firebird854

First, I have never used them put researched them in-depth as I was considering using them.

Second, the jury's still out on literally any of their "scientific" claims:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3990898/ study showed no physiological difference whatsoever between standard and rotor chainrings across the spectrum of power outputs. However, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4879434/ found a minor improvement for maximal efforts when performed with the oval rotor chainrings (literally one of the only papers that I could find that actually sited an improvement anywhere). From my research, it generally appeared that for ergonomics, eliminating dead spot, performing more power at a lower effort for long periods are all pretty much-unverified claims. There's that one paper that did find some improvements on maximal efforts, but the other one I posted does completely contradict it...

Third, they look cool, granted I think that about rotor and absolute black chainrings in general whether they be oval or not.

Fourth, many power meters work fine with them, literally all spider power meters (quarq, p2max), the P1 and P2 powertap pedals, g3 power meter, and many others will perform without any power discrepancy. Rotor also makes 3 different power meters that all work with them, including a new spider one that I kind of want (if it's ever in stock).

burnthesheep

I tried on a free set of pretty worn Q rings that came on my TT bike. I didn't keep them.

To me, it's always advertised that you have more use of your strength where needed and not where it's not needed. But, issue is, any pedaling dynamics podcast (Fast talk recently had Zinn on about this) that they say you're not pulling up to make power. Since you're only really getting the leg out of the way, I can't see how the lesser gearing in that part of the stroke helps.

So, then, you're just winding up with "more on the more end' which is no different than just changing gears or cadence.

It also implies an increased accel/decel of the system, however slight, as you're going in and out of the perceived gearing change through the pedal stroke. Accel and decel costs energy, it doesn't gain it.

I dunno. I'm not totally convinced and I've ridden them before.

IMHO the much bigger thing for most riders is getting a more appropriate crank arm length. All the "leverage" crap and other theories that drive 5-foot nothing riders to ride 175 or 172.5 cranks is junk. Hip angle really matters for power production, it's a key fit consideration for TT at least. Why people don't seem to care for road is beyond me. At some point you're in the drops or in the machine gunner pose on the hoods. Then, that hip angle is going to matter a lot more than some oval chainrings.

But most roadies and clubbies could probably go down a full 5mm less in crank arm length.

jadocs

For those of you with oval rings and power meters....do you find that it affects the accuracy in any way? I have heard Rotor has addressed this in the design of their power meters. Yes, I know Froome has non standard rings and power.

DrIsotope

No difference in power readings for me between oval and round, but I have a Rotor INPower, so there is that.

Hermes

Conventional strain gage power meters measure power by changes in the strain or force applied to the pedals and then calculate power based upon the cadence. However, that assumes that the ring is round such that the tangential velocity of the chain is constant. V=RPMxRadius. An oval ring generates a variable radius and different velocities. This produces a difference in power measurement between oval and round rings. The change is small in absolute measurement but consistent over different RPMs. The take away is that it is immaterial.

Obviously, power meter manufacturers can design to compensate for oval rings.

RChung can elaborate on this if he is motivated and confirm or correct my assumptions.

There are few, if any, secrets in the UCI world tour pro peloton. If oval rings were an advantage and reliable, all teams and racers would have them. I could see them more for time trials where there is less shifting of the front derailleur versus mass start races All it takes is dropping, throwing or mis-shifting the chain one time on the front derailleur at a critical moment and any value of an oval system is gone.

With respect to front shifting, the distance to the bottom of the front derailleur and the teeth of the large chain ring is critical or at least must be in a range. The oval nature of the ring makes that distance variable such that one could shift at a moment in time when the distance is just wrong and off comes the chain or the chain refuses to change rings. And the other variable is which rear cog is being used at the time. So one can ride for some time without a problem and then boom the right combination of chain rings and front chain position, cadence and rear cog drops the chain or produces a missed shift.

