quadripilicate?
"Exact" match is 19 mm -- the tire is .45 mm thick and 69" is very near 20 mm OD at scale. If you scroll down the page to the bottom you will see a comparison chart that indicates you can also stretch the 16 mm tire for a tighter fit.
The 'S' is a slightly narrower tire, 1.3 mm vs. 1.5.
triplicate
duplicate
There is this thread:
https://cs.trains.com/mrr/f/88/t/290013.aspx?page=-1
and it refers one to this website:
https://lovetrainhobbies.com/HO-scale-traction-tires-locomotive-engine-replacements-steam-diesel-HO-scale-traction-tires-lovetrain-hobbies-mm-HO-MAIN.html
I have 2 of the older Athearn Genisis Challenger Locomotives, part number G9133 UP#3983 and part number G9129 D&RGW#3804. Both need the traction tires replaced, they were dried out and falling apart so I completely removed them. Doing this caused a problem as the grove the traction tires fit into is wide enogh that the rail can go up inside the groove and this is causing shorting problems on turnouts.
The manual gives item# 210 but it doesn't give a part number for traction tires, and an internet search for this didn't show anything that I could find.
The manual gives directions on how to replace them but I was hoping for maybe some first hand experience on doing this.
Any tips or suggestions? Anyone know of a video showing the procedure? I coudn't find one in my searches.
I have a hard time working on small parts like this, 26 years of Appliance Repair and 32 years of playing guitar have completely removed any feeling in the tips of my fingers.