This is a question and an experience I would like to share. A year ago, I put and oval chainring on my XC bike with platform pedals and rode it that way all season. I also ride clipless on XC bikes. I researched oval chainrings and their benefits before I make the change and felt that I needed to try it myself.
I now believe that if you are using platform pedals and do a good bit of climbing on your bike, oval chainrings and platform pedals a good option if you do not use clipless pedals. Clipless are still better with a round ring in my experience. I did not experience any real benefit from from twisting trails, downhill, cornering, etc. However, I did not notice anything negative either. There is the dead zone right before the oval expands but, this is not very noticeable once you ride for a time on the oval ring.
I am a bit curious as to how many XC riders use oval chainrings and why not? Your comments are welcome.
I have been riding Absolute Black 32T on my Farley for several years. I am a clipless rider and see no disadvantage to the oval. Actually ordering one for the new Fuel EX 9.8. They can’t be beat for climbing. I now climb several gears higher with the oval than the round.
Just finished my fourth season with a Wolftooth elliptical on my XC bike with flat pedals. I have a circular chainring on my trail bike (and, of course, my road bikes).
The first two seasons I waffled back and forth on the elliptical benefits but, after finishing the third and this latest season, I give the elliptical a solid “meh”….it is neither beneficial nor detrimental, overall.
I have not noticed any benefit with climbing with the elliptical. I have found the motion of the elliptical “soothing” on long flat trails but that’s more a psychological than physical plus.
Technical rocky or rooty sections are a bit of a challenge with an elliptical ring in it interferes with effective pedal-ratchet due to the “dead spot” you mentioned. I’ve mostly gotten used to it and developed the muscle memory to work around it, but it does catch me off-guard now and then.
After seeing the folks I ride with come to the trail with pie-plate-sized 50 tooth rear clusters on their rigs I’ve concluded that good old-fashioned gearing is the only real solution to making climbs “easier.” ; )