The most common and most likely answer to this crossword clue is the 7 letter word TANDEMS
I've seen this crossword clue in Independent
T
A
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D
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Buddy explains!

The straight part
We know that "Cycles" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cycles = tandems.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 TANDEMS mean?
TANDEMS noun- A carriage pulled by two or more draught animals (generally draught horses) harnessed one behind the other, both providing the pulling power but only the animal in front able to steer.
- (transferred sense) A bicycle or tricycle in which two people sit one behind the other, both able to pedal but only the person in front able to steer.
- A group of two or more people, machines etc. working together; close collaboration.