Buying a used road bike as a commuter bike. What to look for, what you can get for $100 on Craigslist.

When most people say they want a road bike, they mean a bike with the curly, drop handlebars, and fast skinny tires.  Some cost $50.  Some cost $10,000.  What's the difference?

The main factors that will influence your bike choice are:
your budget
your size, how tall you are, what size bike you need.
Your riding style, how hilly your area is, how far you need to ride, how hard you want to pedal.

Someone that is riding 2 miles, on flat terrain, mostly in the dry does not need as fancy a bike as someone that rides 10 miles, with hills, to get to work or school, raining or not.

Some road bikes are race bikes.  That only take very skinny tires and have hard, fast gearing.
Some road bikes are touring bikes or cyclocross bikes, that take fatter tires and fenders, have wider range gearing, and fit racks to carry stuff.

Under a $100, your options are limited.  Your best bet is to find a 1980's japanese touring bike or road bike.  Univega, Bridgestone, Nishiki, Miyata, Centurion, Shogun, Fuji are good brands to look for.  These are higher end 10 speed brands, and realistically go for $200 most of the time, but sometimes you can find deals on CL.  Trek made good american bikes, and Raleigh good british bikes.  I hesitate to recommend french road bikes, like Motobecane or Peugeot, or most Schwinn 10 speeds, but that is another topic.

Here's a good example of a $100 japanese 10 speed.

This is a 58cm, Nishiki Royale.  Pretty sure it's a 1981.  This would fit someone 5'10"-6'0" pretty well. This was a $330 bike in 1981.  Not super high end, but good quality bike.  It has a cromoly frame, made in Japan.  Though the tubes are not particularly light, and it does have a high tensile steel fork.  Ideally, you'd want to get a bike with cromoly steel fork, but at $100, you can't be too picky.
It has 27" wheels, which take up to 1 1/4" tires.  Current road bikes have 700c wheels.  :/  The bigger, 27" wheels are a bit heavier, than smaller 700c, but roll over bumps easier, and fit fatter tires and fenders more easily than a lot of 700c bikes.
It has a 10 speed drive train, 2 gears in front, 5 in the back.  The gearing is pretty hard and fast.  Not really any super low, easy hill climbing gears.

The 27" wheels have aluminum alloy rims, made by araya.  They are singlewall, but better quality than what is available new in 27"

The tires do look old and dryrotted.  The best thing you can do to any inexpensive $100-300 bike, new or used, is replace the tires, with high quality, flat resistant tires.  Being late to work or school because of flats gets old.  Sitting on the side of the road fixing flat in the rain, when you just want to be home, is not fun.  Spending $20-40 a tire on good rubber is worth it in the long run.
The schwalbe HS129, $16, is the best affordable choice.
http://www.schwalbetires.com/bike_tires/road_tires/hs159

Better tire for $30 each, is the Panaracer Pasela PT.  It has kevlar belt for flat protection, and is much lighter, 390g, vs 550g for the cheaper schalbe.  It also has nicer tire casing, that has a more supple ride.  Pasela is a faster, better riding tire, and has good flat protection.  Would be my choice.
http://www.niagaracycle.com/categories/pana-pasela-pt-tire-27x1-1-4-steel-bead

The gears on the bike are 2X5, for 10 speeds.  52X40 in the front, 14-28 in the back. This bike does have suntour bar end shifters, which are pretty cool.  You don't have to take your hands off the bars to shift.  You do have to be "in the drops" to shift though.

Same shifters on a different bike.  These are pretty awesome shifters, IMO, super reliable, have very nice feel, and they sell for quite a bit on Ebay.
Most ten speeds from this era are going to have downtube shifters or stem shifters.
Downtube shifters:

Higher end bikes usually came with downtube shifters.  Bar end shifters were more rare, and usually came on more touring type bikes.
Stem shifters:

These are actually way more convenient to use than down tube shifters, you can reach them from the tops of the bars, but at this time, they were seen as for beginners, and that serious bike riders could take their hands off the bars.  So most bikes with stem shifters, are lower end, beginner bikes from this era.  With heavy, soft frames, and cheap parts, and should be avoided.
It should be noted, that stem shifters are very inexpensive, and is pretty much the cheapest way to convert an old ten speed with downtube shifters, to get the shifters up to your bars.
The 2X5 gearing on bikes this old, is not very wide.  52X14 is your top gear.  40X28 is low gear.  Modern bikes with triple rings or compact cranks will have 34X32 low gear, maybe 4 or 5 gears lower than old 10-speed.
Also, old bikes like this, have old fashioned chains and cog tooth profiles.  Shimano came out with HG technology chains and cogs with cutaways, that make shifting way smoother, and chains quieter and smoother, in the late 80's.
One of the best things you can do for an old 10-speed is replace the chain and freewheel. $8 for KMC chain, $15 for shimano freewheel.  $25 to make your bike shift way smoother, and better under load, and increase your gear range is pretty good.

