The Schwinn Airdyne Upright is a classic - virtually unchanged for at least 20 years (I used them at Columbia University's gym back in college in the early 80s in essentially their current form). The lack of evolution speaks to their excellent functionality. The Airdyne differs from most exercise bikes in having a large air-resistance flywheel instead of a smaller heavier flywheel with mechanical friction or an electric magnetic resistance flywheel that needs power and the electronics head to operate it. The advantages are fourfold: 1) the larger flywheel is exceptionally smooth, 2) the air resistance is naturally graduated (i.e. the faster you pedal, the greater the wind resistance and the harder it gets to pedal). This resistance approach means you organically find your level by pacing - with no need to ever set resistance manually. 3) The air resistance flywheel kicks up wind that cools you as you work out. 4) Mechanical resistance devices tend to wear out first - becoming bumpy or uneven; magnetic resistance units become unusable if the electronics head stops working. The air resistance scheme is simpler and is built with tremendous durability. I've owned my Airdyne for 12 years and it has been perfectly reliable the whole time - and it has been moved 3 times and has taken a real beating. The Airdyne's handles are linked to the pedals, encouraging you to work out your arms at the same time. The upper body workout gets most of the arm and a good involvement of the chest and shoulders too. The unit is battleship built of stamped and welded steel - just like a Schwinn bike. The chain is enclosed for safety - and a safety lock lets you prevent things from moving when you move the unit (it moves on small integrated wheels in front). You need those wheels because the Airdyne is big and heavy. This translates to excellent stability when in use.

Is the Airdyne the perfect workout machine? There are some drawbacks: The air flow is nice - but it's noisy too. This makes it hard to watch TV or work out with others in the room. The big wind can send papers flying. The upperbody workout can be distracting from the biking rhythm. I wish there were an alternate set of handlebars that didn't move for when you just want to bear down and spin. The handlebars only allow an overhanded and underhanded grip. I wish the handles curved up at the ends so you could hold them vertically like ski poles. This would result in a more natural arm motion. The big padded seat is comfortable as bikes go - but that's not saying much. Bike exercise has the disadvantage of not being weight bearing - but this is a quibble. My heart monitor confirms you can definitely get your cardio rate up on a bike. Did I mention this unit is big and heavy? The little wheels help - but moving this bike isn't a casual exercise. Finally, despite the clear efforts at safety, ther are still places where cat's tails and children's fingers can be pinched when in use(notably where the handlebars link to the pedals with long metal bars near the bottom of the unit).

If you like to use an exercise bike to work out, and don't mind some noise and wind, the Airdyne will give you a great workout - keep you cool - and last basically for ever.

Followup 10/08: The computer on mine stopped working recently after 14 years - but it doesn't matter to me (I seldom used it anyway). The computer displayed time, rpm, distance, an arbitrary "workout level". It didn't do heart rate so I tend to use a wrist mounted heart monitor which times the workout for my anyway. I could probably buy a replacement computer but I'm not going to bother. The fact is that this bike works fine without it. Try that with any newfangled bike. This bike is like the old Nikon F camera - which mentioned in the instructions that if you accidentally dropped it in seawater you should rinse it in fresh water and then dry it with the film door opened in a an oven set at lowest temperature for an hour! That's how they used to make gear! 4 stars

Surprisingly, my Airdyne was delivered disassembled, and with no accompanying assembly instructions of any kind. I am no mechanical genius, and this didn't look like a job for the faint of heart in the first place. Unable to obtain any assembly instructions from either Amazon or Schwinn, I tried a local bike shop. For an $85 fee, they assembled my machine. When I inquired about the lack of assembly instructions, they told me that this was a deliberate omission, and that self-assembly invalidates the product warranty. I can't vouch for the absolute accuracy of all I was told, but I feel that I should at least sound a faint alarm. CPW 1/07
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After using my Airdyne for several months, I would (if I could) my review from three to four stars. What I wrote above still applies, but the Airdyne is a wonderful piece of exercies equipment. I have osteoarthritis in both knees, and the Airdyne enables me to precisely control how much stress I put on my knees. CPW 5/07 3 stars

I bought one of these in 1988. It was already -quite- old, (probably from 1977, the first year it was made, which means the 30 year warrantee is -still- in effect!), and not well taken care of. Whatever abuse it took only made it a little dirty. It's almost 2007, and it's still working perfectly. The all-steel construction has kept it repair-free while newer machines go into the garbage. Different year models come with different monitors, so I won't go into that, but the machine itself is always the same: No shifting. The fan-resistance increases with pedaling speed. Arms and legs contribute whatever proportions of the total effort you desire, a very natural intuitive movement. For arms only, there's a foot-rest, for legs only, just hang your arms at your sides. (The Airdyne is not a bicycle, not a 'spinner', it is a thing unto itself, but unless road-bike technique is an issue, it will do more than spinning can do for your fitness.)The warrantee, or any other right to complaint, is probably voided if you stand up while pedaling, but I've been able to stand on these pedals for all these years, and the combination of arms and legs while out of the seat is the most intense workout available on a home cycle. (I did eventually get a Schwinn 'Windsprint', because it shifts to increase pedal pressure, but it doesn't 'do' arms. This is still the single best home cycle.) 5 stars

Schwinn's assembly instructions leave much to be desired. Poor, poor graphics and the words didn't help much. Additionally, some of the nuts and bolts are of obvious poor quality. However, once assembled, it provides a good workout.Buying from Amazon was, as always, a great idea. Free shipping and no tax saved my a bundle. Amazon is now my favorite store, internet or otherwise. 4 stars

Seems to be a very good exercise product. But the product description should mention that assembly takes about 2 hours. Stabilizers, arms, computer, pedals, and seat need to be attached to the frame. This should be easy but the assembly instructions are minimalistic at best. The method for attaching the arms to the frame requires quite a bit of strength. 5 stars