Project: Tow-Rat (Lil' Blue)

[6DoF]

All-new direction for this build, old thread was really old, time to re-start.

old build thread:
http://67-72chevytrucks.com/vboard/s...d.php?t=696557

The Truck: 1955 Chevy 3800 9ft box
Engine: Cummins 12V
Transmission: NV5600 6-speed manual
Front suspension: '78 C30 IFS, air bags
Rear suspension: Custom truck arm, 14bolt (cab n chassis), air bags
Chassis: 2x6 0.25 wall box and 2x3 0.25 wall box
Exterior: as-is
Interior: AC, tunes, new paint, etc
Purpose: daily / tow rig

well, basically a year since i unloaded it, it's time to get back to building! started gathering parts, and started to un-burry the truck. yes, i was way more packed in ...

i snagged the IFS cross member off the c30 chassis, and the rear bumper ... threw the 14b behind the shed ... and scrapped the rest. i've decided this truck needs to be tight and right, not just a rat. while doing that i'm going to try to not just throw money at it though, i guess we'll see. for what i'm doing i don't think i needed to spend an extra $3k on the front suspension, so it's all new but "all stock" '78 c30.

[6DoF]

obviously the air bags vs coils, no going back on making this thing low. proper low. i ordered the 3" lowering spindles this time. trial and error learned i need them after messing with the C10 IFS geometry the first go-around.

So the tires on it from the Ram are the exact size i'm getting to build with, and i've decided that i like the front wheel placement in the opening. the rear however needs stretched more. more wheel base and getting the axle close to the hitch will both help towing. so i've moved the fender as far back on the bed as i can, was a 10.5" move. with a tire shift in the wheel opening too, i should be right at 12" stretch. will have the same wheelbase as my 2008 2500 extended cab, short bed GMC, but the hitch 6" closer to the axle.

it's a good thing i bought 2 fuel cells to make the tank with before, they will not get split up and made into saddle tanks.

[6DoF]

picked the wheels i'm going with FINALLY. so it was time to start checking fit and clearance before i bought em. the one big difference i'm doing in the front is to run the dually wheel, but not a dually hub. this will let me run a hub extension of the width i choose, vs what GM made. and i don't feel too bad with 8lug or that OEM's do it.

so the standard dually extension is about 4.5". i plan to use a basic 2" wheel spacer instead. this will narrow the front end by 5" to fit under the narrower front clip of the 55. the old stock wheels off my GMC are the same 17" AL, but are only 5.37" back spacing vs the new dually wheels 7.87". With the 2" spacer the back face of the dually wheel will be 0.5" more inboard than pictured with the GMC wheels.

was perfect! ish. lots of brake, upper ball joint, pretty good steering clearance, and just enough lower ball joint clearance in the worst case of travel. and yes, the wheels i chose were in part chosen because the wheel face ties into the lip vs back in the barrel to give more caliper clearance for this narrowing. brake clearance is great to the massive 1-ton calipers, this would have never happened with steel wheels. the ONLY clearance issue is with the LCA, and only on one side of steering. the LCA lip rolls out and is really thick there, so with a simple welded-in stiffening rib to the bottom side, i can just cut out and clearance what i need. my goal is 45deg of steering thru the full travel. that might get limited by fender clearance, we'll see how that goes.

the tire behind the wheel is the size i'm using, so it's a really a good representative picture. only difference is it's sitting at about 15" and normal height will be 6"

another note is that i'm really glad i am now using all C30 parts vs the c10 bits i started with WAY back. these parts are WAY heavier, just more beef everywhere. including solid, yes solid factory control arm bushings.

