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.
Tags: nordictrack, elliptical, workout, conversion, mileage
29 Comments
Which model are you using?
I’ll check later & update the post w/ the model number. What model do you have?
The machine is a NordicTrack AudioStrider 990.
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?
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.
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.
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.
That was really helpful for me as well!!!
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.
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.
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
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.
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.).
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
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.
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.
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?
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?
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
Wait….will this work for me, I don’t have a nordic track, I have a Gold’s Gym Stride Trainer 500 Elliptical.
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.
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
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.
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
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?)
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!
So, has anyone figured out the odometer yet? What the X 100 means?
Apparently not, I was hopeful someone would at least respond to it. Thanks!
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.
Post a Comment