A relatively short-ish guide focused on what can be easily checked by a layperson, with a handful of simple advice; harder shit omitted. With POST SCRIPTUM: IF YOU’RE JUST LOOKING FOR A BIKE FOR EBT 

Introduction

Tour is much more challenging for bikes than usual riding. A lot of bikes have malfunctions during the journey. A lot of people neglect to check the bike well before touring. Some don’t try, unsure of their capabilites.

EBT is generally open to join with a shitty bike. We also know that it can be difficult to come to the tour from far away and carry the bike with some means of transport. Some come without any bike and put their hands onto whatever they can find/build/buy cheap, but tend to believe that just superficially checking rolling, braking and turning is sufficient.

We carry tools, first aid accesories, we visit bike kitchens and try to support each other in troubles, but it’s nevertheless better to be safer than not and to use less planet’s resources by making bikes last longer; you can try, you can seek advice, too.

Checking a bike can be simple enough! Not everything is quick and easy, but most things are. This guide describes the simple stuff. Use it when obtaining a bike and before heading to the tour. Usually it’s worth it to repeat some checks after a transport (and every now and then, too).

Unfortunately, it’s also pretty simple to destroy most bikes in a day or a month or three – at cost to the environment, too – instead of ca. 10-40+ years it should be usable normally.

Note that you need to apply less liberal standards when joining for longer and if your time of the tour has worse weather, poorer roads or more hills (and/or if you’re (strong and) heavy with your load, too). Don’t worry overly if you find weak spots of your vehicle – we often have ways to help, there’s internet with informations; and after all, it’s still better to know about a problem even if you can’t fix it. It’s recommended to not check the bike last minute, but much ahead, and to test it well in practice, ideally with panniers (even after making some improvements, also).

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Frame and fork

Inspect both visually and with fingertips, looking for cracks, dents etc (if needed, clean it with a moist cloth or sponge, avoiding excess water, especially under pressure). Paint that cracks or chips off often means damaged metal surface. If it’s steel (use magnet in doubt), you may tolerate not too big dents on the main tubes, and on upper rear tubes maybe, if it’s not close to the joints. However, you may want to check for bad corrosion in some hidden place. With carbon forks, check for small cracks and their sound (no-go). The chipped off paint should make you worry if there’s a chance it’s been exposed to much sun (especially mountain/subtropical sun) for long. ‘Full carbon’ forks may need inspecting not just their legs, but also the steerer tube hidden in the frame (and headset adjustment afterwards).

Suspension (shock absorber)

Check for leaks, and if it has a bad play on the legs (the upper and lower telescopic parts should only move up and down in relation to each other, not forward-backwards). Rather rarely smth critical in here. Budget suspensions tend to have some play there often, sadly.

Headset

It’s a set of bearings on which fork turns in the head of the frame. Grab the upper part of the fork and the handlebar stem and vigorously try to find play by moving it forward-backwards. Only a minimal amount is any tolerable. Note that there shouldn’t be a notable resistance in turning the handlebar, either. If there’s no seals, considering wrapping anything around them, even an old sock, especially around lower bearing, to limit sand and dirt entering.
Neglecting headset play may lead to bad frame damage in some cases, especially non steel frames – and makes steering worse.

If your headset is an a-head type (fork sticks out of the frame, has rings between it and the stem, the stem has bolts at the side(s) ), you can reduce the play by loosening the side bolts at the stem, tightening the bolt at the top – usually just a tiny bit – and tightening the side bolts at the stem again, after checking that the stem is still straight, in line with the front wheel – tighten only delicately if the fork is not steel. Btw, the bolts should have thread lock (glue) on them, usually blue.

Bolts

Check if their heads and sockets for wrench/screwdriver aren’t worn/corroded to the extent at which turning would become impossible; in such case, even plain removal will be a mission. It can happen especially to small adjustment bolts for brakes and gears. Sometimes bolts untighten with time from vibrations etc. It can happen in transport, at times. During rides, the rack bolts are notorious in their desire to run away; brake bolts big and tiny, if there’s no thread lock (a glue, usually blue – incompatible with grease) on them, are also prone to loosening, as are stem bolts, chainwheel, suspension, mudguards and bottle basket bolts etc. Pay more attention to bolts if your frame/fork isn’t steel.

