regmudd

What is the wheel circumference for Schwinn Aerodyne?

JanMM

I see a variety of Aerodyne products online but I don't see that they have what I would call a wheel. Looks as if there are various sizes of round fans (?) in the front.

https://www.schwinnfitness.com/schwin...irdyne+AD2.jsp

BlazingPedals

A Schwinn Aerodyne is a classic example of why the question "what's the equivalent mileage for xxx minutes on a stationary bike?" All you can really say is that you rode for xxx minutes and maybe note your heart rate.

thumpism 

May need more clarification on your question. The Schwinn Airdyne used a bicycle wheel for its fan element but I do not know the size used. Probably standard 26" (559 bead seat diameter) but don't quote me on that. I never took one of those wheels out of its cage on the exerciser to measure it.

rumrunn6

Measure the circumference with a string by evenly wrapping a string around the outside edge of the tire. Mark or cut the string at the spot where it reaches back to its starting point and measure its length to determine the circumference.

CREDIT:
3 Ways to Measure a Bicycle Wheel - wikiHow

JanMM

OP needs to share what variety of Airdyne is being asked about.

CliffordK

There are large ones, and small ones.

There is no "tire" per se.

What is your goal of the question? The fans generate resistance, so one gets resistance over time (which is reported by the Airdyne computer if you have one). There is probably no exact correlation of pedaling the airdyne and distance, although someone probably came up with a formula (which may not be uniform with cadence).

Wanderer

The wheel on "The Beast" circa 1990, is stamped 27X1 1/4.......

I do happen to know that 80RPM will kill ya!

Also, you never should have posted this subject....... I didn't want to look at that thing until Dec or January!

AirDyne

If you have an older original Air-Dyne (like about 30 to 40 years old) you can set the circumference to 846 millimeters on a Sigma Pure 1 wired bike computer.

I have a 1988 Schwinn Air-Dyne AD-3. The ergometer broke after about 33 years. Spare parts are hard to find. I searched but could not find the wheel size to use for a bike computer. I borrowed from my Dad’s AD-2 to get mine working again. I setup a bike computer to compare and find what the wheel size should be. I set the circumference to 846 millimeters on a Sigma Pure 1 wired bike computer. This shows the correct speed, distance and time on the bike computer.
More detail and a much longer explanation with pictures can be found at Amazon. Search for "Sigma Pure 1 Basic Bicycle Computer, Wired" or "Sigma Pure 1 wired bike computer" in Amazon and look for the review "AirDyne odometer (speedometer) replacement for 1988 Schwinn Air-Dyne AD3" dated July 15th, 2023. I am not allowed to put links in here yet.

indyfabz

Zombie thread. Sadly, I remember when this was originally started.

UniChris

No, it doesn't.

The fundamental mistake is that the net tangential movement of the resistance wheel is not a "distance" in any meaningful cycling sense.

The only way you can get a meaningful "distance" is to take a measurement of power and use that as input to a cycling simulation - what something like zwift does.

There are basically three ways to get power:

1. Measure it directly via torque and RPM, for example what power cranksets and pedals do
2. Estimate it based on RPM and a model of the resistance mechanism - a moderately accurate model for smart trainers capable of doing a spin-down calibration, less so for the case of "we tested simple resistance product X in the lab and found that its typical resistance is..." dropdown selections - and even that only if you're using the actual trainer model you claim
3. Forget about actual power and use heart rate as a proxy for power production in this session relative to personal trained potential

Any original "distance" readout of your exercise bike would have been based on #2, but was lost with those electronics. When you re-created something with a computer intended for an actual bike, you did not put in any meaningful proxy for the effort needed to move a bike, and so you generated a reading that is fairly meaningless, except in the sense of giving you a way to track the proportionate of your persistence yesterday vs today.

But even there, it's important to realize that riding 50 "units" slowly is less workout than riding 25 units quickly, because the power required to move an actual bike on flat ground scales non-linearly with speed to a rather drastic degree.



Continuing an old thread on an issue is much better than creating a new one, since its best that new discussion be informed by what previous discussion already accomplished. And no, the new poster doesn't seem out to push something, they're just genuinely unaware of the underlying issue. That they did some research and found this should be commended; unfortunately having found it didn't lead to realizing why the goal isn't meaningful.

AirDyne

Thanks. I meant that the new bike computer odometer matches the old Schwinn odometer. When the wheel doesn't touch the ground, obviously the "distance" is calculated, estimated, just made up or whatever. But with the circumference set to 846, the old and new odometers show the same "distance", so I can go the same "distance" in the same time and it will be the same as the old odometer.

Maybe that's what you mean by this "except in the sense of giving you a way to track the proportionate of your persistence yesterday vs today". Most of what you said is kind of out of my league.

I have both the old and new odometers going at the same time and they show the same "distance", so it was not "lost with those electronics" and not "fairly meaningless" since all I want is to ride the same "distance" in the same amount of time. I am not interested in power, torque or heart rate. I just want to do what I have been doing for decades without needing to scrounge for old obsolete parts. I don't know how Schwinn came up with the "distance" the old odometer shows and I don't care. I just want the new bike computer odometer to show the same "distance". Setting the circumference to 846 millimeters does the job.