Rotor Q-Rings help to minimize the time spent in the dead spot while pedaling. While oval chainrings have historically been controversial, we believe that allowing a rider to fine tune the chainring position offers opportunities to minimize the dead spot never before realized with conventional chainrings.   purchase

How do Q-Rings work?

Q-Rings reduce dead-spot negative effects due to its effective variable gear oval concept. The effective gear is lower at the dead-spot zone, so it is easier, faster and more comfortable (smoother) to pass through it. Once the pedal is over the dead-spot and enters the down stroke, the Q-Rings progressively increase the effective tooth size as more muscle strength is available.

A 53T Q-Ring at the dead-spots is equivalent to a 51T, so it is easier to move through the dead-spot. But as the pedal goes down and more strength is available you can see how the gear (effective tooth size) gets bigger: reaching the equivalent chainring tooth size of 56T during the power phase.

All models of road and compact Q-Rings are compatible with both Shimano and Campagnolo drivetrains, 8/9/10 speed, and are specially beveled to fit most cranksets such as Dura-Ace 7800, Ultegra, FSA SLK, FSA K-Force (excluding K-Force Light compact), Zipp 300, Truvativ, and most other models. One exception being exotic carbon cranksets with overbuilt spyders. With exception to the singlespeed specific models, all Q-Rings are ramped and pinned and include chain drop prevention pins. The 53T Q-Ring measures 231mm at the major dimension, equivalent in size to a standard round 56T chainring. The 54T AERO Q-Ring measures 234mm at the major dimension, equivalent in size to a standard round 57T chainring. Road Triple Q-Rings use the same standard 130BCD size as the Road Double sets, size 54/53/52/50/48/46T. There is presently only one size middle and inner in the Triple Q-Rings.

Compatibility

A full report of all tested cranksets is available in the crankset compatibility list. Known cranksets not compatible are:

• Stronglight compact cranks: A number of Stronglight compact cranks have been known to pose problems in installing Q-Rings because of carbon fiber reinforcements that interfere with the OCP ring behind the crank arm.
  
• Some models of FSA pre-2005 Carbon cranks and K-Force Light compact: A ridge on the back of the crank arm on (some models of) 2004 and earlier FSA carbon cranksets, and K-Force Light compact crankset, prevents Q-Rings from being installed on these cranks.
  
• Dura-Ace 9-speed Triple cranks: The inner small Q-Ring will not fit the 130/92BCD Dura-Ace FC-7703 9-speed Triple Crankset. The middle and outer rings will fit.
• SRM Dura-Ace Compact cranks: You can use Q-Rings on the 110/130BCD SRM Dura-Ace Compact cranks. Just order the 36T 110BCD inner and 50T 130BCD outer Q-Rings.

Rotor elliptical Q-Rings offer some of the benefits of Rotor Cranks while enabling cyclists to use their current cranks. Q-Rings also offer a somewhat comparable solution to the inefficiency of the dead-spot, at a lower cost and reduced weight, over the Rotor System Cranks.

Q-Rings are unlike the asymmetric Biopace and O.SYMETRIC chainrings inasmuch as Q-Rings are symmetrical.

Q-Rings were conceived and designed incorporating all the bio-mechanical knowledge and experience achieved by the engineers at Rotor during recent years. The concept behind Q-Rings is that they enable you to push an effective bigger gear while in the power stroke, when your leg muscles are able to apply more power, and an effective smaller gear while in the dead-spots; while producing a smooth pedaling motion. Riders report that “it is like dancing up the hill.”

The OCP™ system (Optimum Chainring Position) enables you to customize the position of the Q-Rings where they best suit your personal needs and desires.

Q-Rings chainrings can be installed on most conventional cranks. They are available for most Road (130 & 135BCD), MTB (104/64BCD) and Compact (110BCD) cranks.

What’s different between Q-rings and previous non circular chainrings?

The most often asked question about Q-Rings is “how are these different from the Shimano Biopace and other brands of non-circular chainrings?” The short and simple but not so obvious answers are:

• Q-Rings are elliptical; Biopace and O.SYMETRIC chainrings are asymmetrical. The specific elliptical shape of the Q-Rings provide a very smooth uniform pedaling stroke; there is no sudden acceleration movement.
  
• Bio-Pace chainrings are designed so the maximum equivalent tooth size is at the dead-spots. Q-Rings have the minimum equivalent tooth size at the dead-spots. This enables you to pass through the dead-spots quicker with less stress to your knees.
  
• Q-Rings take into consideration the forces from your legs in static conditions and the inertias of the cyclist and the bicycle. This maximizes the efficiency and comfort of conventional cranks.
  
• The OCP System enables you to customize the position of the Q-Rings to suit your individual riding habits, body geometry, strength and position on the bike.

Q-Rings	O.symetric	Biopace

The Ovalization factor is a simple ratio between the diameter of the chainring at its smallest and greatest diameters. This defines the maximum extent of speed variation your pedals can pass through during the cycle.

