I am considering using an using an oval / elliptical chainring. I would appreciate any advice on the pros / cons of using this shape of chainring or if you have any experience you can share with me on this matter cheers

I run Rotor on the TT bike and have raced them up to 12 hrs.

Pros: not much to be honest. Might improve power a little, might reduce fatigue, do use different muscles and you will feel this.

Cons: can’t run 1x without a chain guard, power meters over-read, might need a new chainset. Cadence falls by about 5% and I’m a spinner so this is noticeably different. Loss of smoothness.

Any effect is pretty modest in my experience. But I paid for them, so I keep them. It’s not been a revelation if I’m honest, marginal at best.

This usually sparks some interesting debate!

I’ve gone oval on most of my bikes, main benefits are:

1) Satisfied my curiosity 😎
2) I *think* they feel better when spinning a higher cadence, which I prefer to do
3) Going oval seems to have co-incided with less knee pain, but I changed a lot of things about my set up and riding style during that period, so it’s hard to say.

I like them, and can afford them. If you can afford them then they’re probably worth a try

You’ll get most benefit if your pedalling action is closer to a square than a circle (which is most of us apart from the resident riding gods). I notice the difference most on smooth fireroad or tarmac climbs – there’s just a steady application of torque. I notice that I’m less fatigued when using an oval ring but whether that’s just the particular rides or my general state it’s hard to definitively say it’s the chainring or not.

You’ll find an oval ring a bit different for all of 30 seconds, a minute if you are particular, and then it’s just get on and ride. It does look a bit odd if you look down at the ring whilst pedalling as you see the relative movement between the front of the chainring and the cranks.

Note that a 32T oval gives exactly the same ratios as a 32T round chainring, all that changes is the torque you are applying at different points of the pedal stroke. With the larger oval rings check that your frame can handle it, a 32T oval is roughly the same diameter as a 34T in it’s longer axis. There’s good info on Absolute Black’s site, though obviously they are trying to sell the concept and their chainrings.

Edit: I don’t run a chain guard on any of my bikes, oval chainring or otherwise, and I’ve had the exact same number of dropped chains using both styles. Zero.

Out of round…

https://singletrackworld.com/forum/topic/oval-chainrings-5/

I “think” my Works Components 12% ovality helps on some of the many real steep climbs I have on my doorstep MTB rides. I’d probably stay on a round ring if my riding was flatter.

Gives a clear audiable warning when my Shimano clutch mech needs a service (squeaks with the wonkyness).

If you use a chain guide you’ll need one that works with oval, such as OneUp Components.

Note that a 32T oval gives exactly the same ratios as a 32T round chainring, all that changes is the torque you are applying at different points of the pedal stroke

Let the debate begin! 😁

I maintain that gear ratios are actually just ratios of torque, so if the torque is different (due to changing diameters) then so also is the ratio. The ‘average’ torque over a full rotation of the chainring remains the same though, so for one pedal revolution you will travel the same distance etc

But you don’t continually pedal one part of a circle so that argument is irrelevant. Pedal for a kilometre with a 32T chainring and say 20T at the back and you’ll have turned the cranks exactly the same number of times.

Oval rings provide smoother output as in closer to a constant speed because they are (supposedly) accounting for the variations in torque our legs input into the system. Ride with a knobbly tyre on tarmac with a round chainring and put some effort into pedalling and you’ll hear a rhythmic rumble as your speed changes slightly on each pedal stroke. Do the same with an oval ring and that rumble becomes more constant and it’s harder to discern any variation

Been riding an oval ring on my 1×11 full sus for a few months now.

Pros – Slightly easier up hill for same number of teeth.

Cons – Feels a bit weird until you get used to it. Bit like getting “sea legs”.

Will buy more, as I’m not on as wide a gear ratio as I could be – so help at the lower end is v welcome.

But you don’t continually pedal one part of a circle so that argument is irrelevant. Pedal for a kilometre with a 32T chainring and say 20T at the back and you’ll have turned the cranks exactly the same number of times.

Agree with the second part, what I’m saying though is that the changing diameter throughout the revolution has the effect if changing between a lower and a higher gear, lower gear in the deadspots and higher gear during the power phase. It’s relevant to some e.g. if you’re going oval kn a singlespeed but don’t want to end up pushing a higher ratio for the sake of sore knees etc.

I’m converted for use on the MTB, not tried it on the road all that much. For me the main benefit is being able to stay on top of a harder gear, notice this when climbing mostly, otherwise wouldn’t know the difference. Took all of a minute or so to get used to.  Hard to quantify but I would say climbing traction on loose climbs is better too, probably to do with the smoother delivery of power, but I certainly seem to slip more on a regular ring than I do with an oval. Running 34T oval Sram Eagle rings on both MTBs now so must like them! Would be tempted by a 36T if I still lived in the midlands and not Wales!

