cycling
24. März, 02:50 Uhr
I see a lot of posts in this subreddit asking about the quality/value of a used bike on craigslist or at a used bike shop. We can tell you what the bike may be worth based on the [bicyclebluebook]( http://www.bicyclebluebook.com/SearchBikes.aspx) value or the style and quality of the componentry, but just as important is being able to access the condition of the bike when you see it in person. I thought it might be helpful to write a guide of everything you should check to avoid getting ripped off on a bike that is going to cost you more in repairs than the asking price. This guide is definitely geared toward road bikes, but most of the process is the same for any bike. If you already have a bike, I would recommend going through this entire process as practice (and because it is good to do this from time to time for maintenance purposes). Also, if you are going on a long ride, it might be worth it to make sure your bike is in tip-top shape. This process is easier to do on a bike stand but you can do it on the ground as well. If you have a bike rack on your car (the type with arms that support the bike from the top tube), bring it along to where you are meeting with the seller and throw the bike up there. The only tool I would recommend buying before checking a used bike is a [chain wear indicator](http://www.amazon.com/Park-Tool-CC-3-2-Chain-Indica/dp/B000BR3LHQ/ref=sr_1_1?ie=UTF8&qid=1458782775&sr=8-1&keywords=chain+wear+indicator). This is a cheap tool that you should have for pre-rides anyway.
If you are a complete newbie to bikes, pull up this [bike anatomy picture]( http://i.imgur.com/YbTcceN.jpg) in one tab for reference.
**Frame**
The frame is the easiest part of a bike to inspect and should be the first thing you look at. If there is a problem here, more than likely there is no reason to continue the inspection—find a different bike. Start by looking for major dents and scratches. On an aluminum frame, these aren’t usually huge problems (as long as they aren’t on welds), but on a carbon bike it could mean the frame is toast. On an aluminum (or steel or titanium or any metal alloy) frame, take a look at the welds individually for any cracks. One common place for this is where the chain-stays meet the down tube. Stay away from bikes that have cracked welds. This is indicative of either poor workmanship or extreme stress on the frame.
**Tires**
Tires are pretty simple. Look for any obvious damage like tears, large puncture marks, or cracks. Check the tread first. If the tire looks flat in the center, it has seen some miles but is rideable. If you can see the [puncture protection layer](http://i.imgur.com/2YpS1S1.jpg) exposed under the rubber, it is time to replace the tire. More than likely though, the sidewalls will go first. Check the sidewalls for any cracks or dry rot. Sidewalls often crack even on relatively new tires due to chronic under-inflation or dry climate.
**Wheels**
First, inspect the spokes. If any of them are clearly [bent or nicked](http://i.imgur.com/yl8wpPN.jpg), they probably need replacement (this can be done individually for damaged spokes, but will require a re-truing of the wheel as well). Lift up each wheel and spin in the forward direction. Stand straight on (or above) and observe the wheel spinning. Look for any deformation (warping) of the rim from side to side. If the wheel appears to wobble, take it off and put it back on, making sure it is properly seated in the dropouts. If the wobble persists, the wheel probably needs truing. Next, grab two consecutive spokes (that attach on the same side of the hub) and squeeze them together. Observe the tension. Spin the wheel a about a quarter turn and do this again until you get back to the first pair. If any of the spokes are particularly tight or loose, the rim could be bent or, more likely than not, the wheel just needs truing. Next, use one hand to lift one of the wheels off the ground. With your other hand, grab the rim and push it perpendicularly back and forth. The wheel should feel solid. If you feel any knock, that is indicative of a hub problem. The hub could need an overhaul, or if the knock is large, you may need to replace it.
**Headset**
While the bike is on the ground or in a stand, hold it steady by firmly grabbing the head tube with one hand. With your other hand, grab the stem and push back and forth. Do this at different angles by turning the handlebars in between iterations. If you fell any knock, the headset probably needs tightening. If it is considerable, you may need to replace the headset.
**Bottom Bracket**
This is a similar process to checking the headset and hubs. While standing/squatting beside the bike, grab one crank arm in each hand. Try to tilt the arms toward back and forth perpendicularly to the pedaling plane. Observe any knock. Pedal the arms backwards and repeat the process with the crank arms in a few different places. If there is a knock, the bottom bracket will need to be adjusted/replaced depending on the severity.
