What is a good Q Factor on a bike?

Due to bottom bracket size, minimum chainline guidelines and chainstay length, there is an acceptable range for Q-factor, which is typically between 150mm and 170mm . Road bikes tend to have a narrower Q-factor (150mm), while mountain bikes tend to have a greater Q-factor (170mm).

How to determine your Q Factor?

Sometimes known as 'quack factor' (a references to ducks and their waddle-y legs), Q Factor is the distance between the outside of one crank arm to the outside of the other . This is an important bike fit parameter as it effects your stance width, which is how far apart your feet end up being when placed on your pedals.

What happens if the Q Factor is too wide?

If the Q-factor is too wide or too narrow for your body's natural stance (and mobility), you can experience strain in your joints (often your knees), resulting in discomfort and which can lead to long-term issues .

What is the Q Factor on cranks?

If you've been browsing our pedals you've probably noticed we bang on about Q-Factor a fair bit. So here's a quick explanation. Essentially Q-Factor is the distance between the pedal attachment points on the crank arms, also referred to as Tread . It could also be described as the width of your crankset.

What should my Q factor be set at?

For most mechanical or electrical circuits, a Q of 0.5 is considered to be optimally damped . A Q of 0.3 would be over-damped, and a Q of 0.7 would be under-damped.

Do you want a high or low Q factor?

Higher Q indicates a lower rate of energy loss and the oscillations die out more slowly . A pendulum suspended from a high-quality bearing, oscillating in air, has a high Q, while a pendulum immersed in oil has a low one. Resonators with high quality factors have low damping, so that they ring or vibrate longer.

What is the advantage of a high Q factor?

High-Q factor resonators offer several advantages in biosensors. They provide high sensitivity and accuracy in detecting biomarkers , making them suitable for diagnostic applications 2 . Additionally, high-Q factor resonators can operate in a label-free fashion, eliminating the need for additional labeling steps.

What is the most accurate way to measure Q factor?

An accurate Q value can be obtained from Q-meter that utilizes precise inductance coils that correspond to a specific capacitance range .

What is the average Q factor?

The Q factor is determined by the bike's chainstay length, chainline guidelines and lower bracket size, which are not easily customizable post-production. The average Q factor ranges from 150mm – 170mm .

How to calculate Q factor?

In this case, the quality factor can be determined from the Fourier transform of the field by finding the resonance frequencies of the signal and measuring the full width half maximum (FWHM) of the resonant peaks. We can then use Q = f R /f where f R is the resonant frequency and f is the FWHM .

Does the Q factor affect chainline?

This chain line measurement is linked to the Q Factor and the rear axle width that determines a chain line measurement .

What is a reasonable Q factor?

Good high-Q capacitors can have a Q factor value of over 10,000 at 1MHz and over 1,000 at 100MHz , while standard capacitors can have a Q factor as low as 50 at 1kHz.

What is a good q-value threshold?

In the absence of other constraints, a q-value threshold of 0.01-0.05 is traditional. A q-value threshold of 0.01 implies that 1/100 of the significant results are actually null. q-values are a multiple testing correction to p-values.

What is a good Q ratio?

For either a firm or a market, a ratio greater than one would theoretically indicate that the market or company is overvalued. A ratio that is less than one would imply that it is undervalued.

Q-Factor Explained | 7 Pictures | | Pedal Chile

Q-Factor. Yes, Q-Factor.
It’s the distance between the pedals at the outside of the cranks. In other words, it’s how far apart the cranks put your feet. Are you walking a tightrope, or giving birth? Pedaling a bicycle or walking like a duck?

Q-Factor Explained | 7 Pictures | | Pedal Chile | (2)

What is Q-Factor on a bicycle?

Q-Factor or crank width is the distance between the two pedal cranks and is a measure of stance width, which is similar to your walking step-width.

QF Range
- 135mm on an aerodynamic Road Bicycle to 235mm for a Fat Tire Bike.

