55.2-59 New Rear Suspension - The 1947 - Present Chevrolet & GMC Truck Message Board Network

twinsemi · 08-25-2025, 06:20 PM

I'm pulling the trigger on the rear suspension. I may have gone a little crazy, but I know it will be fun. Many hours on Solidworks to get the design just the way I want it.
Torque arm with the trailing arms connecting to the OEM forward leaf spring mounts.
Watt link for lateral location.
Pushrod linkage to 7" stroke coilovers from Vi-King that will be very progressive.
Easily interchangeable sway bars that will bolt directly to the bellcranks for the springs.

twinsemi · 08-25-2025, 06:30 PM

The first signs of progress are the waterjet cut parts that I picked up today at Large's Fab in Watsonville. And there is also a pic of the suspension as it has been for the last few years.

**mr48chev** · 08-26-2025, 03:09 AM

That looks like it was designed by BMW, If other companies use 5 pieces a side we will use ten. Before the tree fell on it every time I did something on the suspension I had to buy four or five pieces rather than one or two that would be on a Chevy.

leegreen · 08-26-2025, 10:04 AM

interesting! Can we se a couple more views?

Are the joints all solid bar ends? The trailing arms and torque arm will be fighting to twist the axle without some length flex in one of them, like the sliding rubber bushing on a camaro torque arm front mount?

bump & bounce stops?

twinsemi · 08-26-2025, 05:52 PM

The front joint for the torque arm will be a spherical joint and a pivoting 2-1/2" link so there won't be any binding. during the full 9" of travel, the front pivot will move fore-aft about 1/2" total. Full bump will be stopped by relocating the OEM bump stops for a little more travel. I have two possibilities that can be used to stop the travel from pulling on the coilovers. One is at the bellcrank pivot, and the other is to use nylon straps tied to the outside of the frame that go around the trailing arms.
Adjustability provided by Watt pivot vertical location, Watt link lengths, trailing arm length, torque arm angle, pushrod length and Coilover bracket position.
The general geometry was worked out in Suspension Analyzer v2.4 from Performance Trends to give reasonable numbers for anti-squat.

08-25-2025, 06:20 PM	#1
twinsemi Registered User Join Date: Oct 2012 Location: Soquel, CA Posts: 36	New Rear Suspension I'm pulling the trigger on the rear suspension. I may have gone a little crazy, but I know it will be fun. Many hours on Solidworks to get the design just the way I want it. Torque arm with the trailing arms connecting to the OEM forward leaf spring mounts. Watt link for lateral location. Pushrod linkage to 7" stroke coilovers from Vi-King that will be very progressive. Easily interchangeable sway bars that will bolt directly to the bellcranks for the springs. Attached Images

08-25-2025, 06:30 PM	#2
twinsemi Registered User Join Date: Oct 2012 Location: Soquel, CA Posts: 36	Re: New Rear Suspension The first signs of progress are the waterjet cut parts that I picked up today at Large's Fab in Watsonville. And there is also a pic of the suspension as it has been for the last few years. Attached Images

08-26-2025, 03:09 AM	#3
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 16,391	Re: New Rear Suspension That looks like it was designed by BMW, If other companies use 5 pieces a side we will use ten. Before the tree fell on it every time I did something on the suspension I had to buy four or five pieces rather than one or two that would be on a Chevy. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

08-26-2025, 10:04 AM	#4
leegreen Registered User Join Date: Mar 2022 Location: Surrey BC Posts: 1,397	Re: New Rear Suspension interesting! Can we se a couple more views? Are the joints all solid bar ends? The trailing arms and torque arm will be fighting to twist the axle without some length flex in one of them, like the sliding rubber bushing on a camaro torque arm front mount? bump & bounce stops?

08-26-2025, 05:52 PM	#5
twinsemi Registered User Join Date: Oct 2012 Location: Soquel, CA Posts: 36	Re: New Rear Suspension The front joint for the torque arm will be a spherical joint and a pivoting 2-1/2" link so there won't be any binding. during the full 9" of travel, the front pivot will move fore-aft about 1/2" total. Full bump will be stopped by relocating the OEM bump stops for a little more travel. I have two possibilities that can be used to stop the travel from pulling on the coilovers. One is at the bellcrank pivot, and the other is to use nylon straps tied to the outside of the frame that go around the trailing arms. Adjustability provided by Watt pivot vertical location, Watt link lengths, trailing arm length, torque arm angle, pushrod length and Coilover bracket position. The general geometry was worked out in Suspension Analyzer v2.4 from Performance Trends to give reasonable numbers for anti-squat. Attached Images



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