1991 K2500 SAS death wobble

[Thunderstruck20]

It is absolutely gone now. After 3 years of chasing every loose component and replacing even questionable items it's hard to believe just a simple wheel change was the issue, was a little residual shaking but I will attribute that to bump steer with a bad rag joint and extremely hard tires, stabilizer covered it up entirely until I can track down a Cherokee intermediate shaft.

Sent from my SGH-M919 using Tapatalk

 

[Supercharged111]

Bump steer won't show itself going down a smooth road. I'm not sure you understand what KPI is or, rather, its effect on handling. KPI is like caster's opposite. It's the inclination of the spindle from parallel with the ground. If you look from the side at the arc the end of the spindle makes, it's a frown. This adds weight to the steering wheel as if makes the tire dig into the ground when you deviate from straight. It also causes you to lose camber as the wheel is turned, but gain camber with body roll. The more caster you have, the more camber you gain from turning the wheel but in turn you lose said camber as the suspension compresses. On an ideally set up car, you'll target a certain split from caster to kpi and I want to say kpi leads caster but I'm not 100% on that one.

 

[michael hurd]

Since this is a swap, it's hard to say exactly what the pinion angle is like. Most swaps I have read used rear leaf springs from an older GM.

If there is not enough caster ( from a rotated differential ) it will steer wonky.

Most hardcore guys who put large tires on their trucks with a solid axle drill out the plugs and rotate the axle tubes to rotate the pinion up to compensate for lift while retaining the factory geometry at the knuckles.

 

[Supercharged111]

Since this is a swap, it's hard to say exactly what the pinion angle is like. Most swaps I have read used rear leaf springs from an older GM.

If there is not enough caster ( from a rotated differential ) it will steer wonky.

Most hardcore guys who put large tires on their trucks with a solid axle drill out the plugs and rotate the axle tubes to rotate the pinion up to compensate for lift while retaining the factory geometry at the knuckles.

Man that sounds slick. Not for the faint of heart. I dig it.

 

[Thunderstruck20]

Caster is within 4-5.5 degrees on either side, wobble is it all but gone (just a slight vibration now) with swapping to dually wheels. Still needs a steering shaft but I need to figure out whether a 93 grand Cherokee shaft is identical to a Cherokee or not. Never would've guessed that was the issue but then again that's why I ask people who've had more experience with custom builds.

Sent from my SGH-M919 using Tapatalk