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from John Minnihan, founder of Freepository.

Convert Nordictrack revolutions to miles

We recently purchased a Nordictrack elliptical trainer.  The machine is pretty nice, but both my wife and I immediately noticed a major annoyance: there wasn’t any documentation about how many “miles” the elliptical travels over the course of a workout.  We’re both accustomed to that form of measurement; the number of revolutions per workout was essentially meaningless.

 

So I put on my 10th grade geometry hat and figured it out.  Here’s what I did. 

 

Goal:

 

Use simple geometry to determine how many Nordictrack revolutions equal one mile.

 

First, measure the radius (r) of the encased wheel (this is the distance from the center to the outer edge). For improved accuracy, I measured from the center to the middle of the axle that attaches to the foot platforms. On my machine, the radius was 10 inches.  But we really need the diameter, which is 2(r), or 20.

 

So, we have the first part of equation, diameter (d): 20 ”

 

In order to determine the distance that the wheel would travel if it rolled freely, I need to measure to know the circumference of the wheel. This is the total length as measured all the way around the wheel, like you would get if you wrapped a tape measure around it.

 

Here’s where the geometry comes into play: since I cannot wrap a tape measure around the wheel, I use this formula to calculate the circumference (C):

 

 C = d(PI)

 

PI is that weird number that you remember from school. I won’t even bother with any details; for this explanation we’ll just agree that it is an important number and we’ll say it is 3.14159265.

 

So, the equation starts to take specific form:

 

C = 20(3.14159265) or C = 62.831853″

 

Now that we have the C, we can calculate the miles per revolution. To do this, first convert C, which is in inches, to feet:

 

62.831853″ = 5.236′

 

Now we know that every time the wheel revolves one complete turn (a revolution), we theoretically have traveled 5.236 feet. How many equal a mile? One more calculation:

 

5280 feet / 5.236 feet = 1008.4 revolutions

 

So, to travel one mile on the Nordictrack you have to pedal 1008 (or so) revolutions.

 

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Posted in Sports & Fitness 1 year, 5 months ago at 2:10 pm.

Comments

 

  • Anonymous
    Which model are you using?
  • I'll check later & update the post w/ the model number. What model do you have?
  • John Minnihan
    The machine is a NordicTrack AudioStrider 990.
  • Gary
    I have a Nordictrack 990 and the company said that since it has an 18" stride that one revolution would be 3 feet thus 5,280/3 would equal 1,760 revolutions per mile. So which one would be more accurate, the radius of the wheel or the 18" stride?
  • Anonymous
    The stride can be changed by altering the angel of incline; since the axis of rotation is fixed, this means the lateral stride is reduced at a steeper incline.

    So the radius of the wheel - the one constant that is fixed without regard to the angle of incline on the pedals - would be the authoritative base measure.
  • Gary
    Thanks for the feedback. So could we assume that my Nordictrack 990 would have the same radius as yours? I'd rather not take the screws out to find out. Do you have the 18" stride? If so, I will incorporate your measurements to calculate the miles. I believe yours more so then what the company states because if I workout for 45 minutes at an average of 60 rpms, that calculates to about 2500 revolutions and based on their figures, I would have gone a little over a mile in 45 minutes. Thanks again.
  • John Minnihan
    Yes, your 990 would be the same as mine unless you've modified it in some way.

    Glad to help - this bugged my wife & I when we began using it and I too searched online for what I thought was a simple piece of information. That's what prompted me to sort it out.
  • Anonymous
    That was really helpful for me as well!!!
  • Renee
    So are we going with the 1008 revolutions per mile or the 1760 revolutions per mile? This is very helpful thanks for taking the time to figure it out and post it for the rest of us. I do love my Nordictrack 990.
  • John Minnihan
    Hi Renee,

    I'm sticking with my 1008 revolutions per mile.

