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360 lbs/inch ??


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In principle my D90 (300 tdi 1996) has had a 2 in lift from the previous owner.

However I thing the springs have settled by almost an inch and there is no lift left when fully loaded (as mostly with all the tools, spare parts, roll cage, rear wheel carrier)

Also NASA rang me as the guys in the shuttle coldn't sleep because my headlights were disturbing them.

I think I go very heavy duty and put 360 lbs/inch springs in. What do you guys think? Is it too much?

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i think you need to calculate the weight on the rear suspension and calculate/choose the springs accordingly.

Just jamming on some silly hard springs isnt going to provide the best ride/handling.

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That is crazy heavy, IMO....

I thought I was heavy and I'm running 210. I like soft suspension.

Tell me the spring model number and the normal compressed length when parked on a flat surface. Do it for both front and rear and I will then provide a suggestion.

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the first thing to do is find you nearest axle weigh bridge there is a free one in most larger towns usually at the vosa office.once you have those weights talk to an expert like d44 or gwyn and see what they recommend.

unless you tow a lot or are running at max weight then i would not use 360 springs.i would try and reduce the gear in the truck as you will see a small increase in mpg if you can loose a few hundred kilos of gear from a motor.if you are in the area i use 340-380 rear springs on my 90 when towing the comp car.

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If you don't know it then you could get an approximate calculation of the current rear spring rate. Measure the spring length on level ground and then add weight over the rear axle to shorten the spring by 1/2 inch. The added load will give you close to the lbs/inch of one spring. That would be your starting point. If you know the free length of the spring then you can calculate approximately the unladen vehicle weight on the spring.

Then weigh everything you are going to put in the back of your vehicle and work out from that what length and rate you will need to keep it level when loaded.

You will also need to see where it will be unloaded with the up rated spring as it could end up being very high.

This is only approximate as some of the added load will be taken by the front axle and the pitch of the vehicle as it is loaded will also affect the measurement. To make it more accurate you could measure the spring length unladen and on the level then drive the rear wheels onto a 1/2"board and load until the spring is 1/2" shorter and the vehicle is at the same level as before.

It will be a balance between free length and spring rate to get an acceptable ride quality and height between loaded and unloaded.

It is still better to not carry as much stuff unless it is needed and set your headlights slightly low if you are going to be carrying a load as it is bad to dazzle the space shuttle and other drivers. Also given it is a 90" loading the back will have a bigger effect on the headlight aim then it would on a 110 or 130.

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Thanks to all for your answers.

Very good input.

I'm on a journey at the moment, but will be back on Tuesday.

Red90, thanks for your offer. I will measure the springs as soon as I'm back and see if i can find out what make, model, or color code they have, and will post it then.

I know that less stuff in the vehicle would be better and I would have chosen that if I had a choice. However, that is not an option and I need springs which are up for the job.

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I'm back and have some more info.

RH spring is 28.5 cm (11.22 inch)and LH spring is 27.5cm (10.83 inch) as the vehicle stands now. There is 8.5cm / 7.5 cm between bump stop and axle.

The color code RH ist blue-red. I assume that these are Britpart springs. I found remains of a sticker. Sorry, can't find any more details.

I assume that the roll cage, the gear in the back and the spare wheel are together approx. 180 kg, which is for my case the unladen condition. There will be approx 100 kg additional gear in there when I'm on a trip.

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Your input is once more appreciated.

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Blue/Red are stock 90 rears. By you height numbers, that is what you have. Sorry, but someone lied to you as that is not lifted at 10.8/11.2".......

I get around 900 to 925 lbs on each rear spring, which sounds about correct. A set of normal 2" lifted springs should work fine to get the rear up. Just leave the front as is, if that fits the stance you want.

http://members.shaw.ca/jbarge/springinfo.html

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Thanks Red90!

I think you are right. Looks like standard springs and shocks. Not the only thing the pervious owner lied about.

However, I will change this now. I have ordered a 2" lift kit and will her bring up a little.

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