If one only runs one chain ring then the problem may be solved. Except 1x systems require more chain tension so I am not sure if an oval ring on the front affects shifting and chain stability as the oval ring will change chain tension as front ring rotates. Interesting stuff...so many variables and unknown outcomes.

jadocs

That is what I have heard as well. I would like to know what the delta is between the two.

rclouviere

Well, guess I’ll just stay with my normal boring chainrings. I’m just an old guy trying to find a way to be a little faster than the other old guys...

canklecat

Same. At 62 my window of opportunity for getting stronger is rapidly closing. I started from nothing at age 57, resuming cycling after a 30+ year hiatus, and needing a cane to walk between 2001 when my back and neck were broken in car wreck, until 2014. Then I started riding bikes again in 2015. That first month back in the saddle I couldn't ride 400 yards without gasping for breath.

It took a long time to get back into decent shape. And I may be able to continue to improve my physical fitness for another year or so. But by age 65 it ain't gonna get better, not without PEDs. That's just life. A full course of PEDs administered under expert supervision might prop that window open a little longer, but I'd be surprised if it made a dramatic difference in my average speed. It might improve recovery and help me train harder. But unless I win the lotto and have spare cash to play Frankenstein games with my body, I'm stuck with what I got.

So I'm considering every possibility to make more efficient use of the limited power I do have now. (No idea what that really is, I only use Strava and the Elevate browser extension as infra-referential guidelines. The numbers are relative only to that same standard over time with Strava and Elevate. As long as they don't recalculate that formula, I'm assuming that I really am getting stronger when my average "Strava power" was 90 watts in 2015 and 150 now. But what that translates to with a power meter? I have no idea. A local trainer didn't want to bother with me when I said I was curious to check my FTP in his gym. I'm guessing he only wants to work with younger athletes or those who are interested in a long-term commitment of money.)

By making lots of little changes I was able to get a little faster without actually getting stronger. My upper body strength and flexibility is better now, so I can hold a more aero position longer on conventional drop bars.

I still can't handle TT aero bars for more than a few minutes at a time. But when I do use aero bars, even for only 30-60 seconds at a time, my average speed over 20 miles or longer is better. And I'm trying to get more comfortable with the invisible aero bar position. That's hard to do with old school round bars, so I may try a set of flat top aero drops this year.

More aero kit helped too -- jerseys and helmet. And this is just affordable off the shelf stuff. Oliver Bridgewood with his recent effort for GCN to tackle the one hour record showed that an off the shelf skin suit was measurably more aero, and an pricey custom fit skin suit improved even more, without him needing to get stronger.

Those are probably the most affordable solutions to getting faster without getting stronger. Better core. Basic aero kit and helmet.

I have no way of measuring my perceived differences between round and oval chainrings, other than my average times over many rides and how I feel during and after those rides. But my impression is that non-round chainrings and a slower cadence with harder gears worked for me, on two different bikes (carbon fiber and steel).

I suspect the non-round chainring (Biopace, in my case) is just more forgiving of my choppy pedaling style. Some of my fastest times were on flat pedals on these bikes. I've equaled that with clipless, but not surpassed it by much. That's a pretty good indication that most of my effort goes into stomping the pedals, which tends to negate the minor differences foot retention makes. Non-round rings, with the elongated lobe oriented to coincide with my choppy stomping style, seems to work for me. It might not help folks with smoother pedaling, and might even mess up their pedaling and lead to injury. Dunno. But I'm going to continue trying non-round rings for awhile longer.

rclouviere

Good for you! Looks like you’re staying fit and working hard. We’re the same age.

I think I’ve done about all i can to increase my speed. I have an aero road bike, and TT bike. I train hard and regularly hit the gym and stretch regularly. Ive been riding for about 14 years, and am actually faster now than I’ve ever been. I’m still able to keep up with most of the younger riders. I enjoy this challenge.

What has has helped is entering TT races. This seems to keep me motivated.

Also, based on your post, it seems you don’t have a power meter. This has really helped me in training and measuring where I’m at.

RChung

Close. It's kinda complicated, so if your eyes are already glazing it's time to skip this message.

