Question about leaf springs on trailer

[maverick974]

Re: Question about leaf springs on trailer

Think a little bit folks! Spring hangers are set a tad longer than the length of the spring because this dimension is critical to the UNLOADED vs loaded configuration. When the weight of the trailer sits on the springs the spring deflects, it gets longer, and the bottom end of the shackles will now point to the rear. Look at the design drawing I just posted. Does that drawing not say the shackles should sit 90 degrees or less from the centerline of the two spring eyes? 90 degrees or less does not point the shackles forward, it points them rearward. If they pointed forward that angle would be greater than 90 degrees. But if you are geometrically challenged, I can only suggest you go out and look at some trailers. Please take pictures of any you find with the shackles facing forward. You will find some but it involves another design that essentially flips the rear spring hangers. But you won't find them on a trailer.

Wow, I didn't know this was going to become such a firm discussion but I'm glad to hear all the oposing viewpoints.
While I don't want to upset anybody, I'm going to go with the 26 inch springs. With that said, I now have a few more questions. Everyone seems knowledgeable about the subject so I'd like to hear your opinions on a couple of other concerns I have. Honestly, I just want to do it right so all your help is more than appreciated.
My existing original spring when unloaded, the shackles sit at about 90 degrees. When loaded, the shackles are facing slightly rearward and after all your opinions, that's what makes sense to me.
Now my questions....
The new springs come with 9/16 shackle bolts and the inserts in the eyes of the spring have 9/16 bushings. The problem is my shackles and hangers have 1/2 inch bolts and bolt holes from the factory. So should I buy the 9/16 inch bolts and just drill out the holes to fit 9/16 bolts or do they make 1/2 bushings?
The 26 inch springs are rated for 2000 pounds if I remember right. So I'm assuming the axle is either a 3500 lb axle or a 4000 lb. The new springs have 3 leafs where the factory springs have 4. Does that make any difference at all???
Also, I'd like to give a little more clearance between the tires and the fenders. Could I go with longer shackles or would that mess up the geometry of the suspension???

Again, thanks for your imput.

 

[Silvertip]

Re: Question about leaf springs on trailer

This entire thread was about whether or not spring shackles should point forward or back and that orientation has apparently caused a great deal of confusion. So to simplify things, the upper end of the spring shackle is fixed so that end of the shackle can only pivot. Movement is at the lower end of the shackle so when discussing which direction the shackle points, the lower end is the point of reference. So lets assume the spring eyes are perfectly parallel to the ground. As the design drawing I posted earlier indicates, the bracket should be installed so the shackle is at 90 degrees or less to that horizontal line. 90 degrees is measured on the left side of the shackle in the drawing. Moving the lower end of the shackle to the right means the angle decreases. That also means the lower end of the shackle points rearward. If you view the entire shackle orientation and disregard the top or bottom, then yes, the "entire shackle" would have a forward slant to it. I feel where this train ran off the track was over the forward and backward point of reference. Think of the shackles as the pendulum on a clock. One generally refers to the direction of pendulum position as left or right which is akin to forward and back on the shackles. If I contributed that confustion I do apologize, but if you happen to feel the lower end of the shackle should be forward of the upper end then we still disagree.

 

[Silvertip]

Re: Question about leaf springs on trailer

There seems to be enough metal in the hangers to take the larger bolts so if that's what you have, drill out the hangers and use them. The shackle bolts have knurling near the head so when the nuts are tightened, this locks the bolt to the shackle. The reason for this is to make the shackle bolt pivots in the bushing rather than pivoting on the bolt which would elongate the hole in the shackle and eventually cut through the bolt.

Springs, axle and tires all require capacities that will safely haul your boat. Just because you have 4000# springs does not mean you can haul 4000# if the axle is rated 3500# and the tires can handle only 3500#. Any one of the three components is the weak link in the chain. Yes - three leaf and four leaf springs can have different load ratings and usually do.