Oval on everything nowadays. Whenever I ride a mate’s bike with a round ring it feels terrible!

https://www.pinkbike.com/news/the-quadrant-ring–north-shore-billets-move-to-the-future.html

But that bike needs a square cassette too!

But that bike needs a square cassette too!

They are out April 2020.

I’ve flipped between 32T round and 34T oval a few times on my SS over the last 6 years or so. I prefer the 34T oval – I tend to get further up hills before I stall and appreciate the slightly higher gear when spinning at a higher speed.

On a geared bike I’m less keen, I choose a gear to keep me going and any benefits from an oval ring seem to be negated or minimised. They also concentrate the wear at the point of the larger effective gear, seem to wear fairly quick and are more expensive so I don’t bother for the riding I do.

Cons: can’t run 1x without a chain guard,

I have to disagree with that.

I’ve ran Rotor QX1 chainrings on MTB’s with no issues and QCX1 chainrings on road/CX bikes with no issues either. Both running 1x without chainguards and no chain drops.

I run an oval. I can’t tell any difference tbh. I also don’t usr a chain guide and haven’t dropped a chain.

I’ve got one dodgy knee and a post surgery hip that is mostly ok but prone to flare ups. I have found oval rings keep both quieter than round. I guess this is because they knock the edge off the max torque required at the ‘dead’ part of the pedal revolution. I think. Seems to work regardless.

I can’t tell the difference to be honest, I have oval and round and switch all the time. Only tine it’s noticeable is high cadence in low gear in little ring-then it can be a bit lumpy.

’ve ran Rotor QX1 chainrings on MTB’s with no issues and QCX1 chainrings on road/CX bikes with no issues either. Both running 1x without chainguards and no chain drops.

Mine dropped 12x on a 12 hour TT, mainly changing to the bottom of the casette using 10 speed Di2 – so not misadjustment. I also dropped on a 50mi running eTap on a different bike – only three times that race. It’s not a NW though. Both times I had a chain guide in place, but not one that enclosed the chain as a FD would. By contrast the circular Rotor rings have not dropped at all.

No Experience off road, but I run SS or 1×9 NW Absolute Black 38T without any issues either.

@TiRed – the chainring not being NW makes a big difference IME whether round or oval chainrings. Basically NW = no dropped chains*

*so far for six years!

Not one single chain drop, off road, on my absolute black NW ovals on 2 bikes in 2 years.

And that’s even after remembering half way thru several rides that I forgot to engage the clutch, after releasing it to take wheel out and replace.

It may derail from the biggest cassette sprocket if pedalling backwards, but why would one pedal backwards there anyway?

My old round ring would derail when dropping to the inner ring, but that was most likely limit screw set wrongly.

Oval definitely feels better, when slogging up a long incline on a 1x where I’d normally have 2 more lower ratios on a 2x/3x. But I expect it’s subjective.

No benefit for me. Maybe a touch of knee pain too so I gave mine to a mate. Anyway, itch scratched so I don’t need to go there again.

the chainring not being NW makes a big difference IME

That’s what I found the hard way 🙁 . No oval road NW in my BCD, but as I said, I didn’t find a huge difference with the Q rings, other than slightly more sluggish cadence (I’m a spinner). I still have the ring on one bike – with a FD, and have a spare 53T doing nothing. I’d try a QCX1, but again not available in 130 BCD.

Glad I’ve tried them, and think it’s worth others also doing so. Just don’t expect a night and day transformation. Of interest, my Favero Assioma Uno power meter can adjust for the non-round ring and gave values consistent with a co-mounted SRM PM.

Re chain retention I wouldn’t put a non narrow-wide ring on anything these days tbh.

I went full oval for a while, after really being impressed on the fatbike- I couldn’t really tell any difference most of the time, it didn’t feel easier but there was some evidence that it was a wee bit faster for the same effort. But mostly it was seated plodding- that final climb at the end of a long day- that impressed me, on a rigid fatbike knackered low cadence riding results in a lot of blobbiness, and all that up-and-down bouncing is wasted energy… Doing the exact same with an oval was just ridiculously smoother and that can only mean it’s more efficient. So I figured, if the effect is there then, it probably must be everywhere.

So I put one on my big #enduro bike and tbh, I didn’t really notice a difference at all. Stuck with it, certainly never felt it was bad, just didn’t feel any advantage either. Changed to a round one when it wore out as they’re cheaper and still felt the same.