Technical Mono Leaf Spring Question Please

I built a Model A speedster. I have been unhappy with it because is sits to high. The body is made of wood frame covered with canvas and dope. So fairly light. In the front I have the spring pack down to three springs and about that many in the rear. I have been looking at this reversed eye mono leaf spring but have read both good and bad about them. What is your opinion please as to whether they are safe or not. Thank you.

 

Had mono springs both front and back on my Deuce pickup,never a problem and I have a new one just waiting on the next project. HRP

 

A good friend of mine has a mono spring on the front of his 31 and he has over 30000kms (About 18000miles) all up and down the west coast, and has never had an issue with it, it rides great. I would say they are safe.

 

I had brand new ones on the front of my '55 F100, 350/350, so pretty light. (gross weight 3,100 lbs.)
I had about 2,000 miles on it when 'BOOM!' The right front monoleaf snapped in half, 8" from the rear eye. Axle moved forward, Unexpected turn!?! Stopped safely, drove it home @15 MPH.
Mentioned it on here, many guys said they had the same problem...
Pete Eastwood welcomed me to the 'Broken Monoleaf Club'. Pete's endor*****t goes miles.
My knowledgeable wife ***embled me a pair of 7 leaf stacks, which she flattened and reversed eyes on. Rides like a dream...no bottoming out, sits low, and remains 'flat' around corners.
Monos were 'lofty', allowed excessive body roll...Never again!
The 'critiques' that spring mfrs offer ('unsafe, no companion leaves backup') should be listened to. They will break!

 

Ask Eaton Spring their opinion- they make springs all day. Last I saw they made a couple of mono leafs for
very specific applications, but they recommend spring packs for most applications. Personally I think the safety
factor makes spring packs a no-brainer, I have seen a broken spring pack with the break thru 5 leafs but the
car still stayed level, if it had been a mono leaf it would have had the front s****ing the pavement.

 

^^^ Wow! I had no idea they were problematic. I also used to run them a lot in the back of my mini truck builds (my dark years ) as did a lot of my friends, and I never herd of any breaking.
I will mention this to my buddy with his 31, he maybe on borrowed time with his right now.

 

My 32 roadster came with a front Mono leaf spring. My 392 Hemi with stock cast iron intake weighs over 800 pounds. The car has 16K on it, I put 10K of that myself. This is the best handling hot rod I have ever had.

 

I use a mono leaf. A mono leaf must be set up so there is no binding. This requires the pivot type spring perches. I shouldn't say it but I ran over a deer in my roadster at speed (thrilling ride) and the spring flexed enough to wrinkle the chrome but didn't break. It did bend the spring perches though a**** other things.

 

Early Camaro, Nova, Firebirds came from the factory with mono leafs and they had no issues

 

Where are they manufactured ?

 

New volkswagen caddys come with mono leaf rear also.

 

I have always run a Mono on the front of my Center Door, also used a Mono on the front of the "T" Coupe I built, never had any problems, I would say is buy a good brand.

 

Welcome! Cool speedster!

Here are a few threads which might interest you:
http://www.jalopyjournal.com/forum/threads/specials.720448/
http://www.jalopyjournal.com/forum/threads/coachbuilt-early-fords.569617/
http://www.jalopyjournal.com/forum/threads/hot-rod-sports-cars.956823/
http://www.jalopyjournal.com/forum/threads/fabric-covered-car-bodies.788302/
http://www.jalopyjournal.com/forum/threads/what-defines-a-speedster.639776/
http://www.jalopyjournal.com/forum/threads/ultralight-cars-how-low-can-you-go.246587/

 

I have mono leaf in my 1932 5w coupe. 8years total 100 000km (approx. 60 000miles) without any problem.
I like very much. Works good, good to drive.

 

Ask Frank at Az. So-Cal,
He has several broken ones upstairs, altho Roy Rockwell has one in each of his cars, and just loves them..

 

I am also a member of the good monoleaf club.
Front monoleafs from Durant in CA on my 52 pickup driver since 2004 and about 25K miles.
Got a 3 mile bumpy dirt road from my house to the road.
I like how they ride and want a pair for my rear and get rid of the old original springs with lowering blocks.

 

I recently saw a broken mono spring and the reason it broke is because there was no notch in the frame for spring travel,it kept hitting the frame until it snapped in the contact area. HRP

 

So, there you go. Use a monoleaf and you will die. Use a mono leaf and they are the best thing ever. If it were me, I would simply reverse the eyes on your existing main spring and keep on driving. You can do that in a few hours in your garage. Nothing to buy.

 

I had a Durant mono-leaf on my 1st 32, it never broke but I felt it was too stiff. Changed over to multi-leaf and never looked back. Multi-leaf you can remove leafs to tune ride.. IMO the mono-leaf will be too stiff for your light car. Had the same issue with rear coil over springs, recommended rate was too stiff. Went softer than recommended and made a nice ride.

 

I tried two different mono leaf springs on front of '47 Ford coupe - it sat lower with modified stock leaf set up - reversed eye, etc

 

I've built a 40 Merc. with one on the front and 2 32s with them on the front. Ride great and are easy to adjust.

 

Multi leaf have some damping effect ( friction between leafs ) mono's are like a coil spring good shocks are a must.

 

Chev was the first to use monoleaf springs on the Nova in the sixties. They eventually stopped using them because of spring windup. Started using them in the first place because they are cheaper.

Corvette uses a monoleaf made of some kind of plastic or carbon fiber. So they will work if they are made right, used right and designed for your application.

 

I have a rig to calibrate springs. I found that a stock Model A to 34 front springs have wheel rates of about 125 lbs/in. The usual aftermarket springs are about 250 lbs/in. The monos I tested were about 500 lbs/in. That is pretty stiff for a light car.

 

I have used Mono leafs in several cars without a problem but have friends who have had them break on several occasions. When they break you are in deep trouble. The company replaced the springs and told them they were mounted wrong as mentioned above. No problem has since been experienced. 1940 Fords on both applications.

 

Somebody that actually tests springs....

The biggest problem with lightweight monoleaf spring is wrap up during brake torque [this can be greater than the spring load on a lightweight vehicle]
Not an issue on a crossleaf setup.

A spring is a spring regardless of the style .....you don't see multi coil or multi torsion springs.
Monoleafs are linear in their rating whereas multileafs are progressive

 

A friend had one brake on the front of a 32 Ford. He found that cross member was not flat where the spring sat so it broke at the middle hole.

 

Maybe I'm a little thick in the head, But how is a mono leaf spring any more unsafe than a multi leaf spring? When a main on a multi leaf spring breaks isn't it the same as when a mono leaf breaks?
Pat

 

The main leaf is not usually the one that breaks and if it does, is still tied to the other leaves.

 

So , You have never looked at a spring? I have taken many springs apart and found broken leaves. If you have multi-leaves they are held to gather with a U shaped clamp on either side of the attachment point. Just by "rely-ing on the "pack" will keep you safe, till it can be repaired. Chances of braking the main leaf , in my opinion, its not gonna happen, I have found inner springs broken, but not the multi leaf main. my.02