In looking at your spring mounting, you have everything mounted in the upper holes in the brackets. Move the front end of the spring down. In the rear you have two holes as well. Mount the upper end of the shackles in the lower holes. This will provide an additional inch or so of suspension travel which is a fair amount on a trailer.

 

[maverick974]

Re: Question about leaf springs on trailer

Thanks Silvertip.
The guy at the suspension place where I bought the wrong spring told me that it was a 3500 lb axle. To a point it doesn't really matter because my tires are only rated for about 2100 lbs and the boat is less than 1500 lbs loaded so whatever the ratings are, I'm sure I'm well within limits.
I just want to make sure I get the suspension correct so it tracks straight and the tires don't rub the fenders and ultimately don't run up into the hull of the boat.
So far, from all the information gathered here, I'll get two 26 inch springs, I'll drill out the hangers, get new bolts and shackles and put it all together.
I'm desperately hoping this is the ticket.
My thanks again to all who participated.

 

[Moody Blue]

Re: Question about leaf springs on trailer

Quite a discussion, and very informative.

One more thing to consider when replacing springs is the load rating of the spring itself. If you buy a 5000Ib spring (example) for a 1000Ib boat, it will ride like a tank and transfer all the road bumps to the boat because the spring is too firm.

Try to get a good match between the springs and the load weight.

 

[109jb]

Re: Question about leaf springs on trailer

I just got back online. I have to admit that I misinterpreted the original post. I interpreted it as describing the shackle lean as unloaded (ie: the trailer jacked up by the frame with the wheels off the ground. The loaded spring should have the shackle perpendicular or with the top end forward of the bottom. I was refering to unloaded being acceptable with the top of the shackle aft a bit. In this case I stand by what I said. I also think that that we are describing the same thing different ways. When I say the shackle is leaning forward I envision the top of the shackle forward of the bottom, which I think is opposite of what you guys are thinking.

 

[maverick974]

Re: Question about leaf springs on trailer

I just got back online. I have to admit that I misinterpreted the original post. I interpreted it as describing the shackle lean as unloaded (ie: the trailer jacked up by the frame with the wheels off the ground. The loaded spring should have the shackle perpendicular or with the top end forward of the bottom. I was refering to unloaded being acceptable with the top of the shackle aft a bit. In this case I stand by what I said. I also think that that we are describing the same thing different ways. When I say the shackle is leaning forward I envision the top of the shackle forward of the bottom, which I think is opposite of what you guys are thinking.

Well, thanks for clarifying that. I think we are all in agreement now.
I'll be installing all this stuff on Monday or Tuesday so I'll post here how it all worked out.
I kind of wish this discussion would continue to be honest. One of the best threads I've read in a long time and I'm happy I was part of it.

 

[wicked]

Re: Question about leaf springs on trailer

just buy a new trailer!!!

 

[maverick974]

Re: Question about leaf springs on trailer

just buy a new trailer!!!

I'd love to if it wasn't for my daughter, food, clothing, shelter. Darn kids. Take all a guys money. lol.
I'm stuck with what I've got and I'm happy with it. To me it's function over form. If it works the way it should and it doesn't embarasse me asthetically, I'm pretty happy with it so the original trailer it is. Besides, it's just an old Bayliner bass boat anyway but it works for me.

 

[109jb]

Re: Question about leaf springs on trailer

I'd love to if it wasn't for my daughter, food, clothing, shelter. Darn kids. Take all a guys money. lol.
I'm stuck with what I've got and I'm happy with it. To me it's function over form. If it works the way it should and it doesn't embarasse me asthetically, I'm pretty happy with it so the original trailer it is. Besides, it's just an old Bayliner bass boat anyway but it works for me.

Ha Ha. I'm with you brother. Until my current boat I had one of the ugliest boats and trailers on the water but they never let me down in the 7 years I owned them. The boat floated, didn't take on water and everything worked. The trailer was equally as ugly but was mechanically and structurally sound so I didn't care. This new boat will look a lot better once I get done rebuilding it.

