I did 2 fights in Alcantara as an experiment....along with a rolls and a turbo. However, it made it quite a hard job as there is very little if any stretch.
You deffo want something with a small amount of stretch, which leather naturally has, especially with the aid of a little moisture.
if you are going with real leather then soak it for 24 hours before hand, you want 0.9 to 1.2mm thickness. if you go with something fake (preferable to be honest) then look for something with 4 way stretch like upholstery leatherette
.
the padding comes from the foam, don't get anything with padding stuck to it.
you can get upholstery leatherette on ebay for cheap, buy about twice what you think you'll need, although most places only sell by the metre anyway, this will give you enough to pull it about and stretch it. be aware that it will have a bias i.e. it will be stretchier in one direction than the other, from memory you want it to be stretchy across the saddle not along it.
This what you need, https://www.ebay.co.uk/itm/225597193262
No need to pre treat as it already has enough stretch, use a contact adhesive such as evo-stik or Bostik. When removing the old cover peal it slowly as the adhesive can pull pieces of foam with it, I use a small hand held steamer when doing this to soften the adhesive & they can used to reshape compressed foam.
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