    The stride can adjusted w/ the angle of the pedal; the actual circumference of the wheel is fixed, so it is authoritative.
  • Terri
    I just spoke to a rep and she told me that 300 revolutions = 1 mile on my model which is a nord.800. I bought mine from sears. I too have been trying to find out how many miles I go and it doesnt say. That is really bad I think. My husband tried to be nice and surprise me and didnt know that was something I had to have on it. I cost enough you would think it would have it there.Thanks for the info. T
  • kp
    I'm not sure that calculation is correct. It's an elliptical trainer, which means that it pedals in an elliptical shape, not a circular shape. And you calculations were for a circle.
  • John Minnihan
    The wheel - where the energy is delivered & converted to work (rotations) - is circular. Expressed that way, one can state that n rotations of the wheel is equivalent to x mile[s] in *theoretical* travel.

    The assumption here, of course, is that the machine & I are defining 'revolution' the same way. Since the wheel is the only part of the machine that actually revolves, I'm using 'revolution' to refer to a full circle rotation of it.

    The line that the wheel would traverse when rotated (if free to "roll") is fixed & independent of other factors (assuming no slippage/excess friction etc.).
  • Anonymous
    I was looking up this recently, and tried the service department, they confirmed the 300 revolutions = 1 mile number. Or referencing the chart, 1500 revolutions was 5 miles.

    It doesn't sound like enough, but they checked twice.

    This was with an audiostrider 990
  • John Minnihan
    Thanks for commenting here. This is certainly an interesting topic.

    It would seem that the company & I are either using different definitions for 'revolution' or they are factoring in/out something I'm not considering.

    In my case, I'm comfortable w/ my calcs. I measured my trainer & did the math. It's all theory, though, since the trainer is never going to actually travel anywhere.
  • michelle
    I would tend to agree with your calculations vs. the company. I generally get around 3000 revolutions in just over an hour. There is no way I have gone ten miles in that time. I also have a 990. I felt that for a thousand dollar machine I should be able to get a clear answer from the company. Thank you for your help.
  • dave
    I think the secret lies with Charlette...hehe I thought I'd throw that in...anyone know from where?? Anyway, if you click the odometer button on the center of the console of the 990, it tracks distance, the trouble is making sence of it. It will record a number x 100 at the end of the workout.(It changes while exercising if you scroll that screen whileon it). So the question is, that number times 100 = what distance?
  • Lisa
    Good question about the number x 100 = what distance. I have an ASR 630 model. The tech at nordic trac also told me somewhere around 300 rev = 1 mile. They compare it to a stationary bike, you need to adjust that number according to your stride. I am thoroughly confused.
    I was running outside a ten minute mile( yes i am a newbie), on this machine it shows 2050 total rev. in a matter of 35 mins at an rpm of 70/72. According to the track on the display it tells me only 2/2.25 miles.Am I traveling slower or are the calculations of the machine off? or do i use the 300 ( give or take) calculation?
  • Melodie Chasteen
    THANK YOU THANK YOU THANK YOU for figuring this out. I've been looking online for 20 minutes and can't find anything. I want to get this answered NOW, and can't find anything about the "distance" even being mentioned in my owners manual so that didn't help other than listing a phone number I can call, which I was going to do tomorrow. Instead I'll just do a math equation :-)
  • Melodie Chasteen
    Wait....will this work for me, I don't have a nordic track, I have a Gold's Gym Stride Trainer 500 Elliptical.
  • John Minnihan
    Hey Melodie... the math will be the same no matter what brand or model you have. Just try to get an accurate measurement of the diameter of the wheel & go from there.
  • Barry
    How can I figure out how many miles is in a revolution. I have a exercize bike WESLO HORIZON ERGOMETER Model EB7720!
    Any help will be greatly appreciated...thanks!
    Barry
  • John Minnihan
    Hey Barry,

    The math above may be used to determine the mileage for any type of exercise bike. Simply measure the wheel & plug it into the equation above.
  • Barry
    Hi John,
    I am so confused. I used your equation above, and it said I have to ride 1260 revolutions for one mile. I rode for an hour and only went 250 revolutions. My old bike, had miles on it, and I used to ride 10 miles in an hour. HELP! Any suggestions. Something just don't add up here? I even called the company that made the bike...they said 3000 revolutions per ten miles...none of this adds up at all!
    Thanks for any help!!!
    Barry
  • John Minnihan
    Hey Barry,

    If you trust the company (no reason not to), then stick w/ their calculations. As stated in the above, the companies may be using a completely different definition of revolution than me.

