LOOSE nuts and slack bearings -are the cause of most mechanical defects, not to mention defects arising from lack of lubrication. Neglect to make a minor adjustment may result in considerable labour and inconvenience in replacing a broken or worn part. The golden rule for the cyclist is to keep all nuts tight, all bearings free but not slack, and all moving parts well lubricated and free from dirt.
When tightening nuts always use a well fitting spanner and never exert brute force. To attempt to lock a nut once and for all is to expect it to serve the purpose of a rivet, and the attempt often results in damage to the bolt, the nut, or the knuckles. Nuts and bolts are used for securing components to one another, because they may be removed easily when required. Nevertheless, nuts may work loose by vibration and should, therefore, be tightened periodically, going over the machine with suitable spanners.
The aim of oiling and greasing should be to maintain a thin film of lubricant between the bearing surfaces of all moving parts. Surplus oil on external parts only collects dirt, to the detriment of any clothing that may come into contact with it. Therefore oil sparingly and often, using the oil can in one hand and a rag in the other to wipe off surplus oil.
Checking the nuts and oiling is a ten-minute job and should be made a weekly routine. The amount of time spent on cleaning and polishing is a matter of individual temperament. Dullness of plating and enamel will not impair efficiency, but regular cleaning and polishing of the frame and fittings will prevent the formation of rust on exposed metallic surfaces, will preserve the enamel from flaking and retain something of the pleasant neatness in appearance which characterized the bicycle when new. See Rust Prevention, p. 411.
Regular attention to the details outlined above will reduce running repairs and adjustments to the minimum, but wear is inevitable in long service and certain adjustments are necessary to keep the machine in first class condition.
- 1 Adjustment of Bearings
- 2 Hub Bearings
- 3 Crankshaft Bearing
- 4 Steering Head Bearing
- 5 Pedals
- 6 Adjustments and Repairs
- 7 Road Wheels
- 8 Handlebars
- 9 Saddle
- 10 Brakes
- 11 Variable Gears
- 12 Lamps
- 13 Tyres
- 14 Cyclists’ Tool Kit
- 15 Re-enamelling
- 16 General Information
- 17 Repairing Mudguards
- 18 Tyre Sizes
- 19 Spokes
- 20 Verifying the gear number
- 21 Rust Prevention
- 22 Replacing Brake Blocks
- 23 Brake Cables
- 24 Guarding the Bike
- 25 Speedometers
- 26 Tandems
- 27 Preparing a Tour
- 28 Safety First
Adjustment of Bearings
There are six main bearings in the structure of a pedal cycle, all of the ball and cone type. These are: the hub bearings in the two wheels, the two pedals, the crankshaft or bottom bracket bearings, and the steering head bearings.
In all cases the adjustment should be tight enough to eliminate all play, without preventing free rotation.
If the wheel rim shows any lateral movement between the forks the hub bearings need adjusting. Place the machine inverted on a level floor and protect the handlebars from abrasion with a cloth pad. Loosen the spindle nut on one side and screw in the cone sufficiently to take up excqss play, using a cone spanner. If the cone is taken in too much the wheel will not spin freely and will emit a slight grinding noise when rotated. Use a light touch and go by the feel of the adjustment. Finally tighten the spindle nut. Then spin the wheel by hand to ensure that it rotates freely.
This bearing is housed in the bottom bracket and has an adjustable cup on the opposite side from the chain-wheel. The cup is held by a locking ring which must be loosened, and re-locked after adjusting the cup. Both cup and locking ring are turned by the use of the reverse end of the cone spanner which has two spigots that engage in special holes drilled in the face of the ring and similarly in the cup.
Steering Head Bearing
Slackness in this bearing, though it may not noticeably affect the steering, gives rise to an unpleasant ‘juddering’ when the front brake is applied, and if neglected, sets up uneven wear in the bearing races. At the top of the steering head there is a collar that is locked by means of a nut and bolt passing through a split lug. The adjustment is made by loosening the nut and tapping the collar down to take up the slack, after which the nut is re-tightened. An alternative to the collar is a knurled ring locked by means of a hexagon lock nut. In this case the nut is first slackened anti-clockwise and the ring screwed down sufficiently to take up the slack without restricting free rotation. It is then locked tight with the lock nut. In either case it is well to take the weight off the bearing while making the adjustment, by supporting the front wheel clear of the ground.
