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Arun-Adur Cyclists' Touring Club

Technical Tips

updated 20th October 2009

Contents of this page:

Brakes

Effectiveness
Have you ever descended a hill to find your brakes fading rapidly whilst contravening the radio transmission laws(see Noise) and the road junction looming up all too rapidly! The old-style single-pivot caliper brakes are well past their best and you should upgrade to a better system. However, they can be made to work better by using better brake-blocks.
I use mountain bike V-brake blocks, which come in both post- and nut-mounting, for most purposes. They are longer and are very effective but at the expense of wearing out quicker - I get through them about every six months! To get enough brake pressure on a touring/racing bike, you will need dual-pivot caliper brakes.
Shimano brake blocks last longer but are not quite as effective and can cause increased rim wear!
 
Double-pivot Caliper
A straight replacement for the caliper brake but with much more efficiency. They use the lever principal to multiply the applied force to the brake-block. Some also include a quick-release lever and fine adjustment for centralising the brakes. Depending on the frame and wheel size, you might need the long-drop versions for the brakes to reach the rims. Shimano's long drop version might sometimes not be long enough but there are longer versions but these lose a little efficiency because of the extra length.
 
Cantilever
These are OK but difficult to keep centralised to prevent brake rubbing. Also a broken straddle-wire can snag in the wheel as well as causing a complete brake failure! A fairly straight replacement with more efficiency is the V-brake system.
 
V-brake
An extremely effective system adopted from mountain bikes but you need a frame with the appropriate mounting lugs. The Shimano Acera set includes an optional 'Power Modulator' which acts as an in-line absorber and reduces the initial lock-up effect when grabbing a handful of brake!
If you are fitting these as replacements, you may require extra pull from the brake levers which can be achieved by either using compatible levers or by fitting a V-daptor.
Important Note: I have had the aluminium nipple split apart at the bottom of the 'Noodle' where it locates into the 'Yoke' and is partly covered by the 'Bellows'. This results in a complete brake failure and should be checked at regular intervals(luckily, I found it while replacing the headset bearings). On purchasing a replacement, I found that Shimano had changed the design and replaced the aluminium nipple with a large plastic version.
 
Brake Levers
Brake levers on touring and racing bikes didn't change greatly over the years until the recent introduction of the side-pull mechanism that allows cables to be routed neatly along the handlebars instead of looping over the top. Nowadays, brake and gear change levers are combined in the 'STI' levers (see Gear Levers)
In the '50s and '60s, there were also Safety Levers(sometimes refered to as 'suicide' levers because of their ineffectiveness) fitted to touring and racing bikes. These allowed the rider to use the brakes even when their hands are on the top of the bars. There is now a new equivalent of these that employs smaller versions of flat levers through which the normal brake cables are routed.
Mountain bikes and Hybrid bikes have conventional-style flat levers fitted to their straight handlebars but these vary in detail such as the amount of pull to make them compatible with the different styles of brake.
 
V-daptor
This little device, used on mountain bikes, employs a double-pulley system to increase the amount of pull generated by the brake lever and it saves having to buy new levers when upgrading to V-brakes.
 
Disc brake
A recent innovation is the disc brake but whilst improving wet weather braking, it increases the risk of brake fade due to a smaller braking surface when compared to a wheel rim and also increases complexity. There is a hydraulic version but this introduces even more complication and more things to go wrong.
They are ideal for mountain bikes where the wheel rims get covered in crud and the consequent reduction in braking performance. By moving the brakes to a central disc instead of the wheel rim, it greatly reduces the danger of water and mud affecting braking efficiency. However, disc brakes place more load on the front forks and consequently they have to be much stronger to withstand this force.
Note: Do not remove the retaining lips at the bottom of the front drop-outs when a disc brake is fitted as this can cause the front wheel to rotate out of the forks under high braking forces with disastrous consequences!
 