    Speaking strictly as a math problem though, my approach above will accurately reflect distance traveled per revolution of a wheel on an actual bike that is moving.

    Is this a perfect match? In theory, yes. In practice - every single bike will be slightly different. They key will *always* be the circumference of the revolution under consideration (i.e. is it the wheel, the pedal "rotational sphere", or something else?)
  • Cindi
    I too have always wondered about the distance thing. I didn't do the math stuff though...I just figured if I can run or ride a mile in ten minutes then I was doing the same on the elliptical. Hmmm! I sure like the 300 revolutions per mile vs. the over 1,000 per mile. Yikes! Either way...it is still a great work-out!
  • Karen
    So, has anyone figured out the odometer yet? What the X 100 means?
  • Lisa
    Apparently not, I was hopeful someone would at least respond to it. Thanks!
  • John Minnihan
    Hey Lisa,

    The calcs I did on my Nordictrac work for me. If you notice that the overall mileage calculated on your machine varies w/ velocity, then the machine's measuring technique is flawed - the rate at which "distance" is covered varies, but the distance *itself* does not. In other words, whether it takes you 20 minutes or 40 minutes to cover 2 miles, you still have covered 2 miles.

    This is clearly a topic that is very interesting to many people. I'm a bit surprised that the vendors don't cover this better on their websites. I would start w/ my calcs (appiled to your machine) and then go from there.
  • Sunny
    Hey thanks for figuring that out. I also have the 990 and have wondered that many times. To me the 300 revolutions makes one mile just seems like too low a number. I was thinking just as an experiment to try using my pedometer because that measures miles. I wasn't sure how accurate that would be though.
  • Mark
    Just wanted to note that if the figure of 300 revs/mile were correct, each full stride (revolution) would have to carry us 5,280'/300 revs = 17.6'/rev. Don't think so. Using the figure of 1,008.4 revs yields 5,280'/1008.4 revs = 5.236' (the same number calculated for the wheel circumference above) - to me, that seems much more realistic. I can see a full stride (allowing a given foot to travel the full elliptical path of the pedal once, which would translate to two steps - one left, one right - on land) carrying me 5+ feet. That seems like a perfectly reasonable estimate. So the 1,008 revs/mile number seems like a good one to me. Hope that helps.
  • Mark
    @Karen: I'm not sure why in the world they do it that way, but I believe the x100 thing is part of the revolution count. For instance, if your odometer reads 250 x 100, then you multiply the two to get 25,000 revolutions. Seems like a strange way to do it though. Why doesn't it just say "25,000"???
  • Larry
    Ok, this isn't all that scientific, but after reading all the posts here, I tried to do some logical deductions.

    I'm using the Nord 600 and the stride I measured is 18 in., so a revolution would be 3 ft. That would put a mile at 1760 revolutions. That seems a bit much to me, so I watched the track on the display as I was jogging. (the motion of the elliptical resembles a jog more so than the peddling of a bicycle ).

    Logically, if the designers of the elliptical calculated that the track should be a quarter mile, as is pretty much the standard, it was completed in 360 revolutions. Therefore, a mile would consist of 1440 revolutions.

    This, of course, is based on assumption and speculation. But it works for me and that's what I'll be using to calculate my mileage.
  • John Minnihan
    This topic is getting a lot of mileage... now see, that's funny.

    I advocate using whatever technique or values work for you. My technique & equation are based upon the wholly circular wheel that rotates when you pedal. In classic mileage calculations on a free-wheeling bicycle, that's what is measured.

