The most common and most likely answer to this crossword clue is the 8 letter word CRAMPONS
I've seen this crossword clue in The Guardian
C
R
A
M
P
O
N
S
More clues leading to the result CRAMPONS
Buddy explains!

The straight part
We know that "spiked plates" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case spiked plates = crampons.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CRAMPONS mean?
CRAMPONS noun- An attachment to a shoe or boot that provides traction by means of spikes. Used for climbing or walking on slippery surfaces, especially ice.
- An aerial rootlet for support in climbing, as of ivy.
- A heraldic figure in the form of a bar bent at the ends into the form of a hook.