Oval Chainring on Road and MTB Bike - Pros/Cons

Hi TR and all!!
I have a great questions; What are the improvements in power, pedaling, etc. using an oval plate on a road bike and MTB?
Thanks and have a good weekend!!

JoseLuisXC :mountain_biking_man:

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Looks like your question got lost in the mix. Oval chainrings are not definitive. Those that use them swear by them, but that may be a bit of the placebo affect. My stance is that if they provided some benefits every pro would be using them, but they’re not. Maybe they work for some and not others based on their pedaling technique :man_shrugging:.

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I’ve read & experimented with them. Most things have never been tested. It just depends what it is you want.

If you want more power long intervals it doesn’t seem to work. Shorter intervals are more likely to benefit. Other things like reduced knee pain and traction on a mountain bike haven’t been tested anywhere near enough.

In the end it depends a lot on what you want, but realistically: probably no one will have done an experiment in people like you doing the sort of riding you want to do looking for the benefit you want, so you’ll end up guessing.

I have an oval ring on the bike I use on the trainer but no other bikes. Can’t say I’ve noticed a difference TBH. If you’re running 1x I’d say go with it but if you’ve got two chainrings it does muck up your front shifting so I wouldn’t bother. Sorry - not much help was I?!

I’ve Q-Rings on my bike on the trainer, and round rings on all others. Only reason is that I got two new chainrings for £30 so too good a deal to pass up. (Us Scots are mean with our money!!).

What I’ve noticed is - I can’t make the same power indoors as I can outside. I’ll be switching back as soon as they wear out. Placebo in my view. Same idea as local riders running 55t chainrings on TT bikes when the can’t even spin out a 50/12.

Thanks for you answer :slight_smile:
For this moment, i dont used oval chainrings and i will continue with chainrings normal.
I am not motivated to use oval chainring and it is true that professionals do not occupy it, but a friend uses it to avoid pain in the right knee and it is as it says @eerke

Thanks and good weekend!!

:stuck_out_tongue_winking_eye:

Dropped chains is the only difference!

I have absolute blacks on my Tarmac sl4. Big and small ring. Used them for years.

IMO differences are:

  1. Oval you need to be diligent about changing the chain. As the chain wears it will drop. I change chains every 700-800 miles. My other bikes sans absolute 1000 miles.

  2. Power meter is a tad off. Plus 3-5%

  3. Shifting gears is something that I do with more thought. In order to get to the small ring there is a certain cadence you can must do without dropping the chain.

I don’t think they are the worth it. But the large
Chain ring in black does look buttery on my bike. My 2 cents.

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Here’s my experience:

Oval rings worked great for me when smooth and consistent power was applied. So they were great for TTs or road climbs where I could use high cadence.

I didn’t like them for offroad terrain because of the jerky nature of pedalling. For example, in cyclocross or mtb where cadence drops as you reach the top of a big surge or where you’re grinding it out to get over a big root or rock, you don’t necessarily want that extra “power” at that point in the pedal stroke

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I first switched to oval on my fat bike for racing on the snow. In those settings, we are frequently struggling for rear wheel traction on seemingly benign uphill grades (depending on snow grooming), and the improvement in traction was noticeable. I went through and eventually switched all bikes over to oval. I can’t say I notice any traction improvement in rear wheel traction in any other setting, including XC. Other notes from my experience:

I’ve had mixed results for shifting on double chainring setups. I have Rotor 53/39 on my road bike (Ultegra 6800 mechanical), and Absolute Black 46/30 on my wife’s road bike (Ultegra 6870 Di2) and those shift great. I have another road bike with Absolute Black 48/32 and Ultegra 6870 Di2, and I still get dropped chains every once in a while. That front derailleur got bent in an unrelated incident, but I’ve never been able to bend it back to work perfectly. So, it’s possible to get them to shift fine, but the margin for error/mis-adjustment is decreased relative to round rings. FWIW, I never have dropped chain issue on any of my 1x setups (MTBs, Fat Bikes, CX/Gravel).

I got used to the ovals pretty quickly for almost all intensities of seated riding.
It took a few days of riding and some aggressive groups rides and races with multiple jumps/sprints before it felt normal to sprint on oval rings. Now I don’t notice any issues. If I ride a bike with round rings, I actually feel sluggish, like it takes an extra second to get up on top of a gear when sprinting.

