Look at your tyre. You’ll see a set of numbers as shown below. You want to look at the FIRST number – shown here as 195. If your tyre is a 195, then you’ll need Clamp C.
Clamp A – Suits boats with a tyre width 6.90/600
Clamp B – Trailers, Caravans, Cars – From 165mm to 185mm
Clamp C – Boats, Vans, Trailers, Cars – 195 to 205mm
Clamp D – Sports Cars – 215mm to 245mm
Clamp E – Large 4WDs – 265mm -285mm