There are so many reasons to buy a second-hand bike: the huge amount of money saved is a major one, but also with the continuing constraints on availability, buying second hand can make it easier to come by the model you want. Thirdly, it’s better for the environment to use a bike someone no longer wants, rather than adding in yet more demand.
But whilst a brand-new box-fresh bike needs only a little adjustment to get you rolling, second-hand bikes require that bit more attention and care - and this still applies even if you've followed our tips for getting a great deal on a used bike.
We’re going to take you through the five things we’d always check and replace on any second-hand bike - starting with the most important. Let’s get stuck in.
At a quick glance
In descending order of importance:
- Check and replace the parts of your brakes
- Then do the same for your gears
- Get the contact points (saddle, bars and pedals) set up as you prefer
- Check the tyres and bearings for wear- they'll need replacing immediately if so, or can be a nice upgrade a little later if not.
You probably don’t need us to tell you just how important properly functioning brakes are to a bike. The first thing to check is how much life is left in the pads - whether they’re rim brakes or disc brakes. Chances are, even if you don’t need to replace them immediately, you probably will in the near future. Find our guide to the best replacement disc brake pads here.
As a side note - if you’ve got disc brakes that sound noisy and feel underpowered, that’s a sure sign that they’ve been contaminated with oil. You can try sanding the surface lay off, or try to bake the oils out in the oven, but chances are you’ll have to replace the pads. Just make sure to give the rotors a proper clean with specific disc brake cleaner or isopropyl alcohol before you fit the new ones!
It’s worth also checking the braking surfaces for wear, whether those are the rims or the rotors. These have a longer life than the pads, so you likely won’t need to replace them, but it is certainly worth checking.
Finally, if your cable-actuated brakes are feeling spongy or the lever won’t spring back as quickly as it should, that’s a sign the brake cables and outer housing need replacing. It’s very much worth splashing out here - getting some top level housing and cables will transform the braking performance, making them more powerful and easier to control. It might be double or triple the price of the cheapest sets, but it still comes to less than half a tank of petrol - not many upgrades of this magnitude can be had at that price.
If it’s hydraulic disc brakes that are feeling spongy, that’s a sign that they need to be bleed. If you haven’t done this before, it can sound quite daunting, but in reality it’s as simple as squirting a syringe full of oil through the brake lines. It’s a lot cheaper to do it yourself than to take it to a bike shop, so if money is a consideration, it’s a skill worth taking up.
To sum up, you probably do need to buy new pads for your second hand bike and there is a reasonable chance you might need to change the cables or bleed the system. You probably won’t need to replace the braking surfaces with new rotors or rims - but it is worth checking!
Suffering with clunky bike gears? To make your shifting smooth again, the first port of call should be making sure that the cable tension is set correctly and then checking whether the mech hanger is in alignment.
Investing in what’s essentially a big metal stick might feel like an extravagance, but really they are so useful so often.
If the gears still aren’t shifting right, then you’re going to need to replace the cables. If your bike is sufficiently second hand and has external cable routing, then this might be a job that takes five minutes per derailleur if you’re practised, maybe 15 if it’s your first time.
If the bike has internal cable routing, depending on the model, it could take a professional mechanic hours to complete. If you have the money, it might well be worth saving your time here. If you’re looking to save, then there are kits you can buy that make the process much easier - definitely worth the investment for the time saved.
One of the tools it's worth getting to maintain your bike on a budget is a chain checker tool to check a chain for wear. Or you can use the time-honoured method of pulling the chain away from the chainring and seeing how far it will go. If you can see a lot of daylight, then it’s too worn and needs to be replaced.
Bear in mind, that if the previous owner has been riding around with an extremely worn chain, that will also have accelerated the wear on the cassette and chainrings - to the point that the shifting could be even worse.
