Wheels and Tyres

Wheels an tyres, of correct types and pressures, are an integral part of a vehicles design. Thus the regular maintenance of the tyres contributes not only to the safety but the designed function of the vehicle, as road holding, steering and brakes are especially vulnerable to the use of incorrectly pressurised, badly fitted or worn tyres.

Pressures

Adjust tyre pressures in accordance with the recommendations given below. These pressures are satisfactory for sustained speeds of up to 112 mph (180 kph).
 
165 SR-15 Radial Front: 22 lb/in2(1.55kg/cm2) Rear: 24 lb/in2(1.69kg/cm2)

Note: Should the vehicle be tuned to increase its maximum speed, or be used for competition then consult the respective tyre company regarding the need for tyres of full competition construction.

Never adjust the tyre pressure after a run. Always check them before a run, whilst cold, as pressures increase as the tyre warms up.

To prolong tyre life, avoid severe braking, sudden changes in direction at speed, and driving over or against kerbstones, as this can result in severe damage to the tyre walls. Regularly examine the tyres. Remove any flints or stones from the treads. Check treads and sidewalls for cuts and blisters (bulges) as these can cause "blow-outs" at high speed. Tyres so damaged should be replaced immediately.

Tyre Wear

The characteristics of tyres vary considerably and, therefore, when new tyres are fitted, all four tyres must be of the same type and rating (165-15 radial ply).

Occasionaly examine the tyres for sharp fins, flats of other irregularities. An upstanding sharp fin of the edge of each pattern rb is a sure sign of road wheel misalignment (usually tracking).

Fins on the inside of the pattern ribs indicate toe in. Fins on the outside edges indicating toe out. Sharp pattern edges may also be caused by road camber, even when wheel alignment is correct. In such cases, it is better to make sure by having the track checked with an alignment gauge.

"Spotty" tread wear or flats, can result from grabbing brakes or unbalanced wheels. Check brakes or dynamically balance wheels as necessary. The original degree of balance is not necesarily maintained, and it may be affected by uneven tread wear, by repairs, by tyre removal and refitting, or by wheel damage and eccentricities, The vehicle may also become more sensitive to unbalance due to the normal wear of moving parts.

Excessive wear in the centre of the tread results from over-inflation, in which condition the fabric is more easily damaged. Excessive wear at the outer edges of the tread reults from under-inflation, a condition which causes excessive heating and premature tyre failure.

Wheel Run-Out and Ovality

The maximum tolerances for both run-out and ovality are ...0.070"(0.18mm) Excessive run-out and ovality will result in severe tyre wear and faulty steering.

Wheel Changing Procedure for Car Fitted with Wire Wheels

  1. Place vehicle on firm, level, ground, If this is not possible exercise extreme caution.
  2. Apply the handbrake firmly.
  3. Remove the spare wheel, jack, soft-faced mallet (and hub spanner on export cars) from the vehicle.Spare Wheel Location
  4. Check pressure in spare wheel.
  5. Using the mallet, slacken, but do not remove the hub cap (spinner). The caps are marked right (off)side, or left (near)side and the direction of rotation to remove is clockwise for right-hand side and counter-clockwise for left-hand side.
  6. Place the scissor jack under the chassis member that supports the floor of the passenger compartment (as in the figure) and rotate the jack handle until the offending wheel is clear of the ground.
  7. Undo the cap and pull the wheel off the splined shaft.
  8. Locate the spare wheel on the splines and push home.
  9. Repalce hub cap and tighten as much as possible (in reverse direction to removal).
  10. Lower and remove the jack.
  11. Tighten the hub cap fully with the soft-faced mallet.
  12. After a few miles, check that the hub cap is in fact fully tightened.
Wheel Changing - Front

Wheel Changing Procedure for Car Fitted with Alloy or Steel Disc Wheels

  1. Place vehicle on firm, level, ground, If this is not possible exercise extreme caution.
  2. Apply the handbrake firmly.
  3. Remove the spare wheel, jack and wheel brace.
  4. Check pressure in the spare wheel.
  5. Slightly slacken the wheel nuts with the wheel brace provided.
  6. Place the scissor under the chassis member that supports the floor of the passenger compartment (as in previous figures) and rotate the jack handle until the offending wheel is clear of the ground.
  7. Remove wheel nuts and lift off the wheel.
  8. Fit spare wheel and lightly tighten the wheel nuts.
  9. Lower and remove the jack.
  10. Tighten wheel nuts securely.
Wheel Changing - Alloy


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