Many crank spider-based power meters used to use a single magnet and reed switch to measure cadence: each time the crank went around, the reed switch would click and you could measure the elapsed time between successive closings, so you'd know how fast the cranks were rotating (i.e., your cadence). That's how SRM did it -- I think that's how SRM still does it. But a single magnet and single reed switch won't let you have better resolution than once per revolution so the SRM couldn't tell if the crank was speeding up and slowing down in the middle of a stroke. Most of the early power meters used the same magnet/reed switch combination, so they had the same problem. This comes up because the early Rotor claims were based on tests with SRMs.

Fast forward to today. All the pedal-based power meters, most of the ones with instrumented cranks (like the Stages), and some of the crank spider-based PMs use accelerometers to determine cadence (I believe Quarq allows both). It turns out that accelerometers give noisier data than a simple magnet and reed switch, but you *could* (if you wanted) use it to track changes in foot speed within a crank revolution. A side effect of this is that you *could* (if you wanted) use it to give a pseudo-left-right balance in your pedal stroke, though once again you'd have to average over the changes in speed, not just look at the torque. Here's the thing: AFAIK, no manufacturer has implemented this except (I think) Infocrank. In response to our questions, Garmin has explicitly said they don't use the accelerometer data from their pedals to adjust for varying crank speed. P2M never answered our question, nor did Stages. What this means is that even the L-R balance stuff can be affected by eccentric rings.

As an aside, though you didn't ask, if you ever get to compare the cadence from a magnet/reed-switch crank system with an accelerometer-based system, you'll see that the accelerometer cadence is noisier. In fact, it's roughly about as noisy as the cadence you get from a PowerTap hub, which people used to denigrate for its inaccuracy (not me, though). How to tell that the cadence is noisy is yet another boring post, but I'm guessing that noisiness is why no manufacturer has bothered to implement the varying speed correction.

It depends on the eccentricity of the rings: the more eccentric, the greater the variability in foot speed for each revolution. For "typical" eccentricity, a couple of percent measured on a SRM compared with round rings. Not coincidentally, that's how much Rotor claimed their eccentric rings increased power over round rings.

[Edited to add, because once I get on the high horse it takes a while for me to get back down] How much does a couple of percent matter? It depends on what you're doing with the information. There are lots of uses for a power meter, some of which require more accuracy and precision, some not so much. Training FTP is one of the least demanding things you can do with a power meter -- that's why riders have been able to train well with just a wristwatch and a regular training route, or with a HRM, for decades. Measuring drag is a highly-demanding use for a power meter, because drag varies nonlinearly with speed and power; that means you can't just have precision, you also need to know the actual amount of power in order to solve the nonlinear drag equation. So, you can train FTP with a wristwatch, but you can't measure drag with just a wristwatch. If you were trying to tease out small differences in drag between, say, two different helmets, or two different tires, I would want to have both high accuracy and high precision. Ironically, people used to try to measure drag with coast downs -- that's a case where the power is accurately and precisely known to be zero.

jadocs

Interesting thank you.

Cyclist0100

I recently ordered a Wolf Tooth 42t chainring for my 1x11 setup, and when I picked up the bike from my local shop the mechanic said he went with the oval ring instead of the round. My first reaction was "oh no, I really don't want an oval ring", but he said "try it out I think you'll like it". He knows how I ride and I have a lot of trust in his judgement, so I decided to give it a try.

From the moment I got onto the bike I absolutely loved it. The pedal stroke feels smoother than the round chainring, power transfer to the rear tire feels more efficient. I do not notice any statistically significant increase in speed, but the feel of the oval is heads and shoulders above the round chainring.

Climbing local bridges is where I notice the biggest gearing/speed difference. I do not have to gear down as much with the oval ring to maintain speed. I've now put about 1,000 on the bike since getting the oval ring and it's awesome!

Bah Humbug

I like them, but I won't say they make me faster, and they reduce shift quality enough that I gave up on using them.

What gets me is the people horribly offended that others ride oval rings of whatever sort. Who cares if it's not faster? Why must every piece of equipment be only justified if it makes us faster?

guadzilla

You may have done this already, so excuse me for offering unwanted advice - but have you considered raising the pads a little and also changing the saddle (as well as saddle position)?

