Ukraine, winners at Athens 2004 and Beijing 2008, had started the tournament as favourites and lived up to that billing as they came through the group stage in style.
However, in the showpiece Ramonov's strike was all that separated the sides, as Russia exacted revenge for their final defeat four years ago. It was no less than the Russians deserved as they dominated throughout.
Rasoul Atashafrouz scored either side of a fine strike from Farzad Mehri, and Iran then took advantage of an increasingly stretched Brazil side to add late goals from Jasem Bakhshi and Mehri again.
Weir timed his sprint finish to perfection to take the title in 1:30:20. Switzerland's Marcel Hug came home in second, with Australian Kurt Fearnley taking bronze.
Victory gave the British wheelchair athlete a clean sweep of four gold medals after earlier winning the 800m, 1500m and 5000m - T54 titles.
The USA's Shirley Reilly won the women's Marathon - T54 title in a time of 1:46:33, with Briton Shelly Woods taking silver and Sandra Graf of Switzerland the bronze.
In the men's Marathon - T12, Spain's Alberto Suarez Laso won the title ahead of Elkin Alonso Serna Moreno and Abderrahim Zhiou.
Brazil's Tito Sena prevailed in the men's Marathon - T46, with Abderrahman Ait Khamouch claiming the silver medal and Frederic van den Heede the bronze.
Australia were crowned Paralympic Wheelchair Rugby champions after their star player Ryley Batt produced a virtuoso performance at the Basketball Arena today.
Canada had no answer to Australia's greater speed and organisation. And they did not have a clue how to cope with Batt, who cemented his reputation as the world's best player in a 66-51 win.
The USA, reigning Paralympic Games champions and world number ones, won bronze after recording a comfortable 53-43 victory over Japan.