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Lower car and soften the ride

5K views 13 replies 6 participants last post by  tinhunter 
#1 ·
I have a 39 Chevy 2 door sedan with the original rebuilt rear springs. The car rides a bit rough and after installing a MII front end, the difference between the ride height in the front and the rear makes the car look a bit funny to me. The car has about a 3" lowering block in the rear and I would like to lower it another 3". I'm thinking that if I remove 1 leaf and de-arch the springs that it will solve the problem. I do not want to purchase a rear end set up at this time. I do not think that I need to change the shocks and I'm sure that I have enough space between the exhaust and the rear end. Also, if anyone in the Chicago area knows of a spring shop that can work wonders, I would love to get their information.
 
#3 ·
Michaelbc said:
I have a 39 Chevy 2 door sedan with the original rebuilt rear springs. The car rides a bit rough
I suggest you go ahead and buy a set of springs ...
I installed a set of Durant Mono Leaf springs in a friends 55 Chevrolet and ... man o man ... what a difference ...

They fit perfect and lowered the 55 about 3 inches and improved the ride greatly ...

I am not a dealer and do NOT have any $$$ interest in Durant ... they just work great. The springs were about $400 for the pair ...

Durant
949-673-5625
 
#5 ·
I'm interested in lowering the car about 2 more inches. I crawled under the car this evening and I think 2 more inches would work well. I am also thinking about cutting 2 of the shorter stacked leafs rather than removing them. Any thoughts on how it will affect the remaining leafs?
 
#6 ·
I have a 37 Plymouth w/ original springs. The axel is mounted to the top of the springs to get the car into a lower stance. Full vertical travel is critical to proper spring control along with rear shackle angle and shock travel. Also important is the placement of brake lines. Keep brake lines off the top of the axel housing and the pig. With shorter vertical travel distance of the axle, you have to stiffen the spring to avoid bottoming out on the frame. cutting the leafs shorter will hurt more than helpYou might change the frame bumpers to a shorter type to gain back a little travel distance. Be very careful of the shock travel. Too short and the shock will bottom out first, too long and the shock cannot do its job. The shackle angle should be about 30 degrees back from vertical (rule of thumb). It is dependant on how soft your springs are along with other criteria.

Best bet is to replace the old springs with new wider springs with a spring rate set for your comfort level and spring travel distance and dead weight of the car. The old springs are probably 1.75" wide. Go to 2.5" wide springs and you can get the carrying capacity you need with the stiffness you want at the length to suit your set up.

Hope this help a little.
 
#7 ·
Soften the ride and lower the car

Thanks everyone for the information you have shared with me about my rear wuspension. After I get the car up and running I'm going to check the length of the shocks to see if I can cut the leafs some and lower the car. By the way, I was going to cut off about 25% of the length of each leaf. My thinking is that the ratio of the length of each leaf to the others should be the same as before. I don't know if I explained it correctly but I noticed that the distance from the end of one leaf to the end of the next leaf was not the same. I thought the engineers at GM had a reason for the differences in the length of each, so I thought rather than just cutting 1 inch off of each leaf I would use a percentage of the length instead. I'll just have to see what happens.
 
#8 ·
Shortening the leafs by a proportion such as a percentage is part of the answer. There are a lot of variables that go into spring design. I suggest that you tinker with the first two shortest leafs first and work your way out to the longer leafs only if you cannot get the set and ride you want. The longer leafs flex more because of their length, so shortening them will add stress to the longest leaf increasing potential for failure. The shortest leafs increase overall stiffness. Simply removing the shortest leaf will make a big differance in stiffness and ride height. Do that first. Still not satisfied? Now shorten the next leaf. Shortening the back end only will cause the car to squat more during accelleration. Shortening the front end only will soften the ride some and cause a minor increase in spring deflection under accelleration. Remember, you have to consider dead weight, live load, torque, side sway and thrust forces if you want your springs to perform under all typical conditions. $400 for the proper engineering is worth the money for your safety, comfort, performance and for our safety too. Cutting corners to save a buck could cost you more in the long run.
 
#9 ·
Ride height

Thanks for the info rpg37 on my springs. Your information on spring length was really helpful and will use your infor when I start to make some changes. I saw this as a temporary fix because I'm installing the CE rear spring set up this winter.
In my last post I stated that I would check out the length of my shocks before I tried anything and in doing so, I found that one side had 8 leafs and the other side had seven and was a different spring. The additional leaf is the 3rd. longest leaf. Because springs are diffent I decided not to do anything until I get back from the Nationals.
I appreciate your information and I hope to return the favor.
 
#10 ·
Michaelbc said:
Thanks for the info rpg37 on my springs. Your information on spring length was really helpful and will use your infor when I start to make some changes. I saw this as a temporary fix because I'm installing the CE rear spring set up this winter.
In my last post I stated that I would check out the length of my shocks before I tried anything and in doing so, I found that one side had 8 leafs and the other side had seven and was a different spring. The additional leaf is the 3rd. longest leaf. Because springs are diffent I decided not to do anything until I get back from the Nationals.
I appreciate your information and I hope to return the favor.
The suspension setup you describe is the exact setup I have in my '39 Chevy 2-dr. The MII front and CE rear (early Nova springs) with 2" lowering blocks will give you the stance you're looking for. I'm running 350lb springs in the front, and the ride is stiff but I like it that way as I have only 4" ground clearance with the chin piece and oil pan.

George
 
#11 ·
Soften ride and lower car

George,
Thanks for the info. but I wanted to know if you have power or manual steering. I have 300# springs on the front and if I had it to do over I think I would go with a 275# spring to soften the ride even more however I am pleased with the ride.
Mike
 
#12 ·
39 chev rear springs

Hi Guys, What a great source of info. I have been out of building for a few years and just decided to get back into it, Not having the energy to do another build from scratch , decided to buy a driver and finish to my own tastes, yea, right, Guess I will completely redo what was done, Is a 39 chev.2 dr sedan, M2 frt ( orig. crossmember) which appears to have been installed at least in the correct orientation but will need much more welding and clean up. I have decided to start with the rear suspension which is orig. rear springs,4" blocks under a 10 bolt ( may chg it to 8" ford). The car is sitting at decent height in rear but the builder completely neglected to allow for a scrub line as lower shock brackets etc are below wheels by at least 2", would be a riot if ever a blow out. You fellows have certainly answered a few questions . George I was wondering if you used the complete kit from CE or? Do you have adequate suspension travel without bottoming out on the frame? It seems as I have approx. the same ground clearance as you in the frt.Are you running 14 or 15" wheels? What size of rubber? I have very little scrub line clearance with 14" and 165 x 14 rubber so would like to raise a bit if possible. Lower control arms are horizontal now so spring length is about right. Thinking 15" wheels and larger rubber may work. Sorry for the long post. Thanks ken
 
#13 ·
39 Suspension

Tinhunter,
Thanks for writing me concerning the suspension on the 39. I have a few thoughts concerning your comments starting with your MII. I have heard several times that you should not weld on or at least be very careful in welding on the early Chevy frames. They are made from an upside down channel with a plate riveted onto the bottom side. This is fairly strong but the steel is not that thick which means that any welding requires a good touch. Chassis Engineering can give you the details just call Jim the owner. He is a great guy and let him know that I suggested that you talk with him. I'm very pleased with what I have. I just purchased the rear end set up but I have not put it in yet. I again strongly recommend that you go to Chassis Engineering and get their set up for both the front and rear and also get sway bar set up with it. I know quite a few people that have used the CE set ups and they have all been very pleased.
 
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