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No Clue Crew
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Discussion Starter · #1 ·
I'm running a 30t oval on my old 26" bike. I didn't notice a difference on the switch but I suppose it could be making a small difference.

I just upgraded to a Transition Sentinel and I'm contemplating an oval ring for it. But... I'm not so sure...

They say a 30t oval is like a 32t in the power zone and a 28t in the dead spot. Makes perfect sense.

So my question is if you are pushing a "32" in the power zone then why not just get a 32 round? The dead spot isn't making a difference so the fact that it's easier when your feet aren't in a rotation with power it shouldn't affect the pedaling. Right?

What am I missing? I know they do something but I'm getting lost on if that something is actually making a difference that couldn't be made just by getting a larger chain ring.
 

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Oval chain rings have been around for something like 120 years, just about from the beginning of bikes as we currently recognize them. IMO, if they made a consistent objective or even subjective improvement, they'd be standard by now. Basically, it boils down to personal preference or belief system.
 

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Oval chain rings have been around for something like 120 years, just about from the beginning of bikes as we currently recognize them. IMO, if they made a consistent objective or even subjective improvement, they'd be standard by now. Basically, it boils down to personal preference or belief system.
You have Shimano to thank for them not being as widespread.

OP, it does make a difference. You want really notice it on the flats but when climbing technical or really steep things at the stall point the dead zone reduction is noticeable. It also helps to reduce spin outs in similar situations due to the rise fall of the resistance.

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I just swapped over from a 30 round to a 28 oval yesterday and gave it a ride yesterday afternoon
It feels a lot different, lower gear so climbing was easier, felt myself running thru my gears more to gain speed. few spots I had the wrong gear going down so it will take some time for me to get used to it
overall the ride was faster, was able to maintain speed better on most sections

it was a relatively cheap thing to swap out. worst you can do it give it a try
 

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No Clue Crew
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Discussion Starter · #5 ·
As I thought more about it staring at the ceiling last night I did come to the conclusion that making the relatively small dead spots easier would provide an advantage in super steep or techie stuff where the difference between cleaning and HaBing is literally 1/4 crank turn...

it was a relatively cheap thing to swap out. worst you can do it give it a try
I've tried it already. Still got an oval on my 26er.

Unlike everyone else that switched to an oval I felt no noticeable difference. It took exactly 0 seconds to get used to. That's why I'm questioning if dropping $70 on another is really worth it...
 

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Maybe they make a difference, maybe not. I expect the trend of going 1x has made them players, now. Using ovals on a 3x must have been problematic.
 

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Without a doubt, I noticed a difference in pedalling.
There is a very defined yet not obnoxious "surge" in the pedals when cranking.
I only have 1 bike with an oval. I am not sure however, if I will put another oval on.
I don't dislike it, but I'm not sure it is any better to me.

Honestly, in think it's probably a lot better for people riding flats. Seriously.
The smaller part of the oval should help eliminate "pedal dead spots". With clipless, you should have no dead spots. Especially if it's technical and climbing....
 

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I really like oval for low cadence riding and techy climbs. I hate oval at high cadences because it seems much more difficult to be smooth.

On my singlespeeds I use ovals to help with some of the climbs. On geared bikes, I just use a round chainring.
 

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NedwannaB
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As I thought more about it staring at the ceiling last night I did come to the conclusion that making the relatively small dead spots easier would provide an advantage in super steep or techie stuff where the difference between cleaning and HaBing is literally 1/4 crank turn...


I've tried it already. Still got an oval on my 26er.

Unlike everyone else that switched to an oval I felt no noticeable difference. It took exactly 0 seconds to get used to. That's why I'm questioning if dropping $70 on another is really worth it...
Since you're jumping from 26 up to 29 wheels you might think about a 30t ring, if not 28t(or smaller??), even if you have Eagle. And would think it beneficial on all the techy stuff you're known for mastering!😎 As far as not being "smooth" during higher cadence times I wouldn't think it be as critical on that monster truck rig.
 

