Dmax CV

phs

Well-Known Member
Say the springs compressed 10mm for every 25mm of wheel travel and that there is 100mm of wheel travel up to hit bump stops when at std height. That means the spring would compress 40mm at std height or 60mm on 50mm lift before hitting bump stops. 60/40 = 1.5 or 50% more force (or weight) to hit bump stops with the same rate spring which of course would have to be longer to provide the lift. You would need a spring 1/3rd lighter to get the same amount of suspension travel. Probably very nice for rock hopping but not suitable for road travel.

regards
You are missing my point

" 1/3rd lighter springs to get the same travel "
it's the same travel

So it's takes more force That's a given, how do you know that is an issue for limiting the travel, get the correct spring go 4wding it will hit the bump stop without any issues
 
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muc the truck

Well-Known Member
Say the springs compressed 10mm for every 25mm of wheel travel and that there is 100mm of wheel travel up to hit bump stops when at std height. That means the spring would compress 40mm at std height or 60mm on 50mm lift before hitting bump stops. 60/40 = 1.5 or 50% more force (or weight) to hit bump stops with the same rate spring which of course would have to be longer to provide the lift. You would need a spring 1/3rd lighter to get the same amount of suspension travel. Probably very nice for rock hopping but not suitable for road travel.

regards
I have been trying for years to convince people they bought the wrong 4x4 for lifting if they have irs but is hard to get anyone to accept the facts you understand . Bash plates and stock ride heights better than lifts on irs with the biggest tyres you can fit . Live axles are the way to go if you wish to lift a vehicle .
 

phs

Well-Known Member
I have been trying for years to convince people they bought the wrong 4x4 for lifting if they have irs but is hard to get anyone to accept the facts you understand . Bash plates and stock ride heights better than lifts on irs with the biggest tyres you can fit . Live axles are the way to go if you wish to lift a vehicle .
Muc, match the correct spring to your lift and it will hit the bump stops off-road I can't see the issue ?

I totally agree HD springs are no good
I have always correctly matched my springs and never had any acticulation issues.

Same comments were made with my leaf sprung 79. Yet it had better articulation than most coil rear ends getting around
 

peterfermtech

Well-Known Member
You are missing my point

" 1/3rd lighter springs to get the same travel "
it's the same travel

So it's takes more force That's a given, how do you know that is an issue for limiting the travel, get the correct spring go 4wding it will hit the bump stop without any issues
It may be the same travel but it is not the same result. Lighter springs would mean more body roll when cornering and more wallowing on undulating roads. If you use the same strength springs (but longer) as std with a 50mm lift you will probably need an extra 3/4 of a tonne over the front to get the full travel otherwise you won't be able to compress the springs fully.

regards
 

Jackolux

Active Member
When we buy a aftermarket suspension for our 4x4's we just have to trust / hope who ever put the system together has done some RnD and got it right .
I have had my Ute to a couple of suspension places , I can at least tell them my axle loads front and rear , Dobinsons looked up the spring rates that ARB fitted so did the local spring works , both say they are ok for my front axle weight . I sure they would be more than happy to take my money and replace the springs if they thought it was necessary .
I jacked up one side there is no way the other wheel is going to lift , wouldn't matter how stiff / strong the spring was .
 

peterfermtech

Well-Known Member
I think they give us exactly what we ask for. We want a 2" lift, they give us a 2" lift. We want heavy duty suspension, they give us heavier springs. We don't ask the question what happens when we make those changes. The most likely thing is that you will be lifting a wheel more often which leads to 2 big issues. First the CV will be pushed toward it's limit of flex more often. Second, the Traction Control will be called on to work more often which generally leads people to say the TC is crap so need to buy a locker.:oops:

What needs to be done is for us to actually work out what we really need and what we are willing to compromise or what we are prepared to pay to get it.

regards
 

phs

Well-Known Member
It may be the same travel but it is not the same result. Lighter springs would mean more body roll when cornering and more wallowing on undulating roads. If you use the same strength springs (but longer) as std with a 50mm lift you will probably need an extra 3/4 of a tonne over the front to get the full travel otherwise you won't be able to compress the springs fully.

regards

I agree, the lighter load to compress will keep the spring active more often

I was just commenting on the total travel.
 