[6DoF]

started to science out the front suspension and alignment set up vs max travel. i need to draw a line in the sand so i know how tall the step in the frame will be. this also requires having both new front tires/wheels ... coming soon.

total travel:
factory C30 bump to bump (not including bump compression) - 4.5"
LCA bump and bump mount removed, UCA bump removed - 10.5"

i believe max travel limited by the upper ball joint was 12" when i did it before. this time i am trying to limit crazy camber and keep within a driveable range as much as possible, so the mods are a bit different. without a pie cut on the UCA, the ball joint is the compression limit. droop is stopped when the UCA hits the cross member. i clearance it some for a bit more, but didn't get enough worth having done it.

for comparison:
C7 vette is 5.25" factory to the rocker, probably 4.75" under it, and 3.75" at the from rubber air dam.

i set up this suspension for 0 camber at 6" above full compression, or 6" of ground clearance. this gave me -4.5deg camber at full compression, not bad really and can actually help with fit inside the fender. i also have a max thru full travel of +0.5deg, totally driveable. from 3" above full compression to max, i have a minimum of -1.5deg camber, also very driveable. spend most of my driving at 6", then anything above or below shouldn't wear the tires enough for me to care. even getting into some negative camber when lower with good "camber gain" at a sporty lower height

[dsraven]

have you bolted a tie rod on to check wheel clearance?

[Old57]

Cool project, looking forward to seeing the progress

[6DoF]

Originally Posted by dsraven

have you bolted a tie rod on to check wheel clearance?

yes sir! not only enough running clearance, but room to assemble and disassemble with the wheel on.

the thing i found odd though, was that the C30 Belltech TRE hole was smaller than i expected. i grabbed some spare GM 1-ton TRE's i had on the shelf from one of my Jeeps, and they were too big to assemble. i assumed it would have just been standard GM 1-ton, but maybe the 4x2 used smaller?

[6DoF]

got the LCAs tacked together with the crappy bag cups i built. i just couldn't bring myself to spend the $150 to buy a pair, but next time i might haha. she'll get a good trim back once fully welded.

i trusted the alignment would be the same side to side, HA, no. when i used the suspension itself to mock up and place the cups, the alignment difference side to side made the cups weld in different. checked everything, double checked, tack welded, stood back ... and shoot. so i had to cut my tacks back apart, go thru the alignment and re-do one side.

[dsraven]

I wonder if a viking fender wheel opening could be grafted onto your stock fender so the tires would be able to turn and not rub but also look proper for the tire size/wheel opening size. I know you can cut and flare the stockers but maybe the viking idea would basically do the same thing with less work. gotta be some cheap viking fenders out there since a lot of guys buy the viking simply for the cab and scrap the rest.

[6DoF]

i owned a survivor '55 6400 for a bit, but didn't want to cut it up after all these years on the road. the wider front end is EXACTLY what i need, i almost bought a front clip once too ... but right now i'm going to try and keep this complete blue patina together. once i get the body on the new chassis, that's when i really find out what i'm in for.

other problem is i HATE sheet metal work, so cutting these up is probably unlikely, haha. if i didn't hate sheet metal so much, i'd probably be stretching this cab too. i'm 6'3" and still working out options for more room. i have a plan ..

[dsraven]

It does look like you will need some sheet metal work to get your tires and track width to work. There goes the blue patina. It might be an idea to look for a blue viking. Seems like blue was a common color. You might get lucky in the classifieds.

[6DoF]

i think I'm linking how this is coming out so far. Still needs a lot of detail work, dimension checking, and the obvious front frame horns, but getting there! at this point i'm pretty sure this will be more than sturdy enough for me to do work.

started running numbers for the rear links and ended up really changing up my plan. when i started this i was actually at nearly 150% anti-squat. dialed it in a bit, added some adjustment, and i should be able to achieve 90-120% now.

[G&R's57GMC]

Gee with that tiny clearance there will be NO BENT RIMS for you .

I hope the upper ball joint is an aftermarket extra travel type .

Nice Project , It should haul the freight .

[6DoF]

Originally Posted by G&R's57GMC

Gee with that tiny clearance there will be NO BENT RIMS for you .

I hope the upper ball joint is an aftermarket extra travel type .

Nice Project , It should haul the freight .

what clearance issue concerns you about bending a wheel? that's a comment i didn't expect. though, there should be no contact anywhere in the suspension through travel/turning once complete. the fender though is another issue that i'll address once i get that far into assembly.

the droop bump is in place already since it's just a cut-down stock unit. extended free travel while still stopping a metal on metal stop. without jumping the truck, this shouldn't get used unless on a jack. the compression bump however i can't fab in there until i have the truck at full weight. either a factory bump, or something aftermarket, i intend to set them compressed at full static weight 1/2" above the hard stop.

