Does anyone know how much of the cabin weight eg 2 people of around 100kg is carried by the rear springs?
I went to TJM a couple of weeks ago, one chap there suggested that I use 175kg springs on our dual cab but I thought his maths were a "bit" out. I have around 85kg in the tub as a constant load & a canopy that weighs 70-75kg so there's 160kg to start with without a full fuel tank, any passengers. This is our normal situation - the van is not a permanent fixture.
Fulcrum Suspension suggested I'd be better with 300kg springs with Bilstein shocks for the occasional foray on dirt roads.
Thanks in anticipation of your answers.
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Warren
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If you don't get it done today, there's always tomorrow!
What ball weight is the Van? I upgraded a 2011 Colorado with KONI shocks and I had the rear springs recambered (arched bit more than standard) That got the spring leaves off the load leaves on small bumps, ball weight was 243Kg and I used a WDH, everything worked very well.
Regards,
-- Edited by Mike196 on Tuesday 6th of April 2021 01:47:07 PM
At a guess the rear springs would be taking about 20kg each of the 100kg. Plus your additional weight allowances without deducting what weight would be shared by the front suspension would be around 120kg per spring,
I had a set of Old Man Emu 150kg springs with new gas shockies installed on my 2016 DMax which has canopy and tub liner and a nudge bar and the result was a bit better ride, a lift of 65 mm ( over and above the existing sagged spring height) and with 240 kg tow ball weight the van sits nice and level, don't use a WDH.
So I would suggest, from my experience, the 175 kg would be spot on for your D Max.
Chris.
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Chris & Sharyn.
Tea Gardens. NSW.
2015 VW Touareg V6 Air suspension, 2012 Jayco Sterling 21.
Thanks Mike,
The ball weight is approx 170 -180kg - I don't use a WDH a personal choice.
We bought the car with the "new (in 2018)" 3 leaf rear springs because it was comfortable for Pat who has a bad back (former nurse). When I tried to find out details of the two sets of springs, I was told they had the same rating but they failed to say anything about any defects.
However Isuzu said 6 months after we bought the car that the springs were unsafe as the could break. I found out that they had previously done 2 recalls - without doing anything to improve the safety other than
- (a) replace the 3 leaf set with another 3 leaf set
(b) replace that second 3 leaf set with the 5 leaf "HD" set
(c) the same happened to those of us who bought the 2019 model car. The 2020 car came only with the 5 leaf packs.The dealers said it wasn't their fault - that "Isuzu had it all in hand each time." I wasn't terribly impressed.
Driving over a lot of Qld roads certainly shows the short comings in the suspension, van on or off!
I've looked at the suspension on a relative's Ranger - it is that far in front of my car, it's not funny. My springs are almost completely flat with nothing on the back & there is little movement in the pack to the bump stops, perhaps 50mm & yes they have made contact with the chassis. I measured the gap between the worker & load springs recently - a sheet of A4 paper (however thick that is) just fits between them!
I'm not certain how my warranty would go if I had the springs reset - they are always keen to state it could be in jeopardy if I did something unauthorized. Replacement springs are covered by the sellers' warranties.
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Warren
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If you don't get it done today, there's always tomorrow!
Oops thanks Chris,
I'm forgetting there are two springs carrying the weight!!
I have a steel bull bar but I assume the weight of that would be taken by the front suspension. I was keen to get a lighter smart bar but the loo$1500 difference was a significant amount.
Your gas shocks - are they also OME? I've used them, Munroe Wylie before on my Patrols & had good life from them. Fulcrum Suspension told me single tube shocks get rid of the heat quicker than twin tube but twin tube protect against stone damage too.
Each company tells you different, sometime conflicting info - no wonder why members of the OzIsuzu Forum say that suspensions are a dog's dinner!!
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Warren
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If you don't get it done today, there's always tomorrow!
Does anyone know how much of the cabin weight eg 2 people of around 100kg is carried by the rear springs?
Your own centre of gravity while sitting in the seat would be roughly 200mm forward of the front of the seat upright face of the seat.
So if the wheel base is 3000mm & the centre of gravity is 1200mm from the centre of the front wheels & there is 100kg is the front seat.
1200 / 3000 = 0.4
0.4 x 100kg = 40kg
40kg rear & 60kg front
Just set up a simple spreadsheet, use OpenOffice & the weight of each item & distance from the front wheel.
Put the weight in fields A1, A2, A3, A4, A5 etc.
The distance from the front in fields B1, B2, B3, B4, B5 etc.
In column C in field C1 write =SUM(A1*B1/3000) replace 3000 with your own wheel base length & copy & paste this formula to column C fields C2, C3, C4, C5 etc
At the bottom of column C figures in field C6 write the formula =SUM(C1:C5)
That is the total weight of the 5 items, or how many you have, at the rear of the car.
For items forward of the front wheel like a bullbar the distance is a negative number. Just estimate the centre of gravity of each individual item.
