New tyre installed in truck is capital expenditure

It should be charged off to P&L as regular maintenance of Truck.

Tyre does not seem to be significant (high value) component of Truck in term of Value in order to fall under component accounting and capitalizing it separately from Truck..

Also, need to check below aspects.

What is the truck used for?

Whether you have capitalized the said truck & tyres separately in your books at the time of Purchase?

So its is part of regular repair & maintenance activity and needs to be charged off.

No, As explained in earlier reply, for separate accounting, a component needs to be of significant value in proportion of the main asset, which is not so in case of Tyre as it is low value and it will be replaced regularly throughout the life of truck.

Treat as revenue expenditure and charge to P/L A/c. 

Its not  major overhaul, so expense it under maintenance, and depends if it is direct or indirect.