Do I need a steering damper? 80 Series

[a80crewza]

The other day I got some 2.5degree castor bushes put in to try and fix light steering and bump steer. Steering feels a bit tighter and going over bumps doesn't effect truck as much. But when I drop down a kerb or similar the steering wheel still jerks. Also when driving on an inclined road/corner, truck follows that. So my question is do I need a Rtc steering damper to fix these issues. I'm running 35 inch tires and a 2 inch ironman lift ( seems more). Thanks.

[Jay]

Gidday.. how wide are your tyres out of curiosity? I have 35 x 13.5 on my 80 and they tend to follow any imperfections in the road.

Jay

[Trundle]

It will help , We stock the rtc for 225 and the adjustable ones for 280 , however i would suggest to dial a bit of toe in to the wheel alignment to help with the tracking also , Did you do adjustable panhards ?

[a80crewza]

My tyres are 12.5 wide on 15x8 rims. Yeah still need to get alignment done. But toe doesn't fix loose feeling and bump steer. Had one done post castor bushes. No adjustable Panhards. Trundle what's the different between adjustable and Rtc dampers? Cheers

[Trundle]

The rtc is more for keeping the tracking straight ahead and reducing the wander on the road where if steering shimmy is and issue you can dial the adjustable one up untill it goes away , (does'nt have a spring on it though ,
Do you still have your swaybars fitted ?

[a80crewza]

Yeah still have the sway bars fitted. The problems I have is wander to the left (its possible an alignment would fix this), 'light steering feel' and still have bump steer (drop down a kerb and steering jerks alot), truck also steers when I brake on an sloped corner. Sounds like an rtc will tighten up my steering abit??

[Trundle]

With an rtc you can adjust it to put pressure towards the drivers side ,
Did you take not when fitting the lift that there is a left and right spring ? also have you set your tyre pressures recently ,? running a few mm toe in will definatly assist with your issue as the higher sidewall tyres push out when driving

[a80crewza]

Tyre pressures are fine. Toe will get fixed when i get alignment hopefully.

[shortylux]

But toe doesn't fix loose feeling and bump steer.

Neither does a steering damper.

The loose feel has to be some kind of a geometry problem (not enough caster? but as you say, progress has been made here)

If you are all factory geometry (with regard to panhard vs drag link lengths and mounting positions) then you shouldn't really have bump steer problems per say. Wider (than factory) tires and rim offsets will increase the feed back through steering wheel, when you drive up a curb for example. A steering damper would help for this.

Trundle will have a more informed opinion than me but my over all impression of rtc dampers is that they aim to fix symptoms rather than problems, and I believe that's why Trundle is suggesting other solutions.

[a80crewza]

But toe doesn't fix loose feeling and bump steer.

If you are all factory geometry (with regard to panhard vs tie rod lengths and mounting positions) then you shouldn't really have bump steer problems per say. Wider (than factory) tires and rim offsets will increase the feed back through steering wheel, when you drive up a curb for example. A steering damper would help for this.

Is there a way to check panhard vs tie rod lengths? I thought 2.5 degrees of castor correction for a 2inch lift was enough? Alignment will tell me if castor is out anyway. Would an adjustable panhard do anything for me?

[Trundle]

You can put a sraight edge on your tyres and measure them to your chassies and it will tell you how offset your diff is , There is a slight possibility if you used the lift that was designed for a pre august 1991 cruiser it would have given you 1" more lift than you expected and you may need more castor , How your describing the symptoms seems strange though , Did you lengthen your drag link when you did the lift or are they welded on your model ? if you just straigtened the steering wheel there is a chance that the indexing of the steering box is off to the left causing it to pull ,
But these are all kind of stabs in the dark without having driven the vehicle myself ,
Is there any ofroad specialist workshops around your area ?

[a80crewza]

What should the distance be from the tire to the chassis? Everything else is un modified apart from the lift kit and the castor bushes. Steering was awesome before the lift and new wheels etc. Yes there are.

[shortylux]

Is there a way to check panhard vs drag link lengths?

Sorry, I may have confused the issue. Unless you have chopped/welded factory panhard mounts you will not have any more bump steer than when it left the factory.

You can ignore this bit if you like.
Bump steer being the amount that your wheels move/steer as the suspension cycles whilst the steering wheel is held still. So if your panhard and drag link (sorry, I accidentally said tie rod before) are the same length and parallel then you will have zero bump steer even though your complete axle will move sideways as the suspension cycles.
Though I guess this sideways movement would cause weight changes on each tyre which could also effect steering.

What should the distance be from the tire to the chassis be?

It will vary depending on your tyre/wheel choice. Best to measure from the disc rotor (or similar) to the chassis. It should ideally be equal on both sides at ride height.

[Trundle]

Let me know when you have done the following ,
1 measured the diff offset as mentioned before ,
2 made sure the steering box is central / you have an adjustable drag link to do so ,
3 you have a wheel alignment report ,
There is no doubt that a an rtc will help but every litttle bt helps ,
Cheers
Trundle

[a80crewza]

Cheers guys. Will check that stuff out and get back to you. Thanks.

[a80crewza]

Pic for reference. Anything look odd from pic?

[a80crewza]

Okay an update, got a wheel alignment done today.

Castor before bushes were in: Left > -1.41, Right > -1.30

Castor after bushes: Left > +3.12, Right > +3.17

If stock is meant to be +3.00, would have thought my castor is now OK?

Diff offset is fine I think, its the same measurement on both sides from the wheel sidewall to the chassis.