I remember the older (Gen 1) Frontiers were 10Mx1.25x30. Titans have studs that are 8Mx1.25. You could use an open end wrench to figure out the size of the bolt diameter (hold it up to the hole in the frame). Nissan uses mostly even-sized, Metric sizes, i.e. 8MM, 10MM, 12MM until it gets to the much larger sizes. Then it's just a matter of figuring out the pitch. 10Mx1.25 would be fine pitch and 10Mx1.5 would be coarse, if it's a 10MM bolt. If it's 8MM, it will be 8Mx1.25. For length, 30MM is 1.18-inches.