The Stovebolt Site Forums The Shop Area The HiPo Shop Mustang II suspension on a 1955 2nd Series Truck

Hello all. Have a 55 2nd series with Mustang II coil spring suspension. 375 lb springs. Rides a bit harsh and was wondering if lighter springs would soften the ride. What are you guys running for springs? Thanks

The ride with a M-II suspension is usually either "bad" or "REALLY BAD"- - - - -depending on how low the front bumper ends up. The ones that make the truck look like a blue tick coon hound that's just had a close encounter with a skunk are going to ride rough, no matter what you do to try to improve it!
Jerry

Welcome to Stovebolt Rcates! I would venture there isn't enough info in your post to give the best possible answers or help. What engine/transmission combo are you running? Other modifications to the chassis? What's your goal for ground clearance/stance and ride comfort?

Thanks for your reply.350/700r4.No air.TCI suspension.Lower a arms are pointing downward about 6degrees.375 lb springs.Very little front suspension bounce.I like the stance and realize it will come down a bit to get a softer ride.Am thinking I might cut the coils down a bit and try that before buying lighter springs.Lots of different opinions on this.Got a couple thousand miles on suspension so should be settled.If I knew what other guys were running for coils with similar setup would eliminate trial and error.

Cutting coils will stiffen the ride- - - -not soften it. Think about this- - - -if you stretch out the spring into a torsion bar, and twist it, a certain amount of torque will be needed to make it move. Now cut off a few inches and twist again. It's going to take more force to get the same amount of twist. Cutting coils off of a spring will lower the ride height- - - -but also stiffen it. If you want a softer ride, weaker springs are going to be needed.
Jerry

Rcates, you mentioned the lower A arm is pointing downward. Which direction ? Do you have dropped spindles?

The lower A arm needs to be parallel to a level floor.

Mine also suffered a similar problem, but a really mushy front suspension. A arms were pointing downward towards the center of the truck. Really sagged to the point I had 2 inches of clearance from the Mustang 2 cross member to the ground.

I contacted JW Rodgarage, where i bought the front end.
Big shout out to them for customer service. A real person actually answers the phone. Was told either coilovers or stiffer springs. Springs were cheaper about $85 a pair. Solved the problem. Now 4 inches of clearance


Anyway springs have what's known as spring rate. It's the amount of ft pounds it takes to compress the spring 1 inch. Oreilys rents a spring compressor. Highly recommend one. Hotrod is right, cutting coils will work, but still dealing with a stiffer spring rate.

Keep us posted

Back in my circle track racing days, we used a home-built set of suspension scales made from square steel tubing. Each wheel was placed on a fixture 3 feet long that rested on a bathroom scale. 100 pounds on the scale was the equivalent of 300 lbs. at the wheel. We would adjust spring rates and jack bolts to get the desired wheel loading at each corner of the car. We spent maybe $500.00 on the whole setup, including purchasing the scales, instead of several thousand for a set of electronic scales.
Jerry

Also changing the springs will change ride height, vehicle stance, and under carriage clearance to the ground.

Lower arm is pointing down at ball joint.If I suspend truck with suspension floating and jack up under tires almost immediately raises truck off stand.Very little suspension travel.Shouldi try shortening coils or go to a lighter spring. And what spring rate?Have 375 lb now.I realize it will change ride height.Like the ride height now but a little lower wouldn’t be that bad.

I recommend you look through this thread:
https://www.stovebolt.com/ubbthread...98/dialing-in-mustang-ii-ifs#Post1520698

Your truck is a bit different and will have different needs, but we went through what measurements you need and how to do a lot of the calculations.

I would replace. Check with Mustang 2 vendors. As mentioned cutting coils will really do nothing for ride quality. You would be doing the work twice, if not happy with ride quality.

Been a while since I looked at a Mustang II. If I remember correctly, an option might be coil over shocks. In which case, you would have a lot of choices in spring rates. Plus a dial in of spring height.

No offense but... I'm going to disagree with the bad ride statement.

If the ride is too rough, you need softer springs. Shortening the coils will lower it, but not change the rate.

If you take the measurements from the thread I linked above, we can help you go through the math to figure out a good rate.

Finally got some measurements today.Compressed spring length with lca level 8.5”.Distance from lca bushings to centre of spring mount 9”.Distance from lca bushing to centre of tire 17”.Have no way to weigh front end.55. Chevy half ton with a small block,700r4 no air conditioning.Whats your opinion?

There are some sources to estimate weights. Let me look at it after work and I will see what I can find.

Appreciate it.

Compressed spring is 9.5” not8.5.Sorry

Is this a short bed or a long bed?

Looking at the GM Heritage Center information kit: https://www.gm.com/content/dam/comp...ucks/1955-Chevrolet-Truck-2nd-Series.pdf

A short bed is a 3100 and a long bed is a 3200.

Edit: Adding image details

The information kit says 1975lbs (3100) or 2035lbs (3200).

Those are for an I6 and an SM420. An SBC is a fair bit lighter than an I6, but a 4L60e is similar in weight to an SM420.

The MII crossmember likely added a bit of weight to the front end, so overall the weight is probably pretty close to a wash vs the official numbers.

Short bed

I have Heidts M2 under my 51 3100. I have a LS and use 350 lb springs. It rides like crap. My control arms are parallel to the ground. Truck is lower than I would like with the 350 lb springs so I won't go lighter. Several different brand of shock didn't make any difference.

I cut half a coil off my springs. The A arms are level now. It did lower truck a bit. Haven't had a chance to drive it yet as we’re still surrounded by snow here. Don't know if it’s gonna be better or not but was pretty harsh ride the way it was. Do you think going to coilovers would improve ride?

What size of tires are you running on the front?

205/70/15

Okay just checking you weren't running rubber bands.
How much have you driven it? Probably won't make a difference on suspension settling in. Is it bone jarring or just stiff?

Couple thousand miles. Rides nice on a good road but if you throw in a couple potholes it’s pretty hard. Ain’t holding my breath that the ride will improve with the shorter 375 lb springs. They were no good the way they were so I had nothing to lose cutting them down. Probably try 350 lb springs and try the rubber cushions. I'm thinking with the rubber cushions on the top it will bring the front end up a bit too. Always good to get other opinions.

That might work. At least you won't have body roll in the corners