Jackolux

Active Member
I didn't want a 2" lift and I never got one , I told ARB exactly what I was going to do with the vehicle , I even rang ARB Head Office in Melbourne and talked to the Tech Department twice before I took delivery of the Ute.
It took them 2 attempts to get it right ( if it is ) I supplied weigh bridge tickets before the second time .

This weekend we are going bush again , a mate with a completely stock Dmax I hope is coming , it will be interesting to see how his goes on the same tracks as mine . I expect the wheel travel to be pretty much the same .
 

muc the truck

Well-Known Member
Muc, match the correct spring to your lift and it will hit the bump stops off-road I can't see the issue ?

I totally agree HD springs are no good
I have always correctly matched my springs and never had any acticulation issues.

Same comments were made with my leaf sprung 79. Yet it had better articulation than most coil rear ends getting around
Like anyone else that disagrees with me and peterfermtech you don't under stand what we said or don't want too. Vehicle lifts on irs are a sensitive to criticise the owner of something that just reduced flex. re read peterfermtech coments again . Your leaf spring set up has got nothing to do with the irs set up. piss easy to get extra droop out of leaf coils over life axle.
 

phs

Well-Known Member
Like anyone else that disagrees with me and peterfermtech you don't under stand what we said or don't want too. Vehicle lifts on irs are a sensitive to criticise the owner of something that just reduced flex. re read peterfermtech coments again . Your leaf spring set up has got nothing to do with the irs set up. piss easy to get extra droop out of leaf coils over life axle.
The leaf spring comment was simply an analogy for peoples perception

Reducing the amount of articulation per pound I agree but reducing its capable travel I don't.

I also think using the correct setup a 2" lift on an IFS benefits out weight there negatives
But it needs to be done properly
 
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peterfermtech

Well-Known Member
I have been trying for years to convince people they bought the wrong 4x4 for lifting if they have irs but is hard to get anyone to accept the facts you understand . Bash plates and stock ride heights better than lifts on irs with the biggest tyres you can fit . Live axles are the way to go if you wish to lift a vehicle .
It was probably about 6 years ago after I had done a 2" lift on my old;) 2010 d-max and I was a bit disappointed with the way it was handling in the bush that someone mentioned, or I read (was it you muc?) about the issue of reducing travel in a lift, that I went off and did the maths myself to see what the effects were. I was already convinced that bigger tyres were the go but unfortunately that model d-max is limited to about 245/75/16 so I had gone down the path of a lift. Remember the days when Landrover tyres weren't much bigger than Holden tyres and you could do a lot of todays 4wd tracks with a few blokes behind pushing and a bit of clutch slipping? Anyhow my calculations convinced me of what I have previously written in the earlier posts. I'm not totally innocent of falling for this trap as I have a 20mm lift on my mux but that is the compromise that I am willing to accept and it gives me with the 265/70/17 tyres a little bit more clearance than the old;) d-max had with the 2" lift.

regards
 
I didn't want a 2" lift and I never got one , I told ARB exactly what I was going to do with the vehicle , I even rang ARB Head Office in Melbourne and talked to the Tech Department twice before I took delivery of the Ute.
It took them 2 attempts to get it right ( if it is ) I supplied weigh bridge tickets before the second time .

This weekend we are going bush again , a mate with a completely stock Dmax I hope is coming , it will be interesting to see how his goes on the same tracks as mine . I expect the wheel travel to be pretty much the same .
Hi Jacko
Sorry for jumping on board so late in this convo and appologies if you have allready discussed this. I just snapped my 2nd CV on the weekend and have ordered an aftermarket one from Burson's. Have you been reasonably happy with the CV's you have bought from them before. Once again sorry as its slightly off topic. I had no lock at the time but was driving it harder than I should up some very snotty rutted stuff.....Very silly as I wasnt using my lockers.
Genuine CV's from Isuzu seem very expensive and from my experience are not overly strong at all.
Any help would be greatly appreciate moving forward.
Cheers
Dave
 

Tink

Well-Known Member
Hey Dave, bugger about the CV. You want to jump over to the ozisuzu forum and vote in their CV poll. Those guys don't believe an Isuzu can break a CV :D
Cool forum name BTW
Tink
 
