Is it a bad idea to buy a used bike that is somewhat expensive ($1000 range) if you don't know much about bike mechanics? Of course you can find a checklist online of what wear/damage to look for, but is it better to buy a new bike if you are not an expert in looking for this kind of stuff?

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    As it is usual with going into a new technical area, the best thing is to take an expert with you. Find someone who knows a thing about bicycles, and use their judgement until you develop your own. Commented Sep 2, 2021 at 10:34
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    Buying a used bike for $50 is a good idea. After a year or two you'll figure out whether you should get something pricier. Commented Sep 2, 2021 at 14:20
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    @DanielRHicks: I’m not too sure. Riding a bad bike is a good way to start hating not just the bike but riding a bike as a whole.
    – Michael
    Commented Sep 2, 2021 at 16:39
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    I agree with @Michael, we bought my wife a cheap bike to see if she'd enjoy cycling. She didn't, the bike was heavy, shifts were rough, our longest ride together was 25 miles and after 6 months she stopped using it. Then I bought a used carbon fiber bike with much better components from a friend -- the wife loved it and 6 months later we did our first century ride together. I'm not saying go all in with a $4000 brand new bike, but I wouldn't start with a cheap $50 bike either.
    – Johnny
    Commented Sep 2, 2021 at 21:29
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    @whatsisname if the seller stole it or if you enough knowledge about bike mechanics to make up for the difference between $50 and the actual value of a good bike ;) . If you live in a rich country, like Switzerland or Austria, you may find people selling nice, unused bike from 10/15 years ago for 50 local bananas, just to free up some space from the garage.
    – EarlGrey
    Commented Sep 3, 2021 at 4:36

3 Answers 3


I don’t think it’s a bad idea, but be prepared to repair stuff.

Things even a novice should be able to check:

  • Frame and fork without damage (i.e. no cracks or dents, nothing bent). Small paint chips or scratches are okay.
  • Shifting to all gears works.
  • Braking works.
  • Wheels are true, no damage to the rim or spokes.

This ensures that the most expensive components are in fairly good shape. You might have to replace a few wear parts sooner or later.

Things you are likely to miss:

  • Drivetrain (most likely the chain) is worn. A new chain costs ~20€. Cassette and chainrings are more expensive but last >10Mm.
  • Cables+housing are worn and have high friction. New cables cost ~20€.
  • Bearings are worn or have play. Greasing&adjusting is free but new bearings (or new components) can be a bit expensive.
  • Brake pads are worn (or bad). New ones cost ~20€ (per set).
  • Tyres are worn (or bad/inappropriate for your use). Check for a tread wear indicator (TWI) mark. New ones cost 15 – 40€ (per piece).
  • The braking surface of the rim is worn down. Only applies to bikes with rim brakes. This is the most expensive wear part since it requires you to replace the rim and rebuild the wheel. Sometimes it’s easier and cheaper to replace the whole wheel. Some rims have a wear indicator otherwise it’s hard to check how much braking surface is actually remaining.
  • Suspension has excessive play (if the bike has suspension). I don’t know enough about mountain bikes to comment on this.
  • Per Adam’s comment: Old or exotic components which can be hard (or expensive) to replace if/when they break. Unconventional wheel diameters on vintage bikes come to mind.

Edit: Oh, one thing I forgot, which is actually the greatest risk:

  • The bike doesn’t fit you (wrong frame size) or is totally unsuitable for what you want to do. For example if you bought a full suspension mountain bike or a city bike but actually want to ride quickly and efficiently on smooth roads. In that case you can really only sell it on and hope you don’t lose money.
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    It could be a good idea to buy a chain checker (cyclingtips.com/2019/08/bicycle-chain-wear-and-checking-for-it) before going check the bike: if the chain is worn out, it is very likely that the rest of the transmission has suffered and you might have to replace more after having replaced the chain (cassette and maybe chainring). A worn chain wears the cassette fast, and you might have shifting problems or jumpy chains if you install a new chain on a worn cassette (or chainring).
    – Rеnаud
    Commented Sep 2, 2021 at 10:19
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    @WeiwenNg: Serious question: How much is “visibly”? If you can measure rim wall thickness, how much is sufficient? I can’t find conclusive answers on the internet. I’ve seen photos of brake surfaces which were literally worn down to nothing.
    – Michael
    Commented Sep 2, 2021 at 12:00
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    @Michael mavic say replace the rim when there is 1mm or more concave against a straight edge held accross the rim track. Source: mavic service centre. Applies to mavic rims!
    – Noise
    Commented Sep 2, 2021 at 12:18
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    Some rims will have a wear indicator, either as a continuous line around the rim or a small circle in the brake track. Not all rims have this, but the ones that do make it much easier to tell when they are worn out.
    – Kibbee
    Commented Sep 2, 2021 at 12:23
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    Depending on the age of the bike, there may have been a generational shift in one or more standards, or it may use an orphaned technology, either of which could make maintaining the bike more trouble. A knowledgeable friend who can look over the spec sheet will probably be able to catch this kind of thing.
    – Adam Rice
    Commented Sep 2, 2021 at 14:38

Rule of thumb: if you are an expert, you may be able to buy for 50 what is worth 200/500/1000, your experience will make up for the 150/450/950 gap.

If you are not an expert, you will for sure buy for 1000 what is worth 100/200/500. You will learn experience points worth 100/200/500. And you will lose a lot of money.

Yes, you may be lucky buying a good second-hand bike for cheap, but it boils down to three possible paths:

  • being lucky (what's the last time you won the lottery?)
  • being a bit naive and buying stolen stuff without understanding it (and now that I told you, you cannot anymore be naive saying "I didn't know about that" ... hey, your fault, asking questions on the internet you will grow up a thick skin :D );
  • knowing your market, either having experience in the mechanics of bicycle or knowing where rich/middle-rich people of your region sell their used stuff when they need space in the garage.
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    yes I need to find a doctor selling his little bikey
    – Lightsout
    Commented Sep 30, 2021 at 22:23

Another potential risk with buying a used bike is that it can be tricky to tell if you fit the bike (or if it can be made to fit you by changing the stem length/position and possibly the handlebar). If someone is a novice, I'd recommend not doing this unless they can get an experienced friend.

The possible pitfall of relying on an experienced friend is that experience with cycling is no guarantee that they are good at elementary bike fitting. I could probably help someone fit a performance or endurance road position, but I'd be a lot worse at a more relaxed drop bar bike position or anything to do with flat bar bikes.

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