Rear trailing arms "cranked"

[natas]

can someone explain how/why these work better than stock on a stock hieght vehicle?
sorry I am clueless..............

rear trail arms

Thanks.

 

[craigyb]

Would be pointless i reckon. They are made to suit lifted motors.

 

[johnlad]

there not intended for standard vehicles

 

[Paul D]

They don't. The crank compensates for the axle 'roll' as the springs are lifted. The axle is held in one plane by the trailing arms, but when it's forced away from the chassis by longer springs it has to rotate about the point at which it's held, so making the spring seats change angle. The cranked arm negates the roll by turning the axle by a similar amount to the roll angle ..

hence a 2" lift needs a 3 degree crank bend, a 4" lift needs a 6 degree bend etc .. 'roughly' ..

 

[Boris113]

The chassis end sits straighter in the bush when the vehicle is parked on the flat which equates to more droop travel before the bush fully compresses.

They are often offset on the axle end also. This is so that when the axle droops down, it can move further without the arm hitting the top of the axle bracket.

Whether this makes much difference on standard height suspension is negligible however.

 

[Boris113]

They don't. The crank compensates for the axle 'roll' as the springs are lifted. The axle is held in one plane by the trailing arms, but when it's forced away from the chassis by longer springs it has to rotate about the point at which it's held, so making the spring seats change angle. The cranked arm negates the roll by turning the axle by a similar amount to the roll angle ..

hence a 2" lift needs a 3 degree crank bend, a 4" lift needs a 6 degree bend etc .. 'roughly' ..

Paul apologies if I'm wrong but is that not only for the front to deal with caster correction on the swivels?

 

[Paul D]

Paul apologies if I'm wrong but is that not only for the front to deal with caster correction on the swivels?

oops, you're right, of course, apologies to Natas, didn't mean to mislead you.

Boris has the right of it .. for the rear, I explained the fronts!!!

Just call me a feckwit ...

 

[craigyb]

oops, you're right, of course, apologies to Natas, didn't mean to mislead you.

Boris has the right of it .. for the rear, I explained the fronts!!!

Just call me a feckwit ...

Feckwit

 

[craigyb]

Now I don't know if I'm right (just a guess) but if you had +2 shocks on, woul it benefit then as the axle has more articulation???

 

[Paul D]

.. didn't mean you had to ... :laugh:

 

[Paul D]

Now I don't know if I'm right (just a guess) but if you had +2 shocks on, woul it benefit then as the axle has more articulation???

Yes. But without +2 springs on, there's the possibility that the standard length springs could be pulled out of their seats by the axle movement, hence the need for matching systems and/or dislocation cones to re-locate the sprinhs when the axle resumes the horizontal ..

 

[natas]

Yes. But without +2 springs on, there's the possibility that the standard length springs could be pulled out of their seats by the axle movement, hence the need for matching systems and/or dislocation cones to re-locate the sprinhs when the axle resumes the horizontal ..

That must be it as I am also getting 2 Rear Springs re locators &
2 Rear Spring Retainers H/D.....????

I am getting what Mr. Lewis suggested.

 

[craigyb]

.. didn't mean you had to ... :laugh:

Yes. But without +2 springs on, there's the possibility that the standard length springs could be pulled out of their seats by the axle movement, hence the need for matching systems and/or dislocation cones to re-locate the sprinhs when the axle resumes the horizontal ..

Not a bad Guess

 

[Paul D]

That must be it as I am also getting dislocation cones.....????

I am getting what Mr. Lewis suggested.

You'll not go far wrong with his advice ..