This guide is designed to give you some general advice and ideas of what to look for when buying used bicycle parts. Buying used parts can be a great way to save money or get that retro/vintage look you're attempting, but they can also be poor investments. This guide will help you avoid those poor investments, and hopefully make buying bicycle parts on eBay a more pleasurable experience.

Wear and Tear
Parts that are worn-out or nearly worn-out are a big problem that you, as a buyer, can encounter. All parts of a bicyle wear at different rates, some more visibly than others. A brief list of major bicycle parts and how/where they wear-out is provided below.

Frame
What to look out for in a used frame depends largely on what type of frame material you're dealing with.

-Steel: Most old (10 years and older) frames are made of steel, although many new frames are steel as well. Steel is very durable and is probably your safest bet for buying a frame on eBay. Steel frames generally last for many miles/years as long as they stay painted (preventing rusting). There are two basic ways in which steel frame tubes were connected together: welding and lugging. Lugs are separate pieces of metal that the tubes slide into. You can tell if a frame is lugged by looking at where the tubes come together. If there is a clean ring all around the end of each tube, it's lugged. Example of a Lugged Steel Frame

If the steel frame you're interested in is not lugged, then it's welded. Welds must be in good shape or the integrity and lifespan of a frame will be compromised. Make sure the picture of the frame clearly shows most of the welds, and if you're concerned about a particular area, ask the seller for a close-up of that area.

-Aluminum: Aluminum has grown very popular in the bicycling industry over the past 10 or 15 years. While the paint on an aluminum frame is not as crucial as on a steel frame (aluminum doesn't rust), aluminum does dent more easily than steel. The integrity of frame welds is crucial with aluminum frames as well.

-Titanium: Titanium frames will also not rust, but having good welds is just as important as with steel and aluminum frames.

-Carbon Fiber: Since carbon fiber frames are not made by combining multiple tubes, they are not welded or lugged. They are, however, the most easily damaged and ruined of all the common frame materials. If a carbon fiber frame has a chip in it, it is very likely ruined. When buying used carbon fiber frames, be sure to inspect all the seller's pictures closely to check for chips and scratches. If possible, go to see the frame before buying it.

 
Fork

Forks are, just like frames, are made mainly of aluminum, steel, and carbon fiber. This guide’s recommendations for checking welds, lugs, and chips/scratches also apply to forks.

 
Headset, Bottom Bracket, Hub

These three types of parts are a bit risky to buy used since they all contain ball or cartridge bearings, which can, if not maintained, ruin the part as a whole. Buying these parts only if the seller accepts returns is not a bad policy.

 Newer bottom brackets tend to use sealed cartridge bearings. These types of bearings either work properly or fail. It can be very hard to tell whether or not a cartridge bearing is working properly by looking at the outside of the part housing it. If you are unsure of which type of bearings the part you’re interested in has, simply contact the seller. If the seller cannot answer the question, then shouldn’t buy from them.

Non-cartridge bearings are much more high-maintenance than cartridge bearings. They need to be kept clean (free of everything but grease) and be kept under a certain amount of pressure. New hubs and headsets are still very often of the non-cartridge style, so when buying fairly new parts, it’s important to know what type of bearings you’re dealing with. If a hub or headset of this type has been well maintained, then it can last a very long time, but a hub or headset that is too dry (lacking grease) or under the wrong amount of pressure/tension, can and probably will be damaged. Under these circumstances, bearings tend to lose their roundness, and eventually damage the races and cones holding them. Races cannot be replaced. Avoiding parts with thousands of miles on them may be a good idea, since it’s hard to know how well maintained they are without seeing/feeling them yourself.


Cranksets, Freewheels, Cassettes

These components generally last a long time. They all have gears that wear out slowly over a period of years (typically).

 -Crankset: When buying a crankset, it is important that you can see the spindle in the product pictures. The spindle is the opening in the metal that the bottom bracket slides into. A spindle that looks out of shape can result in several types of problems.

