Chainring Matter

afham07

Hi Guys,

I am currently on Praxis Works 52/36 chainring. I am thinking to change to Rotor Qarbon 53/39. The reason is 36 on current setup does not give much use. So I am thinking 53/39.

The main issue is the shop does not have normal round shape. Instead, inner ring is oval, outter is round shape. Is this setup normal? Will it cost problem such as in shifting?

akh

I ran an absoluteblack oval inner ring with a standard Shimano round outer ring for 12 months without issue. The combination was 36/50.

Shifting felt no different, but the feeling pedalling was noticeably different to me, and the change was quite unpleasant. I actually prefer the feel of oval and eventually switched the outer ring to oval to.

lemonenema

Its already been designed as a shifting ring so no its fine, I bought an absolute black oval inner ring for my road bike and it shifts the same as the shimano one.
The reason its oval on the inner ring only is because oval gives better power delivery during low speed higher effort pedalling - same reason its used a lot off road riding. Theres little or no benefit in the larger ring being oval also.

Edit - same as AKH said!

Spartacus1981

Got some Rotor Q Rings in 53-39 (5 bolt) if you're interested. Original owner and still have packaging. Probably done 5000km or so on them last year but went back to other rings so years left in them.

simon_masterson

lemonenema wrote:

The reason its oval on the inner ring only is because oval gives better power delivery during low speed higher effort pedalling

Does it?

imposter2.0

lemonenema wrote:

The reason its oval on the inner ring only is because oval gives better power delivery during low speed higher effort pedalling - same reason its used a lot off road riding. Theres little or no benefit in the larger ring being oval also.

That doesn't make sense. If there was any identifiable power delivery benefit (which I don't believe there is any evidence to support) then the laws of physics suggest it would have to exist in all circumstances - and not just on a certain size of chain ring.

A link to support your assertion would be useful..

Matthewfalle

《fetches popcorn》

akh

I have no idea if there is a performance benefit to oval rings, but they do feel different to me. I like the feeling, but I'm sure others will hate it. I could probably be happy with either if I spent enough time to adjust back to round, but I'm happy with oval for now. What I didn't like was the different feeling between my two chainrings. I wouldn't run a mis-matched pair again.

Can't you wait for a matching pair? What happens if you don't like the oval? Aren't QCarbon now discontinued? Rotor's website has them in the "Previous Ranges" section.

afham07

AKH wrote:

I have no idea if there is a performance benefit to oval rings, but they do feel different to me. I like the feeling, but I'm sure others will hate it. I could probably be happy with either if I spent enough time to adjust back to round, but I'm happy with oval for now. What I didn't like was the different feeling between my two chainrings. I wouldn't run a mis-matched pair again.

Can't you wait for a matching pair? What happens if you don't like the oval? Aren't QCarbon now discontinued? Rotor's website has them in the "Previous Ranges" section.

No, the shop said they cannot order because it is already discontinued product but they have both oval tho.

I was using oval in the past before bought new bike 2-3 months and it absolutely fine to me. I did not feel the extra power or power saving as claimed, etc but I probably new in cycling. Too new to notice those. It is just that I prefer to use round chainring because the chain movement is straight rather kind of wave on oval. haha.

First.Aspect

AKH wrote:

I have no idea if there is a performance benefit to oval rings, but they do feel different to me. I like the feeling, but I'm sure others will hate it.

This just about sums it up. If you prefer the feeling, or if they work better for how you apply the power, there could be a performance benefit for you personally. I mean, you are going to run faster in comfortable trainers, right?

So, oval chain rings aren't quite up there with L-shaped cranks, but I take issue with more global claims of greater efficiency. There's a lot of talk around at the moment about power losses from chain links, vs cross chaining. I'd be interested to see how this fits in with the huge amount of chain slap and vertical motion that oval rings cause.

step83

First Aspect wrote:

So, oval chain rings aren't quite up there with L-shaped cranks, but I take issue with more global claims of greater efficiency. There's a lot of talk around at the moment about power losses from chain links, vs cross chaining. I'd be interested to see how this fits in with the huge amount of chain slap and vertical motion that oval rings cause.

I cross chain 50T - 32T because I'm a sinner and should burn. Maybe I should invest in some Oval rings and L cranks, in for a penny in for a pound so to speak.

lemonenema

anyway each to their own, I certainly prefer them for off road use. Even if you dont feel theres any benefit, theres certainly no negatives to using them either.

Heres what AbsoluteBlack say

https://absoluteblack.cc/road-chainrings.html

Bumo_b

Love it Step83. Talking of committing crimes, I still worship at the alter of triple speed front for my road bike, 34 rear on a long cage. A reflection of my poor climbing ability-definitely, but it gives me evil satisfaction I can get up most gradients without stopping whilst others get off and push! I also wear my glasses the wrong side of my cycling helmet straps and have a tool pouch behind my saddle!

on-yer-bike

Do you cycle downhill all the time?

Bumo_b

Sadly not, tell me where it is possible and ill be there!

First.Aspect

Bumo_b wrote:

Sadly not, tell me where it is possible and ill be there!

Escher, in Surrey