The pedal bearings are adjusted by means of an adjustable cone and lock nut. After removing the dust cap the lock nut is loosened and cone adjusted by screwing clockwise with a cone spanner, the same care being exercised to feel the right setting.
If it is necessary to remove a damaged pedal, use the cone spanner which fits the flats on the shoulder of the spindle which screws into the crank arm. Note that the pedal on the right-hand, or chain wheel side, is screwed with a right-hand thread and the one on the left-hand side with a left-hand thread, the object being to prevent the left-hand pedal from coming unscrewed by the action of pedalling.
Adjustments and Repairs
The chain. This item being exposed to the effects of road grit and mud, requires a little extra attention. Accumulations of dirt should be wiped off with a rag and each link should be given a spot of oil that is thin enough to penetrate between the rollers. This may be followed with a smear of grease on the rollers or the teeth of the chain wheel. The chain is joined by a link that has a detachable side plate held in place by a spring clip. When the spring clip is prized off and the plate removed, the link can be extracted to allow the chain to be removed for cleaning. It should be thoroughly flushed in a bowl of paraffin and then placed on a hot stove to dry out all trace of residual paraffin. It is then immersed in a bath of fairly thick oil (containing graphite) heated to ensure complete penetration.
The chain adjustments should be such as to give ½ in. of sag when depressed at a point half way between the two sprocket wheels. The adjustment is made by loosening the nuts on the rear wheel spindle and sliding the spindle in 4o6 IN THE GARAGE the slotted forks to the required position. In re-tightening the nuts make sure that the wheel is in true alinement, I.e. that the spindle is set at right angles to the longitudinal axis of the machine.
To check for a twisted or buckled wheel the cycle is placed inverted on the ground, and, with the wheel spinning, a stick of chalk is held against the forks with its point lightly touching the rim. If this produces a continuous chalk line all round the rim, all is well. Any gap in the line denotes that the wheel is out of true. If the amount of error is not great it should be possible to bring the rim back into line by manipulation of the spoke tension. Examination of the spokes in the region of the gap may reveal loose or broken spokes. Loose spokes can be tightened with a nipple key after their opposing spokes have been slightly slackened. A broken spoke should be replaced by another of exactly equal length and gauge. It should be threaded through the appropriate hole in the flange of the hub with the head facing either inwards or outwards after the manner of the old spoke. The screwed end is then inserted in its hole in the rim of the wheel when the nipple may be engaged on the spoke thread and correctly tensioned with the nipple key. A wheel that is seriously out of truth or buckled should be placed in the hands of a capable cycle repairer as the job requires specialized skill.
At the top of the handlebar stem is the hexagon head of a long bolt which passes right down inside the stem to a conical nut at the bottom. When the screw is tight, the nut is drawn upwards into the stem, which is split at the lower end, and is thus expanded to grip the fork tube. To alter the height of the handlebars, the screw is undone several turns and tapped down to free the cone from the bottom of the handlebar stem. The handlebars can then be raised or lowered with an alternate twisting motion while the front wheel is gripped between the knees. The screw is re-tightened when the handlebars are at the desired height and at right angles to the front wheel. The height of the handlebars should be slightly above the saddle level.
The position of the saddle must be adjusted to suit the individual needs of the rider. As a general guide the tip of the saddle should be 2 in. back from an imaginary line perpendicular to the bottom bracket, and the height should be such that it is possible to reach the pedals with the heels at the fully extended position.
A nut underneath the saddle provides for adjusting the position forwards or backwards and setting the tilt, which should be slightly upwards. The height can be altered after loosening the nut at the top rear of the seat tube.
Wear in the brake blocks should be taken up by means of the adjusting nut on either the Bowden cable or rods. There should be equal clearances between the brake blocks and the rim on either side of the wheel. Unequal clearances may indicate that the wheel is buckled or not in true alinement between the forks. Hub brakes are fitted with internal expanding shoes and are adjusted at the arm on the outside.
The two chief types of gear changing devices are: (a) the hub gear, in which the mechanism consists of a set of gear trains enclosed within the rear hub, and (b) the Derailleur system in which the rear wheel is equipped with two or more related cogs with a cable-operated device for transposing the chain to any selected cog.
The hub gear, being totally enclosed, runs in oil and is protected from dirt and grit. In normal use it needs no attention other than oiling. It is controlled by a cable connected to a selector lever mounted on the top tube or the handlebars. The setting of the selector is a sensitive one. Any stretch or play in the cable that develops in use must be taken up by means of the adjusting nut provided on the cable so as to retain the correct setting. Lubrication of the moving parts of the control should not be overlooked in the general oiling routine.
