Offset wheels

[tinytim]

I read about this somewhere but I can't find it now.

I'm trying to get some alloys to replace the steel rims I have at the moment but I don't understand this talk of offset wheels.
If I have the right figures the front are offset 35 and the rear 45 but what does it mean?:confused:
Tim

[Steve_M]

Thats right front offset of 35 and rear of 45.

Normally refered as ET35 or ET45. its the measurement of how far the mounting face is from the centre line of the wheel.

See pic of a 4J x 13 ET35 wheel

[tinytim]

Thanks Steve,
Now the next question.

If I want to put alloy wheels on all I'm restricted by is the wheel arch protrusion and the overall wheel/tire diameter.

I've been to ozsamurai site (some good stuff there) but I'm confused with the wheel sizes suggested.

ie. normal rear-165/60R14. Tire profile = 99mm +14" (357.56mm)
Dia 555mm ish

Suggested 185/55R15.. Tire profile = 101.75mm + 15"(383mm)
Dia 586 mm ish.

Surely that will blow the speedo reading?

Or am I being daft?

Tim