Hubs

If you have quick release skewers to attach them to frame/fork dropouts, make sure they hold. It’s nice if they still have the springs on both ends, altho not critical. They should be closed strongly enough that it would a struggle for an average person to open with one finger only, but better not much tighter (first some turning – not until it stops turning, but some – than close the lever and check if’t is right, adjust if needed and try again). The closing should take place when the bike is on its wheels and after it’s pressed down, when the axles find their natural position in the frame/fork.

Grab the edge of the wheel and try find play to the sides, like described below for BB. Even a small one is a real problem, but you may, unfortunately, get confused by slight bending of the wheel rim under your force, which feels somewhat similar. If you have play at the bearings, it may mean just a need for a small adjustment, or (much more often) a big quest, maybe some inner parts replacements… pretty often the hub will turn out to be damaged permanently and worth replacing with the entire wheel, or to require rare replacement cones (for cup-and-cone type)… sadly, it’s usually difficult to quickly assess just like this. Because of the risk, give it a priority and seek help.

Note that the hub bearings should also run smoothly; hold the ends of the wheel with fingertips as it rolls and you will feel. Often, you will see a significant resistance (worse are cases when it’s sharp at some point(s) of the turn than constant but slighter one). Provided there’s not play, a harder rolling you may want to tolerate, if you don’t have very ambitious plans; even though it’s most probably nearing end of its lifecycle, you might still be able to use it no problem for over a thousand kms if lucky. Hard to describe it exactly, especially without a small surgery… in many cases, nothing can really help and in some, a tricky mission may ‘steal’ some more of last bits of life or even save the wheel health in the last second. However, if you have industrial bearings (hard to describe it, check pictures, ask experienced riders), there’s no urgency, the wheel is not gonna go to trash as a whole, the replacement usually is simple, quick, and requires few tools; with harder designs, car mechanics in the middle of nowhere may be able to help you.

Try to disengage chain and roll the sprockets around, looking if they wobble side-to-side. They shouldn’t wobble more than just a bit. If they do, it may be or be not a Very Bad problem (usually, it’s not a big deal if you have a shallow axle with quick release skewer and a casette and a freehub, not sprockets integrated with/into a ‚freewheel‘).

Neglecting hub play makes steering worse, may cause slight brake rubbing that’s hard to detect, and greatly increses the risk of bringing the wheel into an irrepairable state.

Wheel rims

Clean the areas around the spoke nipples and look for cracks, especially if it’s old and spokes are much tensioned, and there’s a slightly visible ‚hill‘ around (a) nipple(s). If you use rim brakes, not disc ones, check if the side wall against which brake pads hit does not have a groove from something sharp stuck in the brake pads. It may also not be flat anymore, but ‚fall‘ to the inside where the brake pads hit; if it’s deep, it also may at some point break.

Another thing is the trueness (meaning whether wheel still has it’s true shape, not of an egg or a taco, commonly also visualised as a digit 8). If it’s badly ovalized, it would be in most cases ‚just‘ about constant bumps under one’s wrists or butt. If it is bent to the side(s), wobbling sideways when rolled, despite lack of play in the hub, it may rub against rim brakes (if such are present), leading to massive energy losses and early damage of the wheel and brake pad. Consequently, with such brakes, one must keep wheels more or less true, even if not caring about their long life, just to be able to brake when needed and not brake when not needed.

Usually, slight wobbling likes to worsen with time and use, and a wobble greater than, say 2 mm to one side is already pretty bad, with 3 mm being a catastrophe (depending on other factors, tho). Rim bent sharply at some point(s) is often difficult or impossible to correct, if it’s not just a loose spoke that has untightened. Rim bend that doesn’t show suddenly to your eyes (when you look at the wheel rolling slowly), but increases gradually over a longer section of the rim circumference, is often correctable, if condition of the spokes and nipples allows.

Spokes

Shouldn’t be rusty or bent. Consider packing a spare or two in the right size. Shouldn’t be loose. It would be good if they didn’t vary very much in tension (by touch or by ear when plunked), for a true wheel (however, it’s normal and expected that all left ones on the rear wheel are much looser than all the right ones). Neglected spokes often lead to wheel deformation.

Spoke nipples

Check if their sides aren’t worn and rounded, especially if the’re from aluminum, not brass. The threads on the ends of spokes should be not visible or only barely. Sometimes, if stuff looks old, it is still adjustable (so that you can correct the shape of the wheel when needed), sometimes it’s stuck and you can expect problems.

