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Oval chainrings.

trib

not worthy of a Rux.
Jun 22, 2009
1,456
388
Roadies love 'em. Barel used one (maybe still does) to help compensate for a weak knee. I think they have real benefits on bikes that see very smooth pedaling at a near constant cadence.

Rotor oval rings are offered in a bunch of guises - and are drilled to allow flexibility in their set up.

My only experience with oval rings is an ancient Shimano Biopace ring on my commuter set up, don't love it, but don't hate it enough to warrant a change, especially as it's a beater bike.
 

Nick

My name is Nick
Sep 21, 2001
23,927
14,440
where the trails are
as I understand the wave of current oval rings aren't the same as the old biopace shapes. they're designed properly to minimize dead spots in your pedaling. @dan-o uses them IIRC and says they're legit.

32 oval = 30 at dead points, 34 at leveraged points
 

Toshi

Harbinger of Doom
Oct 23, 2001
38,029
7,549
They're oriented 90 degrees from Biopace, I believe.

I run a 28t oval ring on my 5010, because I am fat and don't like to climb. 28 x 42t is about right for my pace + desire to not blow my heart up. I dig it.
 

RoboDonkey713

Monkey
Feb 24, 2011
678
462
Maine
The life of these Oval rings is quite a bit shorter than a round ring. The teeth at the top of the oval wear down before the the rest of the ring because when you climb and sprint, these teeth take most of the abuse. After mine wore out in under 6 months, I put a round ring back on. I made it about a week on the round ring before I ordered another oval. I am a fan of them. I know Wolf Tooth is making them in Stainless and will go that route next time.

I notice the difference on short punchy climbs and technical sections that you can power thru without feeling you have to shift. I don't think they would be worth while on a DH bike or any bike that shuttles more than it pedals.
 

StiHacka

Compensating for something
Jan 4, 2013
21,560
12,504
In hell. Welcome!
I've done a bunch of miles or mine. For most part, they work fine. But when you need that extra bit of torque in super steep low speed technical stuff, they kinda suck IMO (cranking +2 teeth when you'd prefer -2).
 

boostindoubles

Nacho Libre
Mar 16, 2004
7,839
6,145
Yakistan
I put an absolute black on my singlespeed and noticed a difference. Mostly in the chain tension, but it works out and haven't had any issues. I like the extra power and it seems to lend itself to mashing on the SS well.
 

marshalolson

Turbo Monkey
May 25, 2006
1,770
519
tried an AB oval ring, took it off and sold it after 200mi.

just too used to pedalling circles i guess, but only noticed downside (less output, higher heart rate, pronounced choppy pedal action on the road, had to move saddle much more forward) and no benefit. felt instantly at home back on a circle ring, and immediately pedalled more efficiently.
 

ChrisRobin

Turbo Monkey
Jan 30, 2002
3,346
190
Vancouver
I went from a round 30T ring to 32T oval One-up components ring. Not a massive difference but I found I was able maintain momentum a little better up steep switchbacks.
 

Jm_

sled dog's bollocks
Jan 14, 2002
18,852
9,557
AK
I went from a round 30T ring to 32T oval One-up components ring. Not a massive difference but I found I was able maintain momentum a little better up steep switchbacks.
So basically you were running a 31T.
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,907
1,252
SWE
I like them! I found that they give an advantage on punchy climb, like if they are averaging your power output so that you don't loose traction as easily. I now run 2 to 4 teeth bigger front ring than what I would with a round one.

Theoretically they should also change how much the bike bobs.
Not sur if I am ready for this level of nerdiness yet... ;)
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,031
5,920
borcester rhymes
I have one, I like it. It smooths power output and helps to maintain traction a little bit better up climbs. You notice it for about 100ft, and then it just does away. I too try and spin circles, and it just doesn't bother me at this point. I think they are worth the switch, but probably not worth replacing a good ring with one just for the switch. I think my favorite thing is less of a dead spot when climbing very technically challenging things, such as when you are in slightly too high of a gear and just need one more crank to get over...you'll get it with the oval ring, but you'll stall on the round ring. That was something I noticed with swapping bikes with two different rings.

FWIW regarding anti-squat and bobbing, I think the timing works itself out to be problematic (ie, you put down maximum power when anti-squat would be lowest with these rings), but the net effect is incredibly small compared to actual changes in pivot height.
 

marshalolson

Turbo Monkey
May 25, 2006
1,770
519
huh? why was that??
The timing of the oval was off a touch for me. Moved the saddle ~1cm forward to the the top and bottom of my power output matched to ovality of the ring. Having my hips and knee too forward relative to the cranks and bb defiantly slowed me down climbing smooth fast trail.