Unfortunately, that means you may end up needing to buy a new cassette and rings as well. But it’s worth using this as an opportunity to consider your gearing - if you need something a little lower and easier, or if you want a tighter spacing for more even changes in cadence. As chainrings are typically included when buying a new crankset - this could even be an opportunity to change your crank length.
So, to sum up, adjust your gears, but also probably buy some new cables and outer housing (it’s worth investing in these as with brake cables). Check your chain and probably buy a new one - bear in mind you might need to buy a cassette and chainrings too.
3. Fresh contact points
As with buying any bike, it’s quite unlikely that the stock saddle is going to be a perfect fit for you. You might be selling your current bike in order to back-finance this new second hand one - in which case you can just swap the saddles over and save yourself the money.
Otherwise, you’ll be having to shell out for another saddle that you know is right for you - the best bike saddle for one rider may result in saddle sores for another rider as we're all shaped a little differently.
New bar tape almost goes without saying - for something that can look (and smell) quite so bad and costs so relatively little to replace, it’s amazing how many people go without. And how many people will splash out on new wheels whilst keeping their tape the same season after season.
Plus, the best handlebar tape can start from as little as $17 / £13, for Sram’s Supercork Bar Tape for example.
As your final contact point, you probably don’t need reminding, but you’re going to need to either swap in or buy a new set of pedals.
4. New tyres
Now we’re coming to the upgrades that can maybe be left a little longer after your initial purchase of the bike.
Definitely do check the tyres for heavy wear, but generally there will be some life left in them. That said, a set of the best road bike tyres, lightweight and fast rolling these really does transform the feel of a bike. In terms of performance - as well as keeping your ‘consumable’ components refreshed - new tyres are a great investment.
But even if you’re not obsessed about speed, it’s unlikely that the tyres specced will have quite the right balance of puncture protection, or be optimised precisely for the terrain you're riding.
Should you wish, you could even take the opportunity to go tubeless - if the bike isn’t set up that way already. You’d get the benefits of greater puncture protection, ability to use lower pressures and a decrease in rolling resistance and weight, although the technology does work best with wider tyres.
5. Bearing overhaul
Finally, your bearings. These do tend to last quite a long time, but equally that means this is an area which typically gets neglected.
The bottom bracket, which is what allows your cranks to spin, will probably protest the loudest - especially if the frame is designed for press-fit BB cups, rather than threaded.
It’s worth noting that it is possible to get a ‘thread-fit’ bottom bracket these days for press-fit frames - which consists of two parts that screw into each other. These mean that you don’t need to hit them in and out of the frame, which makes maintenance much easier – although you will need a specific BB tool to screw them in with, as with any threaded system.
And, of course, you will need to get the current BB out in the first place. A bike shop is usually best for this.
Your wheel bearings may need servicing - especially if you can wobble the wheel from side to side. On cheaper wheels (and on some select higher end ones) these tend to be cup and cone bearings. To service them, you’ll need some degreaser, some fresh lithium grease, and potentially some new ball bearings if the current ones are worn. It’s a little fiddly and requires some specific spanners, but the tools are cheap and you do get used to it.
Wheels with sealed cartridge bearings will need a specific bearing puller and a drift for slamming the new ones on. These kits tend to be rather more expensive and we wouldn’t advise trying to bodge this. If in doubt, a bike shop is best.
Finally, there’s the headset bearings which allow your handlebars to move. These protest the least and don’t have as much of a negative impact on your speed - so they are the most often neglected and can be really quite corroded by the time you get to replacing them - but it’s very much worth doing - not least so that rusty grease doesn’t keep seeping down your fork.
To sum this one up: you’ll know if your BB needs replacing – and if it’s press fit, it’s worth getting a ‘thread-fit’ replacement. Wheel bearings need swapping if they feel wobble or gritty when spinning – cup and cone ones are cheap but fiddly, sealed cartridge ones require expensive tools. Headset bearings often get forgotten, so it's really worth checking these. If unsure, the bike shop is always your friend.
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