NLMT 2 & 3 Left Rear Grooving Patterns
Grooves and sipes can enhance grip as well as maintain tire temperature.

Grooving and siping are techniques used to enhance the performance and traction of tires, especially in motorsports like dirt late model racing. The grooving process involves cutting shallow channels (grooves) into the tire's tread, while siping refers to making small slits in the tire surface. These techniques are commonly used on softer compound tires to improve their grip and handling characteristics on the track.

Here's a step-by-step guide on how to groove and sipe softer compound tires for the left rear of a dirt late model:

Materials Needed:

  1. Soft compound left rear tire
  2. Tire grooving iron
  3. Tire siping tool (siper)
  4. Marker or chalk
  5. Measuring tape or ruler
  6. Safety gloves and goggles


  1. Ensure safety: Wear gloves and goggles to protect your hands and eyes before starting the process.
  2. Examine the tire: Check its condition to ensure it's suitable for grooving. Please make sure there are no significant cuts or damage that could compromise its structural integrity.
  3. Determine groove pattern: Plan the groove pattern you want to create on the tire. The number and depth of grooves can vary depending on track conditions and personal preferences. Generally, grooves are made in a diagonal or zigzag pattern across the tire's tread.
  4. Measure and mark: Use a marker or chalk to mark the positions where you want to create the grooves. Measure the distance between the grooves to ensure uniformity.
  5. Grooving: Heat up the tire grooving iron and create grooves along the marked lines. Be careful not to cut too deep, as excessive grooving can weaken the tire or cause it to overheat during racing.


  1. Inspection: Examine the tire's tread surface again and identify areas that may benefit from siping. Siping is particularly useful in providing extra grip on wet or slick tracks.
  2. Plan the siping pattern: Decide on the siping pattern you want to apply. The sipes are typically made in a crosshatch pattern across the tire's tread blocks.
  3. Siping tool: Use a tire siping tool (siper) to create the small slits in the tread surface. Siping tools come in various designs but generally consist of a handle with a cutting blade or multiple blades.
  4. Sipe carefully: Apply even pressure as you sipe each tread block. Avoid cutting too deeply, as excessive siping can reduce the overall tire strength and stability.
  5. Balance: Ensure the siping pattern is consistent across the tire for balanced performance during the race.

Important Tips:

  1. Practice: If you are new to grooving and siping, practice on old or unused tires first to get a feel for the process.
  2. Track Conditions: Adjust the groove depth and sipe pattern based on the track conditions and the type of race you are participating in.
  3. Left Rear Tire: Grooving and siping are commonly done on the left rear tire in dirt late model racing because it helps improve traction during cornering on oval tracks.

Remember, grooving and siping should be done carefully and with precision. Over-grooving or over-siping can compromise the tire's integrity and may lead to failures during the race. Always follow the rules and regulations of the racing series or track regarding tire modifications.

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