Brake Centering
One advantage of the newer brake systems is that most include small adjusting screws that allow you to set the distance of the brake blocks from the rims. This is ideal for reducing drag and stopping that annoying brake rubbing noise that was virtually unavoidable with the older caliper and cantilever brakes.
After applying and releasing the brakes, notice how much each brake block moves away from the rim. If the small adjusting screws are set correctly, they will move the same amount. If not, turn in the screw on the lever that moves the least(this increases the spring tension against the brake arm). If you run out of adjustment, slacken the opposite arm.
 
Noise
Brake squeal, like all other sounds, is caused by vibrations. The noise is generated by the brake oscillating back and forth as the pad grips and then slips on the rim. The remedy is to try to eliminate all slackness in the brake mounting and pivots. Check this by applying the brake hard and then try to move the bike forwards and backwards. If the brake rocks back and forth with the wheel, then there is excessive play in the pivots and/or the mounting. Also, brake alignment is an important factor. I always set my brakes pads to be absolutely square to the rim although some say that the leading edge should be nearest to the rim but after several heavy applications, wear will soon cancel this out.
 

Frame

Size
Frames are measured from the centre of the bottom bracket to the top tube. In the case of a compact frame with a sloping top tube, the measurement is to the position where a horizontal top tube would be or sometimes they simply measure the length of the seat tube. You can get frames from 18.5 top 25.5 inches(47cm to 64cm) but generally speaking, a short person should go for a frame around 20inch(50cm), an average height person should go for around 22inch(56cm) while a tall person should go for a 24inch(60cm) frame. There is a small variation to this in that you can have long legs and an average body compared to a long body and average legs. This can be accommodated by modifying the reach(seat to handlebar distance).
Too small of a frame will require longer handlebar stems and longer seatposts, the former not being recommended because of the loading exerted on it.
Too large of a frame will cause over-stretching which will be uncomfortable and can cause back and knee injuries.
The weight of a bicycle can be quite critical especially when it comes to climbing hills so it is always ideal to go for a lightweight frame.
 
Alloy versus Steel
A lot of performance racing bikes are being made of alloy nowadays which is fine if you only intend to use them for a few years - racers like Armstrong and Ullrich have a new bike for every race! The problem with alloy is that it hardens with age and then becomes brittle, consequently you really must check the frame for cracks as it gets older. Also, alloy welding tends to be lumpy and ugly compared to the intricate brazed lugs of a steel frame.
One other point is an alloy frame tends to be much stiffer giving a somewhat harsh ride when compared to the more comfortable ride that you get from a springy steel frame. This can be remedied by the use of forks, rear stays and seatposts made out of carbon-fibre.
 
Carbon-Fibre
This is used for lots of applications and in cycling, it started with front forks and has now extended to frames and complete bikes.
In the case of front forks, some still use metal for the steerer because of the headstock bearings and handlebar clamp but this requires a bonded joint between the fork blades and the steerer. I have seen this joint break in some cases and I question their use for on-road touring especially with the state of some of our roads!
In the case of frames, the manufacturers still have to use metal components where heavy loads, bearings and clamps are required, i.e., bottom brackets, rear wheel hangers, headstems and seatposts. Therefore, unless you are a serious cyclist, I would stick to a conventional frame for touring.
 
Titanium
This appears to be the best material for bicycle frames as it is very light, yet very strong and gives a ride similar to that of a steel frame. The only drawback being that titanium, though relatively inexpensive, is difficult to work and consequently manufacturing costs are high!
 
Top tube - sloping or not?
The latest fashion trend is for sloping tob tubes which has come down from mountain bikes. The idea behind it is that you get a lighter frame by reducing some of the tube lengths(pretty marginal!) while compensating with a longer, but lighter seat post. it also helps to stiffen the frame which is essential in an alloy frame as any flexing can cause cracking.
I personally think that sloping top tubes were introduced to save nasty injuries when the off-road going got very rough!
 
