Proper bike fit is extremely important if you want the best possible riding experience. Even the best designed bike with top of the line components isn't going to ride well if you have the wrong sized frame, your saddle is at the wrong height, or your stem is too long.
Free Online Fit Consultation
We are partnering with Chris Balser at Bicycle Fit Guru to provide a complimentary pre-purchase online consultation for all bike sales. He will help you not only determine the best frame size but also the optimal stem length, headset spacer height, and saddle position. We will then use his fit information to ship your bike with the proper stem and spacers so you don't have to buy extra parts to make the bike fit you.
Contact Chris here to start the process.
$100 Discount on in Person Fitting
Already have a Voytek? See Chris for a $100 discount on a comprehensive in person fitting at his studio in Minneapolis.
Who is Bicycle Fit Guru?
Chris has been fitting people professionally for 25 years.
His qualifications include doctoral studies in anatomy, physiology, biomechanics and kinematics; yoga philosophy, teacher training and yoga therapy; Coaching; IBFI Level-4 Classification, multiple "fit"-certifications (Wobblenaught, BG, SICI, Trek, Fit Kit, BIKEFIT, etc.), Bike CAD, and Body Mind Centering.
Chris is the guy we've been using personally for years for all of our bike fit needs. He is also the only bike fit professional we know with extensive experience fitting people on fat bikes. After two years of using a Fit Bike with marginal outcomes he completely revamped his fat bike services with a custom trainer, wheels and skewers.
Chris generated the material below to explain in detail what Q-Factor is and how it impacts knee biomechanics, muscle recruitment, and bike handling characteristics.
Q Factor 101
Q-factor is a term used to describe a crankset’s width, measured in millimeters at the outside edges of the assembled crankarms.
This value typically ranges between 147 and 223, and is a function of crank spindle length, bottom bracket width/type, and chainstay specifications to ensure proper chain-line relative to tire dimensions and rear hub spacing.
The table below shows a list of typical Q-Factors based on bicycle type and discipline. For reference the Otso Voytek can be built with a 183mm Q-Factor.
Hopefully you can see that tire and wheel size impact these dimensions. Larger tires require wider chainstays; wider chainstays require increased hub spacing, bottom bracket width, and crankset q-factor.
Q-Factor is NOT Pedaling Base
Seeing as how there is no patent term to discribe the distance between a rider’s feet when pedaling, I am going to use the term “Pedaling Base” – a liberal adapation of “Walking Base” in Gait Analysis – to describe this feature.
For the sake of simplicity (and argument) let’s identify this location at the intersection of forefoot and pedal axle. A riders sum-pedaling base equals q-factor plus distance between each forefoot and crank at the pedal spindle.
Biomechanical Implications of Exceeding Appropriate Pedaling Base
Tibiofemoral (knee-joint) Biomechanics
Exceeding a cyclist’s pedaling base typically increases knee adduction moments (torque), and accompanying biomechanical anomalies that can cause acute pain or injury.
In simple terms, the knee is more likely to drive inboard towards the top-tube when an individual is riding outside his/her pedaling base. The impact of this feature on lower limb function can be injurious.
Muscle Recruitment Patterns – Training Effect
Altering a cyclist’s pedaling base impacts lower limb muscle & ligament tension and recruitment patterns established through training.
According to competitive cyclists’ reports, the period for adaptation is between 2 & 6-weeks. This means that if you switch from a bike with a narrow pedal base (like a typical road or mountain bike) to a bike with a very wide pedal base (like a typical fat bike) it will take 2 to 6 weeks to train your muscles to achieve optimal performance. Put another way if you train on a typical fat bike for several months and then switch to a road or mountain bike you will lose some of that hard won leg fitness until you adapt to the muscle recruitment pattern of the narrower pedaling base.
Bicycle Handling Characteristics
A lateral shift in pedal force (relative to the frame’s central axis) requires additional counter steering to maintain a “neutral” position when cycling.
In addition, the resultant z-plane pedal-force vector is pushing the tires laterally, which is not ideal for traction in snowy conditions.
The illustration below illustrates how the resultant pedal-force vectors impact handling. Closer stance drives force in a vertical trajectory and wider stance drives a trajectory towards the bike's mid-line at the tires. This essentially causing rolling of the bike underneath rider in snowy conditions. Large tires tend to offset this altered trajectory by grabbing more contact area. Reducing the trajectory allows for similar stability when traction is limited or when running narrower tires.