Rebound Requirement For Jacking Point

[Nishant Jain]

The height of the tube is required to be such that:
There is a minimum of 75 mm (3 in) clearance from the bottom of the tube
to the ground measured at tech inspection.
With the bottom of the tube 200 mm (7.9 in) above ground, the wheels do
not touch the ground when they are in full rebound.

The bit about the rebound, I dont understand. Can someone please explain the last sentence?

[Nishant Jain]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The height of the tube is required to be such that:
There is a minimum of 75 mm (3 in) clearance from the bottom of the tube
to the ground measured at tech inspection.
With the bottom of the tube 200 mm (7.9 in) above ground, the wheels do
not touch the ground when they are in full rebound. </div></BLOCKQUOTE>

The bit about the rebound, I dont understand. Can someone please explain the last sentence?

[Drew Price]

Nishant,

That would be clearer if it read:

"With the bottom of the tube 200 mm (7.9 in) above ground, the rear wheels do
not touch the ground when they are in full rebound."

The jacking point is on the frame. When you lift it the rear wheels must come off the ground when the jacking point is 200mm from the ground. Something in your suspension must limit the droop travel of the rear wheels so that they do not touch the ground when the rear of the car is jacked up to the specified height.

I always assumed this rule was so that cars could be reliably removed from the track if they suffered a powertrain, drivetrain, or rear suspension failure so that the 'dead' wheels don't drag and make the car hard to move.

Best,
Drew

[Anday]

This means that when they use the quick jack to lift the jack tube 200mm above the ground, the rear wheels must lift off the ground. When the chassis is lifted, the wheels are in rebound or 'droop'.

[Nishant Jain]

drew, anday: thanks guys.