Down tubes - round or oval?
Another trend is for large flattened oval down tubes and again this is necessary for alloy frames to prevent flexing. Whilst giving more rigidity and strength, tube design and shapes have now become a fashion statement.
Conventional diameter steel frames have been around for many years and a really good steel bike can be the equal of any other type plus you can't beat the aesthetic look of a classic bike!
 
Maintenance
There isn't a lot of maintenance to be done on a bicycle frame except for headstock bearings and the bottom bracket.
Headstock bearings should be regularly checked for lubrication and any looseness. Check the latter by applying the front brake and rocking the bike forwards and backwards. Any clonking noise or visible movement should be fixed by adjusting the top locking nuts on threaded headsets.
If you are using the latest A-head post, I would recommend a head-lock bolt that passes right through the post and can be tightened to apply pressure to the bearings before locking the A-head stem. This also stops ingress of water and other such foreign matter into the bottom of the steerer tube.
With an alloy frame and an integrated headset, it is essential to maintain the headset because any movement will cause wear in the frame!
 
Bottom bracket bearings should also be checked for lubrication and any slackness. To check, simply hold a crank near to the pedal and try to rock from side to side, e.g., away from the frame - any movement will require adjustment to the bearings. On older style bearings, undo the locking ring on the non-chainring side and rotate the inner bearing cage to remove any play, then re-tighten the locking ring.
Stripped threads can easily be remedied by fitting a threadless bottom bracket.
With the new sealed bottom brackets, there is no adjustment and they should be replaced if worn.

NOTE: Using loose ball bearings instead of caged bearings allows more balls of the same size to be inserted into a bearing. Because the permissable load, and consequently the friction, on a bearing is relative to the contact area, more balls means a better bearing. However, building bearings from loose balls is much trickier so we have all taken the easy option but if you have the time and patience, you should return to the original method. However, they do require more maintenance if you ride in adverse conditions.

One other point about sealed bearings. Car manufacturers introduced similar products like sealed ball joints and track-rod ends but these wear out after a number of years whereas the old style with grease nipples will last forever as long as you regularly grease them.
 
Corrosion is a problem with any frame with the possible exception of the carbon fibre versions. There are three places where attention should be paid; i) front forks, ii) bottom brackets and iii) rear hangers.
i) Check for cracks where the wheel hangers are joined to the tubing and where the forks are fastened to the bottom of the steerer post. Corrosion can occur up inside the steerer by the water sprayed up from the front wheel but this can be prevented by lubrication and by fitting an insert that plugs up the hole in the bottom of the post.
ii) Corrosion occurs both inside and outside the bottom bracket from water sprayed up from the wheel and by riding though deep floods. The frame should be sprayed with WD40 on the inside when fitting or replacing the bottom bracket.
Note: If the bottom bracket threads have stripped in the frame, this can be easily resolved by fitting a very inexpensive Ofmega Threadless Bottom Bracket.
iii) Check for cracks where the wheel hangers are joined to the rear stays.
Running oil occasionally into the frame through the various holes that are drilled into it or down the seat tube, is a good idea if you intend to keep the bike for a long time and wish to ride in safety!
 

Lubrication

There are lots of lubricants on the market but as with all things, some are better that than others. Some lubricants thicken and harden with time while others become sticky. In both cases, this will increase resistance to rotation and cause drag. I personally use a synthetic grease for wheel and crank bearings plus a good light oil for general purposes and used regularly on the chain.
 

Transmission

Rear sprockets
The design of the rear gears has roughly changed three times over the years. In the early days, the freewheel was integral with the hub and the sprockets were slid over a set of splines and locked into place by the last threaded sprocket.
Then, the rear sprockets were built into a single assembly called a freewheel set which was screwed onto the threaded part of the rear hub.
Now, the manufacturers have reverted to a separate freewheel component that is fitted to the rear hub then a cassette of sprockets are slid over the splines and locked in place by a separate locking ring.
 
