 180gr for the 3 pieces. I hope I'll test them in the holidays

As there is several position to mount it, have you an explanation? I've put mine on the first angle I choose decent.

All the technical info is in some images at the official ebay sale page: http://www.ebay.com/itm/131661544771

The 5 positions seems to offer an option to adjust them in regard to your own dead spot (like Rotor has the OCD adjusting system)

Yep i've got this.

But what's the main difference between a 18° and a 16° angle ? In which case are you spinning faster?

I've still not used them, but as far as I know, that 18-16º angle represents the point where your power production should be higher, and the dead spot should be then correctly located in the narrowest diameter of the chainring. So they offer you 5 positions to "find it" (or get near to it) in the outer ring, and 2 in the inner ring.

What I mean, is that the dead spot is not supposed to be at the 12 o'clock always, it depends of the position of the saddle in regard to the bottom bracket (think about a Time Trial bike and a normal road bike... saddle is way more forward in the TT).

Anyway... all my knowledge is based on internet reading :), don't take it as a fact.

Focus more on peak gearing than the dead spot, but it's difficult to do yourself unless you have access to things like high speed video.

I have my rotor set at position 2 which feels good at medium to high cadence but is pretty awful at low cadence. Which ever way you set up your rings, make sure you fit a chain catcher!

Those doval rings can be horrible to set up. In terms of front mech alignment. This is tricky on most oval rings but I find doval the worse because they aren't totally flat.

I seem to get on far better with the oval outer ring. When I'm climbing steep stuff at lowish cadence I don't like the oval little ring.

I've had q rings, osymetric, and now doval.

Q-rings = too little ovalality to tell much. Nice little ring for climbing.

Osymetric = great when under constant torque. But the sharp decrease in effective gear is uncomfortable when you're Pootling. Not great for low cadence climbing. Although taking a 38t little ring to the alps was stupid regardless of shape.

Doval = in between the 2. Less quality in manufacture though.

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Plan to go QXL 52t, Q-ring 36t next.

Reckon that'll be my sweetspot.

The big point with doval is that you actually could push less and have the same power. I try to explain myself.
With a regular (circular) chainring, you need to be constant. With an Oval, you could easily have a dead point and then put more watts. So it's helping you to climb with a smaller cassette at the same speed / pace, or with a bigger cassette, faster than with a circular one.

i have a Doval 52/36 and it is good when in gear and when cadence normal, shit when changing front gear, and shit when cadence drops such as on long steep climbs. I won't be replacing it with another.

If you normally ride a 52/36, should you be looking at a 52/36 oval? As they are equivalent to 55/39 or something at the widest points. Which may be why i struggle with it at low cadence...

In my experience it's the sudden loss of resistance at the dead spot that throws you. Obviously this is the whole point. But at low cadence it's just not helpful.

I got on well with a 34t Q-ring. So plan to get a 36t Q, to match a more oval QXL 52T.

That Felt looks daft.

If it looks daft there.

You don't want to see it with reversed seatpost, stumpy tritone saddle, and clip ons.

If you're gonna go aero, you might as well go full aero.

On topic, I have a q-ring inner and I much prefer it to round. Makes it feel much more like climbing on fixed. Didn't get on with the big ring though.

I like biopace rings and have them on a couple of bikes.

Do you not feel a bit like a twit when you pull up outside a cafe on Batman's bicycle?

Folk tend not to notice the bike, when you order an expresso wearing a Cape and mask......

@bertocq, how are you getting on with your doval rings? Tempted to try a pair, and looks like they can be picked up on ebay for about £35 new.

From what I've read and based on what I'm currently running (52/36), it's sounds like a 50(16%)/34(12.1%) might be best/equivalent and might reduce the difficulties of low cadence steep stuff in the small ring.

Does that sound like it makes sense?

They are sold through ebay, but take some time to arrive to Europe (no pun intended), but @CarlosBI have some in stock to ship right away from his home (although he's living in UK now).

I've used 110BCD 52/36 16% (both) for about 9000km, and on the previous bike got 50/34. I feel like I can ride the same, but feeling less strain on the legs while climbing on the saddle at low cadences and also a bit easier to spin the pedals faster while out of the saddle.

Can't compare sensations with Rotor or Osymetrics, but learned something buy mistake: while cleaning the bike for the 1000km brevet. I was a bit sleepy and mounted the rings on the wrong position... meaning that at the point that I could deliver more power, the chainring was in its smallest size (instead of the biggest).

That was funny because when I started riding the bike I felt something was wrong, like if I had a lenticular wheel installed... but since I hadn't ridden that bike in almost a month... I supposed it was just me getting used to the Doval's again (my commute bike is a brompton).

At the first brevet stop (119km) I was feeling ok again, my legs had settled in with it, but I took a look and realised my mistake. After changing the rings position, it took me another 4 to 5 hours to get my legs again feeling normal in the "new" position :) really strange feeling while riding at night. No muscles or tendons where hurt... I finished in 55h (37h of pedaling) but for other reasons (I'm from the north and the heat kills me from the inside out, and guys riding with me where from the south, thus at night where slow as hell and when sun was hitting hard they didn't want to slow even a bit for me)

But that may not be your case, maybe your legs will feel a bigger difference or not get used to it as fast as mine, using a lower asymmetrical than 16% could help. But being so cheap I just thought "lets get the most of them, or nothing :D" So 16% should be!! Also cassette is 11-28, not sure what you got and how stepper your climbs are, but I got less problems with 36-28 than with 34-29 past year (maybe because of the increased physical form).

So, I'm not sure going smaller would help more than going smaller with circular chainrings, I would get the 52/36 16% and feel the difference just from the change of shape. It doesn't get harder, or easier, it just gets faster when you can't make much force, and slower when you can deliver most of the power

I've always been put off from buying doval chainrings by the sheer concept of having a philips head screw anywhere on my bike

can that screw be replaced by a torx just for the sake of it?

Ah berto, love your comprehensive replies! Cheers for all the details :) I too am cheap, so I've gone for your recommendation of 52/36 16%. Go big or go home, right?

I'll let you know how I get on when they turn up and I get around to fitting them... Cheers!