I would vote for 1969. It has all the drama of the 85/86 and of 89 and more! Let's look back to 67 to start.
Simpson dies after the climb of MT Ventoux. Drugs contributed to this, but perhaps the use of national teams played a part also as Simpson who badly desired a Tour win and had the individual ability was deniged the teammates he needed to compete.
1968 would have strict doping controls and be the last year of national teams in the tour. 89 may have had 2 riders in contention, 68 had several. Here is the table going into the final time trial:
1. Herman Van Springel, the leader: 132 hours 29 minutes 17seconds
2. San Miguel @ 12seconds
3. Janssen @ 16 seconds
4. Bitossi @ 58 seconds
5. Gandarias @ 1minute 15seconds
6. Aimar @ 1minute 38 seconds
7. Bracke @ 1 minute 56 seconds
8. Wolfshohl @ 2 minutes 12 seconds
9. Pingeon @ 2 minutes 28 seconds
10. Gomez del Moral @ 3 minutes 38 seconds.
And one can not forget that Belgium had suffered a drought in the Tour which now looked to finally be ending. But Van Springel finished second in the TT, 54 seconds down to Janssen.
In the 1969 Giro Eddy Merckx is leading until fails a drug test, one that he and many writers to this day say was a put up job.
This is the background to the 1969 Tour. Eddy enters the Tour not properly prepaired, the events of the Giro had been a major distraction and still bothered him.
Entering stage 17 Merckx had a lead of 8 minutes and 21 seconds over second place Roger Pingeon. remembering 68 many of the Belgian papers of that morning had headlines saying things like "Eddy Be Careful". And that is just what he was until they were almost to the summit of the Tourmalet, the next to last climb of the day and 140 Kms from the finish. When he decided to go over the top first, only his teammate Vandenbosche can stay with him. He opened a lead of about a minute on the elite group of 7 that had been near him at teh top by the end of the decent. Riding briskly he had widened the lead to about 6 and 1/2 minutes by the final pass. He would finish 7 minutes and 57 minutes ahead of a group of 7 riders who even working as a group could not pull back any time on him (OK Vandenbosche wasn't helping). The next group was 14 minutes back.
In the end Eddy would win by 17 minutes 54 seconds. More than combined winning margin of the 7 previous tours and more than any tour since. He would take Yellow, Green, Polka Dot, Most Agressive. Faema would win the team championship and Eddy would win the final stage.
For Belgium the drought was over. In 70, 71 and 72 Belgium would take all 3 jerseys each year, something no other country has ever done.