Grant petersen & Quack Factor

Grant Petersen, the founder of Rivendell Bicycle Works, bike author, and originator of the term Q-Factor says in his book, Just Ride: A Radically Practical Guide to Riding Your Bike:

"Q-Factor is the term I made up in 1990 to describe the distance between the outside of the left crank's pedal hole and the outside of the right crank's pedal hole."

and

"Crank makers talk about Q-Factor, but few know that the Q stands for "quack." Ducks waddle with their feet far apart relative to their leg length, and thus have high Q-Factors."

Q-Factor Explained | 7 Pictures | | Pedal Chile | (3)

Q-Factor & Frame Clearance

Q-Factor is set by the crankarms, and is generally limited by bottom bracket width and tire clearance. Because of this, Q-Factor will differ between bicycling disciplines rather than between cyclists of different sizes.

Q-Factor size is largely determined by the frame clearance:

Rear tire-width clearance
- Larger tires need more clearance and thus have larger Q-Factor (Fat Tire vs Road Bicycle tires)
Number of chainrings on your crankset
- Mountain Bikes with multiple chainrings have larger Q-Factor (1X vs 3X drivetrain)
  - Single-speed bikes have lower QF compared to geared bicycles due to several factors including narrower chainstays

For example, larger tires require wider chainstays, which then further requires more hub space, then a wider bottom bracket, all of which increase the Q-Factor or distance between the pedals.

The image below, from Otso Cycles, shows the difference between bike components and their effect on Q-Factor.

Q-Factor Explained | 7 Pictures | | Pedal Chile | (4)

Q-Factor Range & Bicycle Discipline (135 - 235 mm)

Road/Touring/Gravel Bike

135 - 157 mm

Cyclocross

154 - 157 mm

Q-Angle, Q-Factor & Pedal Stance Width

Q-Factor, Q-Angle, and Pedal-Stance Width are NOT the same.

These 3 bicycle terms are not synonyms and should not be used interchangeably:

Q-Factor = horizontal width between pedals

Q-Angle (Quadriceps Angle) = measure of alignment between the femur and tibia
- (Q—Factor does affect Q-Angle)
Pedal-Stance-Width = distance between the midpoint of the two feet

Q-Factor Explained | 7 Pictures | | Pedal Chile | (6)

Q-Factor & Performance

Bicycles designers try to keep the Q-Factors as narrow as possible, regardless of bike type. Smaller Q-Factors are better for aerodynamics, handling, and are more natural for pedaling.

Q-Factor Explained | 7 Pictures | | Pedal Chile | (7)

Optimal Q-Factor & Walking

Q-Factor (QF) in cycling is similar to step-width in walking. The average walking step-width is between 70 to 120 mm and increases to 130 to 170 mm while climbing stairs. Even bicycles with very narrow QF are wider than the average walking step.

Since walking ishuman nature,it makes sense that bicycle engineers create bikes that put cyclists in their most natural position, which for Q-Factor means more narrow than wide as this more closely mimics our walking pattern orgait.

Q-Factor Explained | 7 Pictures | | Pedal Chile | (8)

Best QF for Bicycling

Before Q-Factor became a term, this same dimension was called “tread” over 100 years prior. However, not much scientific research has been conducted to determine the ideal Q-Factor, since the majority of studies focus their attention on seat height and aerodynamics.

What the available research says:

Narrow is better (up to a point as too narrow is possible)
- Muscles work less the further the pedals are moved out (also up to a point….think about squatting at the gym)
- Narrow QF improves riding efficiency (better power generation and more aerodynamic)
Hip-width to pedal-width (QF) is probably not that important
Every rider has a unique QF
- Do you suffer from knee pain while cycling and have tried everything else?? A closer examination of your Q-Factor might be prudent

If your feet are positioned too narrow or too wide you may experience pain on the side of your knees or in your feet and will be more pronounced for those who ride clipless pedal systems.

Final Thought

The difference in performance between 90mm and 180mm is 5-watts. As Q-factor gets wider, especially for mountain bikes, your pedal efficiency suffers in order to increase downhill performance.

Q-Factor Explained | 7 Pictures | | Pedal Chile | (2024)