Tires

Check for cuts; if there’s a puncture-protection layer, even (some) cuts may be acceptable. Check for cracks in the rubber when deflated (higher puncture risk, for instance). Check if tire sits evenly on the rim – no bulges, the tire doesn’t present an eye-striking bump on its circumference when rolled around. Check the tire sides too for signs of walls breaking (often times, slight cracks there are not that risky). Tires that have a steel wire inside (cheaper), may deform if stored long deflated, especially on a bike, and loose roundness, possibly leading to uneven or unsafe seating on the wheel. You may want to try to reshape it with force.

If you can, uninstall the tire and check it on the inside, whether the wire doesn’t come out, wating to damage the inner tube. Remove the tube, too. Check if rim tape, that protects the tube from the spoke ends and edges of the holes in the rim, is intact (if not, you may try repair with a few layers of power tape, in case new tape is not available). Check if spoke ends do not protude outside their holes, touching the rim tape. Check if the inner tube doesn’t have patches that started going off.

One of the most critical things to do is proper pumping. There’s no cycling without a pump equipped with a manometer (regardless of them being imprecise, and pressure rising maybe 15 or 20% in sun and heats). You can not assess the pressure well with hand. There are good calculators of optimal pressure on the web (tho, not all take into account speed, surface wetness and most crucially, the weight distribution between wheels). Otherwise, because of the panniers, rear tire should usually be pumped near it’s stated maximum, written on it (slightly less if it’s a bit used, and perhaps corrected for the heat influenced raise if relevant). Front one should often have rather more air than less – but by a bit. At least if you don’t ride big enough tires. Don’t use knobby, off-road tires on asphalt, it’s very important! (If there’s lots of bad gravel etc, it’s wet/sandy/muddy, and you’re extra concerned with safety: a semi-slick one, with some pattern at the sides only, on the front wheel only, or also at the rear if it’s also hilly, may be better).

Underpumping the tires is not just dramatic energy loss and discomfort, but affects safety and damages the bike and raises the risk of inner tube puncture. Overinflation (rarer) also results in some discomfort and energy loss, affects safety on wet/uneven surfaces and may even damage the tire.

Brakes and levers

Working brakes are way more important than any helmet. It’s highly recommended to have two working brakes, with at least the front one working really well.

The basic test is to squeeze the brake lever and push on the bike with all might and all weight (maybe also on a slope): to the front for checking front brake and to the rear for the rear one. Bike should freeze in place, maybe the other end of the vehicle could lift into the air. You can check it also with half-squeeze, or in wet conditions if we speak rim brakes (non-disc ones, with jaws).

• If your brakes have discs (rotors), but no wires, they are hydraulic. Check the levers and the brakes carefully for leaks. The lever, when pressed, should not instantly fall deep towards the handlebars (it also shouldn’t feel very badly ’spongy‘, but less of concern). If your rotor is bent and you can’t straighten it enough (and if it’s not possible to adjust caliper position), you are screwed, you will be braking with every turn of the wheel until disc replacement.
• If your brakes have discs (rotors), you can shine some strong light inside the caliper and try to spot the brake pads – if you succeed, make sure they’ve at least 1 mm thickness left. In the same time, you can check for caliper position misadjustment (they like to move from vibrations etc), it should be in straight line, parallel to the (straight) disc, with constant, preferably pretty small gap(distance).
• For any non-hydraulic brakes, rim or disc, all that are connected to levers with wires. There should not be splitting at attachment points or ends, and these ends should be secured, not bare. A splitting wire can fail precisely when you need it the most, during a strong braking. Check the housing of the wire, that covers it (usually it’s black). If it loses integrity, it limits the braking power.

  • • It’s of utmost importance that brakes don’t work when not asked to. A wheel rolled freely should not make sounds of touching the brake pads. If they do…

  — For rim brakes, it can be a problem of play in the hub and/or a bent rim and/or misadjustment of the brake. If it’s a ‚v-brake‘ (type with a pipe coming from the side to one of the jaws), and one brake pad touches the rim sooner than the other side pad, you can try turning in a tiny bit (for start 1/4 of a turn) a small bolt at the side of that brake jaw, and/or loosening on the opposite side. Or loosening the brake grip a bit by turning a barrel on the cable, at the lever, a bit in, with blocking its further movement by the ring next to the barrel – it moves away both brakes, so you should rather use it if both brake pads are closer to the rim than 1 mm. If you managed to evade the menace of involuntary braking, check if you didn’t slip into a nightmare of not being able to brake enough.