Generally speaking most 'racing' bikes in the early days had 5-speed freewheels with single or sometimes double chainrings. Nowadays, this has increased to 7, 8, 9 or even 10 at the rear with double or triple chain-rings giving anything from 14 to 30 gears. While this sounds great, you can spend more time changing gear than cycling as well as having duplicate ratios!
 
Adding one extra gear can be done without too much trouble as the sprockets are closer together and so will fit in the same space. Any more than one extra sprocket and you will have to 'spring' the rear frame by a few millimetres. If you have an old-style gear change, it won't matter how many gears you have so long as the lever and the mechanism has enough travel. However, indexed gear changers may only accept a change of one extra gear if at all.
 
Chainrings
Changing from a double to a triple chain-ring is straight-forward so long as you have a bottom bracket that gives the necessary clearance between the innermost chainring and the frame's rear chain-stay. If not, you will have to change the bottom bracket for one with a larger offset. You will have to increase the travel of the front derailleur by adjusting the setting of the stops and then it should still work OK but if not, you will need to fit one with a deeper chain guide.
 
Cranks
If you are tall with long legs and have a 24inch(60cm) or larger frame, you should use a 172.5 or 175mm crank. Conversely, if you are short(sorry, vertically challenged!) you should change to a shorter crank, say 165mm. The idea is to maximise pedal effort to achieve the optimum cadence rate without too much stretching and stress.
Note: Don't forget to re-adjust the seat height if changing to different length cranks.
 
Ratios
I, personally, find that a 52-12(ratio of 4.33 or 112.67inches) lets you really power down those hills while a 30-32(ratio of 0.94 or 24.37inches) gives you a great granny gear for hill-climbing! Honking should be kept to a minimum as it strains the legs and the transmission.
You can achieve these ratios with a 7 or 8-speed 12-32 freewheel or cassette with a triple 30-42-52 chainring.
A fitter cyclist can do away with the lower ratio sprockets and use a 12-28 with just a double 39-52 chainring giving ratios from 4.33 to 1.39 A 40-52 or a 42-52 chainrings don't quite give a low enough gear and can also produce duplicate ratios. A 39-53 is OK for racing but the step is too great and you will find that you will need to change to a different rear sprocket at the same time as changing the chainring - not the best option.
The latest fad is for a 'compact chainset' which uses 34/48T chain-rings but I reckon that this doesn't give you a low enough ratio for climbing hills and you run out of gears on the downhill bits! You can't beat a good triple.
Ratios are affected by the wheel size, i.e., a ratio of 1.22 on a 27" wheel gives a ratio in inches of 32.94 whereas the same ratio on a 26" wheel gives 31.72inches. Also, different makes and types of tyres have different profiles(height) so they too can alter the ratio. This is why the proper way to measure gear ratio is in 'inches' using the formula, Chainring divided by Rear Sprocket multiplied by Overall Tyre Diameter.
 
Chains
Chains are available from a variety of manufacturers and they vary in quality. I always recommend buying quality chains from a good manufacturer especially as I have now had two chains split on me(one was a Shimano!).
Generally speaking, most chains are rivet-linked requiring a chain tool to fasten them but you can also get ones with various types of split-links. If you ride regularly, I suggest you change the chain every year and do not re-use a chain by re-riveting a link more than once as the rivets are only an interference-fit.
Note: When buying a new chain, you must also buy new rear sprockets at the same time because the chain stretches and wears the teeth. If you don't, you will find the chain will jump on the rear sprockets, especially under load.
Chain wear can be measured by how much the chain has stretched - one outer link plus one inner link is 1 inch in length, so 10(ten) links measure 10 inches when new. 'Honking' or standing on the pedals and grinding up hills in a high gear will really stretch chains and increase sprocket wear. Ideally, you should select a lower gear, stay seated and spin the pedals. However, a little bit of honking will help to use different muscles which will minimise any strain or cramp and relieve pressure points on the saddle!
You will have to fit a narrower chain when fitting a rear cluster with more sprockets to give more gears. There are many widths and Shimano have a size table on their packaging.
The correct length of chain can be worked out by fitting the chain directly from the largest chain-ring to the largest rear sprocket missing out the rear derailleur and then adding a link (one outer plus one inner). It is also advisable to ensure that the centre-line of the chain-ring is in line with the centre sprocket of the rear cassette. You may need to change the bottom bracket for one with a different width to achieve this optimum alignment, which reduces chain wear and gives smoother gear changing.
 
