A typical add-a-leaf is usually too stiff, but a single similar-design leaf added to a spring pack like I think Tony was asking about (?) won't increase the ride harshness more than say, the difference between a 10-leaf 2.5" and an 11-leaf 3.5" spring pack.
Also should not effect flex negatively my much. You could probably measure it, but I'm not sure you could feel or see it under normal conditions.
But I should have added last night too Tony, that even if I do find the old specs, it might not do you any good as not only have the features and design parameters changed slightly over the years (several times in small increments) but even the leaf material the companies are now using is different. Like SAE vs Metric even. Different thicknesses, rates and maybe even lengths.
If we changed the location of one of the clamps, the old leaf specs might not even be valid.
The best way I think, would be to let the spring manufacturer you use do the eyeballing and measuring for you. Choose whether you want a long one mounted up high (the best design I think) or a shorter one mounted mid-pack or lower, and how long it would be to fit into the pack in a natural order.
And with whatever spring materials the guy happens to like using.
Of course, that's a nice cop-out and attempt to get me off the hook in case I can't find out the specs too!%)
I too have always considered springs a wear item, but acknowledge that there have always been several ways to fix an issue. Re-arching, adding a leaf, adding a block, or full replacement. If it works, I've never considered up to a 1" block a bad solution. Not the best option of any of them, but not a deal-breaker either.
But when an individual "fix" starts to get near the price of a new pack though, replacement was always the way to go.
Paul
