[ElliotE]

Hi,

What rear tyre size shouldi be running on my 300 exc? some riders prefer the bigger sizes...Why?

 

[peepod]

Wider tyre will create a slightly bigger footprint offering more grip in most cases,
I'd run a 140 if it's a Michelin your fitting, which is actually the same size as say a 120 Maxxis with the way they size their tyres

 

[ElliotE]

Thanks mate