If the distance between the smallest cog, and the dropout, the distance between the two red lines, in greater than 13mm, 1/2" or so, you have enough room to put a 7 speed freewheel on.  5 speed freewheel is usually about 25mm wide, 7 speed is 32mm.  Plus about 5mm for clearance for the chain and dropout.

I am going to show you a crappier 10 speed, for comparison to the nicer quality bike, so you know what to avoid, and what to look for.

This is a cheaper bike.  It has cottered, steel cranks, heavier, and more prone to coming loose and creaking than aluminum cranks.  Steel rims, heavier, and much worse braking than alloy rims,  And lower quality hi-ten frame and fork.  The stem shifters and brake levers with "suicide levers" are also indicator of low quality of the bike.
Poor quality steel cottered cranks:

One other weird thing about french bikes in general, motobecane, peugeot, is they have french threaded bottom bracket shells.  The tube in the frame the crank spindle/axle goes thru.  Most current bikes, and all japanese and english bikes, have english threaded BB shells.  And parts are readily available, starting at $12.  French bikes, there is one option, and it costs $60, and you have to special order it.  Some french bikes have oddball freewheel and headset/stem sizes as well.  French bikes are much more likely to cause you issues with parts availability and expensive parts than other bikes.

Better quality aluminum cranks on the Nishiki.  These are not super high end, decent quality bike:

This is what cheaper, heavier, steel rims look like, notice the shiny chrome finish:

vs. ligher, better alloy rims.  Softer gray, brushed finish.
You can also see higher quality fork lugs, frame lugs, and paint of the midrange Nishiki:

vs. the cheaper in it's day motobecane:

Another give away of a lower quality bike, is stem shifters and suicide levers:

Getting back to the Nishiki.

So you've got your $100 japanese 10-speed, and have put $30-60 worth of good tires into it.  It's pretty fast and smooth riding, but the brakes don't work that great, and the shifting is kinda clunky and loud, and doesn't have very low hill climbing gears.

The brake levers on this bike, don't have rubber hoods, have exposed cables, and not that good leverage.  Modern brake levers would be a big upgrade, both in braking power, and ride comfort.

$23 Tektros work.  Shimanos are $30, or you could look around for used nicer ones.

The brake calipers on the $100 Nishiki, are aluminum, single pivot, Diacompe 500's,  A decent quality brake in 1981.

However, modern, shimano dual pivot brakes are much stronger, and easier to adjust, and cost $15 per side, hardly more than the $8-10 new brake pads cost.  The main thing you need to make sure you get right, when ordering new brakes, is the caliper reach, that is, the distance between center of bolt the mounts the brake, and center of the brake pad where it hits the rim.  There are 3 differnet sizes, short, medium, long.

Pretty sure this nishiki needs short, 39-49mm reach brakes, like this $15 Shimano Soras.

http://www.nashbar.com/bikes/Product_10053_10052_583012_-1___204965

To me, having brakes you can depend on for ~$50 is worth it.  Plus more comfy hoods, where you spend most of your time riding.

The best old 10 speed brakes are the type like this mafac racers.  Weinman and Diacompe also made similar brakes.  These are quite strong, and new brake pads will have them working about the same as new dual pivots.

Lastly, is the gears.  The old fashioned teeth on freewheel and old style chain, make a racket, and shift poorly.  Just putting a $8 KMC Z50 chain on will make a big difference.
Putting a $13 shimano freewheel on, with HG shift cut outs, makes shifting WAAAAY smoother.

This is the gear ratio chart for the stock 52/40 X 14-28 gearing.  7.5% top gear.  2.9% low gear.