Oops thanks Chris, I'm forgetting there are two springs carrying the weight!! I have a steel bull bar but I assume the weight of that would be taken by the front suspension. I was keen to get a lighter smart bar but the loo$1500 difference was a significant amount.
Your gas shocks - are they also OME? I've used them, Munroe Wylie before on my Patrols & had good life from them. Fulcrum Suspension told me single tube shocks get rid of the heat quicker than twin tube but twin tube protect against stone damage too. Each company tells you different, sometime conflicting info - no wonder why members of the OzIsuzu Forum say that suspensions are a dog's dinner!!
Yes, a dog's dinner Warren.
I went to local ARB, had a discussion, placed the order,(he did suggest 300kg springs) but I didn't need them. They installed 2 weeks later, all good so far.
You can go to their website and punch in your car details and it will give you I think 3 suggestions.
The shockies are OME Nitroes from memory.
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Chris & Sharyn.
Tea Gardens. NSW.
2015 VW Touareg V6 Air suspension, 2012 Jayco Sterling 21.
Does anyone know how much of the cabin weight eg 2 people of around 100kg is carried by the rear springs?
I went to TJM a couple of weeks ago, one chap there suggested that I use 175kg springs on our dual cab but I thought his maths were a "bit" out. I have around 85kg in the tub as a constant load & a canopy that weighs 70-75kg so there's 160kg to start with without a full fuel tank, any passengers. This is our normal situation - the van is not a permanent fixture.
Fulcrum Suspension suggested I'd be better with 300kg springs with Bilstein shocks for the occasional foray on dirt roads.
Thanks in anticipation of your answers.
hi, can not answer your first question as we are touring.
We had Fulcrum do our Navara, 300kg rear springs, Bilsteins all round, King spring on the front. Sit a bit higher.
Best $2500 I spent, the car rides extremely well on dirt roads and of cause any other road while towing or not towing the caravan.
My lady fincial controller said you have one chance do it right. I believe she is impressed with the ride.
Thanks everyone,
Even here I have two answers - Radar has 300kg springs fitted, Chris has 150kg springs for almost the same situation. Chris, the website suggests the 300kg set as did ARB when I saw them just after Isuzu said they had to be changed.
I know that new springs can add extra height - between 30 & 65mm seems to be most common. And it seems the springs rated at 0-300kg are commonly 150kg.
While I was certain the TJM chap said 175kg, their website mentions only 100, 250 constant load & 400kg constant load sets.
One point I found almost humorous was at Fulcrum Suspension - it was suggested that the springs are most comfortable at their rating - eg 300kg. If my car wasn't that heavy, I could add a load (a number of 20L water containers in the back). The dealer when it goes for a service, gets a flash print out that says "I'm not driving to their ideal & getting the best fuel consumption." I'm certain adding some drums of water in the back won't do that any good!
Whenarewethere - I missed a couple of points out - I have a steel bullbar (approx 75kg) hanging on the front suspension & we each weigh around the 100kg but I assume the formula would still work (60/40 - on each side).
Radar, it sounds like your partner is similar to mine - I got the car only because of the slightly extra load it can carry. She wanted (& still wants) the MUX - with less carrying capacity of the GVM modified Patrol!
So I'm still pondering!!
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Warren
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If you don't get it done today, there's always tomorrow!
Whenarewethere - I missed a couple of points out - I have a steel bullbar (approx 75kg) hanging on the front suspension & we each weigh around the 100kg but I assume the formula would still work (60/40 - on each side).
You know the weight of the bullbar. Have a bit of a guess at its centre of gravity. Let's say that is 700mm forward of the centre of the from wheel.
So type in 75 & -700 in the fields. Easy
Type in all the items weight in the car including floor mats & their distance from the front. Calculate a reference point within the car, say from the gear stick & add known distance to the wheel.
Or do all the calculations from the rear, what ever is easiest.
If you want you could also do a left right reference point so you know that you are not overloading the left side with beer & wine!
Spreadsheets are brilliant. You can put in all the items in the car & keep adding formulas for different information.
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Procrastination, mankind's greatest labour saving device!
50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.
I don't know whether the TJM guy quoted you "Lovells" Springs and Shocks or another brand, but from personal experience I would recommend the Lovells. They actually perform as they claim.
I had Lovells suspension fitted to a vehicle that was used extensively for towing a van and long distance gravel road work (Great Central Road, twice + many others) and the gear performed faultlessly.
Next vehicle, same application, I went with OME through ARB and was bitterly disappointed. The front springs sagging badly and were replaced under warranty once, I had to pay for labour), they then sagged again to less than standard ride height within 10 months. The rear springs sagged also and the bun fight to have them replaced was considerable. I would never go near OME suspension again.
Don't discount Lovells, they are a good Aussie company making a quality product that just works. I will be using them for any future upgrades that I do. I am not in any way associated with the company, just a satisfied customer.