Thanks Tink!!
You have gotta be kidding me. There are more writeups about dmax's snapping CV's than there is on baby Jesus birth.
You blokes are at least trying to diagnose the issue and determine a way forward. And dont get me wrong I know that Dmax's arent the only vehicle affected by this......but so far im having a rather crappy run.
I believe my lift is probably a bit excessive for the vehicle but I was hoping to get away with it....However I may need to address this.
Any help would be greatly appreciate lads.
Dave
 

Jackolux

Active Member
G'day Dave I have broken a Bursons CV but the original CV broke just as easy , at least it lasted 30K the first CV went bang at 7.5K , not that that means anything .
I replaced the Bursons CV with another Bursons 35K and it's still going around , still have the original CV on the RHS .
I'm happy enough with the Bursons CV , plenty will say aftermarket CV's are no bloody good , no one has ever come up with any evidence, not that I have seen anyway .
The local Isuzu dealer wants $960 for a CV , there is a authorised Isuzu Truck service place not fat from me he quoted me $750 for a genuine CV .
I fitted a Diff Drop after attaching a GoPro under my Ute and actually seeing the angles of the CV when on a 4WD track
have a look at the video there is a link above .
I Diff Drop will help but I don't believe it's a complete fix ,
What suspension do you have , where are you from .
 
Hey Tink

I do have a diff drop fitted. However I dont know how much it dropped the diff as I bought the vehicle with most of the kit on it.

Yeah thanks Jacko. I have watched all your clips with the GoPro attached. Great angle and was a great insight into what they are actually doing when out on the tracks.

I live in Canberra mate. Please dont hold that against me ;-)

Local Isuzu quoted me $1050 for a CV. I found this post and decided to give Bursons a try after reading about your experience.

I have Bilstein 2-6inch adjustables in the front, The bloke reckons it was adjusted to a 3" lift after he snapped a CV at 4" lift. To be honest I think it has sagged and wouldnt be a true 3" compared to a new ute. But after snapping one on the weekend I was considering lowering the car more.

I have front and rear E lockers....however I wasnt using these when I snapped the CV. I climbed the same track several times with the lockers engaged without a problem. I stupidly tried to show my mate that he would make it up without lockers and bang....snapped the CV. The front wheel started spinning as it lifted and snapped when it came back down. In hindsight my driving technique was pretty bad.

Im going to have a crack at replacing it myself as I think I might have to carry one spare. I would hate to snap one in a situation where I need 4wd to get home. I was lucky on the weekend that I could just reverse down the hill and drive home in 2wd.

I really appreciate you blokes getting back to me so quick!!
 

Jackolux

Active Member
The Bilstein Shocks won't be adjustable for length it will only be for dampening all aftermarket front shock are the same length as std for IFS vehicles , there might be 10mm in it but that's all .
When some say they have a 3 and 4 inch lifts ( 75 - 100mm ) it just can't happen , it's the spring that lift the vehicle and the shock is just pulled further out , you actually have less down travel .
If you measure from the centre of your wheel to the guard you can compare lifts between vehicles a std new Dmax is 520mm centre wheel to guard after a few K's they settle to 510mm with std bumper at least the few I have measured were that and believe me I have looked into Suspension and CV's a fair bit with a few Dmax .
My Ute measures 540mm Diff Drop is 30mm , CV angles should be std . I also have 2x eLockers and I'm very careful how I drive this thing , I don't care what anyone says I have done enough 4wding over many years with plenty of other IFS 4x4's to know these Dmax CV's are fragile .
 
I agree with you muc the truck, that part of my problem was the high rated ironman spring. My Dmax only have a bullbar and a winch in front n have nothing on the roof. I'm changing to a medium spring.
I have ironman 2 inch lift kit. Jeep wrangler. Great for 3 months. Its getting removed because the highly Overly sprung coils have dramatically stiffened and the ironman shocks have completely failed after 7 months. The vehicle is so highly sprung and poorly damped it launches you off the road. Adding weight creates more downpressure on tyres but increases wild rebound.. I regret purchasing that brand immensely now after 7 months total 4 of those literally fighting the vehicle to stay on road anything above 80 klm and any corrugation of any kind or pothole on corner and you will be dead. Petrified or scared to drive anymore... Beware cheap springs and crap shocks are a deadly combination. No joke.
 
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