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#1 |
Registered User
Join Date: Mar 2015
Location: Florissant, CO
Posts: 16
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72 C20 lowering a tow rig
Ok yall all the searching that I have done for lowering this truck does not tell me if it affects the towing capacity.
I want to lower my truck as much as I can without taking away from the towing capacity. Do bags or drop spindles/shakles? I am looking at towing a 36ft gooseneck to take 2 race cars and tools/parts. Suggestions? I am new to these trucks and have never modified the suspension of a towing truck. I can weld and do most of my work myself or with the assistance of a machine shop. |
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#2 |
Registered User
Join Date: Mar 2015
Location: Florissant, CO
Posts: 16
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Re: 72 C20 lowering a tow rig
I think I like bags, but anyone have real world experience with towing with this truck on bags?
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#3 |
Registered User
Join Date: Nov 2013
Location: Oxnard,ca
Posts: 98
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Re: 72 C20 lowering a tow rig
I have a 70 c10 suburban just put CPP 4inch lowering HD springs in rear with there shocks also there shock relocaters I'm hooking up my 19ft travel trailer to night fingers crossed
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#4 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,717
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Re: 72 C20 lowering a tow rig
You probably don't want to hear this, but if you are looking at a big trailer with a 1000# pin weight, you should do air bags. But NOT to lower it but to increase load capacity. I left my C20 at full height except for 1 1/2" shackles in the rear at the lower of the 2 settings. This allowed 1500+# in the bed without being on the bumpstops.
But lowering more than a little WILL impact the load carrying ability, and a trailer the size you are talking is probably too much for the platform anyhow. That would be a challenge for my SB/EC Duramax truck. Posted via Mobile Device |
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#5 | |
Registered User
Join Date: Nov 2013
Location: Oxnard,ca
Posts: 98
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Re: 72 C20 lowering a tow rig
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#6 |
Registered User
Join Date: Nov 2013
Location: Oxnard,ca
Posts: 98
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Re: 72 C20 lowering a tow rig
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#7 |
Registered User
Join Date: Nov 2013
Location: Oxnard,ca
Posts: 98
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Re: 72 C20 lowering a tow rig
The coil still has room to bounce 😁
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#8 |
the boat guy
Join Date: Jul 2007
Location: springfield mo
Posts: 2,339
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Re: 72 C20 lowering a tow rig
Billy the axle is clearly sitting on the bumpstop. Not that that has ever slowed me down.4-6 drop sitting on the bumpstops with a full fuel tank in a 1/2 ton.
__________________
67, swb, fleet, tach, throttle, 5.3, 4l60e, 3.73's, fuel cell, 5 lug, p.d.b., 4-6 drop. great little truck 66, stevens drag/ski 18' silouette, 350, 2.02 doublehump heads. comp extreme marine 278 cam, vette 7 fin valve covers, old polished edelbrock intake, velvetdrive, casale v-drive, adj cavitation plate. 28, model a rpu project, |
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#9 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,717
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Re: 72 C20 lowering a tow rig
My 29' Gooseneck is a 14,000# GVWR with a 9,000# load capacity. Your trailer will weigh close to 8,000# at least, maybe more depending on it's setup. The cars plus the tools and parts will add 5000# more I'd guess? That's a 13,000# load. Heaviest I pulled with my '70 GMC C2500 was probably 7,500# and it did that fairly well. But double that, I have my doubts.
I think my '02 Duramax truck is rated to 16,000# max trailer weight. And there is no doubt that it is a much more robust chassis and driveline. As much as I love these old trucks, my opinion is that's WAY outside of the truck's safe operating abilities. Even more so if you expect to do that lowered. YMMV but be safe either way.
__________________
44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
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#10 |
Registered User
Join Date: Nov 2013
Location: Oxnard,ca
Posts: 98
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Re: 72 C20 lowering a tow rig
Yea it is I'm going to have to install air bag helper lol. Your truck has an Ls swap ?
Last edited by Billyburban; 07-26-2015 at 11:30 AM. |
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#11 |
Registered User
Join Date: Aug 2010
Location: Edwards, CA
Posts: 7,503
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Re: 72 C20 lowering a tow rig
Agree the basic problem is you probably don't have the capacity to start with.
Here are Chevrolets published max GCW (gross combined weight) ratings for a 72 C/20 pickup. 400 bbc .... 4.10/ 12.5k..... 3.54/ 10.75k 350 sbc .... 4.57/ 10.5k..... 4.10/ 9.6k Considering a truck that curbs around 4500lb leaves a 8000lb trailer and cargo load at best.
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Thanks, Tim * VIN/Model Decoders * Power Team Charts (engine/transmission/gear ratio) * Post Your Pickup SPID ** Blazer SPID ** Suburban/Panel SPID * RTFM ... Read The Factory Manuals... download 'em here Highlanders ** Do you have a 1972 Plaid Pickup? ** Plaid Blazer ** Plaid Suburban |
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#12 |
the boat guy
Join Date: Jul 2007
Location: springfield mo
Posts: 2,339
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Yup 5.3 swap. Nothing fancy just clean.
__________________
67, swb, fleet, tach, throttle, 5.3, 4l60e, 3.73's, fuel cell, 5 lug, p.d.b., 4-6 drop. great little truck 66, stevens drag/ski 18' silouette, 350, 2.02 doublehump heads. comp extreme marine 278 cam, vette 7 fin valve covers, old polished edelbrock intake, velvetdrive, casale v-drive, adj cavitation plate. 28, model a rpu project, |
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#13 |
Registered User
Join Date: Nov 2013
Location: Oxnard,ca
Posts: 98
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Re: 72 C20 lowering a tow rig
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#14 |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,859
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Re: 72 C20 lowering a tow rig
Let's stay on topic here. How did we get to talking about hauling a smaller camper with a Suburban and all this other unrelated stuff? This thread is about lowering a C/20 pickup and hauling a two-car trailer, and that IS way too much for the capacity even with beefed up springs. This is 1t or heavier territory. Just do the GVW math. You CAN lower a truck in a way to maintain hauling capacity...within limits. The right bags are fine. They were largely used on heavy rigs way before anyone put them under a pickup. Lowering reduces travel and so does weight, so watch for that. Brakes are a consideration along with suspension. Then there is steering parts, frame, cooling, to name a few. Actual weight of tow vehicle comes into play with larger loads, no matter how tough a truck is.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#15 | |
Registered User
Join Date: Nov 2013
Location: Oxnard,ca
Posts: 98
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Re: 72 C20 lowering a tow rig
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