A factor of 1 means the chainring is perfectly round, and a factor of 2 would mean the chainring has a large axis that is twice as large as the smallest. This factor is important for a number of reasons. The difference between a chainring ovalization factor of 1.1 and 1.4, though seemingly small, is very large : for example, a diameter difference of 1.45 is the usual variance between a mountain bike inner and middle ring.

When done properly, ovalization has a positive effect on the efficiency of the cyclists spin, contrary to what many conservative cyclists will say. The ovalization factor also defines the compatibility of the ovoid chainring with conventional derailleur systems. As you can see, the ovalization factor is crucial for the feeling and useability of an ovalized chainring.

The Form factor is the most complicated aspect of chainring design. This describes both the shape and the area of the chainring: Arcs and Ovals, Angles or flat sections. This factor is important for the pedaling dynamics: where is the speed constant and where are the accelerations? How sudden are those accelerations? is the chainring symmetric or asymmetric?

This attribute, in combination with the orientation factor, is crucial for knee health. The combination this and the Ovalization factor influences drivetrain stability: intelligent design will prevent sudden free chain length growth, eliminating the risks of dropping your chain through tension problems.

Holland's Marianne Vos, 2006 World Cyclo-Cross Champion, won on Q-Rings

What’s different between Q-rings and Rotor Cranks?

Many people have asked us what the real difference in performance and functionality is between Rotor cranks and Q-Rings since launching Q-Rings.

Q-Rings were designed to emulate the biomechanics of Rotor cranks, without the independent crank arm movement. This way you receive some of the benefits of the Rotor Cranks for a lower price tag, and the weight weenies can still sleep well at night knowing that Q-Rings wont make their bike heavier. Both systems orient the maximum effective gear ratio in approximately the same position, a few degrees past the horizontal, in order to benefit from both muscle strength and leg inertia. Both Q-Rings and Rotor cranks can be adjusted for different riding styles (standing sprinting or seated spinning, for example), bike geometry and terrain requirements. Q-Rings cannot not apply the same degree of variance in effective chainring diameter as Rotor cranks do, as this variance applied to two legs simultaneously would effect the cyclists spin negatively.

The advantages of Q-Rings, in general:

• Makes pedaling more efficient, and climbing much easier.
  
• Reduce lactic acid level production and reduces heart rate demands.
  
• Low weight.
  
• Simplicity.
  
• No extra pivots and bearing races, so maintenance is zero.
  
• Less intense dead point than standard chainrings.

The disadvantages compared to Rotor Cranks:

• The Dead point is not eliminated: only it's intensity is reduced.
  
• Biomechanical gains are less than those of Rotor Cranks.

What’s the best OCP setting for my road bike and my riding style?

• For road bikes, use the default setting as recommended in the user guide (OCP #3)
  
• For forward positioned TT and tri bikes, start with the outer Q-Ring OCP #3 setting for two weeks, then try the #4 setting and see how it feels. Each rider has different needs and preferences ... one of the best features of Q-Rings is that the OCP system (multi-position bolt holes) are designed to suit your individual riding habits, body geometry, strength and position on the bike.

What’s the best OCP setting for my traithlon or time trial (TT) bike and my riding style?

Most studies show that cyclist achieve max power (NOT max torque) at about 18 degrees below 3 o’clock (regardless of where 3 o’clock is found) so, at the #3 setting, the 53t outer Q-Ring becomes a 56t, and at around 12 o’clock, it is essentially a 51t ring. The problem is that this is based on a 73° seat angle so it is not the ideal setting for most triathletes.

Each setting changes the orientation by 5 degrees, so, for the outer ring: #1=8° below 3, #2=13°, #3=18°, #4=23°, and #5=28° below 3 (still on a 73° seat angle bike).

So, if you ride a 78° seat angle bike, you have essentially moved your saddle forward by 5° and with it, you move 3 o’clock down by 5° as well. So going to the #4 setting on a 78° seat angle bike makes the Q-Ring hardest at 18° below 3 o’clock on your 78° bike.

Now, here’s the interesting part. Because we ‘assume’ that you are climbing while on the inner ring, and hammering on the outer ring, the orientation is slightly different when comparing the outer ring to the inner. This is because when you are climbing, (1) your front wheel will be elevated by a few degrees, (2) you may tend to slide back on the saddle (as opposed to creeping forward while on the aero bars) and (3) you may recruit different muscles while pedaling (engage the hamstrings more); so in essence, the geometry may change.

So, for the inner ring, the change is still only 5°, but: #1=13° below 3, #2=18°, #3=23°, #4=28°, and #5=33° below 3 (back to the 73° seat angle bike).

We recommend you start on the #3 setting as this is the setting that works best for a majority of riders on a road bike.

Now, just because this all makes sense on paper, its not to say that we don’t have riders on a road bike using the #4 setting or on a Tri bike using the #3, these are again “in theory”. In fact, we have pro triathletes that use the #5 setting on their bikes when conventional thinking tells us that they should be using the #4. #1 and #5 are pretty extreme and seldom used, but you have the option to use what suits you best.

As each cyclist has a different pedaling style, the point at which they reach their max force potential is different. Those of us who have done a spinscan will be familiar with these variations.