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No Clue Crew
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Discussion Starter · #11 ·
Since you're jumping from 26 up to 29 wheels you might think about a 30t ring, if not 28t(or smaller??), even if you have Eagle. And would think it beneficial on all the techy stuff you're known for mastering!
The Sentinel came with a 30t round and with the Eagle drive train it seems comparable to my 11 speed 30t oval with an 11-42 cassette on my 26er. Trails that require granny on the 11sp were requiring it on the Eagle. The 30t/50t combo seems to be about as slow as I'd need to pedal and still be able to remain upright. If I do get another oval it'll likely be a 30t. Even if it's a little hard in the beginning the legs adjust eventually.
 

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No Clue Crew
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Discussion Starter · #13 ·
Cool. Can we expect some new Vim vids on the Sentinal? Be cool to see some redemption on your Superman Waterfall run from 3 years ago. Dam your buddy went bass akwards in that hole!ooo
Working on video now :) Got a little idea for decommissioning the Pitch and introducing the Sentinel...

You may have seen already but thought id throw it in since there's a current post:
http://forums.mtbr.com/drivetrain-shifters-derailleurs-cranks/eagle-oval-1052324.html
I did see that and, to be honest, I don't see spending over $100 on a chainring with SRAM on it when everyone else has 'em cheaper. That said, I don't know what effect their X-SYNC 2 tooth design will actually have... May be a benefit, maybe not...
 

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Much information here, much confusion caused by incompleteness. anyone providing experience should list what oval chainring this advice is based on.

first, the old shimano ovals were designed wrong (wrong angle for the deadpoint). so anyone telling stories how bad that was 30 years ago won't help you here.

Second, some companies' ovals are less oval, more round. The most oval and well designed one seems to be Absoluteblack. I recently upgraded my fatbike to oval. It really works better at low cadence situations and situation where you are "stuck", like in sand or snow. with round chainring I switched between slipping and being stuck, now I seem to deliver constant torque. i yesterday attended a race (yes i sucked!), but could well climb without slipping (even with the worst tires of the group) because power delivery was smooth.

Third, I paid $45 for my chainring on ebay. Not sure what you picked to quote $70. Mine was 64mm BCD, other sizes may be more expensive.

On normal riding I may be one gear higher than with round. Spinning at high cadence also seems to work fine. it took me 20 feet riding to get used to it.

I actually got motivated to upgrade my hybrid to 1x just to get an oval chainring.

I know I may experience confirmation bias because I want it to be better after I upgraded. But I try to be as critical and objective as possible.
 

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Much information here, much confusion caused by incompleteness. anyone providing experience should list what oval chainring this advice is based on.

first, the old shimano ovals were designed wrong (wrong angle for the deadpoint). so anyone telling stories how bad that was 30 years ago won't help you here.

Second, some companies' ovals are less oval, more round. The most oval and well designed one seems to be Absoluteblack. I recently upgraded my fatbike to oval. It really works better at low cadence situations and situation where you are "stuck", like in sand or snow. with round chainring I switched between slipping and being stuck, now I seem to deliver constant torque. i yesterday attended a race (yes i sucked!), but could well climb without slipping (even with the worst tires of the group) because power delivery was smooth.

Third, I paid $45 for my chainring on ebay. Not sure what you picked to quote $70. Mine was 64mm BCD, other sizes may be more expensive.

On normal riding I may be one gear higher than with round. Spinning at high cadence also seems to work fine. it took me 20 feet riding to get used to it.

I actually got motivated to upgrade my hybrid to 1x just to get an oval chainring.

I know I may experience confirmation bias because I want it to be better after I upgraded. But I try to be as critical and objective as possible.
I agree with this too. If anything it forces the rider to focus on smooth circles when spinning at high RPMs.

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I went with a Wolf 28t oval on my sb4.5 XO1 Eagle drivetrain, and love it. I found it completely invisible from the first pedal stroke, except that I dab/bail a little less, and my troublesome knee doesn't hurt.

I'm 59, not 29, and that may be why I prefer the smaller than stock ring.