    So - pedal on!
  • Larry
    Yes, you're right John, this is getting funny, but all this calculation on our part shouldn't be necessary. The makers of the Nordictrack should have provided their customers with this basic information in the manual.
  • Confused
    I have a NordicTrack CX 1300 and have also been wondering this.

    I figure that you go 40" every time one revolution goes by, because the machine's stride length is 20" and I have two feet.

    40" stride per revolution
    5280 feet/(40in/12) = 1584 revs per mile

    On the other hand, when you wonder how much the wheel has gone,

    Diameter of my wheel: 22.25 inches (self-calculated)
    5280ft*12ft/in = 63,360 inches per mile

    C = pi*d = pi*22.25 = 69.898
    = 906.464 revolutions per mile

    So I'm unsure of which should be considered the correct value. I would have thought these should have come out to be the same thing, no? When we calculate a bike don't we use the circumference? Why would you measure it based on what your feet were doing, rather than the output?

    Sincerely,
    Confused
  • John Minnihan
    This is a confusing topic because each machine is different and I've made the assumption here that "revolution" refers to the rotation of the wheel, while the manufacturers seem interested in measuring the stride of the pedals.

    Don't forget that the lateral stride increases or decreases when you adjust the pitch of your sliding pedals (which aren't really pedals at all) if yours are adjustable; mine are. So any calculations involving stride become immediately suspect. That's another reason why I choose to use the wheel as the authoritative element of measurement.

    Since the wheel is round (a perfect circle) & the pedals are delivering work in the form of rotation of that wheel (a traversal of the circumference of the circle), it makes sense to me to use the calculation I describe in the post.

    In my mind, since the miles travelled by the trainer are theoretical only, it is perfectly reasonable to use the measurement that makes the most sense to you & best meets your exercise goals.
  • Confused
    I discussed this issue a while with my brother. He said that measuring the stride using an ellipse is probably the most authoritative method. With this method, I measure a major and minor axis of motion and plug these axis lengths into an ellipse circumference calculator (google it).

    With this method I got close to 1500, vs 907, revs per mile.

    Our circumference-of-the-circle method was treating the elliptical like a huge bike, which it is not. But, that would definitely be the way to measure how far the elliptical would have gone if it was not stationary (imagine that).

    The stride method will give us a linear approximation but modeling the motion using an ellipse is even more accurate. I believe the elliptical measurement will also account for any incline, etc. But keep in mind that Work = Force*Distance. Just because the distance is the same doesn't mean the human body is doing the same work! So, none of these measurements prove anything except the distance part. The force of an elliptical and a treadmill is different on our body.
  • John Minnihan
    I'm amused that this post has generated so much interest over the past year...

    You've certainly put a lot of thought into this, and I am intrigued by the notion of elliptical circumference. This doesn't change (for me) the fact that the only "thing" rotating is the rear wheel to which the pedal mechanism is attached. As stated above, that's one of my basic assumptions.

    It would very interesting to study a video of someone using an elliptical trainer, and markup the frames of video to prove/disprove that the ellipse maintains the same size throughout a workout, without regard to adjusting the pedal mechanism.
  • Cannon91
    John, I think that's the difference between your calculation and the manufacturers. I too have a 990 and just got off. I looked at the odometer and it said 25. I was like ok, I'm going to figure out what the heck that means and I came accross your post (thank you). In comparing the explanations, it would appear that while the wheel revolution is important, one cannot discount the stride. It's either the wheel revolution or the stride (wheel up and down on the guide ramp). So in your example, you've calculated the revolution of the wheel, however it doesn't take into account the actual stride, that can vary, of the individual and I think it needs to. Imagine taking the two "pedals" and spacing them far apart. Each revolution of the wheel would result in two very large steps, possibly longer than the circle, correct? Somewhere in that is the answer but of course I agree that it cannot be exact because your foot placement ultimate determines the actual distance. I'm looking at the stride right now to ensure it's 18", if not 20". Then I calculate from there based on simple tests. Regardless of the elevation the stride appears to remain the same, as I've used a pencil to make the points of the wheel guide depending on the height. It first appeared that the stride changed but it was just the wheel moving in relation to the elevation, the length or "stride" appears to always be the same. So it's 1760/mile for 36" strides or 1584/mile for 40" strides, if that's what you feel is authoritative.

