Hi! I’m Vicky, one of the Double Drop Ambassadors and a Bike Mechanic. As an ambassador for Double Drop I believe in spreading the MTB passion as far as possible and, for me, that includes how to keep bikes running safely and smoothly. I teach bike mechanics to women at my local bike project – The Canterbury Bike Project – and in my blogs here I will be looking at basic bike mechanics and hope that they will encourage women (and men ?) to start working on their own bikes.
My adventures in mechanics started a few years ago when I decided to upgrade my hybrid to make it more trail-friendly. With a mate giving me instructions down the phone I managed to change the stem and wheels/tyres. Not only did I feel a huge sense of achievement and independence from knowing I could do the work myself but I also found it strangely calming working on the bike. In the same way that riding trails and playing on bikes delivers a few hours of mindfulness practice so does mechanics for me. Having been a stay-at-home Mum for years I decided I wanted to get back to work and I approached my local bike shop, Biketart, about doing work experience. They agreed and I fell even further in love with mechanics and went on to train as a Level 3 IMI mechanic. I now work freelance for businesses like Wiggle and Chain Reaction Cycles while also teaching bike mechanics. I still have much to learn and a long way to go by comparison to many seasoned mechanics, but I love working on bikes and sharing that knowledge with others, especially women and girls.
Double Drop works closely with a local bike shop (LBS) and I honestly can’t recommend that enough – there’s a balance between what is possible and economically viable to do at home and what is better handed over to the professionals, if nothing else because they have the kit to do it! However, never let that stop you learning about how to do the key jobs yourself!
In this first blog on mechanics I am going to address the basics that you can do in the run up to a race. Racing, even grass roots racing, is a mind game and your confidence and enjoyment is going to be enhanced massively if you’re happy your bike is in good working order and running smoothly. This is not a time for your gears to be ghost shifting or for your brakes to be feeling soft and unresponsive. With all these suggestions below, pop along to your LBS if you find anything unusual or that you cannot fix yourself.
Wheels/tyres
- With the wheel off the ground (either held up or with the bike upside down) spin your wheel to see if it’s running straight (this is called being true).
- Looking at your wheel you will see parallel pairs of spokes on each side of the wheel. Starting at the valve go round the wheel squeezing these pairs to see if they feel even tension.
- Run your fingers round the wheel rim to see if it feels smooth or if you can see any dents or dings in it.
- Check your tyre pressure – tubeless tyres will run at a lower pressure than ones with an innertube. In wet or muddy conditions you can run the pressure slightly lower to increase the amount of tyre on the ground, which increases grip.
- If you’re running a tubeless set-up then top up the tubeless sealant every few months. The easiest way to do this is to remove part of the tyre from the rim and pour in fresh fluid. Generally, if a tubeless tyre has been happily seated and sealed on a tubeless rim then it will go back on easily.
- Most tyres have a line or strip that sits just inside the rim and is parallel when the tyre is seated correctly. Check this is the case, if it’s not even you can inflate the tyre further to force it into place. Just remember to reduce the tyre pressure before you ride.
- Check the tyre for cuts and worn patches that will affect its strength.
Brakes
- Check the pads for wear.
- They are usually held in place by a split pin or a bolt that is undone with a small hex key (this bolt will have a small retaining clip preventing it from coming out if the bolt unscrews).
- Remove the wheel (if removing your rear wheel, shift into the highest gear/smallest cog before removing the wheel.
- Do not pull on your brake levers once you have removed the wheel as the brake pads are controlled by round pistons which will not return fully if they’re activated when a brake rotor is not present. Don’t panic if you do this though (we all do it sometimes and definitely in the early days!) – you can usually push the pistons back into place by putting a flat head screwdriver between the brake pads and pushing flat against them on each side.
- Before you remove anything more, have a look at the calliper (you can take photos so that you have a record of how it looks so that you can check when you put it back together).
- Can you see the pistons pressing on the brake pads when they’re not engaged via the lever? If they’re out slightly you can try pressing them back into the calliper using the screwdriver inside the brake pads (see above). If they won’t go back into the calliper or come back out it’s worth taking them to your local bike shop for a check.
