What initial improvements can I make to a Schwinn Sidewinder?

$50 - $100 isn't going to get you much in parts, especially any that would be an "upgrade" from your current setup. If you're riding your bike often, it's possible that you'll spend an amount approaching that this year on new tubes and/or tires when you get a flat or wear your tires out.

My suggestion would be to ride this bike and enjoy it. You'll get your exercise and it'll give you time to research bikes and save for one that will fuel your desire for more advanced riding down the road when you gain your fitness. Visit some bike shops in your area and talk with the staff there to find a bike that is in your range of needs and budget. Test ride lots of bikes to find one that fits properly.

You don't need the "fastest" or most modern/expensive bike if you just want exercise. You just need something that is safe and functions for your needs. The best upgrade you can give your bike is the motor (yourself).

First, keep in mind that maintaining a bike well doesn't cost much, but it makes a major difference in the long run. Keep it clean, check tire pressure weekly, adjust and oil it as needed. A well-maintained $100 bike works better than a neglected $1000 bike.

That said, I've eventually changed the following parts to most or all bikes I've ever owned:

• Tires. They may be ok, but particularly in a cheap bike they more likely are not.
• Brake pads. At least they wear out, and new, good-quality ones aren't expensive.
• Pedals. Cheap ones tend to have slippy surface and sticky bearing.
• Handlebars. A major comfort factor and inexpensive to upgrade if needed.

Some essential add-ons include:

• Speedometer.
• Bottle holder.
• Light.
• Rack and maybe panniers, depending on what you use your bike for.

I don't see much point in "improving" the bike until you decide what improvements you need. About the only thing I can think of that you might want to change right off is the tires, if they're heavily lugged (which I can't tell from the description) and you prefer road to off-road riding. And, of course, you may find that a different seat would suit you better -- that's a fairly personal thing.

Otherwise, wait to see what bothers you and fix it as you make up your mind. The bike appears to be of at least decent quality, and replacing components (other than the tires or seat) is not likely to change how it rides in the near term. What you may want to do is add a rack, headlight, etc, based on your specific needs, but these are pretty much the same regardless of bike quality (and could be transferred to a new bike, should you ever decide to "trade up").

After a month or two (after the cables and brakes have "broken in" a bit) you should take the bike to a bike shop for a tune-up -- adjust the brakes and shifters. After that the tune-up should only be needed once/twice a year.

I own a sidewinder. Replace the hard seat, Aztec 2 threaded brake pads, True the wheels keep it cleaned adjusted and lubed and adjusted and just ride it.

The first thing I got was a comfortable seat.
Second was lights and a lock.
Third was rear rack and saddle bags.
A new inner tube was just maintenance.
I'm thinking about handlebars with a bit of a rise to them.

I think like you some bikes are just too expensive; I got my Schwinn Sidewinder at a pawn shop. The dealer said to me all frames are about the same, it's the components that make the bike.

I might think about a multi tool.

Regular maintenance and just ride it. Keep in mind though, that a lower end bike purchased from a bike shop ($230-$250) isn't that much more than what you pay at places like Walmart or Target and are 10 times (at least) the bike.

You probably would like a more comfy seat, tires that fit your intended usage (road/off-road) and probably better pedals. Other than that, maintained well, you'll get a lot of use and fun out of a Sidewinder. It's not the lightest frame but it is sturdy. I also did not think much of the forks' suspension.

A better bike ($200+) will be lighter weight, better suspension and have better shifters.

I thought these the weakest points about the Sidewinder. I bought mine at WM for $149 last year and ride 2-3 times a week. I've changed nothing except add a head and taillights, but I wish it was lighter and shifted smoother. My tires still have the little nibs on them, and I ride mostly on road. It's an ok tire for trails, but not great on road.

I did take it on a 50k road trip and felt the weight and tires as a disadvantage!

I'm 6'0, so handlebars seem an inch too low, especially when raising the seat.

Bottom line, it's a decent bike for the $$ for an occasional rider.

Get kenda kross plus 26" 1.95" tires with Mr tuffy liners 1.90 or 1.95 and a bell honey comb gel seat I have a schwinn same bike and love it I don't know if that seat is sold at Walmart anymore but you can get it on ebay also as the owners manual say keep it oiled I use mine for commuting getting back and forth to work and just to ride so I make sure I do the regular mantnance

For the kind of cash you are looking to spend, in all honestly I would invest in any gear that would help you to get out and ride it more. On that respect I'd say a set of lights, a backpack and some waterproofs. The best bike in the world is the one you have in your shed because you can get out and ride right now, you can't do that with a dream. If you get the bug, excellent, outgrow your bike (in terms of your demand of it) and upgrade.