The Stovebolt Site Forums The Shop Area Driveline Pros/Cons of Lowered Springs

1949 3600 235 SM420 12V

Getting ready to replace my original leaf springs. It's a little harder to find 3/4 ton rear springs (the fronts are the same as the 3100?), and most springs on offer are 'lowered.' I don't really care about the look one way or the other, my springs are already flat as pancakes and I'm riding on the taller option tires. But are there sacrifices to driving on the lowered springs? Does load carrying or ride suffer? I imagine they control sway better in corners. There's a couple places (like Posies) that will make a 'custom' set of OE springs (kind of an oxymoron) but charge extra for that. The places online that list stock height springs are all out of stock.

Check with Eaton Detroit Spring.

My '37 has slightly lower spring, not on purpose, but I had new ones made with softer spring rates so the set a bit lower. Ride is much better, but around where I live there are a bunch of speed bumps to control traffic. The front will bottom out pretty easy on the speed bumps, but normal roads are just fine. I have a sway bar on front but did find the cornering is a little better, I don't feel like I'm going to roll over. I don't carry any load so no information on that.

I would talk with Eaton Detroit, I was happy with them. Be prepared for the cost, they are not cheap! I was after a softer ride, so I borrowed a set of four corner scales and weighed the truck with and with out occupants, and sprung weight and unsprung weight. In the end, its was around $300 per spring including the shipping, maybe 7 years ago, don't remeber for sure how long its been.

They can make anything you want.

Joe

PapaDisco,
Do you carry any heavy loads in your truck? Such as pastry snacks from Downtown Bakery?

But seriously, if you never carry any heavy loads, I guess a lowered spring setup might be very comfy.

The thing is you don't get to try these before you buy them. I've had friends who bought lowered springs and some of them spoke so badly about them, I think I'd be inclined to search for stock height/strength and go with those. Good luck!

Unless you notch the frame or do something else to compensate for the reduced suspension travel, you're probably going to bottom out every time you encounter even a moderately bumpy road.
Jerry

I agree with Jon G. (Hey, that rhymes!)

Stick with stock height. Even the stock ride isn't that bad. It's a 76 year old truck for crying out loud. What kind of ride are you expecting?

Keep the suspension stock and concentrate on your seat springs and better foam cushioning for a softer ride experience.

A PO of my '47 had, from what I could gather from a receipt, the front leafs receive an Eaton Spring 'hot rod drop'. I like the stance is (Monoleafs on the back) but there is not much clearance between the axle and the bump stops. Considering getting them re-arced a bit at a local spring shop.

St. Louis Spring is also very good. I've gotten stock springs from both Eaton Detroit and St. Louis Spring and the springs were both very good. The times I ordered from St. Louis Spring, I was in the St. Louis area and called in my order in the morning and they had them made and ready for pickup in the afternoon. I have no affiliation with them other than a very satisfied customer.
Samantha

I prefer the original height, it's just that they're hard to find in stock (with the exception of pricey Detroit Eton). Seems like everyone has some version of the lowered springs in stock, and they're cheaper.

Eton Detroit springs are $350each front, $475 each rear for stock height springs versus St. Louis Springs $168/front each, $295/rear each.
Posies Springs are $550/pair for the rear and stock height, but if they make them stock they don't include the teflon sliders.

Rock Auto has the front springs for $107, $155, and $204 each for the front depending on brand.

I've purchased leaf springs from Rock Auto for a '79 F-100 and they work just fine.

Just a note about the Posies springs since they were mentioned. Their front springs are reverse eyed and are advertised to be a 1" drop. In reality, they're likely not going to be any drop at all from where you're at now if your springs are old. At least not until they also start sagging. I bought some to replace mine because my stock springs were worn completely through the bushings and into the eye metal. They were about the same height as my worn stock springs.

The Posies rear springs are supposed to be a 3" drop, but again, if yours are worn, they might only be 1 or 2" from where you're at now. I'm not sure about the frame on your truck, but on my '36 there is a ton of room for rear end clearance without the need to notch the frame. My truck was lowered 3" (front and rear) and I still had plenty of clearance in the back. (front is dropped axle). I just took off the top load springs. Never bottomed out on me, and my truck doesn't even have shocks, just the springs (that is gonna change).

Ride quality to me is fine, but I am not planning to ever haul a load.

The Eton Detroit Spring for $350 is the original 1949 8 leaf two stage (5-3) spring with a rate of 365 and a 3 ¾” arch (22-166). If the St. Louis Spring is the same I would buy it. It’s probably the 8 leaf spring with a rate of 315 and a 3 ½” arch (22-184). That is the spring they sell today for the 1947-1955 ½ and ¾ ton truck.

Try General Spring front 22-184 $149 and the rear 7(4/3) 22-173 $224.

The three front springs sold by Rock Auto are all listed as part # 22-184 and are 8 leaf springs. I'd suspect that they are all made by the same company as General Spring.

I’ve also had good dealings with St. Louis Spring. I believe they will build you a softer and/or lower spring if you want. The ones I purchased were stock.

As for lowering springs, my favorite stance for an AD truck (or almost any vintage truck) is lowered JUST enough that you ~think~ it’s probably lowered, but you’re not quite sure.

Interesting detail, thanks! I don't know what the "rate" number is referring to?

As to the St. Louis springs they quoted me, the fronts were 1 3/4" and 9 leaves. No rate number specified. The rears they were quoting were 2" wide and 11 leaves.

The General Springs listings look like what's on my truck now: 8 leaves front, 7 leaves rear. Good price on those.

Spring rate is 1" of compression for every 100 lbs of weight on them. Coils or leaf, both use the same rate standard. A variable rate spring is just that, one end of a coil is softer then the other end. With out a load, the truck rides on the soft portion, load it up, the soft portion is compressed down to the heavier rate portion. A variable leaf spring would likely have a few top leafs arched more so they have room to work before hitting the heavier leafs.

Less spring rate is a softer spring. Average load of deflection is what GM calls the spring rate.

Pull up the GM Heratage site information packet for your truck, usually about have way through the information is the spring information. I would use it to compare any new springs. https://www.gm.com/content/dam/comp...hevrolet-trucks/1949-Chevrolet-Truck.pdf

You could try Deaver Suspension in Santa Ana, CA. They can provide replacements or rebuild yours to stock or
any configuration you require.
Good people to deal with and prices are fair.
Fred