Hello Mr Rocket man.

I looked the tire size up online and it said it was 130/70-13

The tire before my current one was 130/70-13 so I just assumed that was the oem size.

In light of your post I went and had a look at the manufacturer's sticker under the seat (don't know why that didn't occur to me before)

Anyway, you are correct. The oem recommended tire is 150/70-13.

Thank you.

I'd stick with OEM sizes, because if a unfortunate claim against insurance came along they are within their rights to knock back the claim if they spot any changes to OEM spec tyres. They try anything these days.

I'm sure you are right.
It seems I was confused as to what the oem size actually was