A V rated tyre is rated to 149mph sustained speed. However, after 130mph, the load the tyre can take reduces by 5% for every 10kmh increase in speed up to 149mph.

Max Speed Max Load (%)
190kmh (118mph) 100
200 (124mph) 100
210 (130mph) 100
220 (137mph) 95
230 (143mph) 90
240 (149mph) 85

Therefore, as the speed increases above 130mph, the load reduces. These tyres are drum tested (ECE reg 75 conditions which are more severe than DOT high speed conditions) for ten minutes at each speed but with a different percentage load due to take account of the fact the tyre is running on a curved drum rather than on a flat road.

This is why if you run a tire at sustained high speed with too heavy of a load you can wear out a tire quickly. It's also important to make sure you are running the correct tire pressures.

--Sukoshi Fahey (Ms.)
Sales Manager, North America
http://www.avonmotorcycle.com/