- Do the pads look evenly worn from the top?
- Make a note of the code on the calliper. This number will help you find the correct replacement brake pads (either branded or unbranded).
- Can you see any signs of brake fluid leaking? If you can then pop along to the LBS to get their opinion.
- Remove the brake pads and check for wear. If they are unevenly worn or have less than 1mm replace them. You can find the correct brake pads by searching for the code that is on the current pad or looking up the serial number that is on the brake calliper. If in doubt though, have a word with your LBS ?.
- Using disc brake cleaner, clean your brake rotor before returning the wheel to the bike. Spin the wheel while checking for any rubbing (listen for it but also look down from above the calliper and watch the rotor spinning through the pads. If you spin the wheel slowly you can spot anywhere that it may be rubbing.
- A simple trick to set brakes is to loosen slightly the bolts that hold the calliper in place on the frame. Spin the wheel quickly and then pull on the brake lever so that the wheel is held in place. Keeping hold of the brake lever tighten the calliper bolts so that it is secure.
Gears
- Most new mountain bikes run a 1x system with a single front cog and only a rear derailleur. However, the principles are the same for either front or rear derailleur systems.
- Gears are the means of controlling the chain, using a cable to make it change from one cog to another. Simply they ‘pull’ the chain up into a bigger cog or ‘drop’ it down into a smaller one. In order to pull it up the cable has to be made tighter – a well balanced cable tension means that the chain will shift up and down the cogs evenly.
- If your chain starts jumping between gears or taking its own sweet time to change once you’ve clicked the lever, this is often because the cable tension isn’t right. Cable tension is super sensitive and fine-tuning can be done at the barrel adjustor – either on the gear lever, on the cable outer near the front of the frame or where the cable comes into the derailleur (not all systems have a barrel adjustor here).
- It always seems counter intuitive to me but to tighten the gear cable turn the barrel adjustor anti/counter clockwise.
- If you don’t have a bike stand you can still set cable tension if it’s not behaving correctly.
- Visually check your cables to see if there is any fraying that will prevent them from running smoothly – gear cable moves within the outer housing (gear outer) as you shift gears.
- As a rule of thumb the right cable tension can be found by pressing the gear shifter to change to a larger cog, then turn the cranks a single rotation. If the chain doesn’t shift within a single rotation of the cranks then add a small amount of cable tension until it does.
Dropper post
- Cable droppers tend to run well once set up, unless the cable frays or comes loose.
- Hydraulic droppers can get air in the system, in the same way as brakes. If your dropper stops working properly it may need bleeding. An easy way to check this is by pulling the dropper control lever towards you. If there is movement and no resistance the dropper would benefit from a bleed.
Contact points
- Make sure your bike feels secure and comfortable where your body comes into contact with it.
- Are your handlebar grips securely on the bike, are they comfortable?
- Are the levers at the right angle for your wrists – this is quite personal but lots of people like them to be at about 4/5pm on a clockface so the wrists are not under tension when you’re pedalling.
- Are the saddle bolts solid and is the saddle at the right height? When your leg is extended can you still drop your heel and put strength through the leg/foot?
- Do your pedals spin freely?
Bolts
- Check that no bolts are loose on the bike. Ideally use a torque wrench (X Tools do a good one for about £30) – every bolt on the bike will have a torque setting. This is the amount of force needed to do it up safely. If bolts are torqued correctly they should not come loose, however over-tightening them can cause a whole world of damage (more on that in a future blog). You can find torque settings on the thing you’re screwing the bolt into (eg look at your stem or seat-post clamp), the technical documents or you can use generalised torque settings (see below).
Chain
- Using a chain checker tool, check how worn your chain is. If it’s more than 50% worn change it. As a chain wears it wears away the cassette and by the time a chain is 75% worn, it’s likely that a new chain won’t run smoothly on the existing cassette. If you change the chain at 50% worn you will be able to extend the life of the cassette greatly.