Rear derailleur.
There are several different manufacturers of rear derailleurs(mechanisms) and they come in a variety of different shapes and sizes. The main criteria is how many sprockets, e.g. 7, 8, 9 ,or 10 and what size is the lowest ratio sprocket. The first factor governs how much travel is required and the second governs how much clearance is required by the cage(the frame containing the two jockey wheels).
A Short derailleur will only accommodate up to a 28-tooth sprocket whereas a Long derailleur will accommodate up to a 34-tooth sprocket.
 
Note: There are a lot of different components available from gear levers to sprockets and mixing them is not recommended as each has it's own requirement. However, there is some tolerance and some combinations have very small discrepancies so they can be made to work together but it can be expensive finding out.
Recent articles in the CTC magazine, Cycle, make good reading and go into much greater detail offering some fairly satisfactory combinations.
 
Gear Levers
There are five types of levers that are in use on bikes today, namely Down-Tube, Flat-bar, Bar-End, Indexed and STI.
Down-Tube levers are somewhat old-fashioned nowadays but they were the only ones at the time. Their advantage is that they have a shorter cable run and being the friction-type changer, they can accommodate any number of sprockets/chain-rings. The disadavantage is that you have to ride one-handed while you move your other hand down to change gear. You also have to become adept at judging the exact amount of movement to engage each gear.
Flat-bar levers are fitted to touring, hybrid and mountain bikes that have flat handlebars. Earlier versions were friction but nowadays, they are all Indexed.
Bar-End levers are similar to down-tube levers but as their name implies, they are fitted into the end of drop-style handlebars or tri-bars. The main advantage being that you do not have to let go of the handlebars to change gear.
Indexed levers work on the ratchet principle and have a series of clicks which relate to each change of gear, e.g., Shimano Index System(SIS). The advantage is that changing gear is very quick and simple when they are set correctly. Their disadvantages are that you can only change one or two gears at a time and they have to be compatible with the derailleurs.
STI levers are the "new kids on the block" and they are basically a combined gear and brake lever in one unit. The advantages are that cable runs are neater and gear changing can be performed while braking at the same time. The disadvantages are that they are expensive and they have to be fitted along with compatible brakes and derailleurs.

At this point, I feel I should make a mention to Safety Levers. These were fitted to brake levers in the '50s and '60s and consisted of an extra lever that was fitted to the inside of the brake lever and followed the contour of the handlebars. This meant that you could ride with your hands on top of the bars and still be able to operate the brakes in an emergency! Their disadvantages were that they were inefficient (this was compounded by the poor brakes in those early years), they made it difficult to fit a bar-bag and they rattled due to wear in the aluminium pivots.
However, with recent improvements in brakes, these are very useful items to have(I have two old bikes fitted with them) and nowadays you can get a kit to fit separate mini-brake levers on top of the bars and in-line with the normal brake levers.


