How to repair your bike safely

Tools and bike gears laying on the ground.

Ok, we know you can’t wait to get stuck in with the spanners, tuning your bike up from a squeaky shopper into a slick speed machine to turn the eye of the most extravagantly equipped pro. Or at least make it a less squeaky shopping bike! Before you start though, take in these tips on how to fix things without ‘fixing’ yourself good and proper, or repairing one bit of your bike while causing damage to another in the process, with slipped spanners and the like.

We’re not advocating that you cosset yourself in cotton wool. We’re just trying to make sure that when you’re done working on your bike, you’re still 100% fit to ride and enjoy it. Whether you’re a battle hardened workshop warrior or a newbie DIY dilettante, this guide is worth a read.

Wear gloves

Put ’em on! Snap-on gloves, as pictured, or similar, are a hit with car mechanics. They’re really effective at preventing painful skinned knuckles and more insidious repetitive strain injuries to the nerves running inside your palm, incurred from years of wrenching away on hard-edged tools with poorly designed handles. They also protect the vulnerable insides of your wrists, where all the delicate bits converge.

Years of exposure to solvents and oils can lead to increased skin sensitivity, rashes and premature ageing. Use thin rubber gloves where possible. Also, constantly washing greasy hands with harsh soap is no fun, so use a good barrier cream at all times. Almost all consist of a skin friendly paraffin that washes off with warm water, taking the grease away with it.

Protect your lungs

Recent research revealed potential asbestos-like behavior of long carbon nanotube fibers in laboratory animals, and a move in 2006 to classify as a likely carcinogen a chemical (known as C-8 or PFOA) used in the manufacture of non-stick products such as Teflon/PTFE suggests you can never be too careful. Wear an up-to-date mask with an AB1 and P2 filter for very fine dusts, fibers, fumes and aqueous mists.

Innocuous everyday products like spray lubes and by-products like carbon fiber dust from cutting steerer tubes or handlebars can, over time, become respiratory sensitisers, inducing asthma-like reactions in susceptible people. More serious effects are as yet unknown, and while we await the verdicts of ongoing research – which could take decades – play it safe.

Look after your eyes

Don’t gamble with what are probably your most important sensory assets. Hazards to sight, such as spray lube splashes or flying oil, can be sudden and catch you off guard; a rim failure or tyre blowout can be a very unpleasant surprise when you’re not ready for it. Keep your face away from the tyre at all times during inflation. If the bike is raised with the wheels at chest level and you’re using a compressor, you’re more likely to have your face closer to the hazard zone.

Be particularly careful with reinforced sidewall tyres such as Armadillos, or if the bike has been in storage for any length of time, meaning possible perished rubber. Finally, if you’re having a stab at truing a high tensioned wheel – or even a normal one – you might as well put your goggles on. What have you got to lose?

Dangerous torque

The exponential progress occurring in certain fields such as electronics and computing is being echoed in the cycling industry, with advanced materials developed in other fields cross-pollinating bicycle and component production. The race to produce an ever lighter bicycle has reduced certain margins of error that existed when bike bits had extra metal on them. You can no longer just tighten up a stem bolt or seat clamp bolt like there’s no tomorrow, as some can be pretty fragile, requiring as little as 4 or 5Nm.

If you’re unsure about judging torque, hold a 1kg bag of sugar and lift from your elbow. The effort represents about 2ft/lbs of force: 1ft/lb = 1.355Nm, and 1Nm = 0.7375ft/lb. Better yet, get a torque wrench!

Fixed gear finger jam

When a bike is hanging on a stand, the normal state of affairs is that the pedals, cranks and rear wheel are whirling away as you make multiple small adjustments. Perhaps you’re trying to re-install a dropped chain, or maybe truing the wheel between the brake blocks, using your hands to slow the wheel down. Or you might just be messing around, trying to find out just how fast you can get that fixie spinning…

While it’s certainly fun, our advice is DON’T, or certainly be really careful! With a multispeed hub or single speed freewheel, you can stop things a little quicker, but it’s still wise to avoid spinning the wheel backwards while your fingers are anywhere near the chainring or cog. On a fixed, the consequences could definitely be more drastic: there’s so much momentum and no slack.

Adjust accordingly

A frequent way of inflicting damage to your beloved bike is by not understanding how the fastening or adjusting method works. Always read the instructions first, or consult the appropriate literature. The two most common cases tend to be self-extracting crank arms and headset adjustments, which are still a mystery to a lot of cyclists. When removing the former, as in some Truvativ models as pictured (and FSA), make sure that the outer extractor ring is engaged in the crank arm before applying force to the main removal bolt.

Take the same precaution when using a separate extractor on a square-tapered arm. In the latter case, always remember to loosen the steerer clamp first on threadless headset stems before tightening the top cap adjuster bolt. Then re-tighten the stem while respecting the correct torque.

Wheeling and dealing

A frequently seen problem in many years working on the frontline is recalcitrant wheels not properly seated in troublesome dropouts. For a variety of reasons, they can sometimes sit off-kilter; this is usually due to maybe a bit of extra paint, chrome or resin coating the axle seat or, in some instances, a dropout that’s slightly closed up from having been dropped (this is pretty easy to do on a front fork).

Before tightening the wheel, give the bike a little downward slam to help ‘persuade’ the wheels into their correct position. Carelessness is also a frequent culprit; avoid at all costs tightening the skewer over the lawyer tabs (small safety protrusions) on front dropouts. It’ll make them bent and dangerous, and losing a front wheel when you’re hurtling down a hill can bring on a whole world of hurt.

Beat blowouts

Tyre placement and seating is critical, as you might imagine. The best technique for inflating a tyre, especially one that’s giving you a particularly hard time, is to lay the wheel flat on the ground, so as to minimise the risk of the bead being positioned off-center on the rim, which could lead to a dangerous blowout. Make sure you push the valve way up into the tyre, to prevent the tube from being pinched between the bead and rim. Another common danger you need to be aware of is excessive wear of the rim braking surfaces.

A noticeably concave or outwardly flexed rim flange, especially at high pressure, is a surefire sign that it could be ready to fail. When it does, it can be pretty violent. Pay attention to wear indicators on rims that have them – usually a thin groove that disappears when the rim is in need of replacement.

Fear-free freewheels

Trying to loosen a damaged freewheel on that fixie conversion project you’ve finally started to tackle is fraught with knuckle-damaging potential. Step forward the handy bench vice: the pawl seat flats allow the jaws to gain a decent purchase on the freewheel core. But to get to the core, you need to first dismantle the mechanism by unthreading the external bearing cone. This is best done with a pointed drift punch: place the tip in one of the pin spanner holes at an angle that’ll impart a clockwise rotation (they’re always reverse threaded), and strike sharply several times until it breaks loose.

Unthread completely and the entire freewheel internals will come apart, exposing the pawls and springs which can then be removed. Once clamped on the exposed flats, you should be able to break it loose using the leverage of the wheel.

Safe and loose

Safe tightening and loosening techniques are completely dependent on good ergonomics. You need to position yourself in such a way that if, for example, that stubborn pedal thread suddenly breaks loose, you don’t lose your balance and fall, or strike your hand or knuckles against something sharp like an exposed chainring. A face plant in a crowded workshop always hurts. Also, think about using your vice for help: rather than trying to dislodge a tight bottom bracket with the bike upright or held by a wobbling workstand, remove the wheels and use the frame as the lever, with the appropriate tool clamped in the vice jaws. Pay attention to the thread direction. If you’re trying to dislodge a fixed cup, secure it by applying downward pressure while holding the frame level, and turn clockwise.

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