Mark

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I don't see spending over $100 on a chainring with SRAM on it when everyone else has 'em cheaper. That said, I don't know what effect their X-SYNC 2 tooth design will actually have... May be a benefit, maybe not...[/QUOTE]



- I've been plunking around on an Absolute Black Oval mixed with Eagle XO stuff and they work together flawlessly. :thumbsup:
 

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Trail Ninja
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Much information here, much confusion caused by incompleteness. anyone providing experience should list what oval chainring this advice is based on.

first, the old shimano ovals were designed wrong (wrong angle for the deadpoint). so anyone telling stories how bad that was 30 years ago won't help you here.

Second, some companies' ovals are less oval, more round. The most oval and well designed one seems to be Absoluteblack. I recently upgraded my fatbike to oval. It really works better at low cadence situations and situation where you are "stuck", like in sand or snow. with round chainring I switched between slipping and being stuck, now I seem to deliver constant torque. i yesterday attended a race (yes i sucked!), but could well climb without slipping (even with the worst tires of the group) because power delivery was smooth.

Third, I paid $45 for my chainring on ebay. Not sure what you picked to quote $70. Mine was 64mm BCD, other sizes may be more expensive.

On normal riding I may be one gear higher than with round. Spinning at high cadence also seems to work fine. it took me 20 feet riding to get used to it.

I actually got motivated to upgrade my hybrid to 1x just to get an oval chainring.

I know I may experience confirmation bias because I want it to be better after I upgraded. But I try to be as critical and objective as possible.
Here's some objective information to feed into your system. https://www.sheldonbrown.com/biopace.html

How are you going to reason with it? Deny it and stick to your bias (that biopace is wrong)?

I've tried modern ovals (from Absolute Black), and didn't observe any significant improvement or change. It just cost more, forced me to factor in chainstay clearance, and made me worry about additional stress on the RD clutch and my knees. They made me slightly more conscious of my pedaling style, but I eventually dropped the thought and rode it like normal. Anything I struggled to clear before, no matter what technique I tried, was cleared with simply more fitness. If the oval ring helped at all, it's because it got me outside to "test" it, or get used to the different stress it'd put on my pedaling stroke. In other words, there wasn't anything obvious that I could sense, that I couldn't be considered to be placebo effect.

Since I haven't ridden Biopace, all I can do is offer conjecture. The body has least strength with the knee bent sharply. It has the most strength when the leg's closer to being fully extended. For instance, it's considered cheating to do squats or leg presses if you don't bend your knees enough; it's also considered hard on your knees to stress them with so much resistance. Sheldon Brown believes Biopace saves your knees and uses the muscles similarly to running. On the other hand, modern oval rings encourage mashing (concentrating effort when the cranks are horizontal), basing their science on having a bigger gear when you can put more bodyweight into the stroke, and a smaller gear when you're doing "scraping" motion with your legs. It promotes a more piston-like, stair climber style of motion. It claims to help remedy the traction issues associated with such a pedaling style, that it ironically encourages. What's odd is that Biopace marketing says it's optimized for cadence of 90 and below and was criticized for it; I find the modern oval is optimized for even lower cadences, yet it's not criticized for it. I suppose if you're spinning over 90 RPM, you don't need either, since you're already spinning circles.

Here's a problem I'm looking to solve: if I'm looking pedal while descending rough terrain, but worry about bumps throwing my foot off when I have little pressure on the pedal, and my gearing is too low to push low cadence at the speed I'm going, which chainring would be best? I'd like to minimize the dead spot, where I have less weight/pressure on the pedals. Ideally, I'd like to have good pressure throughout the pedal stroke. Does the strategy of reducing the time when the cranks are vertical and increasing time when the pedals are closer to horizontal sound good (modern oval)? What if I were forced to put increased pressure on what was supposed to be the dead spot in order to turn the cranks? Does this effectively eliminate the dead spot, since it's no longer dead due to that part of the stroke seeing more effort (Biopace)?

^Honestly, the best answer is likely to just get higher gearing and/or improve my technique to allow for pedaling on rough descents (spinning circles instead of mashing), rather than rely on a chainring to be a magic bullet.
 
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