  — For disc brakes. Caliper misadjustment and/or cable misadjustment and/or bent rotor (disc). The latter is very common and occurs both in many new rotors (discs) straight from the box and in bikes that were transported, and more:) It can be bent back with a lever from a hex wrench or whatever, however it’s difficult to do it precisely – still, easy to make it at least somewhat better (don’t use excess force). For non hydraulic, wire-connected disc brakes, cable can be loosened at a barrel (block the barrel position with the small ring afterwards), like described above, also with a loss of the braking power to be checked. It’s better, however, to try find a turn or a bolt on the caliper that moves the brake pad closer or farther to/from the disc.

  For caliper misadjustment, loosen a bit the bolts with which it’s mounted onto the frame/fork, move it a bit left-right for a moment, squeeze the brake lever so that it centers itself evenly on the disc (rotor) and start tightening the bolts in small steps (upper bolt, lower bolt, upper again, lower again…). Check afterwards: they often go slightly out of line from the final turning of the bolts… consider microcorrections (also without squeezing) at one bolt. [If the problem returns soon, consider adding thread lock (thread glue) onto the bolts next time.]

  ! Btw, if you ever remove the wheel, make sure the disc brake lever doesn’t get pressed; especially with hydraulic systems, it’s extremely important!

  [for other brake types, many of the advice may apply in a similar manner]

  • • If braking power is insufficient.

  — If it’s a rim brake, and the wheel is true enough (and no hub play) to tighten the jaws a bit more, turn the barrel on the cable a bit out and secure its position with its ring. Check for rubbing. You may want to try wiping the braking wall of the rim with pure alcohol, if it can be dirty with rubber, road oil etc. Check the brake pads position: they should approach the rim wall quite evenly when braking, touching it with their full or large enough surface, without touching the tire or falling under the rim. (If you correct it yourself, release the brake jaw spring if possible, on the side you’re working on – for v-brake type; for cantilever type, where the brake cables make a triangle – it can be tricky to adjust the brake pads).

  — For disc brakes. If it’s non-hydraulic, you may want to try tightening at the cable, like described above. Better: try find a turn or a bolt on the caliper that moves the brake pad closer or farther to/ the disc, then check for rubbing. You can wipe the rotor (disc) on both sides with a perfectly clean wipe or paper towel and pure alcohol (mind, many sanitizers contain glycerol; if not available, warm water with dish soap, then rinse with water, it’s better than nothing), again and again, until it seems as clean as possible. You can drip, or better, spray generously, pure alcohol into the caliper.

[It may happen that nothing helps, even though you tried things. It’s not unheard of that brake pads of a disc brake get contaminated. Almost every bike has the resin type, which ‚drinks‘ all the grease and lubes at the slightest contact and doesn’t release it, becoming slimy and sliding over the surface of the rotor instead of stopping on it. Replacement can be tricky, and all models have a different shape, so you may not be able to even buy it. It’s good to purchase and carry a spare! It may be enough to touch the rotor with some grease on one’s fingers, accidentally drip a drop of chain lube or spray some WD40 in the direction of the brake to destroy the braking power… perhaps even an unfortunate splash from the motor oil on the road. Some magic that may (or not) help or improve the situation if it’s still bad: check how to remove the brake pads, do it, remove the outer layer with fine sandpaper, soak in pure alcohol, apply heat by putting it on the stove for a good deal of time, even hours; reinstall.

Luckily, most disc brakes, and hydraulic brakes especially, offer good braking power, also in wet conditions, so they may forgive imperfections. It’s much more common for disc brakes to rub than to brake insufficiently.]

• For rim brakes, inspect the brake pads. It’s easier with the wheel removed, or jaws released and extra light. The surface should not be any silver-ish…use a file! if sandpaper, check the surface thoroughly again, afterwards→, and most importantly, there shouldn’t be any small stones or metal or glass pieces stuck into it, as they damage the rim side wall.
• If the brakes tend to get blocked after applying the brake, it may be old cables (spray in WD40 or smth thin, don’t use chain lube unless desperate), it may be uneven surface (you can use a knife) and wrong position of the brake pads, falling below the rim surface towards the inside of the wheel and not being able to easily return from there, getting stuck. Sometimes it helps to tension the springs with small bolts at the sides of the jaws (v-brake type), both, evenly (check the effects!).
• For typical rim brakes. The small bolts at the sides of the brake jaws should have a drop of thread lock (thread glue) put, as they are prone to untightening from vibrations; otherwise, check brakes as often as possible, because they like to fall out of adjustment very easily (and brake constantly instead when you apply the lever).
• for rim brakes, for the v-brake type (with a pipe), it can be sometimes too strong. Make sure the brake pads are not closer to the rim than 1 mm (adjust with the cable barrel, see above). There is a way to create some cable slack without compromising braking power, which is not described here.
• make sure you can place and keep your fingers on the brake levers comfortably with your fingers reach to brake in a fraction of a second. There is often an adjustment bolt on the levers for it.

