Mud-club
Vehicle & Technical => Discovery => Topic started by: sardonicus on September 20, 2009, 22:09:49
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I've been looking for some new tyres for my disco and thought I'd get some new modular rims too. I'm going to get some 31/10.50/15's, so need some 15x8 rims, so, The options seem to be between -60 offset and 0 offset. I think I get where offset is measured (between the hub face and where the inside/outside of the rim is.) so on a standard disco steel the centre of the hub is nearer the outside edge ,so most of wheel is inward of the centre ,therefore - offset.which is about 13cms ish i think.?
So......- 60 offset is hub face 60 mm from the inside edge ?? and 0 offset whould be half way ??
The question is would a 0 offset rim be too wide with these tyres to fit within standard wheelarches of a disco with good condition standard springs and no lift ,as its the distance between the diff and ground I want,and to keep a good turning circle, not bling factor. :)
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Wheel offset is normally measured from the centre line of the rim to the face for the hub.
The distance from the inside edge of the rim to the hub mounting face is the "back spacing"
(http://www.partsprovider.net/images/wheel-offset-backspace.gif)
Standard discovery 1 wheels are 33mm positive offset. So for example a zero offset wheel will increase the track width by 66mm (33mm each side) and a -60mm offset rim would increase the track width by 186mm
I run 33x10.50-15 (measured) tyres on 15x8 rims with -7mm offset which increased the track width by 80mm and the wheels can turn to about the same angle as the 205r16 all terrains on standard RRC alloys can without touching the radius arms. One downside to these wheels and tyres is the stick out so far that the aluminum outer skin of the wheel arches had to be heavily chopped about to make sufficient room and wheel arch extensions added to cover the tyres properly. I doubt that even a zero offset rim would prevent this. This was with a range rover, but basically the wheel arches are the same, the only noticeable difference being the shape of the rear arches which are like a discovery's with a camel cut.
You could prevent arch cutting by lifting and reducing tyre upwards travel relative to the body, but that will cause other problems.
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Aha! Brilliant explanation :D I almost got it right,just got the -ve and +ve the wrong way round.! so thats what the 33 stamped onto lr rims means.I measured the wheel every way possible and couldnt find anything that was 33,doh.
So 0 offset would be the same as fitting 30mm spacers to a standard wheel.
As for a 2inch lift ,I'm not so sure,maybe some heavy duty standard height springs ,might do.From what i've seen on other vehicles,a 2 inch lift wont do much for articulation offroad unless you remove the arb's,then it wobbles all over the place round corners on the road.
Well,I'll see what happens when theyre on the truck. Thanks for the reply clbarclay. :)