https://reviews.mtbr.com/rotor-3d-mtb-cranks-and-q-rings-review/img_3668Rotor is a company from Spain that manufacturers very high end components. They've been making waves with with their 3D+ crank system and Q-Rings and they sent us a set of of their 2x10 crank to try out.
I've been using the 2x10 crank for about a month and it has been a revelation. First off, the cranks are incredibly stiff. They are able to fit a 30mm crank spindle on to my old Santa Cruz with standard bb shell. This spindle with these crank arms is stiff and it is noticeable. The system is light too at 690 grams complete with BB so it's a few grams lighter than the Shimano XTR 2x10 crank and BB.
The big revelation though is that these cranks actually make a difference. I have ridden SLX, XX XTR and many carbon cranks and it's pretty darn hard to tell the difference. The difference is mostly in shifting and durability . None of the cranks make me faster, slower, or smoother. The Rotor Q-Rings seem to do that. It makes my pedal stroke smoother and it seems to give more power, longer. The 2x10 chainrings I got were 40-27 teeth. That seems like an odd combination but it is very similar to a 39x26 double chainring. When I'm on the 40 ring, I get the equivalent of a 42 tooth ring at my sweet spot, which is right under the 3 o'clock position. At my weakest point, thich right at top at 12 o clock, I get about a 39 tooth ring. This ring is ovalized and is constantly changing size on my as I go through my uneven stroke.
So instead of pedaling in squares where you struggle to get the pedals over the top, Rotor aims to smooth out your stroke and even out your power. This is most evident when you're pooped or going for a Strava KOM and can't turn your pedals over. It will help you stay at a heavier gear and help you deliver more consistent power. It can also help with back pain and knee pain where the rider is experiencing stress as we compensate for the dead/weak spots in our stroke
The cool thing for me is on my first ride, it felt good. It just felt smooth and it I could tell its effects when I was knackered and when I usually lose my spin. I thought it would take me weeks to adjust to it but it was pretty natural actually. The reason for this is our body really has an uneven pedaling stroke. At the 12 o'clock position, we really have much less power than at the 3 o'clock position. We've been trained over the years to smooth out this stroke but folks have varying degrees of pedal smoothness specially at full effort.
We've only used it for a month so we are still collecting data and haven't tried to break our Strava PRs yet. But stay tuned.
Meanwhile, we saw this site called mtbr.com and it has a ton of user reviews on the Q-Rings. We checked them out and it is a treasure chest of real-world experiences by people who have paid for the product and used them long-term. The feedback is great and it confirms a lot of our observations. We've collected the strengths and weaknesses of reviewers below.
3D Cranks: https://www.mtbr.com/cat/drivetrain/crankset/rotor/3d-mtb/prd_455167_115crx.aspx
Q- Rings: https://www.mtbr.com/cat/drivetrain/chainring/rotor/q-rings/prd_412521_112crx.aspx
| (33 Reviews) |
- Works as intended
- Reduces knee pain/discomfort
- Free speed on the rides!
- Awesome difference
- Riding bigger gears
- Less fatigued after a ride,
- Back pain after an epic ride is GONE .... just try them .
- Options available are designed specifically to replace major brands with minimum fuss
- Better acceleration
- Don't have to get used to it
- Good quality
- Light
- Possibility to finetune the chainring position
- Can buy just the Q-Rings to start off
- Pricey, Pricey
- Does not shift as well
- Does not fit all carbon cranks
- You'll probably have to upgrade all your other bikes as well.
- Confusing terminology in manual - "regulation points"
- Folks will think you have 'biopace' and you won't hear the end of it.
At any price, it is worth trying out. Consider the Q-rings first to see the benefit and if it makes sense for you. Of course the risk always is you'll like it so much that you'll feel compelled to upgrade all your bikes in the stable.
Price:
3D+ Cranks - $660
Double Q-Rings Set - $245
Website: https://www.rotorbikeusa.com/index.html
Background Reference:
Traditional Elliptical Chainweels
Around the turn of the century, shortly after the development of the chain driven bicycle, someone came up with the bright idea of elliptical chainwheels. The idea was that the large radius of the chainwheel would drive the chain when the cranks are horizontal and the small radius would pull the chain when the cranks are vertical.
The theory was that while the cranks are horizontal you can pedal more efficiently, and thus can push a higher gear. When the cranks are vertical, you get a lower gear due to the smaller effective radius of the chainwheel. The lower gear is easier to push, and you get through the dead spot sooner. This is the basis for the Q-Rings design.
Biopace
Biopace is a patented non-round chainwheel design made and licensed by Shimano. It looks the same as Elliptical but it acutally is the exact opposite of the classical elliptical design. The product of extensive research and computer-aided design, Biopace chainwheels have the small radius engaged when the cranks are horizontal, the large when they are vertical. This is because the Biopace design is based on a dynamic analysis of the motion and momentum of moving cranks and legs, unlike the static, geometric analysis that produced classical ellipticals.
The theory is that during the power stroke, when the cranks are more or less horizontal, you are using the power of your legs to accelerate your feet, which get going quite fast in the lower gear provided for that part of the stroke. Biopace relies more on momentum to get around the pedal stroke instead of optimizing for the power of the user. Biopace is really a flawed theory and venture and have alienated many users from trying standard elliptical designs.