Crash.Net WRC News
WRC 2013 tyre regulations explained
18 January 2013
Homologation and tyre lists
There are two nominated tyre companies authorised to supply tyres to competitors in the 2013 FIA World Rally Championship: Michelin and DMACK.
There are two lists of homologated tyres. List one covers all cars except world rally cars and each tyre company must register with the FIA one gravel tyre, one asphalt, one winter asphalt tyre and one studded snow tyre for the 2013 season.
World rally cars must use tyres from list two only. Again, tyre manufacturers must register one gravel tyre, one asphalt tyre, one winter tyre and one studded snow tyre for the 2013 season. It is possible for list one and list two to be identical. List one tyres must be commercially available but list two tyres may not be.
Tyres for gravel events
For gravel events, the gravel tyre will be available in two different compounds, usually a hard and soft compound, but will still have the same tread pattern and tyre construction. No extra grooves are allowed to be hand cut into the tyre.
Tyres for asphalt events
On asphalt events, two different compounds will be available but both will again have the same pattern and construction. However, for Rallye Monte Carlo only, competitors will be offered an additional 'extra soft' compound but will still only have a total of two compounds available for use on the event.
Asphalt tyres must be E-marked, have two radial grooves and at least 21% of the surface area must be made up from grooves. At all times during an event, the tread depth of asphalt tyres must not be less than 1.6mm across at least three quarters of the tread pattern. A winter asphalt snow tyre is also available for use on Rallye Monte Carlo and can be used in studded or non-studded form.
Tyres for snow events
On Rally Sweden, the only snow event of the season, competitors must use a tyre which fits on a 7 x 15 inch wheel, the same size as a normal gravel wheel.
Each tyre company can register one replacement asphalt and one replacement gravel specification tyre once each season. This is commonly referred to as the joker tyre and the new specification will replace the original specification which cannot be used thereafter.
For each event, a tyre manufacturer must choose one compound in advance which will be its nominated compound for the rally. When specified by the event regulations, 16 tyres of the other compound may be used instead of the nominated compound. However, the same maximum number of tyres is allowed on the event.
Manufacturers and WRC Teams must nominate one tyre supplier for the 2013 season. P1 privateer drivers, P2 and P3 drivers of 4WD cars must use tyres supplied by the nominated tyre companies. Drivers or entrants are allowed to change tyre suppliers a maximum of two times during the year. All entrants of 4WD cars, except 4WD two-litre turbocharged GpN cars driven by non-priority drivers, must use nominated tyres.
Non priority drivers of 4WD two-litre turbocharged GpN cars, non priority drivers of 2WD cars and P3 drivers of 2WD cars may use tyres from any tyre company as long as they comply with Appendix V.
However, from 1st May 2013, all drivers of 4WD cars using 18 inch rims on asphalt rallies must use the 'world rally' type asphalt tyre which has more grooves than a traditional moulded slick tyre. From 1st October 2013 all drivers of 2WD must additionally use these tyres for asphalt rallies.
A maximum of seven tyre changes is permitted on any one rally. To calculate the total number of tyres allowed per rally, organsiers consider a maximum of four new tyres per change, except for P1 and P2 drivers on the Acropolis Rally who are allowed five tyres per change. Tyres may be reused on the same event as long as they comply with any rules around minimum tread depth.
The exact quantity of new tyres for use at each event will be detailed in its supplementary regulations.
Competitors contesting the support championship WRC2, which includes the Group N Cup, must use tyres from the two nominated tyre manufacturers.
Competitors in the WRC3 series for 2WD cars must adhere to the general tyre regulations regarding 2WD cars.
Feature courtesy of DMACK