"Standard" Ride Height

Sebnuts

Well-Known Member
From what I've been able to find, the "standard" way to setup the ride height for the front suspension is to have the lower control arms parallel to the ground(from the front end alignment thread). For the rear, the tie rods are parallel to the ground. I've seen the number of around 7" from the ground to the bottom of the frame in the rear.
Does this sound about right? Does DF have a recommendation for the rear, and if so can someone post up a link to it?
Front View:
Stock_Front.JPG
Rear View:
Stock_Rear.JPG
Side View with resulting ground clearances.
Stock_Side.JPG
 
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Gtstorey

Goblin Guru
I think the rear is set with the lower control arms level, although getting a single measuring point to determine this isn’t really possible. The tie rods may be parallel to the control arms though.
 

Desert Sasqwatch

Goblin Guru
I'm curious of the CG location at 35.5 inches forward of the rear axle? Is this a measurement you obtained from a source?

Measurements obtained from a couple completed builds, by corner weight measurements, indicates the CG to be located approximately 24 inches forward of the rear axle and 14.5 inches above the bottom of the lower frame rail. This location is variable with the options, accessories and modifications made during the build and can shift the CG from this location by about 2ish inches forward, 1-2 inches left-right or about 1 inch aft or vertically. The fuel tank is centered at the CG, so changes in fuel weight has little effect on CG position.
 

Sebnuts

Well-Known Member
I'm curious of the CG location at 35.5 inches forward of the rear axle? Is this a measurement you obtained from a source?
Using baustin's corner weights:
baustin.pngCG_Loc.jpg
Wf = 295.2+297.8 = 593, Wr = 519+529 = 1048, Wt = 593+1048 = 1641
Summing the moments about the rear wheel:
Wf x L = Wt x b -> 593 x 97 = 1641 x b -> b = 35.1

My body weight will move it forward, using chubs weights with him in the car, b = 36.88. I don't weigh as much as chubs, and I will be adding some extra weight in the rear with SLA, so I just took a SWAG at ~35.5.
 

Desert Sasqwatch

Goblin Guru
Hmm, not sure what I did with the calculations to get the 24 inches...but yes you are correct the CG is 35 inches forward. I reran these numbers again and did come up with your values - DOH! I will need to redo my anti-geometry calculations, as they were based on the incorrect 24 inch location. Thanks for the correction - now my rear suspension geometry will definitely change again! :oops:
 

Sebnuts

Well-Known Member
Just another data point that I forgot to mention in the initial post that corroborates the rear setup mentioned.
I set my model dimensions up with the rear coilover images provided by DF here. Assuming ~520lb rear corner weight and the 300lb/in springs, you get ~1.5" of static compression (using a motion ratio of 1.033). This setup in the model is what drove the 6.7" rear measurement in the image, and the tie rod is nearly parallel as well.
 
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