    Hey but in the end, if anyone doesn't agree, make it whatever you want as long as it motivates you right? I have a treadmill that WAAYYYYY over estimates calories burned. My wife and I still laugh at it but it became a great motivator in the end to see who could out do each other.

    Again, great post and thanks for sharing your calculations.
  • John Minnihan
    "...make it whatever you want as long as it motivates you right?

    Absolutely.
  • polecat
    John, your math is correct, that is the distance traveled as far wheel rotation. The distance of one's stride is yet something else. An 18" or 20" stride is a linear number and serves no purpose in figuring an eliptical stride.

    The debate rages on.
  • T. Bannister
    We just bought a NordicTrack Audio 990 and, like so many others here, have wondered what distance we are "traveling". In fact, when I did a web search on this question, this was the site that had the most rational discussion, so compliments to Mr. Minnihan and the others who have commented on this topic.

    With regard to pure distance travelled, I think the JH approach using the diameter of the wheel is the most accurate (though I measured 18 inches for the axle movement diameter, rather than 20 inches). The elliptical movement approach is interesting, but if that mimics the movement of our feet, we don't usually include the distance travelled by our feet as it arcs upward and downward as we run or hike, but rather the distance along the ground we have traveled; so, I fall back to the distance travelled by the wheel as it is translated to a linear distance (like a bicycle).

    Now, I wondered why my heart rate was so high after walking only 0.6 of a mile and in only 20 minutes. When you factor in an incline of only 10 degrees (the minimum angle setting), it is like climbing a hill 0.6 miles along the incline and an elevation gain of 550 feet. That is equivalent to a 55-story building! A distance of 0.6 miles on a perfectly flat surface is much different than climbing 0.6 mile along an incline that is 550 feet high.

    (The resistance setting I suppose is like simulating walking through snow, dry sand, or mud, so that's a whole other complication, but it doesnt effect distance.)

    So, that's my 2-cents.
  • Joseph
    John thank god for guys like you I just spent over half an hour with Nordictrack asking them the same question and they had no answer....you rock!!!!!
  • Jerome
    Did anyone ever figure out what the odometer (X100) calculated and how?
  • Confused 2
    no sure on the distance - are the calculation based on riding a bike or running. There is a big diffence going 1 mile by running or riding a bike.
  • John Minnihan
    Thanks for the recent comments everyone.

    It would be great if manufacturers took this as cue to improve the information that they make available on their websites - clearly many people have this question. Even those folks that are generous enough to comment here don't completely agree on exactly how or what to measure to derive this piece of data.

    Hey NordicTrack - are you listening? We'd love to hear directly from you.
  • Misty
    Thank you so much for providing the information I was looking for. This is very helpful. When we set up our new elliptical Nordictrack, lack of knowledge of the miles was my only complaint so far. Have a wonderful weekend. Misty
  • Misty
    Thank you so much for providing the information I was looking for. This is very helpful. When we set up our new elliptical Nordictrack, lack of knowledge of the miles was my only complaint so far. Have a wonderful weekend. Misty
  • Becky
    Thank you!! This was very helpful!
  • nb
    Thank you!!!
  • nb
    The manual says that one complete cycle around the matrix (the track that is displayed is 1/4 mile), double check the count when the matrix goes blank (it does that after each completed lap) then multiple by 4, but I like the approx. 1000 count for now..
  • Bernadette
    Thank you so much!
    I should be able to figure mine out now!
  • kab
    I spoke with nordictrack about my 800 and they said count how many times your knees go up and 1760 = 1 mile
  • yennta
    Wow, thanks, all. I'll go with the 1008. Thanks, thanks.
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