charlie strayarc
Member
Wheel offset is a measurement taken where hub contacts inside of rim and is relevant to the centreline of the rim and the depth of the dish.
It will be a positive mm or a negative mm or a zero offset.
A zero offset is the centreline of the rim. From this point a positive moves hub contact area outwards and a more shallow dish and negative moves it inwards for a deeper dish.
Standard D22 rims (for eg) have positive 40 offset, this means hub contacts rim 40mm over centre line towards outside of vehicle. If I replace them with a zero offset rim my tyres would stick 40mm further out towards outside of vehicle by way of a 40mm deeper dish. If I went to negative 10mm offset my tyres would stick 50mm further out.
Rim Width.
Standard rim width is 7 inches, if we change to a wider rim, say 8 inch, this extra inch is allowed for by a half inch each side of the offset. I will call a half inch 12mm.
So if I change a positive 40mm 7 inch rim to positive 40mm 8 inch rim, my tyre will stick out 12mm further on my new rim.
If I go 8 inch zero offset my tyre will be 52mm further out and a negative 10mm 8 inch rim would take it to 62mm.
Wider tyres are the same if you go to a 285 from a 265, you get 10mm each side of centreline, so it would not be unreasonable if going from 7 inch positive 40 with a 265, to expect your tyre to move outwards approximately 60mm if going to 8 inch zero offset with a 285, by way of 12mm from thewider rim, 40mm from the offset and 10mm from wider tyre.
It will be a positive mm or a negative mm or a zero offset.
A zero offset is the centreline of the rim. From this point a positive moves hub contact area outwards and a more shallow dish and negative moves it inwards for a deeper dish.
Standard D22 rims (for eg) have positive 40 offset, this means hub contacts rim 40mm over centre line towards outside of vehicle. If I replace them with a zero offset rim my tyres would stick 40mm further out towards outside of vehicle by way of a 40mm deeper dish. If I went to negative 10mm offset my tyres would stick 50mm further out.
Rim Width.
Standard rim width is 7 inches, if we change to a wider rim, say 8 inch, this extra inch is allowed for by a half inch each side of the offset. I will call a half inch 12mm.
So if I change a positive 40mm 7 inch rim to positive 40mm 8 inch rim, my tyre will stick out 12mm further on my new rim.
If I go 8 inch zero offset my tyre will be 52mm further out and a negative 10mm 8 inch rim would take it to 62mm.
Wider tyres are the same if you go to a 285 from a 265, you get 10mm each side of centreline, so it would not be unreasonable if going from 7 inch positive 40 with a 265, to expect your tyre to move outwards approximately 60mm if going to 8 inch zero offset with a 285, by way of 12mm from thewider rim, 40mm from the offset and 10mm from wider tyre.