Does a spring perch.........

[choppinczech]

... need to be angled when using 4 bars? I get the need with hairpins or radius rods due to the arched path. But with a 4 bar's 'vertical only' movement, shouldn't the spring perch be parallel to the bars? [S

 

[31chevrod]

good question I would like to know as well!!

 

[IAM-LDS-2]

Your spring perch needs to be at a 6-9 degree angle . This will put you pretty close to what your particular vehicle needs to be at . You can fine tune this angle using the adjustable attachments on the end of your hair pins . If you mounted the top of the spring level ( without the 6-9 degree tilt ) you would have to get all the tilt using the adjustment bolts causing the top of the spring to be in a bind .

 

[choppinczech]

From this photo I found it looks like either way needs some angle.

So the angle on the spring is for castor?

 

[05snopro440]

Yes, it is for caster, for better handling. It doesn't matter what bars you use, you need that caster angle in the front end.

 

[choppinczech]

Thanks guys

 

[donsrods]

If you don't angle the perch to match the angle of your caster, there will be a bind on your spring. I try to add in a little angle to the perch to compensate for the rake of my car. For example, if I want a 7 degree axle caster I might lay the perch at a 10 degree angle because my car is raked 3 degrees. If I didn't do that I would lose 3 degrees when the car was finally resting at it's raked position.

Don

 

[RPM]

The angle of the spring perch depends on how the spring attaches to axle!!! On our tube axles the perches are set at zero.

With a spring behind, suicide style the spring has a SPRING PIVOT. This allows the axle to rotate on the pivot to set the caster. If you are using a Ford I beam type axle with the stock perch bolts then YES the perch needs to be at what ever caster angle you want. Usually 5-7 degrees. If you don't tilt the perch then the shackles will bind on this type suspension set up.


On this one that was pictured it has a pivot bolt in the set up so this one it does not matter what angle the perch is. It will work like the spring behind set up.