**Drivetrain**
This is an important part of the process. Knowing how to identify parts that need replacing will tell you a lot about how much you are going to have to spend to return the bike to ideal condition. First, look at the chainrings. The teeth should look like little [plateaus, not sharp peaks](http://i.imgur.com/4L6vNJH.jpg). If there is a tooth or two consecutive teeth that looks considerably shorter than the rest, don’t worry, that is there to assist in shifting. It is not damaged. Next, measure chain wear using the chain wear indicator that you picked up before you came to look at the bike. Slide the rounded end into one of the links. Let the other end fall down on the chain. If the square end falls into the chain, that means the chain is worn out. If it is the side labeled “.75,” it is time to replace the chain. If the side labeled “1.0” falls through, it is more than likely time to replace the chain and the cassette. Speaking of the cassette, evaluate the wear here in the same way as the chainrings. Look at each gear, as oftentimes riders live in the middle of the cassette, so the most extreme gears will look fine while the inner gears will look worn. With all three components in the drivetrain, observe any rust. Also touch the chain and feel for lubrication. If the chain is dry or anything is rusting, it is a good indication that the previous owner didn’t lubricate enough and more than likely didn’t take care of the bike.
**Shifters/Derailleurs**
First, look at both derailleurs and observe any rust or bent components. It takes some experience to identify damaged derailleurs by looking at them. The real test is going to be when you see how they function. Inspect the full length of the shift cables. There shouldn’t be any rust or fraying. The housings shouldn’t have any nicks or cuts.
*If you want a more in depth look at the wear of the shift cables. Follow the instructions in this italicized paragraph. Shift the chain onto the largest chaining in the front and the largest position on the cassette in the back. Now, without pedaling, shift the rear derailleur into the opposite position. The chain shouldn’t move. This will give you plenty of slack in the rear shift cable. Take the cable out of it’s mounting position and pull the cap off the housing. The ends of the rubber housing and the wire housing liner should be flush with each other. If there are a bunch of wires sticking out of the rubber housing, the cable and housing should be replaced. Shift the rear derailleur back to the highest position and then repeat the process for the front shift cable. If you can’t get enough slack for the front cable, hold the derailleur in the highest position after you have down shifted. This should give you enough slack to get the cable out.*
For the next part of the inspection, you will need to have the bike on a stand or take the bike for a test ride. While pedaling, shift through all of the rear gears while in each of the front chainrings. The bike should shift one gear at a time. Observe any rubbing of the chain on the front derailleur. On road bikes, there is often a partial shift feature that will allow you to shift the front derailleur a small amount without changing gears in order to prevent rubbing. If there is still rubbing, the derailleur may need to be adjusted. If the chain comes off at any time, the derailleurs probably need adjustment. If the bike jumps multiple gears at once, the derailleurs probably need adjustment. The shifters should feel crisp and return to their natural position quickly. If it is difficult to fully engage the shifter or it returns slowly, you probably need new shift cables and housings. A well-adjusted derailleur system is quiet and crisp. You should hear a short click every time you shift. If you hear loud thunks or constant rubbing, it is not properly adjusted.
**Brakes**
First, you should inspect the brake cables and housings. Look at the exposed portion of the cable (near the calipers). If it is frayed, it needs replacement. Squeeze the brake levers. If they are slow to return to the original position or feel impeded during the squeeze, more than likely it is the rubber housing receding again, and you will need to replace the cable and housing. Next, check the pads themselves. On caliper brakes, you will need to disengage the brake using the [quick-release lever](http://i.imgur.com/XE40sXZ.jpg). This will give you a better look at the pads. On most caliper brakes, this still won’t give you a full view, so go ahead and take the wheel off if you want. The pads should be [segmented into 3 or 4 parts](http://i.imgur.com/iN0rMPr.jpg) separated by small channels. In the channels, there are wear indicators. When you wear a pad to the indicator, the segments will connect. If the pad looks like [one continuous, flat surface](http://i.imgur.com/PdiNVzO.jpg), it is worn out. Also feel the pads with your finger. They should feel firm, but pliable. If they are dry and cracked, they need replacement. Please note, with disc brakes this doesn’t apply. With disc brakes, wear is a problem when the pads are uneven or approaching the metal.
**Conclusion**
This process obviously looks tedious and possibly more extensive than you may care to perform, but it is worth it. Every worn out part that needs replacement costs something, and these expenses add up quick. If you have to take the bike to a shop to replace/adjust components, it is even pricier. I work for a bike shop, and we charge $10 a pop for new cables and housings with labor. Most old bikes that haven’t been maintained need 4 of these plus new brake pads, tires, and a chain at the very least. This can easily up the cost of your bike $150 with labor. So, before you consider the craigslist bike for $300, remember that getting it back into riding condition could put you in the price range of a new bike.
I hope this will help those of you who don’t know what to look for mechanically in a used bike. Or, if you like to service your own bike, this should be a good refresher in how to perform a complete pre-ride inspection. If you have any questions, feel free to comment or shoot me a message. I am not a bike mechanic by any means, but I pre-service several bikes per day and have learned how to identify problems (and correct some of them) without any formal training.
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