Neither of the Australians was able to master the tricky course, although the event winner, the USA’s Noelle Pikus-Pace, set a track record on her way to a four tenths of a second victory.
Chaffer was 11th after the first run and was hoping to improve on run two, but she dropped time on the bottom part of the track to set the 18th best time.
“Not the result I was hoping for. I had a good run in the first heat and was looking to build on that in the second,” Chaffer said.
“It was close and I knew if I slid the way I did in the first I could move up. Unfortunately a hit out of horseshoe (corner) meant I lost all my speed and the result was a drop to 16th place.
“I have to learn from this and keep moving forward to next week.”
Steele set the 18th and 16th quickest times and was 0.22 of a second faster on her second run, but it wasn’t enough to see her finish any higher than 17th.
“I am disappointed with my racing today,” Steele admitted.
“I usually love sliding this track, but wasn’t feeling it today. I have everything I need for good results, so just need to look to the next race.”
The result sees Chaffer and Steele 13th and 16th in the World Cup standings after five rounds.
Australian Skeleton athlete John Farrow has had a break-through performance in St Moritz, recording a personal best 12th place finish.
In the women’s bobsleigh, Australians Astrid Radjenovic and Jana Pittman put in a much improved performance, finishing in 12th place, just 1.07 seconds behind the winning Canadian pair of Kaillie Humphries and Heather Moyse.
The Australian sliders return to the ice next weekend for round six of the World Cup, in Igls, Austria.