Tyre Question - only for advice

[graham78]

Hi guys

I have just sorted myself another 4x4 after my divorce repossed the last one!!!

Got a Discovery 2 modded already adn ready to go, question I have is regarding the tyres - I rna my old 4x4 on 31/10.5/15 this has 33/12.5/15 on.  Is it normal that the ride is a little soft?

The vehicle is hard work to keep in line at anything above 40 ish mph...  I have not had a dry enough day to get under it to look round yet but was wondering if anyone can shed a little light on this...

I am thinking on getting some "road" wheels at 31/10.5/15 to reduce fuel consumption (currently approx 25 mpg) and get a better ride...  before i fork out could someone help me out?

Many Thanks in Advance

Graham

[lambert]

I'd be checking the tyre pressure first.  You can calculate it using the axle weight and load index of the tyre or alternatively start with about 32psi and see how it feels.

[Budgie]

When you say Disco 2, is that the 300 TDi engine or the TD5 version Disco you have?

I've had 33x12.5R15's on a 300 TDi and it needed a suspension lift and the arches cut to fit them in. If yours has has raised suspension than an inch then check if it also has caster correction radius arms on the front axle, otherwise the steering will be extremely light and twitchy.
If it hasn't then changing the tyres won't really help as the steering geometry will still be out. 

[Range Rover Blues]

I'd agree about the castor correction, I don't know if the parts are available for D2 as easy as D1 though but at least the front prop shouldn't be a problem.

I'd also check the bushes in the panhard rod because tyres that big will accelerate any wear and make the steering vague.

If you do a significant lift you might also need to adjust the toe-in.  Start with it nearly parallel which will sharpen up the feel.

It almost goes without saying that mud terrains that size will not give you great road manners, but I think you've figured that out already.