Round vs Oval Chainring

[dasilvarsa]

Reviving old thread.

 

I currently run a 1 x 12 with 10 50 cassette and 30t chainring on 29er. 16kg bike.

 

I was looking at getting a 32T oval chainring, would this be a massive jump? And not be really easier to pedal up hills?

 

Or just get a 30T oval to help me a tiny bit up those hills?

 

Believe 30t oval will feel like a 28t and 32t?

Whereas a 32t oval will feel like 30t and 34t? But will the 34T on highest point be huge difference? I'm average fitness level

On 10-50 cassette you should consider a 34 round

30 tooth is really for 11-36 and 11-42 Casette

[Jbr]

On 10-50 cassette you should consider a 34 round

30 tooth is really for 11-36 and 11-42 Casette

Agree, that’s why I asked your weight, if you are 74kg on. 50 cassette 32 should be absolutely fine. Even with a slightly heavier bike. But it is your choice and the 30 will also work just fine

[DieselnDust]

How much faster [emoji12]

From 567th to 609th back to 437th.

 

Winner

[Frosty]

I have a 34T oval and find I run out of gears on the long flats and gradual downhills. 

It was only when I was in the Overberg region that I truly appreciated the 34-50 ratio, and even then I could have got way with a 36-50 - assuming the cage can take this bigger jump (my MTB knowledge is a little lacking to the norm).  

[MajG]

Agree, that’s why I asked your weight, if you are 74kg on. 50 cassette 32 should be absolutely fine. Even with a slightly heavier bike. But it is your choice and the 30 will also work just fine

This is what I was wondering, and why I came to the hub for input.

Didn't want to buy 30T and its barely any difference, when 32T would be an all-round better choice

[Steady Spin]

I'm definitely going to give it a go, was just wondering if 32T oval would make me suffer more with the 34T at highest point being too much of a jump from the 30t round.

 

I'm ok with 30t round, more interested to see if I will be less fatigued with an oval and not chasing a faster times per say, more saving my legs.

 

Rapide stopped offering 30t oval as he advised its not really popular as the 32t oval and that made me wonder if should go 32t oval instead of 30t oval.

I went from 30t round to 30t oval and back to 30t round.

 

I noticed absolutely zero difference. One thing for claims on paper but out on the trail it was all psychosomatic for the first ride.

 

I actually forgot i had an oval until i found that my chain was busy eating at my chainstay protector when running down in 11t at the rear.

 

That and the extra strain it puts on the clutch wasn’t worth it.

[ChrisF]

..

 

 

The ovals is supposed to prevent knee pains but I don't think it will reduce fatigue in your legs.

Interesting statement ....

 

A friend that was a serious road rider said that many went back to round due to knee issues with ovals ....

 

 

When I had my bikefit done I was told to avoid oval rings, due to my bust knees...

 

Later the physio and also the bio said the same.

 

 

PS I have only riden with round rings, so have zero personal experience.

Edited March 23, 2021 by ChrisF

[Wimmas]

I have a 34T oval and find I run out of gears on the long flats and gradual downhills.

It was only when I was in the Overberg region that I truly appreciated the 34-50 ratio, and even then I could have got way with a 36-50 - assuming the cage can take this bigger jump (my MTB knowledge is a little lacking to the norm).

This is very interesting... Did you run out of gears on tar or gravel? 10t or 11t back?

 

Running 32t round with 10-50 back. Checked this weekend on tar and I can comfortably spin at 50km/h with this setup. On gravel I have never come close to spinning out. Guess the trails here in Gauteng don't allow it or I am just a useless rider...

Edited March 24, 2021 by Wimmas

[ChrisF]

This is very interesting... Did you run out of gears on tar or gravel? 10t or 11t back?

 

Running 32t round with 10-50 back. Checked this weekend on tar and I can comfortably spin at 50km/h with this setup. On gravel I have never come close to spinning out. Guess the trails here in Gauteng don't allow it or I am just a useless rider...

Wow !

 

Wimmas what is your cadence when you spin out ?

 

With a 36 to 11 I am comfortable to about 46km/h. Going to 54km/h is possible, but that cadence is way past comfortable ... JIP, that is on the tar between home and the trails. I have never spun out on the trails

Edited March 24, 2021 by ChrisF

[Frosty]

This is very interesting... Did you run out of gears on tar or gravel? 10t or 11t back?