[G&R's57GMC]

Sorry I was refering to the picture with the muddy wheel and tire .

No Problem with the new wheels .

[6DoF]

Originally Posted by dsraven

It does look like you will need some sheet metal work to get your tires and track width to work. There goes the blue patina. It might be an idea to look for a blue viking. Seems like blue was a common color. You might get lucky in the classifieds.

i set about estimating this again now that i have the actual wheels.

factory C30 IFS wms-wms: 65.8 (per Wiki ... will reconfirm myself later)
55 fender lip inside to inside: 72.5 (directly measured on my truck)

wheel face to wms: about 1" (wms being further out b/c front dually wheel)
wheel face to tire: about 1" per a few samples around the shop
wms to tire: even

dually adapters used for this: 2"
my total wms-wms: ~70" (should also be outside of tires)

so straight up i should have about 1.25" per side clearance fender lip to tire as i tuck, gaining more as i gain camber at droop. seams like a reasonable plan while it's all apart to also cut half of the wheel lip back, and fold what's left up. shouldn't affect fender structure, completely hidden in the fender, and should gain me another 0.75" per side clearance. 2" fender to tire at worst when the steering is straight seams pretty good. this should get the tread inside the large roll at the top of the fender without getting it into the inner wheelhouse. TBD on the inner wheel house really, but it can get chopped up n tubbed.

while at full droop, or driving at a bare minimum height, this may limit my steering a bit. however my scrub radius is pretty small considering the inside of the tire is actually right at the ball joint axis. by the time i get to a 6 or 8" ride height, i hope to have all the clearance i need.

:nerd: (where's this emoji when ya need it!)

[6DoF]

a few missing details, but i think this chassis is close to wrapped from the firewall back. now time to focus on the front. the odd channel brackets are for saddle style fuel cells.

[6DoF]

while i start getting the steel together ... anyone have opinions on these?

-windshield wiper upgrade?
-big chinesium AL radiator with fan?

-lexan back window?

-where does everyone prefer to buy their rubber and general replacement parts from?

[6DoF]

got the chassis wrapped up in 3D and got the steel a few days ago. did a quick mock-up for motivation and to check a few last minute dim's before cutting the last chassis in half to save a few bits. the C30 IFS is 3"+ narrower than the ram suspension currently under the truck. the mock-up picture is at that chassis' max drop, what should be about 3" below ride for the new chassis. not going to say i'll never rub a fender with the tire, but shouldn't be too bad.

[6DoF]

smashed out some progress! i don't know why, but i love the frame "kit" picture.

i also managed to fixture the main rails and get the rear legs welded on before realizing the main rails were backwards. the miter at the front end went out vs in. lucky for me, i still need to cut the rear to length, so i just re-mitered the front and lost 1/2". redid the 3D and we're good.





and tonight it's a whole thing! tack welded and ready to start crossmembers. also need to get Colin to cut my plate soon!

[Rickysnickers]

As usual, asking dumb questions. Do you have to fishplate, or somehow reinforce the angled portions of the frame?

[6DoF]

Originally Posted by Rickysnickers

As usual, asking dumb questions. Do you have to fishplate, or somehow reinforce the angled portions of the frame?

Never a dumb question, ask em all. Have to? Maybe not. Will i? For sure!

If you look back at the last picture of the CAD, i have a specific plate for both sides of each joint. Its cheap insurance, and after all, it looks good.

[slammed57]

Really cool build you got goin

[Rickysnickers]

Originally Posted by 6DoF

Never a dumb question, ask em all. Have to? Maybe not. Will i? For sure!

If you look back at the last picture of the CAD, i have a specific plate for both sides of each joint. Its cheap insurance, and after all, it looks good.

Thanks . I missed that in the rendering.

[big_dan]

Definitely going all out. Love it.

Following for sure.

Dan