Tyres

Tyres have a major effect on performance. Consider, at the extreme, the difference between a knobbly tyre and a narrow racing tyre. On the road, the knobbly off-road tyre gives lots of drag(and noise) making it harder to push along whereas the racing tyre is thin and light and so allows you to ride faster with ease. Both of these have their rightful places and that's how it should be.
Now consider different road tyres, i.e., touring and racing. These tyres behave the same as the above but to a lesser extent. It is considered an impossibility for a bicycle tyre to aquaplane because of the weight exerted through the very small contact area with the road, therefore tread design, although psychologically re-assuring, is somewhat immaterial on the road.
The ideal tyre is a lightweight narrow tyre with a different rubber compound on it, e.g., hard on top and soft on the sides, e.g., Continental Grand Prix/Ultra Gatorskins, Vittoria Rubinos or Hutchinson Excel Kevlars. However,these are not ideal for long distance touring where you need a more robust, more puncture-resistant and more comfortable road tyre, e.g., Schwalbe Marathon or Marathon Plus.
If money is not a problem, you could get a pair of lightweight narrow wheels and tyres, e.g. Bontragers or Mavic Kyseriums with Continental Supersonics, for sprinting and fast rides as well as having a set of stronger wheels and tyres for touring(or better still, two different bikes!)
When fitting a tyre, always make sure it is seated properly on the rim otherwise, it will not run straight and will cause wheel-wobble. To check the seating, there is a line in the rubber moulding just above the rim and you should be able to see this clearly and evenly spaced from the rim all the way around the wheel on both sides.
 
Punctures
If, or I should say, when you get a puncture, you may decide to mend it. If you are out on a ride, it might be easier and much quicker to simply fit a new tube. Of course, you do carry a spare tube! And don't forget to check and remove the offending thorn or flint in the tyre first!
To minimise the number of punctures, it is a good idea to buy puncture-resistanttyres which are usually identifiable by the addition of Kevlar in their construction. The thickness of the Kevlar layer and consequently, the resistance to punctures, varies from tyre to tyre, but generally speaking the Schwalbes are amongst the best.
When mending a puncture, always check the tyre for inward facing thorns or flints that have been forced through the tyre before fitting the replacement tube. Sometimes these pieces of debris can be very difficult to spot and you don't want to repair it twice! If you squeeze the sides inwards, this will open up the tread area making it easier to see or feel any objects buried in the rubber. Alternately, remove the tyre completely and turn it inside out and check for protruding objects.
One common form of puncture is nicknamed the "snake-bite" because of the appearance of two holes on either side of the tube at a particular point. It is caused by the impact with a pot-hole causing the tube to be pinched against the rim. It is more likely to happen with under-inflated tyres.
You should consider replacing a tube whenever it reaches the third patch as it will start to become mis-shapen giving the tyre a wobbly appearance(see Wheel balancing )
 
Tyre-saver
If you suffer with lots of punctures, you may consider fitting a tyre-saver assuming that you are one of the more considerate club riders who fit mudguards. This is a bent piece of wire with a plastic sleeve which is usually attached to the lower end of the mudguard and the sleeve part runs on the tyre. The idea is that the tyre-saver catches flints and thorns so removing them before they get buried deep into the tread by the subsequent rotations of the wheel.
Note:  I recently re-tensioned the spokes in my rear wheel and found two very small pieces of flint buried in the tread. If I had left them there and continued to ride the bike, the tyres would have punctured eventually!
 
Puncture-resistant
Nowadays a lot of touring tyres are claiming to be puncture-resistant usually by the addition of Kevlar. This claim tends to be of a somewhat varying degree and only after quite a few purchases and some experience, will you decide in favour of one particular tyre. I prefer the Schwalbe Marathon as I have only ever suffered one puncture in four tyres. I even passed a hedge-trimming machine near to Ardingly on the 2001 Mid-Sussex Hilly and while others were busy with their puncture repair kits, I amazingly rode through the lot and on to the finish. It was only the next day that I found my front tyre as flat as a pancake due to two thorns!
A recent introduction by Schwalbe is the Marathon Plus which has a gooey rubber layer under the tread that actually forces foreign objects back out and on a particular test, a drawing pin couldn't puncture the tyre! However, there is also a weight disadvantage of nearly 1kg per tyre!
 
Pressure
It is important that tyres are run as close to the recommended maximum pressures as possible. Under-inflated tyres make for increased rolling resistance, harder pedalling and a susceptability to sidewall failure. However, over-inflated tyres will give a much less-comfortable ride and the danger of a blow-out due to heat from the brakes or exposure to strong sunlight. I usually inflate my tyres to 90% of the maximum recommended pressure which is marked on the sidewall of the tyre.
I have also experienced several punctures caused by the valve body separating from the tube. After a lot of experimenting, I have come to the conclusion that they are cheap tubes for the Far East. You should also take some care when inflating tubes with long valve bodies.
 
