Alignment before setting corner / cross weights?

[openwheeler37]

After replacing the shocks, springs, and rod ends my car is in dire need corner weight and alignment set-up. Im hoping you all can help clear up some questions for me. Car in question is a Speads F1000.

1.) Do I set Ride Height, Camber, Caster, and Toe before scaling? I'm curious to this as I would change ride height to adjust corner weights and a ride height change can / will change camber / caster settings correct?

2.) Whats more important; Equal or close cross weights and unequal ride heights or more level ride heights and less equal cross weights?

I spent most of the day today making adjustments and did nothing but chase my tail and waste 5 hours of my Saturday. I set my ride height and than started to make adjustments to set cross weights. But by the time i had my cross weights close my ride heights were all over the place.

Thank you in advance for any and all help

[Pi_guy]

To pitch one more item to you is rake. If your running a diffuser rake is very important to have it function well.

You set all the basics before you scale the car. Normally changing the length of the pull or push rod does not change camber, caster or toe. but not familiar with that cars geometry and have been wrong in the past. But if you have changed a number of parts it might be best to trammel all the links to see if the suspension is equal.

One observation is you should get repeatable numbers when you push the car on and off the scale. If not there is something else wrong.

But I know I have spent time on alignments and chased my tail at times and it is a little bit of a compromise.

[mark elder]

OK. Disconnect the anti roll bars (I wonder if you did not do this). Set your tire pressure to your hot setting. Put enough weight in the car to match yours; I have 20lb gym weights; discs. Lock the front wheels straight ahead (rack stops or something; not "I just roll it forward in my garage and it seems straight")

Do the front first. Work out your desired rear ride height, park the front wheels on a level surface (your garage floor with some thin packing will do; 1/16 plywood squares from a model shop etc etc). Jack the car, take the rear wheels off and lower the car to your desired rear ride height. The back must be pivoting on something on the centerline (the large bolt on the Hewland or similar; if not, make an attachment for your jack). So now you have a tricycle pivoted at the back on the midline.

Then set front toe to ZERO, then set the ride height and then camber. Recheck toe. Go around again. Camber changes with toe because we have caster. Finalise toe, camber and ride height (ride height should be same on both sides; usually this equates to the front chasis being level). Now do caster if you want. Typically the ride height was done using the pushrods. Lock them now and do not touch again (and do not play with them on the scales; they are locked and loaded).

Now put the rear wheels on and lower onto a level surface, adjust ride height, set toe to zero and do camber. Recheck all 3.

Jack the rear up until one wheel just clears the ground. Now adjust the opposite rear pushrod until the other wheel just clears the ground. Lower and recheck ride height (adjust both rear pushrods an equal amount only now; the car will sit slightly lower with this method before you reset the height)

Now put it on the scales. The only thing to adjust is one of the rear pushrods; it will be very close (this method should get you within 5lbs everytime before you do any adjusting of the pushrod.)

And finally, while it is on level scales, do your toe and adjust the length of the antiroll bars.

Why set toe to zero until the end; it saves endless messing around (learnt this on this forum; thanks Mr L).

The beauty of this method is that it lets you finalise one end of the car completely; 2 things are easier to sort than 4.

Just my 2 cents worth.

[S Lathrop]

I am going to suggest one step to what Mark described. I find it makes the alignment process a lot easier.

Remove the shocks and set the car on blocks for ride height. Set the blocks higher than the actual ride height you plan to use because unloaded the tires will be larger in diameter. The adjustment for loaded tire diameter will be close to 1/4" front and 3/16" rear.

Get every thing set as you want it. Without the shocks, you can do bump steer easily.

I will double the advise that after you make any change in the settings, you reset the toe to zero and then take you measurements.

The last thing you do is balance the car and set the ride height, with the shocks on the car..

[RussMcB]

I set my ride height and than started to make adjustments to set cross weights. But by the time i had my cross weights close my ride heights were all over the place.

Once you get your front and rear ride heights correct, you should make your corner weight adjustments symmetrically so you do not affect the ride heights.

For example, let's say your RF and LR are heavy. Lower each of their spring perches (or however weights are adjusted on your car) a small amount, and do the opposite to your LF and RR corners. That way you correct the corner weights and leave the ride heights where they were.

It's a pain and extra work, but that's how you leave ride heights (mostly) unaffected while adjusting corner weights.

on edit - The advice above from Steve and Mark are probably worth more than mine. I usually try to get it close (good enough for my driving ability) without spending hours. :-)