[If your brakes make high pitch sounds, it doesn’t necessarily mean a problem. If you mind, it can be something about the brake pad, rim or disc surface, but it’t the strong braking without rubbing you need to achieve, not absence of squeak].

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Bottom bracket (BB), cranks

A set of bearings at the center-bottom of the frame, on which the axle that connects the cranks (on which pedals sit) turn. Grab both cranks and see if the move left-right; they shouldn’t. See if maybe just one of the cranks – likely left – seems to wobble? (If you have a classic system, with 8 mm allen bolt or a 14 or 15 mm thin walled socket wrench bolt under a usually plastic cap, to tighten the crank – 14/15 you can find on the crank puller tool – this may turn out easily fixable; mind, it’s the place where you normally apply much force… however, neglecting it often leads to damage of aluminum cranks).

The bottom bracket should roll relatively smoothly, but usually you can only feel it after taking the chain off. By turning the crank, pay attention how it runs, keeping in mind that small, constant resistance is normal, and moderate, constant one is usually not the end of the world.

If the bottom of the frame has a hole (bigger than minimal), block it and cover with power tape, more than 1 layer, especially if you have an old style BB (with a lockring on the left cup, which is not the multi-spline type like on most bikes or similar). If any cup looks non-typical, with flat edges, pin holes or something – btw, markings ITA, 36, 24 are a bad sign too, and if the frame bottom is 70, or even 73 mm wide, too – you need to be double careful and prepare for possibly bigger/harder work in case.

Crank chainwheels

The teeth should not look sharp or thin. If you have a few chainwheels, the smallest one is usually in best condition for comparison, the middle one in worst. The smaller the chainwheel, the more risk it wouldn’t hold the chain when teeth are sharpened. Excess wear is not a super common problem (some is tolerable), but may surface only when you pedal up some mountain (or sprinting), standing, and suddenly fall. With the chainwheel(s) made of steel, wear is very unlikely – and the chains also last way longer. Sometimes the chainwheels are bent and do not run straight but wobble to the sides when turned. 1-2 mm is surely tolerable. Even more, it will probably not fall apart anytime soon, and it can be attempted to straighten it with much heat. Some chainwheels and cranks have uncommon Bolt Circle Diameter (BCD), check if replacement is realistic if it’s worn.

Chain

Shouldn’t be rusty (maybe unless just somewhat only on its outside parts). Check for elongation with a chain ruler. If you don’t have it, any workshop will lend it for a sec for free. If also not possible – shift chain to largest chainwheel, at about the 3 o’clock position, try pulling the chain straight away from the teeth… If you can expose a significant portion of a tooth or pull the chain far from the ring, the chain is likely worn (worn teeth affect results, though).

Chains need relatively frequent replacement before they start damaging the more expensive parts due to its invisible elongation. Even if it’s still okay, it will likely elongate too much at the tour, so you may consider installing a new one (that is, if the chainwheels and casette are healthy, otherwise they may not want to cooperate with a good chain anymore, but only with worn ones and for a limited time). It should be cleaned with solvent, lubricated with bike chain oil (even good wax is good only for good weather and asphalt) and wiped clean on the outside. Chain length should allow using the biggest gears both in front and the rear in the same time, even though it’s a setting to avoid.

Casette (rear sprockets/cogs)

See chainwheels for the description of the possible problem. Here, the standards of tolerance are tighter. A casette, or a single sprocket/some of them, with thin teeth (compare to other, usually the smallest one) will likely not work safely (or not work at all) with a new chain. If teeth become pointy, they may not even work with any, even worn, chain (then you need to replace one/a few sprockets/ entire casette as well as the chain, and to pray that the chainwheels will be still okay enough for it). Check for dangerous ‚chain skipping‘ under big load and kicking on pedals when standing on them, in safe traffic conditions and with carefulness: you can simulate a climb with the use of brakes if necessary.