Rolling resistance
Assuming you keep your tyres well-inflated, you also need to have tyres with a minimum rolling resistance to make cycling as easy as possible. Rolling resistance(or drag) is the friction between the tyre and the tarmac, but unfortunately most manufacturers don't provide this type of information. However, on some high performance tyres, they do specify different rubber compounds for the top and sides therefore implying better(or less) rolling resistance.
You all know how hard it is to pedal a mountain bike with knobbly tyres on the road as compared to a touring cycle on smooth tyres. Ideally, tyres that produce the least noise on tarmac are the most desirable as noise is another by-product of rolling resistance, e.g., more noise equals more resistance!
I generally use Continental Ultra Gatorskins which happen to be cheaper than the Schwalbes but claim to be just as puncture-resistant and give less rolling resistance. They are certainly quicker as they run at higher pressures, e.g.,100-120psi and have less tread. They have also covered several miles of rough tracks without any problems but I would not recommend doing this too often with these tyres. I have also used Continental Grand Prix, Grand Prix 3000 and 4Seasons which are faster still. Another point worth mentioning is that in recent tests, coloured rubber tread does not wear as well as conventional grey or black rubber compounds.
To go quicker and to climb easier, the best upgrades to your bike will be a lighter set of wheels and tyres. The lightest tyres are skinny, i.e., 700 x 23, and instead of a wire beading, they have a kevlar beading and are usually called 'folding' tyres.
However, a very narrow tyre does not necessarily give better rolling resistance than a slightly wider version of the same tyre. The reason for this is that the same weight pressing on a smaller contact area produces a greater load and consequently, more deformation of the tyre resulting in more drag.
The ride factor of a tyre is also affected by it's size compared to the wheel rim, i.e., a narrow tyre on a slightly wider rim will give a very harsh ride whereas a slightly wider tyre on a narrow rim will give a more comfortable ride.
When buying tyres, take into account the type of roads that you ride on, the size of your wheel rims and the all-up weight of you and your bike.
 
Maintenance
The tyre is the only point of contact you have with the road and your life can literally depend on it. Always fit good tyres and replace them when they get badly worn or they have deep cuts. The last thing you want is a blow-out when you are descending at 40+mph.
Also, leaving a tyre for long periods in damp conditions and in sunlight can cause the rubber to perish, harden and crack. Always keep tyres inflated as the sidewalls will crack when they are flexed too much for long periods.
One other important point is that when taking your bike to hot climates, you must not have tubes with any patches, i.e., puncture repairs, as the patches will lift in the heat!
 

Wheels

Two round ones are the best option for most bikes and that's where the similarity ends!
Wheels and tyres should be as light as you can possibly afford because it's the rotational mass that consumes the power of the rider. Hence, lighter means easier to push up hills and faster on the flat.
The earlier 27" wheels and their corresponding tyres are getting harder to find but are still available. Tyre widths are usually 1.25" and the rims are the standard flattened-U shape and that's about it.
The most common sizes now are 26" and 700(metric) which are available in various rim shapes from the standard flattened-U to a very deep aerodynamic V-shape. You can also get them with a variety of spoke holes from 14 up to 40 and even carbon composite versions.
For strength and the most comfortable ride, you should choose a fairly conventional U-shaped rim with the normal 32-hole front and 36-hole rear number of spokes. However, if you want to go time trialling or racing, then deep aero-rims or carbon fibre wheels with fewer spokes are for you depending on the depth of your pocket!


Note: MAVIC are voluntarily recalling all models of their R-SYS front wheels as a precautionary measure due to the possibility of the carbon tubular spokes breaking under certain circumstances. MAVIC have been exchanging the wheels since 31st March 2009 and if you need any further information, use this link to contact MAVIC.
 
