How come only 1 tyre needs replacing? I'm assuming puncture or something along those lines.
What's the tread like on the other tyre? If it's going to need replacing in a few months anyway, just do it now.
Front left is only a few months old. Ran up a kerb and the last one punctured. Rookie error
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So replacing both sides isn't really a favourable option and it's still almost new.