Putting aerobars on a road bike is possibly the single most uncomfortable thing i can think of, as it completely closes your hip angle. Moving the saddle further forwards helps tremendously. It also helps to have a saddle where you are sitting on the nose, with your boys dangling off the front (were it not for the bibs). If you want to use the bike for TT duty, the easiest way to do that would be to have a second seatpost with the different saddle positioned in the correct place, which you can just swap in. If you plan to switch between the tuck and a regular road position on the same ride, you will have to find a sweet spot with saddle position that lets you do both - this will be a fair bit forward than a typical road position, though.

The other part of comfort is height. If you are using clip-on bars, consider something which lets you raise the pad height. On a typical road bike, clip-ons result in a very aggressive position. When i used to do more TTs, i just cared about getting low (within reason) and comfort be damned. Now that i am doing medium-course tris, i need a position which i can hold for 2.5 hours or so - the simple fix was just to raise the pads by about 25mm. Now it feels like i am riding a couch - super comfy and I dont need to move aroound (thereby destroying the aero gains of a more aggro position), nor do i have much of a drop in power either. And it is low enough to be a big improvement.

canklecat

Yup, agreed about trying to turn an old school road bike into a proper TT bike. The geometry that's so well designed for long, fast rides in the traditional saddle positions defies the optimal aero position.

My Profile bars offer plenty of adjustment, but it's still a compromise on a road bike if I also want to retain the optimal road bike setup. And that old neck/back/shoulder injury I love to whine about thwarts my best efforts at a compromise setup with a road bike.

I do have an older Trek aluminum TT frame, a decent starter bike. But there appears to be a hairline crack in the weld at the top of the seat tube. A rider's weight would probably prevent the crack from worsening or failing (it's a massively overbuilt seat tube, as many aluminum frames tend to be). And it may only be in the paint. But I stripped the bike to inspect it as thoroughly as possible before deciding whether to rebuild it or just get another frame. I have all the components from the bike, including some nice Dura Ace bits, so eventually it'll make for a proper TT bike.

I did ride that old Trek TT bike a time or two before discovering the crack, and it was much more efficient. But I didn't have time to set it up properly for myself. If I did I would have set the top of the stem as near level with the saddle as I could get, and I'd need a longer stem. It was too low and twitchy for me. I figure an aero tuck that I can maintain over time and distance is better than nothing, even if it's not as low as some folks would choose.

And more/continued physical therapy will help. It's already made a big difference since I started with structured PT in a clinic last year, and I've continued at home on my own.

guadzilla

Oh man, tell me about it - at the local TT races and even Ironman events, I see so many people showing up on bikes with intimidatingly aggressive positons. Then i see them on the course and they can barely put out any power because of their position.

Yeah, core and some strength training goes a long way towards being able to maintain the tuck - as is spending time on it on the trainer. Again, back in the day (damn, i feel like i should have a get off my lawn moment now), i used to do all my intervals on the TT bike. These days, i do my weekend long rides on the TT-coverted-to-tri bike. And as a side note, i find that the overall strength and fitness i have gained from the additional training of triathlon makes me feel a lot healthier than when i was a scrawny-armed roadie only. Good luck dealing with the neck/back/shoulder injury, amigo.

ChrisAlbertson

I have a 26" bike that has a triple ring biopace on it. I was made by Diamondback as a "mountain bike" before they invented suspension. So it has hard forks and tail. I use it as a "ride to the store bike" My normal road bike has round chainrings, So I ride both.

I find the biopace is easy on my legs and comfortable. It would not work well for a 100RPM cadence as it is so uneven. But for slow riding with jeans and sneakers, it works well.

Bah Humbug

I have a friend who wanted to convert from being a semi-great runner to a triathlete. He started with an older CAAD and had it set up properly for an aggressive roadie fit. Then one race he absolutely slammed the stem to "get more aero" (without running this brilliant idea past me first). Not only was he slower, he then got off and couldn't even outrun me because his hips were so locked up.

He went back to running.