Front and rear gears

Check the cables (for rust, dirt – don’t lube with chain oil, though, you can spray in some WD40 or smth – plus for splitting ends to secure) and their housings with their endings. Try different gear combinations with bike hung or put upside down. What’s crucial to check here is that the chain doesn’t fall off the sprockets, to the outside or to the inside. The upper small wheel of the rear derailleur should be in line with the smallest rear sprocket teeth when on the fastest rear gear, and with the largest rear sprocket teeth when on the slowest rear gear; not further. Check periodically.

At the front derailleur, try pushing the chain to the biggest sprocket with the shifter, hold, turning the cranks fast and shaking the bike – chain shouldn’t fall out of the chainwheel. With falling to the inside, when on the smallest chainwheel, it usually happens on bumps and jumps, taken with some speed, pedalling or not pedalling.

Adjusting gears properly may sometimes be tricky, the above steps only cover what’s safety-relevant (in many cases tho, at the rear gears, for the noise and poor shifting to the softer, it’s sufficient to do a 1/4-1/2 turn left of the barrel on the cable – after checking the extreme positions of the upper small wheel of the rear derailleur). Small bolt at the back of rear derailleur should rather be more in than out.

The lower of two small chainwheels of the derailleur should not have very pointy teeth. The long-ish metal plates of the derailleur should run more or less straight, especially when the chain is sort of in a straight line (if it’s tilted badly to the inside, you may need to get a new ‘derailleur hanger’ for your frame model, which can be rare or hardly/non- findable; one may heat it up and bend it back, but it’s less safe and precise, and works to an extent only). Re-check in case of fall to the right side!

Inner tubes

Take min 1 spare, fitting size. Check the valves, if they look okay (also, they shouldn’t be tilted) and allow easy enough pumping. Pump to a good pressure and check if it didn’t drop significantly over a couple of days, especially if there was patching.

Seatpost

Check if it moves and can still be adjusted. If it’s a usual metal seatpost, it best be removed and greased where it sits inside the frame, if needed (neglecting it can cause some water going inside, or worse, if it’s different materials touching, seatpost getting stuck quite permanently). Check the clamp or tightening bolt/skewer. Check the bolt(s) holding the saddle (and their locknuts if present), also the threads. Carbon seatposts need checking for cracks (sounds often don’t indicate one but are quite ok), and should be installed with a dedicated paste, not grease!, to prevent getting stuck and to hold in the frame with minimally tightened bolt (no paste? you may try rubbing chalk (or better, climbing chalk, or tooth powder; don’t use toothpaste nor ash) evenly on the surface and hope for the best).

Mudguards

Sometimes, a bike without at least a rear fender is equal to useless. If desperate, cut out something from a big plastic bottle and attach behind the seat to its rails with zipties.

Pedals

Check for play and resistance like other bearings. It’s super common (and hardly avoidable for most designs) that they are far from good, next ones won’t live long either fairly likely, so you may want to keep them anyway until it’s real bad. What can be very troubling, though, is when you can’t remove them anymore. To prevent it, try to untighten them (usually 15 mm flat wrench, the longer the better) with much force, keeping in mind that the left one uses opposite thread direction. If successful, reinstall with grease (normal force).

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The rear wheel is the most critical part of your vehicle, both in the sense it’s the heart of it and in the sense it’s vulnerable. If everything is awesome, but rear wheel is poor, then everything is poor. If frame, fork, tires, chain, front brake and rear wheel are good, the bike has good chances of surviving.

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POST SCRIPTUM: IF YOU’RE JUST LOOKING FOR A BIKE FOR EBT – nearly universal facts, nearly regardless preferences (which I here either skip or mark as such)

• consider length of your stay, terrain and weather and surface, your weigth and body type etc, budget (if not for the bike, than for part replacements)
• very rarely you can get a fully healthy bike, even for good money. Set your priorities

Overall type: trekking/touring or MTB without rear suspension (damper) – even the front one better be not a budget one and not too old, with blocking option (for climbs/good surface). MTBs are more sturdy, but weight matters too! Utility/commuter/city bikes seem sturdy and comfy, but are absurdly heavy – even for their reduced strength in case of skirt-friendly design – with super badly distributed weight – and a nightmare to change rear tube or tension the chain. Gravels are an ok choice especially for relatively light rear luggage, relatively fast rides, especially in the wind. Maybe some gravels – as some are made for racing. They’re too short at the rear and some – at the front, too. The head (front) tube is too close to vertical, too short, and often the handlebars too low; wheels could be stronger. Still, an ok choice, and very universal, lighter, of much use outside the tour life. (Especially some gravels, with some adjusting at the peripheral parts for the tour: v. good).