This what the gear ratio chart for a current road bike, with 50/34 compact crank, and 11 speed 11-32 gearing looks like.  There are 3 easier gears, going to down to 2.1% low gear.  And 3 harder fast gears, going up to 9.2%  And the jumps between gears is smaller.

You can add gear range to the old 10-speed, pretty inexpensively.

Cheap Singlespeeds. SS $100 bike, $200 bike. Walmart thruster. 6KU fixie. Bikesdirect Dawes Streetfighter SST

Singlespeed bikes.  The simplest type of bike.  If you live somewhere flat, hate maintenance, and like to pedal hard on hills, these are for you.

DON'T get a $129 walmart Thruster!!!

It's a pile.

The cheapest, decent quality singlespeed  is the $200 6KU.

The frame and fork are high tensile steel, which is a bit heavy, but is quite durable.  The wheels are nice, with super strong deep V rims, and good hubs.  The fork is threadless.  It fits fatter tires and fenders.  The cranks are pretty nice.  This is a good bike for $200.

There are even are a ton of frame and wheel color combinations to choose from, too.

http://www.citygrounds.com/fixed-gear-single-speed-bikes#brand=6ku

The main crappy things on this bike, things to upgrade to make it a more durable commuter.  Are the freewheel, it has junky chinese one that will fail.  The freewheel is the gear on the back wheel, that coasts and makes the clickity noise.  Good quality  ACS, Shimano, or GT ones are $15-25 dollars.

And the tires.  Good quality, flat resistant tires are key to a bike you ride everyday.  Continental gatorskins, Schwalbe Marathons, and Panaracer Paselas are all good tires, between $30-40.

At $230, you get the Bikesdirect Dawes Streetfighter.

This bike has a cromoly steel frame and fork, which is lighter and stronger, better quality.  Realistically, most people won't bend the hi-ten 6ku frame, and it is maybe 2 pound difference.  But the streetfighter is definitely the better frame. 

The tires and freewheel still need urgent replacement.  The seat, seatpost, bars are a bit junkier than the 6ku.  Not a huge deal, as these are parts many bike riders will replace anyways to make their bike fit better and more comfortably.

The $230 Dawes SST is similar bike, except with drop bars

Bikesdirect Motobecane Mirage SL $450 STI 700c road bike

Bikedirect bikes.  Loved and hated.

The Mirage SL is the cheapest road bike I would consider from bikesdirect. If you live in an area that has a good used bike marketplace, you can likely find a better quality, barely used bike.  Good brands to look for are trek, giant, specialized, trek.  Search craiglist from $250-500.  Post up what you find on https://www.reddit.com/r/whichbike/ and bike nerds will give you advice,

If you like somewhere with a poor used bike market, the $450 mirage SL might be your best option for a road bike under $500.
http://www.bikesdirect.com/products/motobecane/road_bikes/mirage_sl.htm

This is a bike shop quality bike.  From the aluminum frame, to carbon fork, to beefy wheels with cassette hubs. Shimano Claris STI shifters with 2X8 , to FSA compact 50X34 cranks, this is a current, decent quality road bike.  It compares favorably to bike shop bikes costing $700-800.  For example the $770 Trek 1.1

Sure, the tires, bars, and seatpost are a bit nicer on the Trek, but those are things you might change anyways.

One big advantage of the bike shop bike, is that it is assembled and adjusted by someone who knows how to work on bikes, and uses proper lubes.  This makes a huge difference!  If you bring your BD mirage SL to a bike shop, to have them put it together and adjust it, expect to pay $50-75 labor, and it's worth it!  If you are mechanically inclined, and willing to invest $25 or so in tools and lube, and willing to do a little research, you can do it yourself.  Mostly putting on the front wheels, pedals, handlebars, seat as far as assembly goes, pretty easy.  Adjusting the gears, and brakes, and truing the wheels is a bit trickier.  You will need: good bike chain lube, like triflow or prolink, grease, car bearing grease or white lithium is fine.  Metric allen keys.  Cable cutters.  Eventually, you'd want a chain tool.

Unlike other budget options, like department store bikes, this bike comes in many size options, so you can get a bike that fits you if you are tall or small.

