Lendl was raised on carpet but played a lot on clay and won his first GP titles on that surface, although he also won a few ones on hard and indoors ( beating Borg in those 2 finals).
His problem was , as he got a better indoor and hard court player, round 82,83,84 he lost patience and did not enjoyed cc tennis for those 3 years, even if he won the RG event in 1984, beating peakest Mac and a very very strong Wilander.
it took some Roche´s and Gym habits, to squeeze out any dark clouds on his head regarding clay, and by 1986 till 1988 or 1988 he regained top clay court form.
At the end of his career, from 1989 to 1993 or 1994, however, he became unpatient again and did not enjoy clay, in the same way as in 1981-83 where Wilander,Noah, Clerc had better cc results than Lendl.I think afther the 1989 match vs Chang at Paris he decided that concetrating on clay was not worthy and he gave his best trying to win that elusive Wimbledon title for 3 years.
"Read my lips.No more taxes" RR in 1980