Steve- I think Mohair is no longer made from Wool, and is a synthetic (acrylic) material, so one rarely sees a faded black top on a Mercedes or BMW convertible. Haartz is one of the big makers of synthetic fabrics used for convertible tops, though they do not use the term "Mohair" to describe any of them. Stayfast, Twillfast and Sonnenland. They also make different sorts of vinyl materials for tops, as do others. Duck tops are still available for those concerned with originality over longer lasting. Many professional installers use tops ready made for specific cars models by Robbins.
> Twillfast-- fails scrutiny as early MG top material because it has a diagonal weave, and the canvas used for Duck has a traditional square weave.
> Sonnenland-- is more expensive than Stayfast, as it has some sort of fancy cloth layer that car occupants see inside when the top is up. It's marketed for cars that are considered luxury cars or high end sports cars.
> Stayfast-- is a common pick in woven convertible tops, often used in pre-made tops like by Robbins, and sold at many places retail, like where I got my tan Stayfast TC top and side curtains.
https://www.topsonline.com/model/Conver ... _MGTC.html
Wigan has a finer weave than duck canvas, and is lighter weight than double duck.
http://www.woolies-trim.co.uk/p-1422-wi ... black.aspx Traditionally Wigan has been a cotton fabric coated in latex rubber. As the synthetic fiber cloth is indistinguishable (as far as I can tell) from natural fiber materials when made into a car top, I would guess that (if still being made) Wigan is now a synthetic fabric coated in latex rubber, to avoid color fading.
Not sure how the weight or weave of the Stayfast or Sonnenland or various "Mohair" fabrics compare to the original Duck canvas. To my eyes the Stayfast material that the top I got was made with what looks like natural fiber cloth, like a canvas..
Too thick a top material will make a top difficult to operate, while too thin a material will be prone to tearing.