we have been using a set of q-rings in our household and have discovered an interesting bit of info: the position numbers on the chainrings correspond to *different *positions on the inner vs. the outer chainrings (in our case, a 40/53 set).
i thought i’d post this because this info is not included with the rings, and is sort of buried in the rotor website (i think it was recently added to their FAQ).
i think if rotor emphasized this info, they’d have more customer success with their chainrings. and then we (and most folks) would get the rings ‘dialed in’ a lot faster, and with less changing and re-torquing.
anyway, so, for the basic settings:
#2 = 13º for the 53t, but = 18º for the 40t
#3 = 18º for the 53t, but = 23º for the 40t
#4 = 23º for the 53t, but = 28º for the 40t
so, if you wanted the 23 deg. positon on both your rings (the 23 deg. apparently favors TT riders, more forward seat positions, and slower cadences), then you would have to set the outer ring on “4” but the inner ring on “3”.
I think Gary has said many times on here to put the outer ring on position 4 and the inner ring on position 3.
perhaps, but as far as i know, nobody has said the why.
That’s very good information, thanks. I’ve been riding4-4 and noticing that I wasn’t climbing all that strongly. I’ll give 4-3 a shot and see how that feels.
I saw this post tried the switch from outer/inner = 4/4 to 4/3 and it felt really awkward for the first couple minutes on the computrainer. I kind of forgot I had made the change till I switched to the inner and was like wtf for a second till I remembered. Since I hadn’t tried anything except 4/4 ever, I was suprised what a big difference the positions make (which is intersting).
The other strange thing is the site faq that I think you reference (I stuck it at the end below) suggests the inner ring is set differently because when climbing your front wheel is up - but when climbing on a computrainer, my front wheel doesn’t move regardless of the grade :). My only thought is that going uphill on the computrainer changes the resistance profile as I spin the crank, because the rear wheel doesn’t have as much inertia, so it’s less spinning and more grinding. Another thought I had was that at a lower cadence when climbing, but I played around with that making sure it was the same and it still felt wrong.
Anyway, interesting thought but for whatever reason, I feel better at 4/4 so I think I’m switching back.
from http://www.rotorcranks.com/frequentquestions.shtml#q15 Why is the oval positioned differently for the inner and the outer Q-Ring?
The orientation of the oval is positioned differently for the inner and the outer ring because each ring serves a different purpose: inner for climbing and outer for time trialing or sprinting. We changed the orientation for the inner as your geometry, body position and pedaling changes when you are climbing (front wheel is up).
OCP settings changes: hardest part of the pedal stroke per each setting; measured in degrees below 3 o’clock. Most studies show that we generate the most amount of power about 18º below 3 o’clock.
Setting # #1…………… 08º for the 53t…………… 13º for the 40t #2…………… 13º for the 53t…………… 18º for the 40t #3…………… 18º for the 53t…………… 23º for the 40t #4…………… 23º for the 53t…………… 28º for the 40t #5…………… 28º for the 53t…………… 33º for the 40t
“We changed the orientation for the inner as your geometry, body position and pedaling changes when you are climbing (front wheel is up).”
Does that really make sense?!
Power is generated through a biomechanical system of levers and muscles, the combination of which produces peak power at a specific crank orientation relative to the rider’s body. Assuming the rider maintains the same position, the orientation between the rider and the crank should not change because s/he is riding up a hill, down a hill, or upsidedown. I understand there is a “gravity” component to the pedal stroke, but I would think that it would be relatively small relative to the biomechanical component and certainly not large enough to justify a 5° change in crank orientation.
Does that really make sense?!
you are correct, that does not make sense.
the only thing that should affect q-ring orientation would be body position relative to the cranks, and one more thing: the angle at which the chain leaves the cranks, i.e., where is the rear wheel relative to the cranks.