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I'm a poor student and I bought a used bike. I don't have experience with bikes and I want to make sure that the bike is safe for me because actually I found the bike in a garbage container and the owner offered to sell it for 15 euros. Now I really need to be sure that it's safe!

I saw some videos on youtube to understand what gears are and so on and I found that the gears are working and the chain is switching correctly between the chainrings and the cogs. I also checked the breaks handles and I saw that the bike stops correctly when I press them. The rear breaks need a little adjustment to better stop the back tire.

The only thing I did so far is cleaning the bike. Actually I'm so happy about it that I go outside every few minutes just to look at it. I never had a bike when I was a kid but I know how to ride them :). But anyway back to subject!

Here are what I'm planning to do:

0- One of the breaks handles are not so tight, so it is safe to leave it?

1- Remove the rust from the chainrings, cogs, screwdrivers and other parts. (actually i have no idea how to do that and no idea how to do that in a cheap way, so I posted a question Restoring the original color of metal and chainrings)

2- Change entirely all the cables in the bike because I found them rusty.

3- The tires are completely damaged and I need to fully buy new ones. This is the most expensive thing ever to me since I realized I need to spend 25 euros on that.

So that is basically what I thought of for safety check but I wonder if there are other stuff I need to check or buy/change.

Here are some pics for my bike:

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More pictures here: Painting a bike with minimum cost

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No time to write a proper answer, but as for safety, make sure it is solid. Tighten up the cable slack on that brake, inspect all of the welds to make sure it isn't cracked anywhere, check the tightness of the headset (see Google for this), check for any loose bolts/nuts, check air pressure and most of all; make sure the brakes actually stop when going down a hill. I can tell you right now that the rear tire is toast. Get a new one. – canadmos Jun 8 '14 at 20:51
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To add to that, the rear brake cable looks frayed. I would replace that cable. The brakes and tires are two (three?) of the most important things to not neglect on a bike of any kind. – canadmos Jun 8 '14 at 20:54
    
The rust is pretty much just aesthetic - I wouldn't worry about it. By the time it becomes a problem, you won't be a student anymore. I'd probably also outfit new pads just to be safe. – Batman Jun 8 '14 at 21:03
    
Adjust the brake pads to make sure they don't foul on the tyre. The rear tyre sidewall is really torn up; I reckon the brake pads have done that. – headeronly Jun 8 '14 at 22:34
    
@headeronly: Good advise, although I have seen exactly the same failure from very old tires (these tires are possibly 25 years old now). – mattnz Jun 9 '14 at 0:36

By far the most reliable way is a visit to the Local Bike shop, find a smaller one with lots of kids bikes and entry level bikes (They know about tight bidgets). It should take less than 5 minutes for them to give you a quick assessment of what needs to be done to make it safe, and most will happily do the assessment for free (especially given they will get a sales of at least 2 tires and tubes)

Tires and tubes - replace.

Wheels - remove from bike and check bearings, adjust if required. If noisy not really a safety issue, but if too loose it is. Check rims for wear from brake pads and big dents. Check spokes for tightness. Check where spokes go into rim for cracks. Ensure the QR levers are tight (They should leave a dent in your palm when you press down to do them up). Check wheels to ensure they are true (Wobble from side to side or up and down) - only a safety problem if the brakes cannot be adjusted tight enough.

Brakes - Adjust so they are tight. Check pads for wear. Lube cables and replace if budget allows. Frayed rear brake is not a safety issue unless the tension side is frayed.

Seat - check seat post is tight and seat bolted on to seat post.

Steering / Handlebars - are all attachements tight (stem, handbars, brake levers and shifters). Do the handles bars turn freely and without play in the head.

Bottom bracket/Pedels - do they spin freely and smoothly without play. Listen for creeks and grinding noises. Look for cracks and damage to the cranks.

Frame - look for visible cracks - its steel so sudden failure is not likely. Go for a ride and jump up and down a few times, listen... Pick the bike up and drop it onto its wheels from about 300mm. Listen to the bike for rattles, squeaks etc. Some are normal, but it can give away a lot.

Rear derailuer and shifters - not really a safety issue unless the chain jumps off and jams. , but do read up how to tune it. Make sure the chain stays on the cogs.

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I'm always worried that the chain could break down (split) because the bike is old. I'm not sure if this is the case here or not. But do you think the chain is a safety issue? – Jack Twain Jun 9 '14 at 9:00
    
Chains can and do break, and more so when old. However its usually due to factors other than just being old - bad gear shifts under excessive load are the main cause I have seen. If concerned, a replacement chain would be advised as its not nice when they break, especially for boys..... – mattnz Jun 9 '14 at 20:25
    
what do you mean by not nice especially for boys? what happens?!! – Jack Twain Jun 9 '14 at 21:12
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When the chain breaks, the pedals suddenly have no resistance, the pedal with pressure (Usually a lot) suddenly rotates downwards, the leg and attached body above the leg follow and tend to keep going down. The frame has a cross bar that stops the body going down.......... – mattnz Jun 9 '14 at 21:51
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Labial and clitoral bruising hurt, but not apparently as much as testicular and penal (?) bruising. – RoboKaren Jun 13 '14 at 17:03

Basic used bike checks:

  • Look at the bike. Look for obvious signs of damage (bent rims, etc) and for any cracks in the frame. With an old steel frame cracks are rare and you're really only looking for a broken frame from being run over or whatnot, but with newer aluminum and carbon frames one must check very carefully.