The same applies to the control of the Derailleur gear. This system, having a direct drive to the selected cog, is more robust than the hub type gear where the drive is transmitted through an intermediate train of gears. It is therefore particularly favoured for use on tandems where the transmission is subjected to the extra strain imposed by two riders. It has a further advantage to the enthusi: st in that with little extra expense in alternative set of gear ratios can be obtained by substituting cogs of different sizes.
If a lamp fails and the bulb and battery are in good order, the fault will probably be found in the switch. Where a dynamo supplies front and rear lamps the wiring and connections should be examined for breaks, faulty insula- tion, or short circuit due to a loose strand of flex touching the lamp casing or frame. The ciixuit can be tested by connecting a battery in place of the dynamo, and if the fault is thus narrowed down to the dynamo it should be returned to the dealer or manufacturer for servicing.
Tyres should be kept hard to ensure long life, and embedded flints should be picked out with an old pen-knife. Any open gash left after the removal of a large flint should be filled with tyre filler, obtainable from any cycle dealer.
Instructions for patching a punctured tube are given with the puncture repair outfit; but first it is necessary to find the puncture. A fast puncture, one that lets the tyre down in say half an hour or less, is in most cases easily traced. Examine the tread for such things as a nail or flint. If one is found extract it, and having pumped air into the tyre, place a wetted finger over the hole and look for bubbles. If you are able to locate the puncture in this manner mark the location of the puncture with chalk. Next let down the tyre by removing the valve, and lever the cover off the rim in the locality of the leak. Pull out the tube and find the hole by visual inspection.
Clean the area around the puncture with a rag moistened with petrol. In the absence of petrol the head of a match makes an effective cleansing agent. First apply a small quantity of water on the spot to be cleaned, then rub the match over the area until a paste of sulphur is formed and wipe dry with a clean cloth. Apply a thin coat of rubber solution worked in with the finger tip. Select a suitable patch and peel off the linen backing. Leave both tyre and patch exposed to the air for as long as possible to dry out the volatile solvents. This is important; many cyclists experience trouble with patches lifting in the heat of the summer, causing a slow leakage of air that is sometimes difficult to trace. This trouble is the result of using too much solution and not letting it dry out. To repair a puncture and adjourn for tea while the solution dries, is a practical insurance against future trouble.
Place the patch in position and press firmly, dust the patch generously with French chalk, re-fit the tube to the wheel and replace the cover. Take care when using tyre levers, not to pinch the tube and create a new puncture. A little air pumped into the tube reduces the risk of pinching.
To trace a slow puncture the tube must be taken wholly out of the cover; in the case of the rear wheel it should be taken out on the side away from the chain. The tube is then pumped to stretching point and it may be possible, in quiet surroundings, to hear the escaping air by passing the tube slowly round close to the ear. Having thus located the approximate position, examine it closely for a minute pinhole and test by a wet finger for bubbles to prove the existence of the puncture. Failing this, the last resort is to pass the tube slowly through a bowl of water and look for bubbles.
Last, but not the least of the precautions for locating a puncture is the testing of the valve with a globule of water on the inlet stem before attempting to remove the tube. If this is overlooked, a leak due to faulty valve seating may be temporarily rectified in the course of deflating and re-inflating the tube, causing some perplexity when all subsequent efforts fail to reveal a leak.
In any case valve rubbers need to be changed from time to time. In doing so, see that the. Valve seating is free from adhering fragments of perished rubber, and that the new valve rubber fits well over the tapered shoulder of the inlet stem and extends a little beyond the bottom of the stem.
Cyclists’ Tool Kit
Puncture repair outfit containing patches, rubber solution, and French chalk.
Pump and connector.
Oil can, cycle oil, graphite grease, and rags.
Combined cone spanner and cup key.
Selection of set spanners to fit ½ in., -¾-in., ½ in. and -fin. Nuts.
Spoke nipple key.
Spare chain joint link.
Secondhand bicycles when purchased are fairly frequently in need of a coat of enamel and even the well cared for machine may eventually require re-enamelling. The first consideration is the selection of a room or shed from which the dust on the floor has been thoroughly removed. The room air should from this point of view be as free from dust particles as possible.
