Suspension Optimization and Tuning Help

[AutoX_a_Truck?]

Sounds like a plan Tyler.

Can you convert your excel spreadsheet into a JPG file & post it up? If you have Photoshop or Adobe Pro, those will do it. Otherwise, you'll need to post them up manually.

I see the spreadsheet JPG did not work the first time so I had to reattach it as a PDF.

Suspension Pivot Point Mapping Worksheet Scout II v.Final.pdf UPDATED on 2/14/2014 because there was a round off error for the Passenger Lower arm rear pivot.

Also, I'd like to see more photos showing all angles of your rear suspension & steering. Post some of bottom view, side view & front or rear view.

Here are some pictures I have on hand of the steering and rear suspension. For the rear suspension, obviously it was easier to use a few older pictures from earlier in the build. I can try to get some better views if necessary.






Ignore the wide spacer on the front end. That was just a mockup for a narrower set of front wheels that I used on the street with the truck body.








For the steering, I also included an older picture of center link and tie rod setup too because it was slightly better.




A few questions for you to answer ...

1. Is that an aftermarket spindle? It looks kind of like a CPP.

Yes, the spindles are generic aftermarket drop spindles, but I do not know what brand they are. I bought them used. If the brand is important I might be able to find some identifying marks, but I did not see anything obvious such as part numbers or markings.

2. Does each truck arm have its own pivot or do the two arms join at the front forming a triangle like old Model A suspensions?

The two arms join at the front forming a triangle. It is 48” from the center of the pivot point to the center of the axle.

3. Get a height measurement to the front pivot(s) of the truck arms.

5 3/8”

4. Get a height measurement to the mating surface of the truck arms & the housing brackets.

10 1/2”

5. Did you measure motion ratios of the springs? If not, please do.

I quickly searched through a few of the threads here and at Lateral-g, but I did not find a definitive gold standard method for measuring the motion ratio in the front suspension thread. In the past, I have used the simple method of distance from LCA pivot center to shock mount divided by LCA pivot to center of ball joint. Currently, works out to 0.578 (8.5/14.7), but I am open to suggestions on gathering a better measurement.

6. List the spring rates front & rear.

Front: 450 lbs/in
Rear: 150 lbs/in

7. Have you calculated effective rates on the sway bars? if not, I'll show you how, but I need photos showing me the shapes.

In the past I have tried a few methods I have seen online to get a rough estimate, but I do not have accurate numbers. Here are some pictures of the sway bars. The front is what the larger (33mm on the bottom) looks like compared to the original in the top picture. The bottom picture shows the rear sway bar, which is 32" long with 8 5/8" arms that have some adjustment.