The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 47-55.1 Ground Clearance

dsraven · 04-28-2020, 12:58 AM

quick questions:
what type of springs are under the front, coils or air?
how do the lower control arms look on the front end?
if all is new with coil springs and no weight on the frame then the control arms are likely angled down towards the wheels. with weight on the frame like a finished truck the control arms should be parallel to the ground for proper geometry. what I have done in the past during mock up is remove the springs and shocks, then use some threaded rod where the shocks go to adjust the ride height to what it should be for proper suspension geometry. they should be parallel to the ground at ride height. figure in your rake angle, front to rear, and the control arms should be level fore to aft at this point. that's in a perfect world but if your control arms are angled down to the wheels right now then the truck will be even lower with the weight on it. if you have room to jack the engine and trans up a bit you may save some headaches later. the rear springs are possibly going to be the hard part to get right in the end. the front springs, if coils, will also need some time to find their "set" height after some driving time. trying to get the suspension to ride height without knowing how the weight will distribute over the wheels will drive you bonkers trying to figure it out. best is to get the body parts back on there and see what it looks like. even better would be to find somebody with a set up like you have and have them weight the truck at a commercial scale. total weight, then weight on each axle with no driver inside. then you could simulate that with sandbags or whatever if you really want to get the weight like it will be, well, close anyway.
don't drive yourself crazy till you get the truck assembled for body mock up, then you get an idea of how it will sit. after that you can mess with different spindles, coil springs, leaf spring packs, lowering blocks if the axle is above the springs or flip the axle to be under the springs, different leaf spring shackles etc if it isn't like you want. you are not the first guy to have the issue but we can't tell you exactly how to fix it for a specific ride height until the truck has the weight on it. otherwise it will be a guess just like you would do. that is unless somebody on here has the exact set up as you, with the engine placed like yours etc etc.

here is a gearing calculator, there is also one on the tire size calculator link if you poke around on the tabs at the top of the page

https://spicerparts.com/calculators/...rpm-calculator

here is a tire size comparison chart with some extra stuff in different tabs

https://tiresize.com/comparison/

both are pretty handy. another source to understand how the MII should be set up is Heidts. they have a quick read called "understanding independent front suspension" and they will usually send you a link to download it if you call them. it is very informative and explains some do's and don'ts when you are setting things up.

another informative quick read

https://www.hotrod.com/articles/inde...nt-suspension/

good luck, post some pics of what you're working with.

04-28-2020, 12:58 AM	#3
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 7,858	Re: Ground Clearance quick questions: what type of springs are under the front, coils or air? how do the lower control arms look on the front end? if all is new with coil springs and no weight on the frame then the control arms are likely angled down towards the wheels. with weight on the frame like a finished truck the control arms should be parallel to the ground for proper geometry. what I have done in the past during mock up is remove the springs and shocks, then use some threaded rod where the shocks go to adjust the ride height to what it should be for proper suspension geometry. they should be parallel to the ground at ride height. figure in your rake angle, front to rear, and the control arms should be level fore to aft at this point. that's in a perfect world but if your control arms are angled down to the wheels right now then the truck will be even lower with the weight on it. if you have room to jack the engine and trans up a bit you may save some headaches later. the rear springs are possibly going to be the hard part to get right in the end. the front springs, if coils, will also need some time to find their "set" height after some driving time. trying to get the suspension to ride height without knowing how the weight will distribute over the wheels will drive you bonkers trying to figure it out. best is to get the body parts back on there and see what it looks like. even better would be to find somebody with a set up like you have and have them weight the truck at a commercial scale. total weight, then weight on each axle with no driver inside. then you could simulate that with sandbags or whatever if you really want to get the weight like it will be, well, close anyway. don't drive yourself crazy till you get the truck assembled for body mock up, then you get an idea of how it will sit. after that you can mess with different spindles, coil springs, leaf spring packs, lowering blocks if the axle is above the springs or flip the axle to be under the springs, different leaf spring shackles etc if it isn't like you want. you are not the first guy to have the issue but we can't tell you exactly how to fix it for a specific ride height until the truck has the weight on it. otherwise it will be a guess just like you would do. that is unless somebody on here has the exact set up as you, with the engine placed like yours etc etc. here is a gearing calculator, there is also one on the tire size calculator link if you poke around on the tabs at the top of the page https://spicerparts.com/calculators/...rpm-calculator here is a tire size comparison chart with some extra stuff in different tabs https://tiresize.com/comparison/ both are pretty handy. another source to understand how the MII should be set up is Heidts. they have a quick read called "understanding independent front suspension" and they will usually send you a link to download it if you call them. it is very informative and explains some do's and don'ts when you are setting things up. another informative quick read https://www.hotrod.com/articles/inde...nt-suspension/ good luck, post some pics of what you're working with.