Whitey
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Hey everyone,
After having measured all the interesting relationships on the front IFS, I thought I’d measure up the rear 4-link live axle suspension geometry.
With coils and shocks out, and swaybar in, I find the following relationship between shock travel and wheel travel;
The shock travel limits are defined by the axle hitting the bumpstop at around 405mm, and the factory brake lines/swaybar binding at around 610-615mm.
This relationship can also be expressed in terms of droop as;
This gives a motion ratio of wheel droop:shock travel = 92/89 = 1.0337.
As I’m running 80 series shocks, 365-618mm, the swaybar links definitely need to be lengthened by around 10mm to make sure the shocks top out before the swaybar binds, which will also give a little more droop.
Toyota also appear to have built in a safety margin of about 50mm (bumpstop height) for the OEM closed shock length of 356mm, with 356+50 = 406mm, where the axle touches the bumpstop. As such, if the bumpstop fails/falls off, the axle should hit the chassis at the same time the OEM shock bottoms out at 356mm.
The factory flexible brake lines are stretched to their limit under these measurement conditions, and will not get stretched in this manner when the live axle is flexing at an angle under normal 4wd’ing conditions.
Even so, I will be replacing my factory brake lines with more sturdy and longer steel shrouded brake lines.
Best
Mark
After having measured all the interesting relationships on the front IFS, I thought I’d measure up the rear 4-link live axle suspension geometry.
With coils and shocks out, and swaybar in, I find the following relationship between shock travel and wheel travel;
The shock travel limits are defined by the axle hitting the bumpstop at around 405mm, and the factory brake lines/swaybar binding at around 610-615mm.
This relationship can also be expressed in terms of droop as;
This gives a motion ratio of wheel droop:shock travel = 92/89 = 1.0337.
As I’m running 80 series shocks, 365-618mm, the swaybar links definitely need to be lengthened by around 10mm to make sure the shocks top out before the swaybar binds, which will also give a little more droop.
Toyota also appear to have built in a safety margin of about 50mm (bumpstop height) for the OEM closed shock length of 356mm, with 356+50 = 406mm, where the axle touches the bumpstop. As such, if the bumpstop fails/falls off, the axle should hit the chassis at the same time the OEM shock bottoms out at 356mm.
The factory flexible brake lines are stretched to their limit under these measurement conditions, and will not get stretched in this manner when the live axle is flexing at an angle under normal 4wd’ing conditions.
Even so, I will be replacing my factory brake lines with more sturdy and longer steel shrouded brake lines.
Best
Mark