Whitey
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Hey all,
I've made some measurements of the separation of the rear coil buckets as the rear shock open length increases.
This will help out when it comes to choosing the correct free height coil springs for different open length shocks, particularly when it comes to long travel setups in the rear.
Here is the data;
There's an important point to note - as this is the coil bucket separation, you need to add at least 10mm to the coil bucket separation to ensure your coils remain pre-loaded and stuck in the buckets. These measurements also include the coil seat which sits on top of the coil.
As a problematic example, I was hoping the new C59-487 coils I got made to 430mm free height would be enough to do the job with my 30mm longer sway bar links binding the sway bar out at 645mm.
When I received the coils, one was 428mm, the other 426mm. If you interpolate from the graph, 645mm open length gives about 426mm separation between the coil buckets. When I put the coils in and checked them at the new sway bar bind open length of 645mm, the 426mm coil is well separated from the top bucket, and I can easily twist the 428mm coil.
So these C59-487 coils won't do the job for me unfortunately, and they really needed to be more like 440mm at least.
Another example is the long travel setup from MetalTech which the FJ guys are using in the USA to get a full 11" of travel right out to the point where the factory lower trailing arms bind on the axle at around 700mm open length. They run a 444-724mm Icon shock, and from my graph at 700mm open length you need something like a 477+10 = 487mm free height coil. The coils they use are 19.25" = 489mm, so right on the money!
Best
Mark
I've made some measurements of the separation of the rear coil buckets as the rear shock open length increases.
This will help out when it comes to choosing the correct free height coil springs for different open length shocks, particularly when it comes to long travel setups in the rear.
Here is the data;
There's an important point to note - as this is the coil bucket separation, you need to add at least 10mm to the coil bucket separation to ensure your coils remain pre-loaded and stuck in the buckets. These measurements also include the coil seat which sits on top of the coil.
As a problematic example, I was hoping the new C59-487 coils I got made to 430mm free height would be enough to do the job with my 30mm longer sway bar links binding the sway bar out at 645mm.
When I received the coils, one was 428mm, the other 426mm. If you interpolate from the graph, 645mm open length gives about 426mm separation between the coil buckets. When I put the coils in and checked them at the new sway bar bind open length of 645mm, the 426mm coil is well separated from the top bucket, and I can easily twist the 428mm coil.
So these C59-487 coils won't do the job for me unfortunately, and they really needed to be more like 440mm at least.
Another example is the long travel setup from MetalTech which the FJ guys are using in the USA to get a full 11" of travel right out to the point where the factory lower trailing arms bind on the axle at around 700mm open length. They run a 444-724mm Icon shock, and from my graph at 700mm open length you need something like a 477+10 = 487mm free height coil. The coils they use are 19.25" = 489mm, so right on the money!
Best
Mark
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