  • Examine the bike for rust. A rusty chain is a clue that the bike has been stored in an unprotected area for a prolonged period of time. It may be a decent bike, but will need significant rehabilitation before riding. The same can be said about significant amounts of rust elsewhere, though a spot of rust here and there is not a concern. Except that if the cables are rusty then they will likely need to be replaced.

  • Examine the tires. In particular, if the tires have been sitting flat for a long time you will tend to see a permanently flat spot. Check the sidewalls of any such spot for cracks, and also examine the sidewalls generally for cracks or for rubber peeling off. Such signs indicate that the tires will need to be replaced, though that is not "fatal" -- it's just something you must plan on.

  • Check the wheels. Check the spokes by "walking" around the wheel with you fingers, squeezing every adjacent pair of spokes to see if they are reasonably tight. Broken/missing spokes will need to be replaced. Excessively loose spokes will need to be tightened, and the wheel trued.

  • Continue checking the wheels. Spin each wheel and observe its outer perimeter from end-on (vs from the side). Observe, as the wheel spins, whether it seems to wobble back and forth relative to the frame and brakes. A little such wobble is OK, but very much (enough to affect rim brakes) will require that the wheel be "trued". Also look for up/down movement of the tire -- a small amount is OK, but too much (especially if it's caused by the rim and not how the tire is mounted) is not good.

  • Finally, grasp each wheel by the edge and attempt to "wobble" it left-right. You should feel no looseness in the bearings. And spin the wheel and let it go -- it should spin freely. Problems here would be due to either bad bearings or problems with the brakes.

  • Squeeze the brakes. Make sure the brake levers operate fairly smoothly. Watch to see that the brakes smoothly open and close as the levers are operated, and that the cables are not sticking. Sticky cables can be rectified, but it either requires replacing the cables or working with them for a good 10-20 minutes to work lube into them and get them to slide freely.

  • With both wheels on the ground, squeeze the front brake and push the bike forward/back. This will allow you to detect looseness in the headset bearings, as the fork "rattles" in the bearings. A little looseness is OK, but too much will require that the headset be serviced.

  • With the bike sitting on the ground, grasp each crank arm and try to push/pull left/right, feeling for any looseness in the connection between the crank arm and the crank axle, or for any looseness in the crank axle bearings. Looseness in the crank arm connection to the crank axle is especially bad, as it likely means that the crank arm (where it fits onto the axle) has been damaged beyond repair. Some looseness in the crank axle is OK, but should be corrected before the bike is used much.

  • Ride the bike. Take it around the block or ride around in a parking lot. Try the brakes. Either front or rear brake, used alone, should be sufficient to stop the bike in ten feet or so from a modest speed (6-8 mph). Both brakes together should be able to do it in five-six feet. (A fail here may mean the brakes only need minor service, or it may mean the pads are shot, the cables are shot, the calipers are hosed, etc. Hard to predict which.)

  • As you continue riding, try the steering. The bike should be reasonably stable and responsive, with no tendency to pull to one side or the other, and no hint of shimmy or jitter. (Problems here suggest either a serious problem with bike fit or a bent or broken frame or fork.)

  • Try out the gears. Shift through the entire range, as well as you can on your "test track", and make sure they shift reasonably smoothly and reliably. But the criteria here are highly personal -- some people can't tolerate the slightest problem with shifting while others are just happy if the damn thing shifts at all. It's up to you to evaluate.

  • While you're riding, consciously feel the motion of the pedals under your feet. A bent crank arm will make the pedal seem to rock back and forth (left/right) as it turns.

I probably forgot something, but that's a start, anyway.

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It's a very inexpensive department store bike. I wouldn't put too much money into it except for a good lock. Even new tires would cost half as much as it's worth.

The nice thing about it is that most bike thieves will also recognize it for what it is and won't steal it, if you have a halfway decent U lock on it.

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Not sure what countries XT equipped bikes are considered "....very inexpensive department store bike.". – mattnz Jun 15 '14 at 4:26
    
walmart.com/ip/… – RoboKaren Jun 17 '14 at 5:04
    
yeh, so what. The OP's bike is NOT a walmart bike. Its a good condition mid range Scott Sawtooth circa late 80's, probably with upgraded components. – mattnz Jun 17 '14 at 6:25

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