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Load index and speed rating

Load index and speed rating — one page per exact question.

The last two characters of a tyre's service description carry more information than the rest of the sidewall: a load index number and a speed rating letter.

Load index

The number is a code, not a weight — it maps to a maximum load per tyre through a published table.

Index Per tyre
91 615 kg
94 670 kg
95 690 kg
97 730 kg
100 800 kg
103 875 kg

The steps are not linear and they are not evenly spaced, which is why the table exists and why "a bit higher is fine" is not a calculation.

Four tyres at index 95 carry 4 × 690 = 2,760 kg — comfortably over a typical car's gross weight, and that margin is deliberate.

Speed rating

Letter Max
T 190 km/h
H 210 km/h
V 240 km/h
W 270 km/h
Y 300 km/h

Note that the sequence is alphabetical apart from H, which sits between U and V for historical reasons. It is the one letter people misplace.

Why the rating matters below its own limit

A speed rating is not only a top speed. It reflects the tyre's construction and its ability to shed heat, and heat is what a tyre accumulates on a long fast run, under load, at low pressure.

Fitting a lower-rated tyre than the vehicle specifies is often an insurance and inspection issue as well as an engineering one — the placard figure is a requirement, not a suggestion.

Going up is usually safe. Going down needs a reason.

Higher load index and higher speed rating are generally acceptable, with a ride-comfort cost from the stiffer casing. Lower on either is a downgrade of the vehicle's design margin.

The pages below give one exact index or rating at a time.

What does 98H mean on a tire?

Load index 98 = 1,653 lb per tire
1,653lb
H means the tire is rated to 130 mph · four of these carry 6,612 lb
Load index 98 = 1,653 lb per tire1,653 lbLoad per tire6,612 lbAll four tires
Load per tire750 kg — index 98 on the ISO scale1,653lb
All four tiresthe ceiling for vehicle plus everything in it, not a target6,612lb
Speed rating H210 km/h — sport sedans and many touring tires130mph
Next index up (99)56 lb more per tire1,709lb
Next index down (97)44 lb less per tire — do not fit this if your door label says 981,609lb

Notes

  • 98H means two separate things. 98 is the load index: this tire carries 1,653 lb on its own, at the pressure printed on the sidewall. H is the speed rating: the tire is built to hold together at 130 mph. The two numbers are unrelated — a high load index says nothing about speed, and vice versa.
  • The load figure is per tire, not per vehicle. Four 98-rated tires carry 6,612 lb between them, and that has to cover the car, the fuel, the passengers and whatever is in the boot. Compare it against the gross vehicle weight rating on the door jamb, not against the kerb weight in the brochure.
  • Never fit a lower index than the door label. The placard inside the driver's door gives the minimum load index the manufacturer signed off on. Going below it is the one substitution in tire fitment that has no upside — it saves a few dollars and removes margin from the only four patches of rubber holding the car down.
  • A speed rating is a ceiling, not a recommendation. H at 130 mph assumes correct pressure, correct load and a tire in good condition. Under-inflation is what actually destroys tires at speed, and it does it well below the rated number.
  • Both markings sit at the end of the size, after the diameter: a tire marked 225/45R17 98H is a 225-wide, 45-series, 17-inch tire rated 1,653 lb and 130 mph.

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Load index and speed rating

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