When I replaced mine with aftermarket, after a few years, the foam on the replacement was ok, the suspension on it was ok but the vinyl had disintegrated under the UV.
Sold that one to a woman who didn't care about the vinyl and was just grateful to get a bit of suspension under her nether regions.
Bought a better quality one than the first replacement (see below), this one with a higher back, armrests (and an optional seatbelt which I have never used and is now rusting).
This seat is in the process of being eaten....vinyl down to meaty chunks of foam.....rats, mice, possums, something out there of a night time enjoys the taste.
Bought another one the same as the previous one as it's good quality at a good price and have vowed to keep it tightly covered with a strong efficacious removable cover.....we shall see.
The moral of the story is that with tractor seats as in life and with buses, you fix one problem and along come three more at the same time.
The foam is very resilient and dense (except when being eaten). Comfortable seat and the back height means you have some whiplash protection from being knocked off backwards (as opposed to the minimalist type often converted to bar stools). Reasonably priced for the quality. Optional flip up armrests are good but not essential. Adjustable back and forward and height. Mostly universal fit, base drilled for most brands, just check for Kubota.
Manufacturer: Bare-co Part No.: B9642 BLACK, B9644 BLUE, B9643 YELLOW Approved Seat Belt Mountings Heavy duty 5/32" thick base Full 3 3/4" thick high density base cushion Heavy duty 3/32" thick vinyl upholstery Multi angle base adaptable to all tractors Fully seam welded frame Fore/aft slide...
www.tractoraddons.com