A good tri-tip marinade recipe is from Food Network, and it uses lemon juice, soybean oil, white sugar, soy sauce and garlic. Another good recipe is a spice rub marinade made from cumin, garlic, coriander, paprika, cayenne pepper and olive oil.
Whip up a 6-hour tri-tip marinade by combining 1 cup of soybean oil, 1 cup of lemon juice, 1/2 cup of soy sauce and 1/2 cup of white sugar in a bowl. Season with 1/2 cup of garlic salt, 1/2 cup of black pepper, 1/2 cup of chopped garlic and 1/2 cup of chopped dried onions. Add two 4-pound tri-tip steaks to the marinade, and refrigerate for 6 hours. Grill the meat on medium for up to 35 minutes.
A spice marinade requires 2 tablespoons of olive oil mix with 2 tablespoons of ground cumin, 2 teaspoons of ground coriander, 1 teaspoon of paprika, 1/2 teaspoon of cayenne pepper and 1 tablespoon of minced garlic. Rub the mixture into the meat, and allow it to marinate for at least 4 hours before grilling for 20 minutes.
Give the meat an oriental flavor with a marinade made from 1 cup of soy sauce, 3 tablespoons of sesame oil, 1 tablespoon of sugar, 1 tablespoon of chopped fresh ginger and 4 minced garlic cloves. Stir in 4 chopped green onions, and pour the mixture along with the beef tri-tip in a resealable plastic bag. Marinate for 8 hours before grilling.