Trueing
Normal riding on bumpy roads and constant crashing into potholes can distort rims. You should regularly check your wheels for being true and for spoke tension. Spokes can be checked by tapping them with a screwdriver as if it was a tuning fork and checking the sound of each spoke for equal tension. Remember to tighten the two spokes on either side at the same time as the loose one in order to keep the wheel rim straight and true. In order to minimise distortion, several small adjustments are much better than one or two big ones.
The benefits are that the wheels run better and more importantly, your brakes will be more efficient because they won't be oscillating from side to side(see Brake Noise).
 
Balancing
Have you ever lifted your bike and spun the wheels fast. Apart from the gyro effect, did you noticed any shaking, i.e., a tendency for up and down movement. This is due to the wheel, tube and tyre assembly not being balanced and it will not run as well as one that has been balanced.
Simply take the wheel out of the bike and ensure that the spindle is free to rotate without any looseness in the bearings(see Lubrication). Now hold the wheel by the spindle and if it rotates, allow it to settle. Of course, the heaviest point will stop at the bottom and you should place lead weights directly opposite this point. If it's the front wheel, use the computer magnet to balance the wheel.
Otherwise, I use small squares of lead sheet held in place on the inward-facing portion of the rim by double-sided adhesive tape. When you have found the correct amount to balance the wheel, you will find that the wheel will stop in any position after giving it a slight nudge to make it rotate. Now spin the wheel fast and it should run smoothly with no shaking!
Note: Always fit the tyre with the manufacturers log next to the valve so that you can position it in the same place every time. Also, if you change either the tube or the tyre for a different one, you will need to re-balance the assembly.
 
Rims.
You can get wheels with a variety of types of rim and they are all designed for a purpose. For comfort, you should stick to the conventional U-shaped rim as these give some 'springiness' to the wheel. V-shaped rims are more aerodynamic, stiffer, stronger but depending on the depth of the V, they give a less-comfortable ride.
Ceramic-coated rims are a neat idea and are supposed to be more effective in the wet but they don't appear to be too popular as there aren't that many about. However, one of our members has had a pair of wheels with ceramic inserts for five years and the same brake blocks and neither have worn out even after many, many miles! You do need special brake blocks for ceramic rims!
Rim wear is something that all cyclists should take very seriously! I know of a few cyclists who have detected rim failures just in the nick of time plus one or two who didn't and ended up with nasty accidents when the brake blocks went completely through the rims.
All friction produces wear and the grey slime that you find all over the wheel rims and tyre sidewalls after riding in wet weather is a combination of brake dust and aluminium powder from the rims! After many years, the rims will eventually become so thin that they will collapse under the pressure from the tyre or the brakes. If it happens because of the former, you simply have a blow out but if it's the latter, you will find the wheel will lock up as the brake buries itself into the rim. This may be a good advert for disc brakes!
It is very difficult to measure the thickness of the rim but the age of the wheel is one indication and something I do often is to press the corner of a flat-blade screwdriver into both sides of the rim in several places. If it is easy to leave an impression in the rim, then it is too thin and you must replace the wheel or get it re-rimmed immediately. Another indication is that the flat side of the rim starts to become concave as the tyre pressure forces the thinning rim outwards!
 
Aerodynamic rims
Lots of wheels are becoming available that have a deeper cross-section rim, e.g., V-shaped, than the classic shallow U-shaped rim. There are advantages and disadvantages as explained below:-
 
Advantages.
    Stronger and stiffer wheels.
    Recessed threaded spoke bosses
    Smoother inner surface for the tube.
    Spokes can be adjusted without the danger of puncturing the tube.
    Less spokes can be used so producing less air turbulence.
    Deeper rims disturb the air less and are more aerodynamic
 
Disadvantages.
    Are less comfortable for touring.
    Can be affected by crosswinds.
    Require tubes with longer valves.
 
Note: Always use a strong plastic rim-tape!