Just one guys experience, but ab-black just didn't work for my own anatomy.
 
Last edited:

iRider

Turbo Monkey
Apr 5, 2008
5,648
3,089
What is going on here???
First everybody came out of the closet with their 29ers and now oval chain rings? :eek:
What's next? Confessions of riding in lycra skinsuits? :fie:
If Kidwoo now admits that he rides with oval rings too then it is proven that the lizard overlords brainwashed everyone! :tinfoil:
 

Gary

"S" is for "neo-luddite"
Aug 27, 2002
7,536
5,470
UK
Is there not another sub-forum on RM for this shite?

oval ring = shite chain retention so has no place here.
Skinsuits actually do tho.
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,907
1,252
SWE
oval ring = shite chain retention
I have more than 1000km on my hardtail with an Absolute Black N/W Oval blah blaah chainring and never lost a chain despite having no chain device. But it might be because of the Zee derailleur and 26" wheelz, well just unreideabru at best! :D
 

Gary

"S" is for "neo-luddite"
Aug 27, 2002
7,536
5,470
UK
I have more than 1000km on my hardtail with an Absolute Black N/W Oval blah blaah chainring and never lost a chain despite having no chain device.
Wow! really? oh... hold on. I don't actually care! I just remembered you're not me. doubt you ride like me and your 1000km almost certainly covers none of the last (or indeed future) 620miles my hardtails rode.
FWIW (ie. fuck all) I have 2 hardtails with N/W and no device. both have lost their chain multiple times. all my geared full sus bikes also run N/W now and absolutely need a chain device (and a round ring so it actually works properly) to retain the chain throughout a full days riding.
 

StiHacka

Compensating for something
Jan 4, 2013
21,560
12,504
In hell. Welcome!
Wow! really? oh... hold on. I don't actually care! I just remembered you're not me. doubt you ride like me and your 1000km almost certainly covers none of the last (or indeed future) 620miles my hardtails rode.
FWIW (ie. fuck all) I have 2 hardtails with N/W and no device. both have lost their chain multiple times. all my geared full sus bikes also run N/W now and absolutely need a chain device (and a round ring so it actually works properly) to retain the chain throughout a full days riding.
Sounds like you switched to oval wheels a long time ago. :brows:
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,031
5,920
borcester rhymes
if there's one thing I know, it's that Gary always stays cutting edge, and is always willing to try something before knocking it.

tl;dr, have you moved up from 7 speed chains yet, Gar-Rex?
 

Gary

"S" is for "neo-luddite"
Aug 27, 2002
7,536
5,470
UK
if there's one thing I know, it's that Gary always stays cutting edge, and is always willing to try something before knocking it.
Oh... don't you worry Sammich.. I've tried plenty oval rings in my million years on the planet.
tl;dr, have you moved up from 7 speed chains yet, Gar-Rex?
Which bike?
Two are single speed
Two are 7 speed
Two are 8 speed
Two are 9 speed
Three are 10 speed (one of these is a roadbike with a compact double)
Newest one is 11

You know what? having a nice wide cadence range and half decent fitness means any more than 7 makes fuck all difference so long as you're honest when choosing your chainring size.
Yes. Size. Not SHAPE! ;)

But seeing as we're in a DH forum. and we're talking gearing (again!) Old skool (CHEAP/STRONG) 7 speed chains with 5 (7 speed spaced) sprockets and a short freehub body would still be my preferred option for a geared DH race bike. Need anymore than that and you're clearly not actually on a DH track.



#7spd4LYF
:wub: :cupidarrow:
 

Muddy

ancient crusty bog dude
Jul 7, 2013
2,032
907
Free Soda Refills at Fuddruckers
Half the time you need something right across the board - you know all the way up, all the way up, all the way up. Where do you go from there? Where?
Nowhere. Exactly.
Use your hips. Turns onesies into ... elevensies.
 

Toshi

Harbinger of Doom
Oct 23, 2001
38,029
7,549
The timing of the oval was off a touch for me. Moved the saddle ~1cm forward to the the top and bottom of my power output matched to ovality of the ring. Having my hips and knee too forward relative to the cranks and bb defiantly slowed me down climbing smooth fast trail.

Just one guys experience, but ab-black just didn't work for my own anatomy.
You're on a 4 or 5 bolt spider, I'm guessing? With the (creaky) RaceFace Cinch system you could have adjusted the timing relative to the cranks in small increments and probably solved that with standard seat position.