There is a large variety of cycle enamels on the market, many of which give excellent results but it is advisable to purchase a well known and generally approved enamel as the constituents do vary fairly considerably in the inferior brands.
Having purchased the enamel and found a suitable room for the enamelling, carefully dismantle the bicycle and clean all the enamelled components such as the frame and front forks, etc. with hot water and soap. Dry them off and using a metal scraping tool remove all the defective enamel, then with a medium grain emery paper thoroughly clean the metal. Wipe the surfaces with a rag soaked in petrol or turpentine. There are proprietary liquids on the market for the removal of enamel but the former method if thorough gives very good results.
Before attempting to enamel the components remove all the flakes of enamel from the floor and the bench if the latter is used. This is an important point as the enamel flakes have an insidious tendency to reappear as spots in the freshly enamelled surfaces.
A good brush with fine soft bristles is also an important accessory to efficient enamelling. Do not purchase a cheap and obviously inferior brush. One about 1-in. wide rather like ‘a flat fitch’ with softer bristles, is large enough.
Now apply the enamel to the surfaces. The first coat should be very thin. It does not matter if the metal shows opaquely through the film of enamel. Having treated the appropriate components suspend them by wire or some similar means so that they hang free of each other (I.e. not touching) and allow the enamel to dry and harden thoroughly.
They should then be lightly glass-papered with a fine grain glass-paper and wiped with a clean napless rag. Apply the second coat of enamel which will adhere quite readily. The second coat may be somewhat thicker than the first but only just thick enough to hide the metal. Allow the second coat to dry and harden. Repeat the glass-papering if necessary and wipe down with a clean rag. The second coat may be satisfactory, however, in which event glass-papering and the application of another coat may not be required, although a series of thin coats does produce excellent results. Never overload the brush with enamel, and do not allow excess of enamel to accumulate at joint angles, etc. as this will cause the enamel to run or collect in unsightly blobs.
When removing the inner tube from the rim of the rear wheel, (I.e. with the wheel still in the frame) to repair a puncture do not take it out on the chain side of the wheel. This measure will avoid the risk of contaminating the tube and the hands with oil from the chain.
If the bicycle carries electric battery or dynamo lamps always take extra bulbs either in the pockets or stored in the saddlebag when travelling at night.
Steel mudguards are the usual standard as fitted to new machines. Some are very satisfactory but others tend to crack or fracture as a result of unavoidable vibration at the points of attachment. If the mudguard is of thin gauge material of the inferior type it may be well worth while replacing it altogether by a new mudguard which can, if required, be of celluloid or aluminium alloy. Temporary repairs at the strut attachment may be made by soldering the crack, riveting on a patch of sheet-metal, or if practicable fitting two large washers at the bolthole from which the fracture radiates. Cracks in celluloid mudguards can be repaired by the application of a transparent celluloid patch after treating the affected area with a suitable solvent. Amyl acetate solutions, available under proprietory names, should be used for this purpose. Fractures in aluminium mudguards may be repaired by riveted patches of similar material if replacement by a new mudguard is not contemplated.
Mudguards sometimes tend to twist or warp. This defect can often be remedied, if the attachments are secure, by bending the supporting struts as required. Ensure that the mudguard is not in contact with the wheel.
Wheels are identified by their diameters. Thus a 26in. Wheel is a6in. In diameter and only 26 in. tyres can be fitted. On the side face of the tyre will be seen a specification such as this:— 26 x if. The latter measurement indicates the depth and width of the tyre when it has been fully inflated by the inner tube. This measurement must conform to the fitting width of the wheel rim. Wheels may be 28 in. diameter for large frames and the width of rim for both 26 and 2Sin. Wheels may be iin. Or igin.; but in any event the outer cover and inner tube to be fitted must agree with diameter and rim width of the wheel.
After considerable use the top ends of the spokes (I.e. in the rim of the wheel) tend to rust and the canvas protective band, which protects the inner tube from contact with any possible sharp edges at the ends of the spokes, deteriorates, allowing the inner tube to bear against the metal. If this is the case remove the canvas band and fit a new band after cleaning the groove of the rim. Smear a very small quantity of petroleum jelly on the inner ends of the spokes, not enough to cause it to soak into the canvas band, as otherwise this will affect the rubber of the inner tube.