 

Running 32t round with 10-50 back. Checked this weekend on tar and I can comfortably spin at 50km/h with this setup. On gravel I have never come close to spinning out. Guess the trails here in Gauteng don't allow it or I am just a useless rider...

I have 11 at the back, and I spin out when chasing people on 2x setups (both tar and dirt).

 

I don’t have any speed/cadence sensor, nor a PM on my MTB, so can’t measure the rpm, but I do know I wasn’t able to get more than 45km/h on a 4% decline.

[bullet77]

I have round on a bike and oval on another, both MTB. I hardly ever ride the bike with the round(hardtail). For me the first thing I feel when riding the round is the crank arms feel longer or the pedal circle feels bigger. I had some knee pain/discomfort after my last ride on the bike with round ring.

[dasilvarsa]

The Industry Standard @ the Moment is 10-51 on a 32 Tooth Front Ring (Round).

It Works Very Well for Most Riders.

A Stronger Rider Specially in Gauteng can Benefit from a 34 or 36 Tooth Front Ring to Increase Top End. (Keep up with the 2X systems).

Edited March 24, 2021 by dasilvarsa

[eala]

I run 32 oval on a 11 x 46 11 speed and 32 oval  a 10 x 50 12 speed cassette .I also run a round 34 on 12 speed cassette .I notice the difference when i swop bikes .Oval climbs easier .A 32 oval or 34 round is all you will ever need .When i choose a new front sprocket it will be an oval 32 again 

[Jbr]

Interesting statement ....

 

A friend that was a serious road rider said that many went back to round due to knee issues with ovals ....

 

 

When I had my bikefit done I was told to avoid oval rings, due to my bust knees...

 

Later the physio and also the bio said the same.

 

 

PS I have only riden with round rings, so have zero personal experience.

Well I guess we're all different. But I started cycling seriously with ovals after a knee injury, and was absolutely fine, I would only get knee  pains at the time when I was riding my MTB with round ring and 175mm. Now my road bike has round and my MTB ovals and I can switch between the two without any pain. Guess your body has to adjust. But my theory about the ovals being kinder on the knees in general could be wrong, it's just that it makes sense to me considering it optimises the load on each pedal stroke.

[Wimmas]

Wow !

 

Wimmas what is your cadence when you spin out ?

 

With a 36 to 11 I am comfortable to about 46km/h. Going to 54km/h is possible, but that cadence is way past comfortable ... JIP, that is on the tar between home and the trails. I have never spun out on the trails

Don't have a cadence sensor, just a Garmin Vivoactive 4 I ride with, not really sure how accurate it is but it has good reviews. Just like the speedo on any car there is probably always some room for error. I am used to higher cadence due to a knee injury I picked up in 2018. Ever since then I ride at a higher cadence to put less pressure on the knee. Slowly been building up strength to ride at a lower cadence and putting down more power, but obviously do not want to rush it and screw up the knee again.

 

I have 11 at the back, and I spin out when chasing people on 2x setups (both tar and dirt).

 

I don’t have any speed/cadence sensor, nor a PM on my MTB, so can’t measure the rpm, but I do know I wasn’t able to get more than 45km/h on a 4% decline.

Makes sense. The 10t should benefit you big time. The jump for me from my second lowest to 10t does feel significant. Checked my last few rides at various trails (Hennops, Avianto, Cradle Moon and Northern Farm) and I haven't exceeded 44km/h at any of them, with the majority being in the region of 39 - 40km/h max speed.

[100Tours]

Interesting statement ....

 

A friend that was a serious road rider said that many went back to round due to knee issues with ovals ....

 

 

When I had my bikefit done I was told to avoid oval rings, due to my bust knees...

 

Later the physio and also the bio said the same.

 

 

PS I have only riden with round rings, so have zero personal experience.

 

I am curious about why the shape of the chainring would make a difference to one's knees (the shape of your pedal stroke has not changed, so your knees are doing exactly the same range of movement as they do with a round ring). I would imagine that choosing shorter cranks would help your knees however, as this would reduce the amount of flexing that they need to do. I am basically an engineer though, not a bio-anything.

 

I find that I can hold a bigger gear with an oval chainring, especially on really long rides. I have always believed that this is because you are basically in an easier gear as your foot goes over the top of the pedal stroke (the 'recovery' phase, using the small radius part of the ring), and the heavier gearing is effective as you move into the power phase (the large radius part, where your biggest muscles are firing). But then again maybe the placebo effect is just strong with me