Generally, weight often means more durability (with the same type, and similar price range), but it’s the most important factor for the easiness/hardness of cycling (assuming good tire pressure, ofc, and not using off-road tires).

Wheels: avoid steel rims at all cost (they bend like crazy). Hubs are waaaaay better if they have industrial bearings or at least intact outside rubber seals (without it, the wheel can be permanently broken after one parking in the rain, especially if not perfectly greased inside). In most or many cases, a problem is to be expected there, and most likely it is a nasty, costly, pain in the ass, slippery slope problem if the bearings are not of industrial type (hard to describe it, check pictures, ask experienced riders). Rear wheel should have a shallow axle (if there’s multiple sprockets/gears). Front hubs with electicity generator may be of some use if you’ll have a phone charger, but at the tour, you’ll rarely need the light powered, and the notable extra resistance you’ll feel constantly, regardless. Rear hubs with internal gears have them not soft enough for climbs with luggage and also practically non-repairable (in some even bearings, not just gears, pose a biig maintenance difficulty).

Wheel size 26” is lighter, stronger, smaller to transport and makes gears effectively softer/slower, but 28/29” offers more puncture resistance and shock absorption for given rolling resistance, depending on the tire width. 27,5” may still use 28” inner tubes, but other replacements are rare (other sizes mean a problem even with inner tubes).

Avoid wheels with less than 32 spokes (maybe 28 at front is worse mostly by being non typical) and ones where they each spoke crosses other spokes less than 2-3 times. Stainless spokes (very slightly yellowish rather than shiny silver) are much better. Modern and higher profile (eg. deep-er ‘v-section’) rims are stronger; otherwise it’s good if they’ve eylets around the nipple holes. They’re stronger with narrow 6 mm valve hole for Presta valve, although it makes it impossible to use car pumps (without an adapter).

Frameset: it should have attachments at least for the rear rack, at least at the bottom/rear end. It’s much better if wheels are set far apart from each other, especially if rear one is far; head (front) tube: better long and not too close to vertical. Material is a matter of taste, but tour may perhaps make choosing CroMo (or better) type steel a bit better than usually. Aluminum forks transmit too much vibrations. Carbon fiber is so prone to abrasion (sanding) that it can get damaged easily in a single small accident (or, btw, from too long/intense use in combination with strong sun, or even without it).

Frame size: it’s critically important. Uncomfortable position is very tiring. There’s a huge undersupply of smaller used bikes; moreover, the common guidelines focus on young people, who also ride faster etc. People have too big bikes very often.

Raise saddle so that you almost straighten your legs (in usual shoes). It should be moved forward to the maximum if it doesn’t cause an uncomfortable bend to your back, and set flat (or minimally nose down); read also below about seatposts. Sometimes it’s possible to adjust – usually raise – handlebars, which affects the reach. Changing the handlebars to ‘riser’ type, flat with raised end, also helps a bit. [With classic headset/stem type, loosen the upper bolt and raise, never(!!) above the safety line, though; with already described a-head type, like you were adjusting the headset play (which you’ll anyway have to temporarily create) and by putting more of the rings/washers under the stem instead of on it, so the stem edge sticks out only minimally over the edge of the fork tube – if it hasn’t been installed this way already… Or, by changing the stem to one that goes more up – which also gives you a chance to adjust the reach, although you may not want to overdo this kind of change perhaps].

If you have any belly, or not too strong lower back, or if you have not so strong arms, shoulders, neck, especially if you are short(-ish), the handlebars should ideally be at least almost at the saddle level, or even a bit higher (especially if not too windy, not too fast). Then the top tube should be rather shorter than longer, if in doubt, and the reach short-ish.

It’s difficult to guess if it’s good by feeling comfortable when just sitting onto a bike. Often, with growing tiredness, people raise their upper body closer to upright position and wish the saddle was forward. Standover height should not be taken into account: when leaning to the side, you always reach the ground safely, plus, touring you don’t (dis)mount so often.

The starting points of reference for the frame sizing. (Assuming other elements as designed by the bike producer, ie. road handlebars for gravel bikes etc, flat for mountain, and so on.) There are too many factors to include to say anything for sure, different bodies etc… no rule of thumb. 165-170 cm height: XS-S//16-16.5”//48-50 cm [of seat tube length, between central points of joints – for the classic design with horizontal top tube (top tube length more relevant, but more complex topic)]. 155-160: XXS-XS//13-15”. 175-180: M//17-18”//52-56 cm. 185-190: L/XL: 19-21”//56-60 cm.

