Just remembered that Drakes have some interesting blurb on their website about knitted ties:

"Knitted Silk
The Ultimate Knitted Silk Tie
What makes Drake's knitted ties?
There are knitted ties and knitted ties. Ours start with first quality raw silk, spun, dyed, and finished in Switzerland in a way that assures the crunchy handle and Cri de la Soie (the crunch of the silk when squeezed) for which our knits are famous. If you examine other knitted ties, you'll find they have a much softer, limper body, a pale imitation of a Drake's classic knit tie. The yarn is knitted on hundred-year-old frames, which are slower than modern machinery, but ensure a superior quality, then sewn down the centre back and put on a mould for 24 hours to achieve the desired finished shape. The ends are closed and finally the label is sewn on by hand. In addition to solid knits, we also offer a version with hand-sewn spots, each spot individually sewn into place using the same crunchy yarn. These are truly the epitome of sartorial refinement.

A word about tying knitted silk ties
Always use the four-in-hand knot, no other knot really works well. Always untie the knot after wearing, and roll the tie up rather than hanging it. This method will ensure its shape forever. And, lest you imagine we haven't thought of everything, we knit our ties slightly shorter than standard length to account for a small amount of natural stretch. Think grey Shetland jackets with Oxford button downs, or chalk-striped flannel suits worn with brown suede shoes."

http://www.drakes-london.com/details/ties/knitted-silk