Verifying the gear number
To determine the fixed gear ratio of the pedal or front sprocket to the hub sprocket is quite an easy matter. It is assumed for the sake of example that the wheels are 26in. Type. Count the number of teeth in the front sprocket and multiply by 26—e.g. 52 teeth x 26 = 1352. Now count the number of teeth on the rear or hub sprocket which we will assume is 14. Divide 1352 by 14. The ratio then is 96.5. The number of teeth on the front sprocket may be anything from 40 to 60 and the number of teeth on the hub or rear wheel sprocket from 12 to 22, thus it will be seen that a wide range of ratios will be obtainable by changing the front and/or rear sprockets For general purposes a gearing of about 65 will be suitable for men and about 59-60 for women.
It should be noted that the numbers 96.5 or 65, 59 or 60 are meant to represent the diameters of circles in inches, and the distance travelled in feet by the bicycle can be expressed by multiplying the diameter by following a simple formula. (96 x 37) H- 12 = 25 ft. approximately.
It will be seen then that the cycle owner may alter the ratios of the front and rear sprockets to suit individual requirements or, alternately, variable speed gear hubs may be fitted.
The enamel on the frame can best be preserved by observing two simple rules. When not in use keep the bicycle under a dry shelter and never allow rain water or mud to remain overlong on the surfaces. Obviously it will not always be possible to store the machine under shelter during inclement weather and also the cycle may often be in use during rainy conditions. But at the earliest opportunity moisture and mud should be removed. Particular attention should be paid to the crevices and joint angles of the frame both on enamel and chromium parts. Do not neglect the under sides of the mudguards, the spokes, hubs and rims of the wheels. Other points that repay inspection are the pedals, brake levers and control rods or cables, etc. Water will readily seep into the small gaps, threads, bushes, shackles, etc. and it is a good practice to prevent ingress -of moisture by applying a small quantity of petroleum jelly to these parts so as to seal them off. This procedure should be carried out at intervals especially during the more rainy months of the year. Nuts and threads should be smeared with oil or petroleum jelly as otherwise they tend to rust after a fairly long period. This will obviate any difficulty in replace- ment of small parts due to a nut having seized on its thread.
Replacing Brake Blocks
Do not allow the brake blocks to wear right down to the shoes. Renew them when they are worn to approximately one-half their original depth. Note also that the ordinary pull-up brake block shoes have a stop at one end so that the block will not slide out of position when it is fitted in place and applied to the rim of the wheel. If new brake blocks and shoes are purchased together this is a point to remember when fitting them to the cycle. The shoes should be just clear of the wheel rim.
If brake cables are used all sharp kinks or bends in the run of the cable should be avoided. Lubricate the cable by allowing oil to filter in at highest point. Do not over-lubricate.
Guarding the Bike
The maker’s number will be found on some part of the framework of the cycle, usually on the frame just beneath the saddle. Make a note of this number. It will be useful in tracing the machine should it ever be stolen. The expense of a small padlock and chain is well worth while as a preventive against theft. Both the lock and chain should be of good strong construction. The lock, particularly, should be of the type that is not easily broken.
Speedometers and cyclometers are generally regarded as luxuries, except for pace-making, racing, etc. But if there is any extensive touring to be done, a speedometer will be extremely useful. A speedometer, of course, enables the cyclist to check and maintain the speed at which he desires to travel. A cyclometer, which measures the distance covered, will afford the additional pleasure of keeping a record book of the distances travelled, and also a reminder on day trips how far the cyclist has travelled and, therefore, how far he will need to go on the return journey.
Tandems require more or less the same treatment as ordinary cycles, but there are one or two points to be remembered. When buying a tandem, do not forget that two people have got to ride it, and the measurements of the machine should suit, both persons. The measurements for the front rider are the more important of the two. Special attention should be paid to the brakes, owing to the additional weight; and three speed hubs are recommended.
Preparing a Tour
Remember these hints when preparing a tour. Travel as light as possible, but be prepared for bad weather and carry a cape. Do not wear clothes that hold perspiration: badly ventilated clothes will spoil your enjoyment. Remember the tool kit and puncture outfit. See that the cycle is well oiled before starting out. Do not be over-ambitious in the distance to be covered. Mark out the route on a map beforehand.
Cyclists are bound by law to have proper brakes and to give proper signals. It is illegal to be towed or to hang on to the back of any vehicle. Remember the safety first rules. Keep well to the left. Never pass on the inside of any vehicles. Keep a sharp look-out on the traffic. Do not ride more than two abreast.