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I first stepped into oval with a 50/34 and still have that on a bike.
The oval takes the edge off at top dead centre and bottom dead centre. Take a 50T ring for example, at the largest point of the oval the size is like a 52T. What the oval does is like switching the size of the chainring quick from 52 to 48 at the smallest part of the oval. It makes the transition from the upstroke to the downstroke easier. For me this was a dramatic and noticeable difference in reduction of pain. You might experience something totally different.
The switch to oval for me was clear. It helped me a ton but not while climbing. Especially when grinding or getting slammed to a near halt. When my knee acts up, I need to cut the power asap. The only way to do that is with granny gears. With this limp mode option I don't put myself out of commission for weeks.
The best read of the topic of oval is a study called:
Comparative biomechanical study of circular and non-circular chainrings for endurance cycling at constant speed.The PDF file is:
Biomechanical study chainrings - release 2Link:
http://www.noncircularchainring.be/pdf/Biomechanical%20study%20chainrings%20-%20release%202.pdfIt's a heavy read but in conclusion, the Rotor and similar shapes are crap, not enough oval, the Osymetric shape is the best. TA Specialties started making a shape very similar. But neither offer a sub compact solution. I'm hoping that one of them make rings for the new GRX. I'll be all over that. In the meantime, the Rotor and Absolute Black 12% oval rings do me fine and allow me to ride more. Your milage may vary.
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Bob_Thod
Interesting about the oval rings - why do you think they help your knees? Did you go for lower gears on them, in which case couldn't it just be the lower gearing that helped your knees and has nothing to do with the ovalisation?
Of course not. The chainline for some combos is always going to be worse than 2x. That's why I don't see the point of 1x for normal road riding.
I've got a 42T cassette that I need to fit up and see if it will work without Wolf Tooth. I read their blurb and WT doesn't support the 46T so I won't bother getting one until I hear about it working on an R8000.
I ride with a Quarq PM so can't go lower than 34T on the front.