I’m hoping to buy a used bike for ideally 200 Euros and make it a hobby project to keep investing in the bike piece by piece to make it a nice bike, upgrading one component at a time when I can afford it and installing it myself.

Are there limitations on the extent to which a cheap bike can be upgraded? Can I put really nice hydraulic brakes on a cheap bike frame? And the best gear shifters? Eventually, I can see almost everything being swapped out piece by piece except the frame; at that point, I could even consider changing the frame when I’m ready to.

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    Bike of Theseus Nov 7, 2021 at 19:24
  • What do you eventually want this bike to turn into? The ideal you're going to upgrade towards is very different for a road racer (where the goal is to drop weight and reduce rolling resistance as you upgrade) vs a commuter (where an ideal bike might have an internally-geared hub and a belt drive for reliability, ease-of-maintenance, and cleanliness). A lot of component choices are driven by the frame, either way (and what frames you can use can be determined by which components you already have on hand and want to reuse). Nov 8, 2021 at 22:59
  • @whatsisname And in comedic form: "This is a very old axe, it belonged to George Washington. I had to replace the handle, and the head." (Michael Davis Ford's Theater part 2 when he entertains a crowd of politicians. OT but highly recommended.) Nov 9, 2021 at 0:00
  • Bolting Ferrari wheels to a Lada don't make it a Ferrari.
    – Carel
    Nov 15, 2021 at 19:05

8 Answers 8


You’ll always be limited by the frame. And buying a cheap bike just to upgrade it is usually not cost effective.

The frame will always be heavy and bad. It will dictate what kind of headset (-> fork, stem), seatpost, wheels and brakes you can install. On old or cheap frames a quill stem and 126mm dropout spacing are still common which severely limits your upgrade options. If the frame doesn’t have disc brake mounting options you can’t install (hydraulic) disc brakes.

Edit: I should add that there are certainly scenarios where it’s possible and makes sense to upgrade a bike. Especially if you can combine maintenance and upgrade.

For example if you have an older trekking bike with a good frame but “only” Shimano Acera 8 speed groupset and rim brakes. After ~20Mm you’ll reach the point where you have to replace the second cassette and seventh chain. At that point the rear derailleur and chainrings also won’t be in great shape any more. So might as well replace the whole drivetrain and upgrade to a 10 speed Shimano Deore. When the wheels (rims, hub bearings etc.) are worn you can also replace them with better ones. But you’ll never be able to upgrade to thru-axle wheels, disc brakes, internal cable routing etc. etc. without changing the frame.

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    You can upgrade the frame. The problem with a fully modular upgrade system is deciding whether it's a new bike or the old one upgraded.
    – Noise
    Nov 7, 2021 at 17:29
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    @JoeK many component choices depend on the frame. In 2005 it would have been almost reasonable to expect that an entry level and high quality frame take the same wheels, bottom bracket, headset, brakes etc but any more.
    – ojs
    Nov 8, 2021 at 8:45
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    @ojs many frame choices depend on the components! A variety of wheels commonly use replaceable end caps therefore will go from QR to thru-axle and sometimes boost; Post mount brake calipers can fit flat mount with easy to find adaptors. Most other components really haven't changed, with derailleur systems still bolting on the same way and the huge variety of cranksets that are all compatible by different bbs with BSC thread, pressfit30, T47 etc.
    – Noise
    Nov 8, 2021 at 14:07
  • @ojs I appreciate the caveat "buying a cheap bike just to upgrade it is usually not cost effective." If we disregard cost effectiveness, then one could build anything (including an awesome bike) starting with a cheap bike.
    – emory
    Nov 8, 2021 at 19:26
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    "If the frame doesn’t have disc brake mounting options you can’t install (hydraulic) disc brakes." There were some early Aluminum frames with "disc and v-brake mounts" that had cracking issues with disc brakes on the rear. A disc brake puts a LOT of effort on a small part of the rear stays. Nov 9, 2021 at 8:35

If you want to go that way, you need to define "where you want to go" in terms of upgrades and choose a used bike that is compatible with these standards. Some research will also be needed to make sure that the components that you plan to buy can be reused in the future bike. For example: wheels (or hubs to be more accurate) that you find on older entry level MTBs are not compatible with frames of current mid-range MTBs. Some wheels are modular and can be used on frames with different standards, but it is something that has to be known before buying a set of good wheels. You'll learn a lot by taking this path, but the amount you want to spend is limited, the risk is somehow higher than maintaining your cheap bike, and saving the money you wanted to spend on components to buy a new one.

Also, upgrading piece by piece is also not always feasible: The most likely is that you'll replace sets of components rather than individual components, if you want significant upgrades. For example, an upgrade of the transmission will require you to replace the crankset, the chain, the cassette, the derailleurs and the shifters and the derailleur(s) — and in some cases the wheel too. Note that by upgrade, I mean significant changes: for instance, it would be to change a 3x8 (3 chainrings/8-speed cassette) by a modern single/double chainring (1/2x11/12). Replacing worn part by better ones of similar specs is closer to "maintenance" than to "upgrade" for me.

