panhard adjustment and the proper way to measure the offset (1 Viewer)

[sunrk]

I've had EFS single-nut adjustable panhards on the 80 from way back. Today to temporarily sort out the punctured rear tyre issue while I get a repair kit I took two of the three Toyota factory 16 x 8 wheels with the 285/75-r16's off my box trailer (I only have three of them) with Chinese full-tread LT AT tyres and swapped them for the two rear wheels on the 80 with quite beaten about Cooper AT-3's. Then I noticed something I hadn't noticed before that the panhard offset seemed wrong.

I measured it (between the inner side of each tyre and the outer face of the applicable chassis rail) and found I get 80 mm on the left side and about 57 on the right side. Very obvious difference when looking underneath. Got me thinking... I currently have 3 inch of lift but used to have 5, and I wonder if I never re-did the panhard offset when I reduced the lift way back then.

What is the *correct* way to measure the panhard offset? The way I did it (with matching rims and tyres each side) seems legit. I'll need to try and check the front panhard now and try to repeat with the steering straight ahead.

It hasn't been causing me any noticable drivability problems, but as the rear doesn't have flares a visual reckoning using the wheel arches at the back gives it away, hence breaking out the tape measure.

I'm going to go out on a limb here and presume that the Toyota factory 16 x 8 steel wheels all have the same offset (claimed to be zero?)?

 

[sunrk]

Today I lifted the back off the ground just to ensure nothing was snagging, put it down, measured again. Got the same numbers - 80mm left tyre to chassis rail - 55 mm right tyre to chassis rail. I checked they are both on the hubs properly and the nuts all the same torque (70 ft lb as I lube the studs with copper grease). So I re-aligned the rear by shortening the panhard about 12 mm, and now get approx the same spacing tyre to chassis rail each side of close to 70mm. I'm not concerned about laser-accurate precision since I did it on the driveway.

For s***s and giggles I measured the fronts and each side was pretty close to about 295 mm from inside of tyre to chassis rail so I left the front alone.

 

[rhc404]

What is the *correct* way to measure the panhard offset? The way I did it (with matching rims and tyres each side) seems legit. I'll need to try and check the front panhard now and try to repeat with the steering straight ahead.

I think the easiest way is to measure the panhard angle or horizontal offset of the mounts at stock weight and height. Then use right triangle math along with the measured stock panhard rod length and new suspension lift to solve for the new panhard length. That will put the mounts back to the stock positions horizontally, which is probably the best starting point for smaller lifts/tires. The longer panhard rod swings in a longer arc, so from there it may need further adjustment for tire clearance when the suspension is compressed.

 

[Somebodyelse5]

They teach Trigonometry down under, right?

The better solution is a panhard relocation bracket. either eimkeith or deltavs

 

[sunrk]

I get what you're saying with the triginometry. Yes I could go hardcore and replace the panhard mounts front and rear with custom ones but I don't do enough off-road to justify that approach. Rampt Customs here in Newcastle oz can do a similar thing. I've had adjustable panhards for 10+ yrs but ran 5 inch lift until about 2016, then dropped it to 3 because of a bunch of issues (not the least of which were issues around interstate compliance for relocating back to NSW).

I'm a believer in empirical solutions whenever possible and for a simple panhard correct that doesn't need a full technical alignment bed to sort out.

 

[Somebodyelse5]

I get what you're saying with the triginometry. Yes I could go hardcore and replace the panhard mounts front and rear with custom ones but I don't do enough off-road to justify that approach. Rampt Customs here in Newcastle oz can do a similar thing. I've had adjustable panhards for 10+ yrs but ran 5 inch lift until about 2016, then dropped it to 3 because of a bunch of issues (not the least of which were issues around interstate compliance for relocating back to NSW).

I'm a believer in empirical solutions whenever possible and for a simple panhard correct that doesn't need a full technical alignment bed to sort out.

Do you want me to do the math for you? If you measure 3 things for me, I’ll do it….

 

[Broski]

The easy way and most accurate way is to remove the tires and with the axle on jack stands, then put a straight edge on the disc and measure to the frame. Rear only
And to be clear a panhard relocation bracket is not just for off road.
It can make your rig more stable at speed on any road that has large bumps or whoops.