 -Freewheels: With freewheels, it’s important to get a look at the threads that screw onto the hub. If these don’t look clean (with clear, distinct, and consistent thread lines), then don’t buy the freewheel, as it won’t thread onto your hub correctly and could ruin the threads on your hub.

 Cranksets, freewheels, and cassettes all wear with the rest of the drivetrain (crankset, freewheel/cassette, chain, derailers). If sprocket teeth are missing on any of these components, they must be replaced. It is likely that putting a new (or nearly new) crankset, freewheel, or cassette on the fairly worn drivetrain of your bike, will result in shifting problems. Do not buy any of these components if they have been used extensively. Heavily used sprockets tend to be only compatible with their original drivetrain.


Wheels

Wheels are another component that should not be purchased if they have been heavily used. As they are ridden, they gradually become out-of-round (or “true”), and must be trued in a truing stand. To sum up the process, each spoke nipple is tightened or loosened to make the rim true. Each time a wheel is trued, it moves closer to the end of its lifespan, as any given spoke/nipple pair can be tightened a certain number of times. Before buying used wheels on eBay, check to make sure they have been professionally trued.

 This guide’s tips for buying hubs apply to wheels as well, since the hub is part of the wheel.

 
Pedals

Except for the really cheap ones, pedals are generally made to last. If you’re looking to get some pedals for really cheap, then just buy new ones. Pedals occasionally have bearing problems, and the clipless type can have springs wear out. If pedals look like they’re in good shape, generally they are functional.

 
Seatpost, Stem, Handlebars

These components tend to be very durable. Cheap or abused tubing can be bent, and heavily used seatposts, stems, and handlebars can develop tiny cracks resulting in creaking noises when they’re under load. Check paint on these parts, as rubbed-off paint can be indicative of a worn out area.

 
Derailers

Front and rear derailers (or derailleurs) are some of the more durable bicycle components. Rear derailers tend first to wear at the pulleys. These are the small cogs (there are 2 of them) that are enclosed in the derailer hanger (the cage that sticks below the derailer body). Derailer pulleys are often replaceable, but check before buying.

 As both front and rear derailers accumulate miles, their springs lose their strength. This typically doesn’t cause any problems, but results in somewhat sloppier shifting than a new derailer.

 As with pedals, if a derailer looks good, then it’s probably functional.

 

Shifters

There are two basic types of shifting: index and friction. Friction shifters are found on older bikes. While they are much less likely to break, friction shifters are harder to find replacement parts for. Index shifting involves shifters with notched moving mechanisms that lock the cable at the exact tension needed for a specific gear. Shifters tend to work perfectly until they fail. When replacing fairly inexpensive shifters, buy new ones as they have warranties and aren’t much more expensive than used ones. Higher-end, higher-quality shifters tend to last fairly long, and therefore are decent investments. Try and avoid really old shifters, as replacement parts may be hard or impossible to find.

 

What Not To Buy Used

-Chains: A used chain is much more likely to break than a new one, and is also likely to cause shifting problems on your bike. For safety as well as function, a new chain is much better than used. New chains are fairly cheap, so buying used just isn’t worth it.

 -Tires: As with chains, used tires will fail more often than new ones. If they do fail, there’s no warranty to cover a replacement. New tires also grip much better than used ones (increasing performance).

 -Cables/Housing: These items are very cheap, and might as well be replaced with new ones as cables tend to fray with use. A snapped brake cable simply isn’t worth saving a dollar.

Sizes

It’s easy to get excited about a particular component after seeing nice-looking digital photographs. Before bidding on a component, make sure that it will be compatible with whatever bike setup you have or are trying to achieve. Make sure that front derailers have the correct clamp size for your seat tube…Don’t make the mistake of buying a 7-speed shifter for your 8-speed drivetrain, etc.

Hopefully you are better-informed for having read this guide. When buying used bicycle components, try and follow the aforementioned guidelines. Buying parts on eBay shouldn’t be a gamble, and it doesn’t have to be. Happy Bidding!

 

Questions? Ask me, PiperArrown3191q.