That being said: I see one case where this kind of reasoning can make sense: big manufacturers sell their bikes in series: you have the same frame sold with different levels of components. If you take entry level bikes (series ranging from 5-600€ to 1200-1800€), frames and standards didn't evolve a lot in the past years. So if you find a used "entry level" version of a series, you can probably upgrade it to something comparable to the current upper- or mid-version of the same series for a reasonable price, without too much hassle to find the components. This is mostly true for hybrid/trekking bikes and mountain bikes. If you are targeting road bikes and want disc brakes, it will be difficult to find an used entry level frame with disc brakes (it's still not obvious now).


I'd consider the "investing in the bike" as misplaced. You're investing in your own fitness, your mechanical competence and knowledge, as well as indirectly by growing your own tool collection. The bike itself is a means to an end, and some of it is consumable parts to use up and replace again.

If you can source acceptable used bikes then that can be a cheap/free source of parts. Many cities have recycling depots attached to dumps/tips where re-usable items are taken from the waste stream. Or you can buy cheap used bikes from craigslist/ebay/trademe/gumtree etc, being mindful of the possibility of stolen ones being fenced.

You do NOT need the latest lightest parts to make an acceptable working bike.

Yes you can put expensive parts on a low-average bike, and as long as you enjoy riding it, who's to complain.

Ultimately, the frame will limit you with the OLD, BB, and tyre clearances. At that point, you look for a better frame and move the good parts over.


Some economics:

  • A good frame costs around ~500-600 EUR. True, you can spend as much as you like because carbon fiber frames are available today but you don't need to. At that price point, there are plenty of good deals available.
  • A good bike built from parts (including the frame) costs around ~1500-2000 EUR depending on the level of equippedness you want to have -- more with fenders, pannier rack, kickstand, bell, front and rear lights powered by a dynamo, full set of reflectors, and less if you want nothing but just the bare bike.

If you buy a used bike for 200 EUR, you won't get a 500-600 EUR frame. Most likely you get a sub-50 EUR frame. Of course it's possible to do a really good purchase if someone has a good very old used bike with frame in good condition, but more likely occurrence is that you get the sub-50 EUR frame.

If you're planning to replace everything and build your own bike, I would instead buy the 500-600 EUR frame than pay 200 EUR for a bike with sub-50 EUR frame and over 150 EURs worth of used components that you're going to throw away anyway.

Best gear shifters? With rear derailleur attachment point in the dropout, and 130mm or 135mm dropout spacing (or if you're willing to cold set a steel frame maybe 120-126mm but it only works with steel frames) you may be able to install modern shifting. You still most likely need a new rear wheel though. If you can find an 8-speed (means 8, 16 or 24 total gears depending on the chainring count) used bike then the dropout spacing and rear wheel are probably fine already. So go looking for bikes with 8 sprockets in the cassette ideally and you may be able to get useful shifting already.

Really nice hydraulic brakes? Sorry but most likely no. Most 200 EUR used bikes won't have disc brake attachment mounts. They have cantilever bosses and either cantilever or V brakes.

Also consider frame geometry. The bike should optimally have frame geometry designed for the type of handlebars you want to use (so not a good idea to convert flat bar bike into drop bar bike), and the frame size should be right.

Most likely if you demand that there must be disc brake mounts, at least 8 sprockets in the cassette and correctly sized frame I can guarantee the number of used bikes you can find nearby is going to be zero. If you're very lucky then perhaps one but it may be more expensive than 200 EUR.

  • You should probably include 142mm in the part about dropout spacing. This has been a standard size on MTB for a number of years now and the OP didn't give an indication of preference for what style of bike they intend to build
    – Andy P
    Nov 9, 2021 at 11:10

I say go for it. A cheap bike, making sure it has modern dimensions, such as a threadless 1 1/8" steerer, can be a good place to start. Inexpensive bikes with pretty universal disc-brake mounts abound. The only real downside is that cheap bike parts tend to be fiddly and need constant adjustment.

There is one big jumping-off point though: don't spend too much on a bottom bracket, & consequently a crankset & chainring, until you have a pretty good idea of what you want your final frame to be. This is an area where price-point limits compatibility.

Just be aware that you'll probably end up spending more than if you just bought the bike you want from the start, albeit over as long a time-period as you want.

I have almost accidentally done just this over the past 10 years on a city/trekking bike. My aim has always been to have a nice bike with no single high-price component that will break the bank if stolen (so I don't need to be nervous chaining it up to a lamp-post & walking away from it downtown), and I've ended up with exactly that, plus almost enough spare parts for a parts-runner, which is not half bad (I have reused the original hubs with new rims, so I'm missing actual wheels). When I tally up what I've spent over time, it's very similar to what I would have spent had I bought a Surly or Kona from the outset & maintained it, with the added benefit that I made it myself, and that because it doesn't have name-brand appeal, it seems to be less likely to get stolen.

