wtf is Q factor

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yeah title says it all

Yes it does, thanx.

It’s got to do with the angle with which a crank points away from the wheel.

Here are two threads with discussions on q-factor.
Thread 1
Thread 2

Its the amount the cranks angle outwards to avoid ankle nailage. Im sure someone else can describe it better.

yeah, the thing i was unsure of, was,

if someone says their cranks have zero q factor, does that mean, their cranks dont angle at all or… ?? :thinking:

yeah zero q factor would mean your cranks have no angle, just straight cranks.

ie. Perfectly perpendicular to the axle.

Q-factor, in practical terms, is how far apart your feet end up (along the axle, that is) when you are riding. It’s produced mostly by the hub, axle, cranks, pedals, and even your footwear, though in some cases your saddle and clothing can contribute.

Each part of the above contributes to Q-factor, but the easiest one to think about is the cranks. Even straight cranks contribute to Q-factor because they position your feet further out from the midline of the wheel. Angled cranks simply position them further out than straight cranks.

In unicycling, the width of the hub and bearings/bearing holders also contribute to Q, and can make a difference in both riding comfort and the actual power the unicyclist can derive during riding. These effects are not absolute, but relative to the rider’s physical dimensions and riding style.

The rider’s dimensions such as hip width, length and angle of each part of his/her legs, degree and direction of pronation and splay footing, all interact with the unicycle’s Q-factor, and for optimal performance, the two should be matched as well as possible. Typically these days those factors are ignored, or sometimes an individual rider will experiment some on his/her own. Most unicycle equipment does not permit a lot of variation in Q-factor, though that situation is slowly changing.

However, distance riders (especially) should be aware that the many 100s of thousands of revolutions they do (order of magnitude courtesy of Andy Cotter) are affected by Q-factor’s interaction with their personal body characteristics, and may derive substantial benefit by working with different crank angles, hub widths, saddles, and pedal types.

The unicycle rolls on a narrow strip of tyre. Even on a fat tyre, the contact patch is only a couple of centimetres wide on flat ground.

The pedals are some distance to each side of this contact patch.

The Q factor is this distance.

Why does it matter?

Because the weight of the crank, pedal and foot (and leg) adds up to quite a lot, and the pedal is “orbiting” the axle. “Centrifugal force” (yes, I know, but we all know what it means) means that the pedal is constantly pulling away from the axle. The heavier the pedal and the faster the rpm, the more it pulls.

So, the further out from the contact patch the pedal is, the longer the lever (the axle) it is pulling on, so the more it affects the steering.

Think about this: if the right pedal is pulling the right hand end of the axle one way, then the left pedal is paulling the left hand end of the axle in exactly the opposite direction.

For a simple demonstration of the effect, hold your uni up by the seat, then spin the wheel hard with your other hand. The uni will wobble jerkily from side to side in time with the rotation of the wheel.

If (for the sake of demonstration) you removed the cranks and pedals and repeated the experiment, the uni would NOT wobble jerkily from side to side.

Now, if you increase the Q factor, the degree of jerky wobbling will increase. if you reduce the Q factor, the degree of jerky wobbling will increase.

When you are riding, you may not notice the effect except at very high speeds, but nevertheless it is there, and you are using energy to compensate for it.

On the other hand, a high Q factor is good for steering, especially with a large wheel.

Like everything in unicycling, it’s a compromise.

As I mentioned in another thread, Q factor is not whether the cranks are angled or not; it’s the distance between the foot platforms of the pedals. A wide hub with straight cranks can have a larger Q-factor than a narrow hub with angled cranks.

wtf is the search feature?