When I told a recent customer we offer a variety of different tzitzit tying customs, he was taken by surprise.
“I was not aware that Tzitzit could be tied using different standards,” he wrote in an email. “I thought they were all the same – so now I’ve learned something new. What are the differences? Is there a tzitzit tying custom based on denomination – Orthodox or Conservative – or region of the world – Ashkenazi/Sephardic?”
I would estimate that at least 60% of the world’s tzitzit are tied according to the standard Ashkenazi custom. In the U.S. that probably accounts for over 80%.
The second most common are Sephardic, followed by Chabad and Yemenite/Rambam.
Techelet Tzitzit Tying
But techelet is a whole different ballgame. The white tzitzit tying customs were meant to fulfill most of the requirements stated in the Gemara that could still be fulfilled once techelet had fallen out of the picture. But for those who now wear techelet there are several tying customs. The Gemara states very clearly certain guidelines — e.g. the first and last loops (or sets of loops) must be white and the total must be no less than 7 and no more than 13 — so all techelet tzitzit tying customs fulfill these requirements in one way or another.
The Ptil Tekhelet Association (which makes the techelet strings) recommends the Sefer Hachinuch tzitzit tying custom, and I think they recommend the Rambam for Sephardic Jews. There are Ashkenazim who seem to be drawn to the Rambam’s tzitzit tying custom, either for aesthetic reasons or because of it’s simplicity, I’m not sure.