The Stovebolt Site Forums The Shop Area Driveline Leaf springs

I have been looking for new leaf springs for my 1950 3100. The only difference I find between different companies is price. Some places are way more expensive than others but they can't explain why their leaf springs are more expensive. So, what is the difference? Why do Eaton springs cost twice as much as Espo? Thank you, Jason

Some companies want to sell springs, while others want to optimize profits. Springs is springs. You can buy from any of them and still have the springs you need.

The could be USA made or off shore made.

Eaton is in the spring business, others might be in the sales business.

Ed

He's my story, I ran stock '37 springs for about 7 years and was never happy with the ride. My truck, a 1937 has a 250 inch engine and automatic transmission. The engine is quit a bit lighter in weight then the 216 so the leaf springs were very stiff and the ride suffered. I started removing leafs, I went from 7 down to 4 in the front, 9 down to 5 in the rear. This worked quit well for a number of years, ride was much softer. I started to worry about 75 year old springs and purchased new front springs from Chev of the 40's. They were factory replacements, so again the ride was terrible. I removed leaves again, 7 down to 4 and added Teflon type slider material between each leaf. I was pretty happy with the whole setup. Fast forward 7 years, wife and I went on a long trip, ( for us anyway ) 250 miles. By the time we were home, we were tired and beat. I was at the point of selling the truck. I started shopping for a car or truck that might ride better but quickly found prices were out of my range, so I turned to the springs again. I call Detroit Springs and talked with the owner about options. I had to do some work before he could build the new springs. I needed the weight of the truck at each corner, the weight of each axle and wheel assembly, type of shocks and a lot more. I used digital race car scales at each corner and spent about four days getting weights and measurements.

Detroit Spring built four custom made springs just for my truck with the spring weights to match the weight of the truck. The ride is 95% better, I have a full 7 leafs per corner for strength, and all new hardware for safety. It was expensive, but way cheaper then starting over on another project. In this case, you get what you pay for. I paid about $1200 for all of including shipping, quite a bit for sure, but I got just what the truck needed.

Joe

That’s what happens when you work with a quality supplier who cares about his customers and the product he sells. 🛠

Thanks for the info. $1200 doesn’t sound bad. Some of these places want $1200 for just stock springs but some places are much cheaper. I don’t mind paying more for quality. I asked one place why their springs are more expensive and they wouldn’t give me any kind of explanation. Joe, you are making me think I should wait to get springs until I have my truck back together again....

Joe H, I have a 54 3100 with aftermarket springs that were supposed to make it ride like a Cadillac, NOT. It does ok but I want to do some adjustments. My front springs are from Eaton Detroit and when I ordered my front springs, it is a Pacer front end they failed to tell me that they were stock springs with 2" cut out them son when they were cut to bring it down for a better stance it rode like a brick and scrapped gravel on some roads, so I had to buy another set. Btw they were coils. The rear were not from Eaton.

Cutting coils only makes for a stiffer ride, I have been down that road before! I cut coils on coil-over shocks once, talk about a rough riding lumber wagon.

I have been messing around with my front shocks. With the travel I have, I am very limited on shocks that fit. I believe I am using rear shocks off a Pinto station wagon of all things. I found a chart that shows how the angle of the shock changes its rate, so I tilted mine about 20 degrees forward from a straight up position. So far it has helped, I need some more drive time before I commit to new brackets, its just temporary fix now. It has taken out some of the stiffness letting the spring move more. I am getting down to the fine tuning now!

Thanks for the chart. Looking at it may explain why my rear shocks don't seem to work that well, only a year old. If I remember correctly the original shocks were almost verticle. Where can I get a copy of the chart?

https://www.jalopyjournal.com/forum...nting-rear-shocks.1024223/#post-11586466 , This is where I found the chart.

For the AD trucks does anyone know if there is a fairly simple rear leaf spring upgrade that can be done? The stock rear leafs are really skinny. I know they make some aftermarket kits but they are all designed to lower the rear.

Thanks, Joe. 49shep I had 79 Chevy Nova springs on my truck for about 10 years and they worked fine. I had to get different ubolts and modify the mounting pin because of the front-rear offset. One big difference is the width of the Nova springs. Eaton Detroit can make what you want.

Thank you. Did you use the shackles and brackets from the nova or did you have to fabricate? Can EATON design the bracketry needed as well?

I would say but I am not sure anymore. I know that I had to have new shackle bolts because one was square because I moved the axle to under the axle luckily there was a shop that fabricates them 20 miles away. I would think you could find a local shop that could do the job for you.

Joe, is your truck lowered? Do you think that is why you had to do such extensive measuring to get a decent ride quality? Where did you get the scales? Can you rent them someplace?

My truck is lower then stock, but not lowered on propose. I would say 90% of my ride issue is just me. I like the smooth, softer ride verse the stock truck like ride. I studied on springs for a while trying to understand them better, the GM site with all the truck packets helped a bunch. 1937 1/2 trucks were over sprung, meaning they had very heavy springs for carrying a lot more weight then they should have been. In '39, GM the cut the spring rate down a lot, yet the trucks weighed about the same and carried the same GVW. Once the trucks began to grow in size and weight, the spring rates stayed pretty constant.

My truck was even worse due to the lighter engine out over the axle. As far as the ride hight, it came down from the softer springs and the arch the spring shop put into them. I could of had them raise it, but it seems to be more steady down a little lower.

1937 1/2 ton, Gross Allowable Weight #4400, 710 - 790 lbs at rest on front springs, 475 lbs deflection rate
1939 1/2 ton, Gross Allowable Weight #4400, 775 lbs at rest on front springs, 260 lbs deflection rate
1946 1/2 ton, Gross Allowable Weight #4400, 775 lbs at rest on front springs, 260 lbs deflection rate
1953 1/2 ton, 810 - 890 lbs at rest on front springs, 310 lbs deflection rate

As you can see the '37 was heavy sprung, the deflection rate is # of pounds it takes to compress the spring 1". So for every 475 lbs, the spring is compressed 1", yet the trucks all weighed about the same. I believe my springs are in the 220 range now.


I had a friend that had a set of digital race car scales. One scale under each wheel all going to a central information box. They worked really well for what I needed. Read down to the 1 lb.

Man, you really did your homework.