EAS - Harsh Ride - Calibration?

jamesmartin said:

or by fitting coils

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There's always one in a group.

The cable just arrived today so it's not adjusted yet. Hope to get it done in the next day or so, work permitting. I have the tyres pumped to 38 at the rear and 28 at the front, going purely by HiQ Online's tyre pressure guide. What would you say is a safe pressure to reduce it to? Anything I can do to improve the ride would be great, but I obviously don't want to knacker the tyres by going too far.

Valiante said:

The cable just arrived today so it's not adjusted yet. Hope to get it done in the next day or so, work permitting. I have the tyres pumped to 38 at the rear and 28 at the front, going purely by HiQ Online's tyre pressure guide. What would you say is a safe pressure to reduce it to? Anything I can do to improve the ride would be great, but I obviously don't want to knacker the tyres by going too far.

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Well the 38 psi is for fully loaded, so i suppose you could drop them to 32-34 or so and still be able to carry the occasional back set passeger or light load. But don't think you'll knacker tyres, the fronts run at 28 with a bloody great engine directly above them and don't wear unduly.

I must admit I thought it odd that the front's listed as only needing 28, that seemed backwards to me as the rear is lighter without load, right? I'll certainly try that then. I also think the tyres are looking a bit old. Not worn.. just very slightly cracked around the edges. I think someone said old tyres could be contributing to the ride quality too.

Valiante said:

I must admit I thought it odd that the front's listed as only needing 28, that seemed backwards to me as the rear is lighter without load, right? I'll certainly try that then. I also think the tyres are looking a bit old. Not worn.. just very slightly cracked around the edges. I think someone said old tyres could be contributing to the ride quality too.

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It just depends on what your used to mine is a lot smoother with a bit of weight in it. Solo it is firm. If you fit poly bushes the ride firms up because there is less give in the bushes that in the rubber ones. The rate of the shockers makes a big difference also. Hope you are not confusing harsh with firm. The P38 is not a Limo it's a very capable off road vehicle. There has to be a compromise in design for it to operate well both on tarmac and off road. As i said earlier set it at high mode and drive over speed bumps at 30 mph. Now that is harsh.

wammers said:

It just depends on what your used to mine is a lot smoother with a bit of weight in it. Solo it is firm. If you fit poly bushes the ride firms up because there is less give in the bushes that in the rubber ones. The rate of the shockers makes a big difference also. Hope you are not confusing harsh with firm. The P38 is not a Limo it's a very capable off road vehicle. There has to be a compromise in design for it to operate well both on tarmac and off road. As i said earlier set it at high mode and drive over speed bumps at 30 mph. Now that is harsh.

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What I'm used to is a 3-series BMW as I've owned three of them over the past 4 years (one after the other, not at the same time)! I've only had the P38 for a couple of months and it's the first Land Rover I've owned, but my father-in-law has always had at least one as long as I've known him (currently an L322 and two off-roading projects), so I have had some experience of what they're like.

To put it briefly, my last 323i was more comfortable to drive down his unmade road than the P38 is, which rattles and crashes its way down - it's not just bumpy, it's bone-shuddering. I couldn't even conceive of driving over a speed bump at 30mph, at any ride height. I have to slow down to walking pace even at standard ride height, otherwise it feels like something will break.

Certainly not just firm, it's harsh. I'm toying with the idea of replacing the whole lot.. Arnott Gen II bags, new shocks (Boge?) and OEM rubber bushes. I'll probably just do the fronts to begin with as there's some overnight sinkage there.

All that said, I'm still going to re-calibrate the ride heights first! Work is kicking my ass at the moment though...

I have a 1998 P38 with Gen 2 Arnotts. It rides OK over bumps and pot holes but not as good as the 10 year old Citroen Picasso I've just bought. As Wammers says, it's not a limo but it is a very capable off roader. Unfortunately, too many people think it is a limo.

wammers said:

Set your EAS as below. All from centre of wheel to wheel arch lip.
Access 405mm.
Motorway 445mm.
Standard 470mm.
High 510mm.
Extra extended (not settable only used if chassis is grounded) 540mm.

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Having read what the ride height should be, I measured mine and found that apart from the access height, mine were all up by 10mm. As I suffer from harsh ride, too, is that enough to cause it?

fentigerover said:

Having read what the ride height should be, I measured mine and found that apart from the access height, mine were all up by 10mm. As I suffer from harsh ride, too, is that enough to cause it?

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I would think so but there are other things like stiffness of shockers to take into account. P38 shockers are double acting, that means they resist on compression as well as on rebound. Drop it to standard settings and see what you get.

wammers said:

I would think so but there are other things like stiffness of shockers to take into account. P38 shockers are double acting, that means they resist on compression as well as on rebound. Drop it to standard settings and see what you get.

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OK, thanks foor the info.

Just a thought. knackered dampers would give a bad ride over broken road.
Can't remember if that was already covered earlier in this thread?

jonbill said:

Just a thought. knackered dampers would give a bad ride over broken road.
Can't remember if that was already covered earlier in this thread?

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So will those bloody great silly wheels fitted with low profile tyres. You also don't need 38 psi in the rear tyres unless you carry a load and or passengers often. All these things can contribute. But having the ride height set correctly is the start point.

Thought I'd best come back and update - weirdly I haven't been getting any emails so I didn't realise there were any news posts, sorry.

wammers said:

So will those bloody great silly wheels fitted with low profile tyres. You also don't need 38 psi in the rear tyres unless you carry a load and or passengers often. All these things can contribute. But having the ride height set correctly is the start point.

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LOL - what bloody great silly wheels? I have standard 16's! The 38 psi is the recommended unloaded pressure by a couple of independant websites (Kwik Fit, etc) though I must admit I thought it quite odd that it only said 28 psi for the fronts - maybe it's a typo and should be 28 all round? But I digress, I've taken your advice and dropped all the tyre pressures to ~30 psi which has taken the edge off slightly.

I also spent a few hours one weekend calibrating all the suspension heights (thanks to Datatek for the cable & software) so it's all riding at the heights it should be now. Unfortunately it still rides as rough as before so I'm thinking shockers are the most likely culprit, but at least one of the front airbags are shot as it sinks overnight, so I'm gonna replace all of the front suspension as soon as I can afford to (it's not a daily driver, so there's no massive urgency).

Anyway - thanks for all your replies - I'm now at least happy to be riding a little more normally, height-wise!

The info from TOPIx is:

Low profile: 25 mm (1 in.) below standard.
Access: 65 mm (2.6 in.) below standard.
Normal: 0mm (0.0 in)
High profile: 40 mm (1.6 in.) above standard.
Extended profile: 70 mm (2.75 in.) above standard.

Not sure if this makes more sense or not? I only ever use T4 with the SPX calibration blocks.

Not wanting to add fuel to the fire here but your issue is crashing suspension, not who is a Land Rover chassis design engineer. Calibration is important in that your normal height is likely to be the most comfortable ride height under normal conditions, but I think more info is needed.

As Stuart mentioned early on, what dampers and bushes are you using, and what condition are they in? Does the ride height feel like it is changing sometimes, although the LED's show the same ride height?

I'm only asking this because I found out a problem with my '38 the other day. The bushes have failed on the front suspension arms at the axle and every time the axle is allowed to twist one way or the other, the EAS drops or lifts the front end, giving seriously bad ride quality.