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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?
I'm disappointed in 1x. It's not as trouble-free as I thought and it is not smooth.
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.
hippy-
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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Tim allen @Soigneur (London bike fitter) wrote his Masters thesis on oval chain ring adaptation. I think he said oval chain rings favour the use of the biggest bit of the quad muscle. However, you need 3 months to gradually adapt. Look at Wiggo in the Giro. He chose to move from
oval rings back to round rings a month before the Giro and pulled out with knee pain. Likely overuse of the muscles that had not had time to strengthen again. You start moving the patella as you strengthen different parts of the quads.I’d guess Bob_Thod has a muscle balance that’s more suited to oval rings.
Bob_Thod
Crumbs
You pull me into another tech talk with this post :)
Have knee issue, have hills, choose to climb, which drives me to experiment with these types of drivetrains. Can do only high cadence with low power. No grinding else it's time off the bike.
I am a believer in the oval chainrings because I have a noticeably happier knee(s). I just picked up the newish one piece Rotor 46/30 oval chainring that fits only the new ALDHU & VEGAST. Looking forward to that. I really want the Osymetric or TA but don't get the 46/30 combo.
Since my last writings on this I've come further with the topic and also setup a Shimano 1x with a 50T Sunrace cassette. Some unpleasant chainline issues that were solved by shimming the cassette outboard and the crank inboard. It's sorta happy now but I'm disappointed in 1x. It's not as trouble-free as I thought and it is not smooth. Tried chains of KMC, Shimano and SRAM all at DA/XTR level. Conclusion, SRAM chains are made to like 1x. The others not so much.
The devil is in the details with this stuff. I'm willing to hash them out with anyone thinking about this but need to know exact model of shifters, F&R mech, and what you are willing to change.
A 46T or 50T in the rear is designed for a 1x.
2x could only work if front rings are very close in size, like CX 46/39 close.
Spent much time on this website comparing gear ratios of what I have to where I want to go. Then reading, buying and trying different stuff.
http://gears.mtbcrosscountry.com
Punch in what you have, then compare it to an 11spd Shimano 11/42(or 40) rear and 46/30 (or 48/31) front.
That is a very solid functioning and achievable setup that doesn't squak or grunt.