What is The Spin Bike Q Factor And Does It Matter?

spin bike q factor feet on pedalsIt is a strange term q factor. It sounds more like it should be a name for a game or panel show about science or mathematics not something to do with pedals and bikes – indoor or outdoor.

I’m not sure why it is called the Q factor but it is simply the horizontal distance between the inside of the left and right pedals where they attach to the crank – you read more here http://sheldonbrown.com/cranks.html. It is felt that narrower Q factor is the more natural for your riding, the more efficient it is and results in less knee injury as it is closer to how you would walk. But there is discussion and debate on how narrow you need it and some of it comes down to personal preference, leg length and hip width – so it will be different for each person.

The general rule seems to be the narrower the better but it can sometime be too narrow and cause knee injury because of twisting of the knee but this is more discussed with outdoor bikes due in part to the way they are made. (See http://www.kneesaver.net/ for more information).

The Q factor for spin bikes tends to be wider than that for outdoor bikes as they need to accommodate the wider frame, the drive guard and the housing.

There is a wide range of Q factors for spin bikes even at the more expensive end with some of these bikes having a wide Q factor.

An interesting thing about this is that not all manufacturers appear to think it is important enough to let you know what it is for their bikes by displaying it in the description on their site or on e-commerce sites. in fact when I asked them by email some of them responded their bikes didn’t have them or they didn’t know it! Not a great attitude to their products and their potential customers concerns.

Anyway moving on.

One of the most popular and highly rated spin bikes is the Keiser M3 plus. It is a great looking bike and it can be seen in many different gyms and clubs around the country as well as in the homes of people who take their spinning and training very seriously. It is a quality bike. It’s Q factor is 7 3/4 inches which is wider than some more affordable bikes like the Sunny Health and fitness Pro Indoor Cycle with a Q factor of 7 1/2 inches.

The Keiser has a lot of great features but the Q factor width is where it does not come up to scratch and some people may not like this especially those wanting to use for indoor training when they can’t get outside on their bike.

If you are used to riding outdoor bikes you might find riding the bike initially a bit like you have legs around a table to get your feet wide enough. Well that is an exaggeration but you may find it uncomfortable to begin with at least. (I write more about how Keiser M3 Plus compares with the Spinner NXT (a bike with a narrow Q factor) in my comparison post). The width is to accommodate the magnetic resistance and the drive housing as mentioned earlier.

Another bike that is narrower and but more mid-price range is the Schwinn AC Sport with a Q factor 6 11/16 – it does come with manual resistance which seems take up less room giving you the narrower distance but is a highly regarded bike.

The company that seems to take this most seriously is Spinner and they are the original spin bike manufacturers. They started the idea of making indoor cycles to give a similar riding experience to outdoor bikes.
They have worked on narrowing the width of the Q factor for their bikes to improve that experience again. The 2 Spinner bikes I’ve reviewed so far do have the narrowest Q factor of the bikes I’ve reviewed for this site. The Q factors are: for the Spinner Sport is 6 7/64 inches and Spinner NXT is 6 7/32 inches.

For many people using a spin bike the Q factor is may not be a huge factor in getting the bike to fit them properly to avoid injury and increase performance. But this depends on how often and how long they are using the bike and what their fitness goals are.

If you are using athletic shoes and sliding them into toe cages it is not likely to be that major a consideration but if you have specialist shoes with cleats for getting foot position optimized you are going to want to get best fit for you.

Overall you do need to expect the Q factor to be wider on spin bikes (except for Spinner) than that on outdoor bikes because of the manufacture and design to accommodate the functionality as well as keep the bike stable while you are riding your heart out.

But there is a choice that can be made in the Q factor width to get the narrowest distance that is right for you and you goals. But do expect to pay more than the more affordable bikes. You can get them at the more afffordable end but you won’t get any of the premium features such as magnetic resistance, belt drive or console.

If you are using the bike for more casual exercise you are not likely to be as concerned with the Q factor as you are other factors but if you are expecting to be using your bike a lot it is worth investigating and getting the Q factor that is closer to your outdoor bike for the more biomechanical fit for more efficient workouts with less chance of knee injury.

6 comments for “What is The Spin Bike Q Factor And Does It Matter?

  1. Justin St.Germain
    October 20, 2015 at 5:35 pm

    The excessively wide Q factor of the Keiser M3 predisposes to joint related injury – in the ankle, knee, or hip joint. The knee joint in particular, being a synovial joint, is only able to do flexion/extension. The excessive lateral vector applied by the wide Q is problematic and can ,over time, lead to abnormal joint responses..

    • Paul
      October 21, 2015 at 10:07 am

      Thanks for this Justin. Do you have a spin bike you prefer?

      • J.St.Germain
        October 22, 2015 at 4:35 pm

        Q angle refers to the quadriceps angle , which is the angle of alignment of the quadriceps; a Q angle of ≥ 20º is considered abnormal and creates a lateral stress on the patella, predisposing it to pathologic changes; contrarily, a normal Q angle does not preclude regional problems–eg, it may underestimate the lateral force on the knee where there is an imbalance between the vastus medialis and lateralis muscles(1). So that being true, my preferred bike is the one where the Q factor allows for reasonable patellar and acetabular movement……extremes are to be avoided.

        Technically, a “Spin” bike would be the one endorsed by the Spinning Program – lately produced by Star-Trac, like the Blade or NXT with a Q factor in the 150 mm range.

        1. McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc

        • Paul
          October 23, 2015 at 9:01 am

          Thanks again. This is good stuff.

  2. Jeffrey Ramsey
    February 11, 2019 at 7:39 pm

    just contacted Sole Fitness about the Q factors on their spin bikes, the SB700 and the SB900 and they were totally clueless as to what this meant. I mean they sell spin bikes and they have no idea what Q factor is, talked to sales, clueless, talked to the service department and you guessed it, clueless. With all the good reviews on their bikes, how can they not know what Q factor is?? Perhaps they should stick with treadmills! Totally disappointed in their supposed customer disservice line and will not be looking at the SOLE spin bikes any longer.

    • Paul
      June 22, 2019 at 4:43 pm

      I’ve had a siilar experience trying to get the SB700 & SB900 q factor from Sole Fitness – they haven’t responded to my emails and contact forms. It is disappointing.

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