BigJimnyMeet (North) 2024 (12 Jan 2024)
14th July 2024
Parkwood Nr. Leeds
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Got my springs from Zanfi
- TomDK
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But, not quite sure what to think just yet. Seems like the Italians measured inches somewhat different that most others do Orange springs is a 2" (3" ) Trail Master Diesel lift spring. I know It's exactly 2" lift because it's 2" longer than a standard Jimny spring. And then there's the Zanfi spring which is definitely more than a 3" lift. More like 4". But since it's a progressive spring, it's not easy to do a direct comparison.
Also note that the spring rod on the TM spring is thicker than on the Zanfi springs. Most spring coils on Jimnys are made of 12mm steel rod. But the TM 3" diesel springs are made of 13mm.
This goes very much against all I believe in when it comes to suspension lift. But as I'm also looking into a bit bigger tyres this probably needed.
Then for the measurements. Since my winch is sitting disassembled on the ground I used a couple of bags of cement as weight. probably around 45-50 kgs in total.
Reference point on TM springs with "winch" = 80.5 cm
TM springs without "winch" 81.3 cm
Zanfi springs with "winch" 81.5 cm
Zanfi springs without "winch" 83 cm
So as you can see, the front end only sags very little when mounting the winch on TM springs. Just as I suspected, these springs are very stiff.
It's a bit different with the Zanfi springs. They sag more and also only provides a very slight lift over the TM springs.
EDIT: Just occured to me. I totally forgot about the 15mm springs spacers I had installed with the TM springs to level out the car. This is because the TM rear springs are only slightly shorter than the front springs. So actually the difference in lift with winch is more like 2.5 cm = 1". So perhaps this all makes sense afterall??
But as this is not only a matter gaining more lift but also getting a bit softer springs this may still turn out okay
Will get back with more info after some testing.
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Very interested to hear your assessment. Keep us posted.
I started out with nothing & still have most of it left
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- TomDK
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will also have to do something about the castor angle. But will probably use the original radius arms and weld new mounts to the axle housing, rotated about 10 degrees. Should do the trick.
Mainly because We're going to Croatia again this year with 2 Jimnys. The other jimny is on a 2" lift with standard radius arms. Much easier if we can share as many spare parts as possible
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- TomDK
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Not possible to fix the castor angle with new radius arm mounts. The track rod will hit the radius arms on articulation even if I just rotate the axle just a few degrees.
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- Posts: 760
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I started out with nothing & still have most of it left
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- TomDK
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Still gonna take the front axle off to either reinforce the existing shocks mounts or make new stronger ones.
Will also reinforce radius arm mounts on both ends of all 4 arms. Will use the standard chassis mounts and weld on some 5mm steel sheet on both sides of the mount. Should do the trick
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- OllieNZ
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- TomDK
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Spring rate is calculated using number of active coils, free length, outside diameter of spring and material thickness in a formula I can't remember But there are plenty of good online calculators that works out just fine. I've tried it using springs with known spring rate.
Most automotive springs are made of the same type of spring steel. So nothing wrong with using these calculators.
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- OllieNZ
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I agree that it doesn't on it's own but when you're comparing 2 springs for an identical application a lower rate (softer) spring will need to have a longer free length to give the same partially compressed length for a given weight.TomDK wrote: The free length of the spring does not itself say anything about spring rate. And as this is a dual rate spring it's harder to calculate total spring rate.
Have you tried the calculator on here? www.pirate4x4.com/tech/billavista/coilovers/Part_1/ it allows you to calculate the combined spring rate of a dual rate spring.
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- TomDK
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One of my concerns with these new springs of the compressed length. With so many coils compared to the TM spring it reduces travel. Just not sure how much. Will have to measure that.
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- OllieNZ
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Diesel spring: 10 coils x 13mm dia bar = 130mm at bind.
Zafini spring: 14 coils x 10mm dia bar = 140mm at bind.
So you've not really lost much. Can the jimny even fully compress the springs at max articulation? I thought the shock would bottom first.
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