OCP System Position three (3) is most frequently often used as the basic Q-Rings orientation. To find out which orientation is best for you, we suggest you try the following: Find a flat section of road, and ride a few minutes using 53/15. After a few minutes, switch to 39/11. Then shift back and forth a few times. You will likely begin to notice that one of the chainring combinations feels more comfortable or more fluid than the other. (If you frequently ride in hilly terrain, it is a good idea to repeat this test using 53/23 and 39/17 while climbing, and remember your impressions both on the flat and in the hilly sections).

If you preferred the inner chainring, we suggest that you try setting both the chainrings to a position one OCP number higher, to test this setting. If you preferred the outer chainring, we suggest that you try the Q-Rings at a OCP orientation one number lower. To go further: If you preferred the inner chainring on the hills and the outer chainring on the flats, we suggest you try the following steps one at a time: experiment riding with the inner chainring at position 3 or 4 and/or the outer in position 3 or 2. This type of experimentation is the easiest way to find your personal Optimal Chainring Position setup.

Setting 5 is an extreme setting, and we only advise this position be used when you constantly stand up directly over the bars on the chainring you wish to use that at setting. Setting 4 would likely be better for this style of aggressive standing riding, including those with a low spinscan and people whose seat is very far forward.

Fitting a 54T or 53T Q-Ring onto a TT/Tri or Road frame

Frame that has a front derailleur mounting boss (bracket) that is molded, bolted, brazed or fixed in some other way onto the seat tube (not a sliding clamp-type front derailleur):

1. Firstly recognize that a 54T Q-Ring is the same OD (outside diameter) as a 57T round chainring, when the 54T Q-Ring is in its major dimension, and a 53T Q-Ring is the same OD as a 56T round chainring.
2. Determine if either a 57T and/or a 56T round chainring will fit on your frame. Contact your frame manufacturer or local bicycle retailer directly.
3. If a 57T round chainring will fit your frame, then the 54T Q-Ring should fit as well. Use a 41T, 42T or 44T inner Q-Ring with a 54T Q-Ring to avoid shifting problems and/or chain drag on the cage of the front derailleur.
4. If a 57T round chainring will not fit your frame, but a 56T round chainring will fit, use the Rotor 53T outer Q-Ring with which you can use a 40T ~ 44T inner Q-Ring.
5. If a 56T round chainring will not fit your frameset, ask your frameset manufacturer if it is acceptable to elongate (e.g. grind with a Dremel) the slot in the front derailleur mounting boss (bracket) to enable the front derailleur to be raised enough to allow for the fitting of a 56T or 57T round chainring.
6. If it is not acceptable or possible to modify the slot in the mounting boss (bracket), and a 56T round chainring will not fit, it is probably not possible to use either the outer 54T or the 53T Q-Ring with your frame. If you want to install a Q-Ring on this frame, the next options are the 52T or 50T Q-Ring, which are the same OD as round 55T and 53T chainrings respectively.

SRM cranks, and Q-Rings

Some notes to be aware of when using Q-Rings on SRM cranksets:

• SRM takes measurements for torque and cadence, not for instantaneous speed or rotational speed.
• For circular chainrings, they approximate the instantaneous speed by the average speed (cadence) which is accurate for high speed (e.g. flat TT conditions) and very close for steep climbing, due to the big accelerations every downstroke when pedalling very hard (twice per revolution).
• When you attach Q-Rings to the SRM crankset, the speed varies twice per revolution, but the SRM system doesn’t know that, so there is a small error in the power displayed.
• Normally you will find that for flat pedalling and the same speed and real power, SRM displays slightly more wattage with Q-Rings than for round rings. The difference of error can be ~1% (more error when using OCP#1, less when using #5 for the OCP). However, as shown in recent testing, the power increase from using Q-Rings can be 1-3% over round chainrings.
• While climbing, the error of difference of data displayed is smaller betwen round rings and Q-Rings.
• As an example, Osymetric (another type of oval chainring) reaches value of 4% for this same error, due to a major elongation and a higher orientation. Oval chainrings display a positive error when the maximum diameter is perpendicular to the crank, and negative when parallel (e.g. Biopace).

Single-speed/Downhill use

The 34t or 38t will work without the need for a tensioning device, but here are a few things you should note:

• If using the 38t DH ring on a DH bike, you will have to use a chain guide such as the MRP System 1 (World Cup 36t-40t model) http://www.mrpbike.com/product-system1.php, in order to avoid the chain from falling off.
• If using either the 34t or 38t on a single speed bike, position the crank between 3 & 4 o’clock (largest part of the Q-Rings will facing up) and then tighten the chain the same as you would on a round ring. Because the effective tooth size is a gradual change, and not that extreme, you will be able to ride in tough terrain without the chain failing on you.
• You will obviously have a small change in tension if you’re feet are at 12 & 6 o’clock, but when going downhill you’re feet will likely be positioned at 3 & 9 o’clock (highest tension). Therefore, the only time you’ll be at 6 & 12 o’clock is when you are pedaling, which means that you will be applying pressure on the chain at this point.