I don’t have any data to tell me that I’m faster or more powerful with oval. A few times, when I was borrowing a bike with round rings and doing sweet spot intervals, I noticed that it was more difficult to hold prescribed wattage (same Stages left arm between bikes). That could be related to the mis-read with power meter. (Worth noting - I have tested stages and quarq power meter readings on round vs oval, comparing to kickr, and I haven’t been able to pick up any difference in reported wattage).

So - maybe it’s a placebo? Or maybe they do work and the difference is just small and difficult to pick up? My career is 100% based around biomechanics and muscle function/performance, so I like to thing I know a thing or two about efficiency, and the concept of non-round rings just plain makes sense to me. With that in mind, unless I see some pretty convincing research to say otherwise, I’ll stay oval for the foreseeable future.

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No improvements that I noticed. Perhaps slightly less top end sprint power for me.

I was given some Rotor Q’s many years ago. Position 3 for the road and 4 for the tt. After about 3 pedal strokes they feel the same for me as round rings. The same for going from round back to the Rotor Q’s. No difference in power. No difference in HR. No obvious cadence difference or feeling in any way.

I’m back to round rings for the last couple years now. I’m left believing they are snake oil. I wouldn’t recommend them unless you have hundreds of dollars to burn for no reason. To be clear, I don’t think they hurt…just that if you are expecting more power or reduced HR for the same power I think you will be disappointed.

I have used them and continue to use them for CX and MTB. I notice that rear wheel slipping is reduced slightly in conditions where traction is marginal. I still have round on my road/trainer bike, and don’t notice any problems switching back and forth.

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I find the exact opposite, as per the below…

I hardly notice any difference to overall feel on my MTB but I do feel that it allows more control on tough techy climbs etc.

I have round on my road bike and don’t notice any difference in pedal stroke feel jumping back and forth.

That’s not the opposite though is it? In fact, both could be true at the same time.

I’ve also heard reports of increased traction, not that I noticed, but that doesn’t mean the “bigger” gear doesn’t still make it tough on big obstacles when you’re grinding

Sorry, you said “jerky” which is the opposite to what I feel. I would say its much smoother on the techy stuff which is why the traction is improved.

Not sure what you mean about “bigger”.

:slightly_smiling_face:

I mean the jerky nature of pedalling on a mtb or cyclocross bike. The disciplines often require a change in cadence, sometimes with half a revolution of big force to get you over that big root or to grind your lowest gear out when reaching the top of a big hill surge in cyclocross. At these points, where you’re pedalstroke is top dead centre and all you need is to just stamp that pedal down, I don’t find the bigger/taller/long part of the oval to be useful and can cause you to stall.

By bigger, im referring to the shape of an oval. An oval chainring essentially gives you a bigger or smaller gear depending on where in the revolution you are.

I don’t disagree that traction can be improved on consistent terrain such as a flat muddy cyclocross corner, a consistent smooth mtb climb and maybe even pedalling through a corner on a crit course

This is where I disagree, I think it IS smoother and better tracton when the terrain gets really techy, rough and erratic. I guess its just one of those agree to disagree things :smile:

So if you are on a mtb climb and come to a big technical root that you need to get over, and you’re already in your lowest gear and just need to grind that gear one last time over top dead centre to power over the root, you think the bigger radius of the oval is helpful in this situation? You wouldn’t momentarily choose a smaller cassette cog to do this, but that’s the same effect that the oval has.

Happy to agree to disagree as long as we understand each other

Disagree. The larger radius of the oval is located in the power position within the pedal stroke. At the point it get smaller not “easier” you’re not on the power, you’re in the dead spot. So this is a gearing issue, not an oval issue.

The hard bit isn’t always on the downstroke. I have a Shimano ring on my Fixie, for the opposite reason to normal (braking not accelerating). I can’t remember what year Biopace are from. Also Rotor Qs are adjustable. Conventionally they are placed with the hardest bit where the legs are strongest. I actually have my two rings 1 position apart as I hypothesise that it changes the pattern of activation a bit on climbs. Both are roughly Power phase though.

I think it also interacts with standing: if you wobble the bike side to side you effectively ovalise a round chain ring, but I get really confused trying to imagine what I do…I think it might replicate the old Biopace, but with added upper body and core muscles…

*Shimano made Biopace oval rings