Oval chainrings cause knackered knees?

Raging_Bulls · Apr 2, 2013

I took out the Laïti for a 35 mile trip yesterday, and now my knees are swollen and painful. Never had this before.
Could this be caused by the oval (Suntour XCM) chainrings? I do notice that I really get a kick in the knees on every pedal stroke when on the middle and smallest chainring. So those might need to be re-positioned. The big one barely has this, but I still feel that I'm not able to spin it smoothly.

Anyone ever had to switch from ovals to round ones for the same reason? Can you even get round replacement XCM chainrings?

Charlieboy28 · Apr 2, 2013

yes it's the rings

http://sheldonbrown.com/biopace.html

i did hear they are again using them on modern racing bikes though

cce · Apr 2, 2013

the theory of oval chainrings isn't bad, as evidenced by modern road pros using them, it's just that they put the humps in the wrong places back in the day

Chopper the ex Copper · Apr 3, 2013

Even the mighty Geoff Apps reports knee problems from using Fireplace rings.

zetecmk2 · Apr 3, 2013

also check frame size....i once rode my daughter's bike when she was tiny.....and my knees hit the handlebars!!!!! ouch, similar to what you describe....the bendy bit of the leg hurt!!

suburbanreuben · Apr 3, 2013

I've used oval Rotor Q rings with no problems .
Are you're cranks longer than usual?

Piperdave · Apr 3, 2013

Charlieboy28":3k9mu7ln said:
yes it's the rings

http://sheldonbrown.com/biopace.html

Are you sure...

from Sheldons conclusion...

"Non-round chainwheels remain controversial, especially among racers who think that everyone should ride racing bikes, but, in my opinion, they are of real value for the vast majority of non-racing cyclists. Unfortunately, this useful option has become all-but-extinct.

Dave

Raging_Bulls · Apr 3, 2013

@ zetec : pretty sure the bike is a bit on the large side for me, so my knees don't go anywhere near the handlebar.
@Reuben : Crank length is 170mm. I'm used to 175, so they're certainly not too long.

The swelling is gone now, so I'm going to do a 30-40 mile trip with my Scott (round XT M730 rings). If I feel ok tomorrow, I guess I'll need to swith the Laïti's chainrings for round ones.

Grockel · Apr 3, 2013

It's a myth

velomaniac · Apr 3, 2013

^^^^^^^^ What he said

Sheldon Brown liked them, so using him as a reference against them suggests the article he wrote was not read properly. Knee problems could be caused by many things, picking the biopace system which was bad mouthed by roadies who incidently used a different oval chainring system does not make sense. However for the OP it could be the rings, everybody is different and reacts differently to pieces of kit others like. I cant get on with SPD's or any system that attaches my feet to the pedals and beliegve me I have persevered.

Oval chainrings cause knackered knees?

Raging_Bulls

Sbike Fan

Charlieboy28

cce

Chopper the ex Copper

zetecmk2

Senior Retro Guru

suburbanreuben

Old School Grand Master

Piperdave

Raging_Bulls

Sbike Fan

Grockel

Dirt Disciple

velomaniac

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