The main cruddy thing for a commuter on the motobecane, are the poor tires.  They get flats easily.  Two of the more popular, fast, flat resistant commuter road bike tires are the continental gatorskins, and the Panaracer Paselas.  Gatorskins start at $40, Paselas for $30 for the PT puncture resistant ones.
This bike can fit up to 28c wide tires, 23c would be super skinny, 25c in the middle.  Fatter tires will be more comfy, and less prone to flats, if slightly slower.  Most commuters run 28c or fatter.

Other wise, it is a good bike, and should wake up call to people that try to sell 90's STI roadbikes that aren't particularly fancy or special for more than $400.

One thing about this bike, and road race style bikes in general, is that is has low profile brakes, that make it tougher to fit fenders, or mud guards.  And make it so you have to run skinnier tires, 28c max.  And 25c if you want to run fenders.   Hybrid, touring, or cyclocross bikes let run have fatter tires and fenders.

This bike is good for someone that wants to get into roadriding, or needs a very fast, efficient commuter for long distances, and is willing to give up some comfort.  The best upgrade you can do to this bike is new tires.

26" Schwinn Sidewinder $149 26" mtb, shimano 3X7 gears.

This is the best bike you can get at walmart for $150, if you are a medium sized person.  Every magna, roadmaster, mgx, huffy, next bike that is cheaper than this is a total piece of garbage.  This bike is actually serviceable, functional, and worth fixing.

The Schwinn Sidewinder is a 26" wheel mtb, with 3X7 shimano parts for 21 gears.

It's parts are pretty decent:

Shimano tourney 3X7, derailleurs and grip shift shifters.

Alloy linear pull brakes and levers.

Wheels with alloy double wall rims and alloy hubs.

It compares pretty favorably to a Trek 820, $380 bike shop quality bike.

http://www.trekbikes.com/us/en_US/bikes/mountain/sport/820/820/p/1008600-2016

The gears, wheels, brakes are the same.  The trek does have better tires, thread-less fork, nicer bars, seat, post.  And it comes in many sizes.

This gets to the main thorn with the walmart bike.  It only comes in one size, 17", or medium, good for people 5'7"-5'10" about. If you are shorter or taller, you are out of luck

The bike shop bike has 5 sizes, XS, S, M, L, XL.

Also, the bike shop bike is put together by someone that knows how to assemble and adjust a bike.  This makes a huge difference!  If you took the Walmart schwinn to a bike shop to have them assemble/tune the bike so it works right, labor would likely be $50-75, and worth it.  That said, bicycles are not rocket ships, and someone with good mechanical aptitude, and willingness to do some research and buy $25-50 of tools and lube can do a good job.

The main crappier parts about the Schwinn is the threaded fork and stem.  And crappy suspension fork.

The handlebars and seatpost are also heavy, cheap steel, where the trek are aluminum.  

Neither of these are that noticible to basic commuter bike rider.

The tires are a weakness.  The stock tires get flat easily, and wear out fast.  Replacing them with flat resistant tires would be a huge upgrade for someone using the bike to get to work.  The knobby tires roll slow on the road.

$13 Panaracer 2" touring tires are a good choice

http://www.niagaracycle.com/categories/tires-pan-tour-26x2-0-wire-bk-bk

Otherwise, just use the bike til stuff breaks.  Most likely things you are likely to run into issues with are the chain. $7 KMC Z50 chain http://www.niagaracycle.com/categories/kmc-z50-chain-6-7-8-speed-1-2-x-3-32-x-116l-silver-brown

Seatpost.  Check the stamp at bottom of post, likely 27.2mm, and get alloy Kalloy seatpost, around $20.  

For people that are not medium sized, or people that live in areas that have good used bike markets, a used 90's MTB from Trek, Giant, Specialized, Cannondale, etc, for less than $150, is a better deal.

Mongoose Stat 29" disc, $219

http://www.walmart.com/ip/29-Mongoose-Stat-Men-s-Mountain-Bike/21191093

Mongoose Stat
-Aluminum frame, size 18"
-29" wheels, fast rolling, comfortable, good selection of tires
-disc brakes.  More consistent in wet weather.  The brakes don't wear out your rims, like rim brakes do.  Brake pads and rims last longer with disc brakes.

Is the stat a decent bike?  It sells for $220, and has been on sale for as low as $160.

The aluminum frame is pretty good quality, and has some nice details, especially for the price.  It has a common 1 1/8" headtube, 68mm euro bb shell, 27.2mm seatpost.  It comes in one size, 18".  Good for 5'8"-5'11" riders.

