Oval or round chainring? (Single narrow/wide)

[Sa Calobra]

Same price and curious, is worth the gamble on oval or is it marmite/have any downsides?

I always go for 30T for my narrow wide.

[keith2.2]

worth trying an oval - they're not for everyone and they take some getting used to. You also need to get it set up at the right angle (obviously).

The first time I tried one I HATED it. You have to change your pedaling style to make it seem right.

Having said this - I'm told once you're used to it you never go back.

Side note - I find the whole oval chainrings being a new and premium option strange - the raleigh montatna (and I'm sure others) circa 1990 had an 'ovaltech' chainset, on a bike costing about 150 quid.

[yellowjack]

keith2.2 said:

...Side note - I find the whole oval chainrings being a new and premium option strange - the raleigh montatna (and I'm sure others) circa 1990 had an 'ovaltech' chainset, on a bike costing about 150 quid.

Nothing new about oval chainrings...


Shimano introduced BioPace in 1983!

https://en.wikipedia.org/wiki/Biopace
http://blog.artscyclery.com/general/shimanos-ill-f...
https://www.bikeradar.com/forums/viewtopic.php?t=1...

[vwsurfbum]

And back then they had them lined up wrong.

I'm a convert and wouldn't go back, they smooth out the pedal stroke and because of that it gives you more grip on climbs.

[vwsurfbum]

https://www.facebook.com/absoluteblack.cc/videos/6...

Biopace

[Sa Calobra]

Does the benefits also apply to uneven ground peddling on a mtb or mostly just road?

I can see the road benefits

[ATG]

I'd imagine that the progressive reduction and increase in gearing leads to a smoother change in torque on the back wheel and therefore more continuous force at the tyre's contact point, so you're less likely to break traction as the peddles move away from TDC/BDC. And I imagine you'd notice that the most off road.

Edited by ATG on Thursday 22 November 17:45

[yellowjack]

ATG said:

I'd imagine that the progressive reduction and increase in gearing leads to a smoother change in torque on the back wheel and therefore more continuous force at the tyre's contact point, so you're less likely to break traction as the peddles move away from TDC/BDC. And I imagine you'd notice that the most off road.

So it might help me to avoid loss of traction on the clinker surface of Brick Hill then? Hmmmm?

[...goes off to Google the cost of swapping to a '1 x' drive train with oval chainrings...]

[gazza285]

vwsurfbum said:

And back then they had them lined up wrong.

Who says?

[keith2.2]

yellowjack said:

Nothing new about oval chainrings...


Shimano introduced BioPace in 1983!

https://en.wikipedia.org/wiki/Biopace
http://blog.artscyclery.com/general/shimanos-ill-f...
https://www.bikeradar.com/forums/viewtopic.php?t=1...

Interesting! Thanks for sharing!

[gp1699]

gazza285 said:

Who says?

everyone... that's why it hurt your knees and didn't work.

[Johnny]

Been running Q Rings on the best bike (road) for a couple of years. Love them. Took some getting used to, but not loads.

I jump between that, my CX on normal rings and SS on the same I don't really even notice these days.

[Fastpedeller]

Can they (if multiple chainrings) give gearchange problems between the rings? ie chain unshipping that wouldn't happen with round rings.

[Bullet-Proof_Biscuit]

Wait, what?!

[Fastpedeller]

Bullet-Proof_Biscuit said:

Wait, what?!

Oval chainrings of course.

[m444ttb]

Fastpedeller said:

Can they (if multiple chainrings) give gearchange problems between the rings? ie chain unshipping that wouldn't happen with round rings.

Apparently so, but it will depend how oval they are. I think Chris Froome was running some very oval rings and his mechanics weren't big fans.

I've just gone oval myself on a twin ring set up, but mine at 54/40T. They're rings from Aerocoach and only subtly oval on the big ring (+1T to -1.5T) and a little more on the little ring (+1.5T to -2T). Apparently enough to make a difference but without giving any potential issues for jumping between round and ovals.

[gazza285]

gp1699 said:

gazza285 said:

Who says?

everyone... that's why it hurt your knees and didn't work.

http://blog.artscyclery.com/general/shimanos-ill-fated-biopace-validated-in-university-study/

https://www.sheldonbrown.com/biopace.html

[Herman Toothrot]

gazza285 said:

http://blog.artscyclery.com/general/shimanos-ill-f...

https://www.sheldonbrown.com/biopace.html

I agree, I rode biopace in the late 80's and through the '90's as that's what bikes came with, I never had any issue with them. I have tried the elliptical stuff that's being pushed at the moment and not liked it, so stuck with round. Maybe Shimano should relaunch Biopace.

[Celtic Dragon]

I run ovals on both of my bikes, and it seems to me at least that it does smooth out pedalling strokes. When I tried a round one recently, I felt like I was constantly stamping on the down stroke.

I will say that Shimano clutches don’t seem to like ovals, I was forever stripping and regreasing my slx clutch mech. We’ll see how my xt one fairs.

[gazza285]

Celtic Dragon said:

I run ovals on both of my bikes, and it seems to me at least that it does smooth out pedalling strokes. When I tried a round one recently, I felt like I was constantly stamping on the down stroke.

Biopace made the ratio easier on the down stroke, but the modern/vintage way is to have the ratio higher on the down stroke, so you should find a round one easier on the down stroke...