Their tread, on the road, is endless (5)

I believe the answer is:

tyres

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'their' is the definition.
I can't tell whether this definition defines the answer.

'tread on the road is endless' is the wordplay.
'tread on' becomes 'tyr' (I can't justify this - if you can you should believe this answer much more).
'the road' becomes 'SesameStreet' (children's TV show).
'is endless' indicates the central letters.
The centre of 'sesamestreet' is 'es'.
'tyr'+'es'='TYRES'

Can you help me to learn more?

(Other definitions for tyres that I've seen before include "Wheel coverings" , "Wheel hoops" , "rubber rings" , "Rubber wheel covers" .)

I've seen this clue in the Evening Standard.

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