Principle

Regrooving consists of removing some rubber from the existing undertread of the tyre.
For this, when a tyre is designed, MICHELIN prescribes an undertread that is thick enough to allow high-quality regrooving without affecting the strength or toughness of the product.

Safety

Regrooving significantly extends the potential grip of a tyre.
Regrooving gives new sharp edges and a tread depth which is about the same as a tyre with one third of its original tread remaining. The regroove process restores the main longitudinal grooves which assist with water evacuation from under the tyre. On some tread patterns, it also restores the transverse grooves which provide the grip or traction of the tyre. Carried out in accordance with our recommendations it has no adverse effect on the product regarding the strength of the crown block or casing.

Regrooving is carried out in the phase in which the tyre has the lowest rolling resistance.

As a worn tyre has less rubber deformation in the tread pattern, it generates less heat and so offers lower rolling resistance and uses less fuel.

For given driving conditions and on a straight road, if the rolling resistance is 100 for a new tyre, it becomes 75 for a tyre worn to the tread wear indicators. Between these two extremes, the rolling resistance is proportional to the wear.
For a tractor and semi trailer vehicle combination used for long-distance haulage, the fuel saved by regrooving the tyres instead of fitting new tyres can reach 2 liters per 100 kms (depending to the number of axles equipped).

This decrease in fuel consumption due to the lower rolling resistance is COMBINED with the increase in total tread mileage shown in the previous section.

Regrooving Recommendations

Carry out the regrooving when there is still 2 to 4 mm of tread

This precaution makes it possible to:
- Reproduce the tread pattern easily.
- Adjust the regrooving depth so as to always keep at least
2 millimeters of compound between the bottom of the tread pattern and the crown layers.

If Regrooving is too deep:

- Result in damage that causes the premature destruction of the casing.
- Compromise the possibility of retreading.
- Allow metal layers of the crown to appear, which may reduce the life of the casing.

Regrooving is not recommended:

If the tread shows major damage:
- Multiple holes and cuts, places where the tread has been torn off.
- If the metal layers of the crown can be seen through damage or cuts.

Regrooving supplies are available through many tyre maintenance supply and tyre repair material distributors.
- P.S.O. (Pneu Service Outillage) in Europe
- Myers Tire Supply in North America
- Tip Top ; reference Rubber Cut Station 5183702

It is essential that the regrooving be carried out by professtionals in accordance with our recommended rules.

Please consult your Michelin representative or Michelin dealer for more details.