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- Thread starter jhk07
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To clarify this question:
If the truck darts in one direction when you apply gas, and in the other - when you let go off gas, most likely, the culprit is radius arms bushings.
If the truck seems to drive okay in a straight line, but is difficult to settle when you get into the curve or in a rapid lane change, it's most likely the caster issue.
If the truck darts in one direction when you apply gas, and in the other - when you let go off gas, most likely, the culprit is radius arms bushings.
If the truck seems to drive okay in a straight line, but is difficult to settle when you get into the curve or in a rapid lane change, it's most likely the caster issue.
Could he be feeling the effects of the front panhard rod no longer being level? When you lift the truck, the panhard rod is not level, which makes it act asymetrically. When the axle drops, it shifts left, when it rises, it shifts right.
FWIW, I'm running 45psi all around on the same tires. No problems. But I'm not lifted.
FWIW, I'm running 45psi all around on the same tires. No problems. But I'm not lifted.
p m said:
Thats exactly what mine does... Thanks now I know what I need to order:bigok:
I know my bushings on the radius arm are old to. So that's a great place to start!
first off, thanks for your input...
UPDATE--- tonight I aired down the front to 32 psi in the front for the trip home... bout 12 miles at 55 mph... As some suggested, this did in fact seem to make it worse...
If this helps, my steering is VERY HYPERSENSITIVE... you touch it, truck goes...Thus the left/ right/ left /right --- waggle so to speak.
There is no play in my steering wheel...????
I did read about castor angle on wikpedia, needless to say, I don't get it yet........
thanks
UPDATE--- tonight I aired down the front to 32 psi in the front for the trip home... bout 12 miles at 55 mph... As some suggested, this did in fact seem to make it worse...
If this helps, my steering is VERY HYPERSENSITIVE... you touch it, truck goes...Thus the left/ right/ left /right --- waggle so to speak.
There is no play in my steering wheel...????
I did read about castor angle on wikpedia, needless to say, I don't get it yet........
thanks
JHK - for comparison, I have a 95 LWB and 95 SWB RRCs. The LWB is at stock height, the SWB has OME HD springs (gives full 2" on a baby RRC). The steering is adjusted exactly the same way - and the SWB is very twitchy in exactly the way you describe.jhk07 said:
They both have the same shocks; the only difference is caster.
Back to reading tire pressure on the door jam: I would use this only as a ratio of PSI from front to back since your new tires may require higher PSI than what was on the truck.
Also, I had the same dart L-R with foot on/off accelerator. I had just adjusted the swivel pre-loads, so I replaced the bushings on the redius-arm frame-side, problem solved.
I run taller/skinny tires and there tends to be a feeling of hypersensitive steering but not too bad.
Also, I had the same dart L-R with foot on/off accelerator. I had just adjusted the swivel pre-loads, so I replaced the bushings on the redius-arm frame-side, problem solved.
I run taller/skinny tires and there tends to be a feeling of hypersensitive steering but not too bad.
I would suggest setting the tire pressure equally and taking it for a spin. See where you are at with all tires inflated equally, and if anything drop the rear pressure a bit, but not as radically as you currently are. Even though the Discovery platform has a good balance of weight distribution the fact still remains the heaviest component to the discovery is located above your front wheels. By softening the front and increasing the rear tire pressure you end up shifting the weight balance of the entire vehicle to the front.
Ron, what is your Rover?Ron L said:
Disco has a horrible weight distribution. The engine barely hits 250 lbs on the scale.
There are two reasons for the factory tire pressure settings - first and foremost, weight distribution. Second, with a slightly lesser rolling radius in front, the Disco will tend to pull straight under load (with a center diff unlocked, of course).
jhk07 said:
Have you checked your alignment? If you have toe-out up front, that would definitely make it sensitive. If you bend your tie bar, it will make the wheels toe out. I'd think it would be a common problem for people who off-road and maybe hit the thing on a rock.
Castor... the reasons why are complicated, but basically it creates a self-centering torque on the wheels. So, if you don't have enough, it can make the truck less stable. Since this thing has leading axle radius arms, it loses castor as you lift it.
That's a good one, too.R_Lefebvre said:
I've realigned all rovers to just a hair toe-in, though, and the difference still remains.
p m said:
Peter,
I have a 2000 D2. I have never had a wandering issue like some report. My truck tracked nicely until my diffs started to let go (first the front then the back). Anyhow... I was making a suggestion based on my experience, both in the disco and on other applications (my Toyota truck, old bronco and my wrangler). I am a firm believer that the factory tire pressure setting ONLY apply to the tires that came with the truck from the factory. With the horrible cupping issues most experience, I am also a firm believer that these ratings are incorrect. My overall experience has been 4 psi more in the front than the back. My discovery tracks perfectly and I get even tread wear across the face of the tire. I am also nose heavy with a bumper and winch. If I am loaded down for a camping trip (rear is full of recovery gear, full Engel fridge, power tank etc...) The truck tends to balance itself out, sitting more level.
Again... this is based only on my experience. When I saw that he was progressively getting worse, It does not hurt to move in the other direction just to see what happens. We are only talking about air.
Disco is fundamentally different from most Jeeps and Toyotas - the latter two nearly always had cast iron engine blocks and heads. Rovers are very light up front (a 300-lb front axle is the only saving grace), and Discos have very heavy rear, due to steel roof, gas tank behind the rear axle, and all the glasswork.
Sure, if you load up the front with 200lb worth of stuff, you may get close to even weight distribution. On the last trip to Big Bear, I've noticed improvement in handling in my Disco by simply moving the snow chains and recovery gear from the rear to the floor in front of the passenger seat. My old 89 RRC handled like a turd with OME HD springs, until I put Dee C's old ARB front bumper on it.
You are the only person I know of who runs lower pressure in the rear tires than in front.
Sure, if you load up the front with 200lb worth of stuff, you may get close to even weight distribution. On the last trip to Big Bear, I've noticed improvement in handling in my Disco by simply moving the snow chains and recovery gear from the rear to the floor in front of the passenger seat. My old 89 RRC handled like a turd with OME HD springs, until I put Dee C's old ARB front bumper on it.
You are the only person I know of who runs lower pressure in the rear tires than in front.
Now I've got to explore the Russian side of me and drop the rear air pressure in the Disco... Man that's scary!
the only reason that lower rear pressure might help is because dropping the rear pressure lowers the rear end and that adds front caster angle.
running to low of pressure could be a issue if you took this to far.
running to low of pressure could be a issue if you took this to far.