If you just build, or if you need to alter the effective size of the frame, read below about the influence of handlebar type (and seatpost). Keep in mind the handlebar stem can often be changed for one with different length and height.

Handlebars: road type (bent down and rearwards) only make sense if relatively wide, high placed, with thick tape and modern, high placed brake levers, on a frame that has top tube short-for-a-given-body height (especially for less fast/flexible people, in worse terrain). With road bars one has better weight distribution and aerodynamics, though. The ‘city’ type (bent rearwards and sideways) has the opposite effect on frame size choice – both have a big effect! Flat handlebars – better not be narrow. ‘Riser’ type ones are also good.

Almost all typical modern road handlebar-dedicated brake-shifters are non-repairable in case and tend to be more expensive, but on a right setup, offer position that’s both aerodynamic and comfortable. Thick rubber grips are better than thin. Handlebar extensions in the shape of bullhorns may feel nice on climbs and for mitigating too small a frame size, too (or inverting them to the rear when it’s too big, in desperation).

Seatpost: Saddle attachment clamp may go over 2 cm behind the frame seat tube line (not invertible), or it can go straight: ‘zero offset’ reduces vibration adsorbing, but greatly improves weight distribution and can mitigate a too big frame problem.

Tires: slick (especially at the rear), nearly always. At least 35-40 mm wide at the rear, depending on wheel diameter – better more, still – and not too much less in the front. Puncture protection layer is nice, esp. at the rear, especially for heavy setups/hard terrain.

If the front wheel and tire are nice, and pressure kept, perhaps tire shouldn’t exceed 35-45 width because of weight and rolling resistance? Btw, plastic (TPU) inner tubes, while marginally more pricey and having different installation protocol, different patches (and 5 bar pressure limit), they not only save grams, but are also harder to damage than rubber. Tubeless systems are more difficult to work with and expensive, but lighter and, with fresh sealing milk inside, largely failproof – though, largely means carry a tube in case anyway.

Gears. Compare the number of the teeth at the small front chainwheel and biggest rear sprocket (cog). It should be in the range of ca. 0.6 (heavy setup, limited leg powers, difficult terrain) to 1. Before you change your casette for bigger and make the chain longer, make sure the rear derailleur is long enough (check model).

The modern setups tend to have no front derailleur and one front gear only, with many rear gears and thinner chains. It’s lighter but much less durable, and the price of replacements is much, much worse (availability can be worse too). Can make sense if that single chainwheel is steel, but it’s rare. By the way, newer front derailleurs are much better than old ones, but all have their compatibilities with chainwheel sizes to be checked.

Saddle: cushioned well (softer is not the better, moderate is). Most afab ppl prefer wider ones than most amab people because of bones geometry. One that’s comfy for very you. Non leather (no Brooks type), even if used (may need to reshape for you, and be waxed, after which it may get bitten by wild creatures). It’s nice if it has a long and soft/wide enough ’nose‘, to allow body position changes with growing tiredness and slope alternations.

Cranks, pedals, bottom bracket. Cranks shouldn’t be longer than 170 mm (engraved on the inner side) if you’re below ca. 175-180, for the knee health. If you are tall, you can get a bit more power thanks to longer ones. If the chainwheels are from steel, they’re heavier, but they’ll last forever, rear sprockets and chain will last relatively much longer, and there’ll be a bit less cleaning. Chainwheel bolts should sit firmly and not turn easily and should not look too worn. If crank(s) have a play, it can be easily fixable or not at all. If cranks are not seated on an empty tube going through the frame bottom, good if they have a cap in the center, and under it, no spline pattern around the bolt place, and the bolt looking healthy. Avoid non-typical BBs! Don’t go for click-in pedal system you don’t use, avoid budget-looking plastic pedals, double check if they’re not stuck (see above).

Brakes. If it’s cantilever type rim brakes (wires make a triangle, no pipe), they usually have less braking power and are typically harder to adjust – sometimes really hard – and have less common brake pad type (installed with both hex wrench and 10 mm flat wrench), if it’s an old type cantilever. For v-brake (with pipe) type, the cheap ones may also have that rare brake pad type.

Headset. It’s much better to have them wider than narrower. A-head type (bolts at the side of the handlebar stem) is better than classic type.