Wheels and Tyres Questions and Answers

Answer: A

The carcass plies of textile or steel cord take the pressure loads and transmit them to the beads, while the rubber seals and protects. Tread rubber provides grip and wear resistance. The cords are the structure and the rubber is the covering. Most errors here come from carrying across a result from a neighbouring case where it does not hold. Naming what changes and what stays the same is the reliable route through questions of this shape. Checking the units of each quantity catches a wrong formula before the arithmetic begins.

Answer: B

A bundle of high tensile steel wire forms an inextensible ring that seats against the rim flange and cannot be stretched over it. The inner liner seals the air in a tubeless tyre. Both are essential but they do different jobs. Naming what changes and what stays the same is the reliable route through questions of this shape. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. A single measurement chosen to respond to the one asymmetry beats several that respond to shared behaviour.

Answer: C

Cross ply tyres lay alternate plies at around forty degrees to the centre line, which couples the tread and the sidewall. Radial cords run straight across at ninety degrees. The distinction governs almost every performance difference between the two. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. A symptom that appears under one condition and not another is what narrows the diagnosis quickly.

Answer: D

Radial cords let the sidewall flex while the belts hold the tread flat on the road, which gives longer life, better grip and lower rolling resistance. Cross ply sidewalls are stiffer. The decoupling of tread and sidewall is the whole advantage. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Checking which component actually carries the load settles most questions of this kind at once. Working one numerical case through both cases side by side fixes the distinction better than any rule of thumb.

Answer: A

Steel belts beneath the tread restrain it against centrifugal growth and keep it flat under cornering load. A nylon cap ply is often wound over the steel belt at high speed ratings, which makes the last option a near miss rather than nonsense. The order in which the effects act is what decides the outcome, so it is worth establishing first. Tracing the requirement back to the physical constraint that produces it makes the answer follow. A single measurement chosen to respond to the one asymmetry beats several that respond to shared behaviour.

Answer: B

The first number is the nominal section width in millimetres measured at the widest part of the inflated tyre. Fifty five is the aspect ratio, sixteen the rim diameter in inches and ninety one the load index. Each element has its own meaning. Checking which component actually carries the load settles most questions of this kind at once. The shared behaviour explains why these belong together and the differences explain why both exist. The quantity that varies and the quantity that does not are worth naming before any substitution is attempted.

Answer: C

Aspect ratio is the section height divided by the section width, so this tyre is 112.75 millimetres tall in the sidewall. A lower number means a shorter, stiffer sidewall. It is not related to the rim diameter. Tracing the requirement back to the physical constraint that produces it makes the answer follow. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb.

Answer: D

The number is the nominal rim diameter in inches, which is why the marking mixes metric and imperial units. Rim width is a separate specification not carried in the size marking. The mixed units are a historical accident. The shared behaviour explains why these belong together and the differences explain why both exist. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. A limit that survives making every external component ideal is an intrinsic one, and worth knowing for that reason.

Answer: A

The load index is a code read from a table, so ninety one corresponds to 615 kilograms per tyre. It applies per tyre, not per axle. Replacement tyres must equal or exceed the original index. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. Most errors here come from carrying across a result from a neighbouring case where it does not hold. A symptom that appears under one condition and not another is what narrows the diagnosis quickly.

Answer: B

The speed symbol V corresponds to 240 kilometres per hour, and H to 210. Radial construction is shown by the letter R within the size. Temperature grade is a separate marking in the American system. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. Naming what changes and what stays the same is the reliable route through questions of this shape. The order in which the effects act is what decides the outcome, so it is worth establishing first.