The fork is a very heavy, cheap, steel suspension forks.  This is one of the worst parts of the bike.  The good news is that it is 1 1/8" threadless steerer tube, the most common size.

A chromoly steel rigid fork would be a good replacement.  This is simpler, lighter, no maintenance, easier to fit fenders.  You don't want shocks on a commuter bike.
This $50 Nashbar fork is a good choice.  Axle to crown: 453mm.

The Stat uses 1 1/8" stem, with 25.4mm handlebar.  These are the most common sizes.  Easy to swap out different styles of handlebars, or different length stems.
Stems are <$20
Bars are $15-35 depending on style.

The wheels use Quando aluminum quick release hubs, F&R.  It uses a freewheel in the rear.  Double wall 29" aluminum rims.  These are pretty nice wheels.
The tires are cheap, knobby tires.  They roll slow, and get flats easily.  Faster rolling, more flat resistant commuter tires are the best change you can make to this bike.  Continental, Michelin, Vittoria, Rubena make nice 29x2.0" fatty city tires for around $20-30 per wheel

29" rims and 700c rims are the same diameter, and their tires are usually interchangeable.  Both 29" and 700c rims have the same 622mm ERTO diameter.  29" rims tend to be wider to work with fatter tires.  700c tend to be narrower to work with skinnier tires.
29" tires are measured width in inches, for example 2.0".
700c is by "c", bacially mm's.  23c= 23mm very skinny.  You can fit fatter 35c and up tires on 29" rims.

These Schwalbe 700 X 40c tires are a bit narrower and faster rolling.  40mm is about 1.6" wide, so they still have some cush.
$25 for the pair is a great deal.

Fenders are another thing to think about when choosing tires.  There are not that many fenders available for fatty 29X2+" tires.  The Planet Bike Cascadia fenders are an excellent choice, but pricey at $45.

More common sizes are 700X45mm fenders, $23.  These only fit smaller width 700c tires, 44c or lower.
Going this route, you are under $50 for good tires and fenders.

The Promax cable disc brake calipers are not terrible.  One bad thing is their brake pads are not commonly stocked at bike shops.

Replacement Cheap brake pads on ebay

Better brake calipers, that take commonly stocked brake pads would be a good upgrade for this bike.
Avid BB-5., $33  These are good brakes and brake pads are readily available for them.  The are better constructed, and easier to adjust.  The promax's are not bad, though.

The brake levers have a plastic body, with an aluminum lever blade.  They work, but they are flexier than levers with an aluminum lever body.  The cables and housing on the bike are poor quality.  Better levers and cables would really improve this bike.
Shimano Acera levers, including cables & housing, $14

The 3 X 7 speed SRAM grip shifters are good.  The shift cables & housing on the bike are poor quality.  Shimano, SRAM, Jagwire make good shift cables & housings.

Shimano Tourney derailleur.
7 speed freewheel & chain.  Drivetrains usually last about 3000 miles.  The replacement parts for this bike are very inexpensive.  The chain and freewheel on the bike are cheap chinese.
The 7 speed freewheel costs $12 to replace with good quality shimano one.
Better quality SRAM chain is $8.
This bike has one of the most affordable drivetrains to replace.

The cranks are chinese, aluminum arms, with stamped steel rings.  They are not light, but they are durable.  The bottom bracket is euro threaded adjustable loose ball.  Replacement shimano cranks are around $40, and bottom brackets around $20.  Though I would expect the cranks to last awhile.

The pedals are pretty nice aluminum BMX pedals.  Most walmart bikes have janky plastic pedals, these ones are good.

The seat and post.  The quality of the seat is not terrible, but it is heavy and has a really tacky cover.  It is one of the cheapest looking things on the bike.

The seatpost is a cheap "seat guts" style post.  These are heavy and prone to creaking and slipping.

 A 2 bolt Kalloy 27.2mm seatpost would be a good upgrade for <$20.

Kalloy 2 bolt aluminum seatpost $14

Singleworks city limit, leather, $20

Overall, the bike is not a bad choice for a commuter.  The worst parts are the tires and fork.  The brakes would be better with quality levers and cables.  Decent seat and post would save weight, look better.
Tires= $25
Fenders= $22
-------------------
Fork= $50
Levers= $13
Seat & post= $34
$144 total.