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    Additionally, you've learned a lot over that time too.
    – Criggie
    Nov 8, 2021 at 19:37

I have done that a couple of tines and the bikes are currently in a very enjoyable state, at least, for me, that is, no more upgrades are needed, until something breaks.

My main tactic is to keep an eye on prices of parts from both, reputable web pages and reputable local stores, and buy when the price is right.

Sometimes you can get slightly used parts for a fraction of its value. Some stores may have "clearance sales". I have had luck buying "OEM" parts (the web site claimed the parts where installed on bikes from factory that the customer wanted to upgrade right away, so the parts where unused and only with "installation marks")

Another way of obtaining good parts was to buy "new old stock", that is, new, unused parts that were a few years old model. When there is a new version of something, the old version decreases a bit in commercial value, and, if sitting on a shelf for too long, it often ends being sold at a discounted value.

Another key aspect of my success was that both bikes are MTB frames from around 1999, that had both v-brake and disc brake mounts, standard threading for bottom brackets and a tube to clamp the front derailleur. And during that period of time, until about 2012, more or less, not many standards changed. Sure, new things appeared but none was as disruptive as the complete change over from 26" to 27.5" and 29" or the almost disappearing of 2x and 3x drivetrains. The point here is that for quite a few years, new parts compatible with my bikes continued to be produced in relatively large quantities.

The advantage of my strategy is that I always had a rideable bike that I could enjoy, even if there where pending upgrades. Some times I used "cheap" or generic parts temporarily, understanding and accepting their limitations, until a good offer on some piece I needed appeared.

There are, however, some upgrades that are simply not feasible when done piece by piece, as other have stated. You could still acquire the parts separately, at different times, but that may pose the risk that later you can't find the compatible parts needed to complete assembly.

I would say, that the limitation is is whether the frame allow for upgrades and whether if is financially feasible to continue buying parts.

If you go on with your plan, do some research before, around the type of bike you plan on buying (Road, MTB, Touring, Etc) and around the type of riding your'e going to do. Search for what changes where there in the industry around the time the bike you plan on buying was sold initially.

Also, check if there is availability of parts for your specific location. (For example, I lived in a city where the local market was filled with the kind of parts that fit my 1999's bikes, On the other hands, to me, buying parts that are available only in Europe, would be nonsense due to shipping costs)


Are there limitations on the extent to which a cheap bike can be upgraded?

The only limit on the extent to which a cheap bike can be upgraded is money.

With a little or no planning and an unlimited budget you can swap parts, and then eventually the frame, and then more parts until you have a bike that is worth half, or less, than the amount you spent to get there.

Along the way you will have learned a great deal and you might have some interesting stories to tell. Only you can say if the experience was worth the cost.


My wife had an relatively early mountain bike (2006 maybe), entry level, Merida Juliet I think, 26 inch wheels, Aluminum frame, 3x6, v-brakes (no disc mounts), hardtail. I have upgraded it to SRAM NX Eagle 1x10, and I think 11-42 rear cassette.

For the goods: It is 1x. No chain grinding against rear or front derailleur due to not being in the best choice of gears. Gear change is simple - one lever for higher, one lever for slower. Basically very little thinking required. The range is just a bit higher (3.60x between highest and lowest originally - 3x6, now it's 3.82x It looks nice.

But there are some bads too: You can't drop (for example) three gears in a split second (as you can with a 2x/3x) (my wife doesn't care) While the bike is overall lighter, there's extra mass on the rear (the cassette is heavier than the original 12x30 or whatever it had originally)

And now the list of upgrades (which had to made at the same time): -new rear wheel (it had screw-type cassette, the NX has splines). It was cheaper than to re-do the rear wheel on new hub -new chain (but that's to be expected) -the NX Eagle - derailleur, cassette, shifter -the bike had rotating shifters, so I had to buy new, longer grips -everything related to pedals (it had pedals on one hunk of squared iron, now it has Shimano Hollowtech II) - pedals, bottom bracket, crank, and of course the narrow-wide sprocket

All in all, it's nicer. Yet, it rides the same - relatively tame and pleasant for a short bike (size M for women I think).

Is the money spent worth it? The answer is a resounding MAYBE. For less than the money I spent, I bought for my son a Focus, 3x8, Aluminum frame, hydraulic disc brakes, 29" wheeled mountain bike (Shimano Acera I think, so relatively entry level too). The Focus for my son was under 400 Euro, and the upgrade for my wife was more than 400 Euro.

Your mileage - as usual - might vary. If you find a bike that rides like a dream and fits you like a glove, upgrading is indeed a good way forward.

I have bought a road bike for 200 Euro - Shimano 105, 2x8, 42-52 teeth front and 12-26 rear. I have invested more than 200 Euro - new bar tape, new cables and cable housings, smaller front sprocket (so now 39-52) and larger rear cassette (12-30). That investment was definitely worth it - at least when climbing and shifting :)

EDIT: my road bike was basically "maintained" by replacing "like with like" and not UPgraded like the wife's mountain bike. Most of road bike parts are still original in manufacture, and all are original in intent.

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