 

[maverick974]

Re: Question about leaf springs on trailer

Ha Ha. I'm with you brother. Until my current boat I had one of the ugliest boats and trailers on the water but they never let me down in the 7 years I owned them. The boat floated, didn't take on water and everything worked. The trailer was equally as ugly but was mechanically and structurally sound so I didn't care. This new boat will look a lot better once I get done rebuilding it.

Actually, my boat looks pretty good but I need to install new carpet and the upholstery on the seats is starting to show their age. In a previous life I was a carpet installer for many years and I still have connections so I scored some nice marine carpet just yesterday. I should have it done by next weekend if I get of my lazy butt. The seats? Well, that might take a little longer. Been out of work since last June. Come to think of it, June 27th last year. lol.
Still have enough $ for fishing a couple three times a week so all is well. New seats are in the future though.
Other than that, it's in pretty good shape and I didn't spend 40K to get on the water.
Gonna look great when it's done. Even if it doesn't, it still fishes good so I'm happy.

 

[Moody Blue]

Re: Question about leaf springs on trailer

So after all is said and done, can someone please post a picture of the correct relationship between spring and shackle? This discussion is too open to interpretation as has been seen in previous posts.

A picture is worth a thousand words

 

[109jb]

Re: Question about leaf springs on trailer

So after all is said and done, can someone please post a picture of the correct relationship between spring and shackle? This discussion is too open to interpretation as has been seen in previous posts.

A picture is worth a thousand words

Look at the attached pdf file with 3 sketches labeled 1, 2, and 3. 1 is acceptable when there is no weight on the suspension as long as the loaded suspension looks like number 2 or 3. The loaded suspension should look like 2 or 3 is the bottom line.

 

[Moody Blue]

Re: Question about leaf springs on trailer

Now that's something we can relate to without misinterpretation.

 

[maverick974]

Re: Question about leaf springs on trailer

Ok, now that I know what length springs to get, I have another question.
What weight capacity springs should I get????
The guy at the suspension place told me it was a 3500 lb axle but he is also the guy that sold me the wrong springs. He even looked at the trailer.
The original springs had 4 leafs but I don't know what capacity they are.
I can get 1500 lb springs with 3 leafs or 2000 lb springs with 4 leafs. Either one is the 26 inch springs.
According to Nada, my boat weighs 1496 lbs dry including the engine.
So what are your thoughts on that????

 

[109jb]

Re: Question about leaf springs on trailer

If your boat is ~1500 and the trailer is going to be another couple hundred sprung weight, then you add some gear in the boat you are looking in the 2500 lb range loaded. You said that the axle is a 3500 lb axle. You also said earlier that you were worried about the tire hitting the boat/fender. If it were me I would probably get a set of springs for for the 3500 pounds that the axle is rated for. This would be stiffer than the load you will actually have, but will help with the not bottoming out. Trailer springs are rated per spring so the spring rating is 1/2 the load (ie: 3500 lb load needs 1750 lb springs.) If you are worried about it being too stiff, you could go lower and choose anything between the 2500 lb load (1250 springs) and the axle rating of 3500 lb (1750 springs).

 

[maverick974]

Re: Question about leaf springs on trailer

Thanks for your reply. It's a bass boat so there is not much that goes in the boat. A few fishing poles, 2 tackle boxes, 2 life vests, the front trolling motor and gas. I do have 2 extra batteries for the trolling motor so that would add about 70 pounds. It's only a 15 gallon tank so even a full tank would not weigh more than about 105 pounds. If figure the boat on the trailer would not weigh any more than 1800 pounds when fully loaded and I rarely have much more than 5 gallons of fuel in it. I fish very small lakes around here so I don't need much fuel. I mostly use the electric trolling motor.
There is only one place locally that sells suspension parts so my choices are a 3 leaf spring rated at 1500 lbs or a 4 leaf spring rated at 2000 lbs. I was just wondering if it's ok to go with springs rated a little lower than the axle rating? With such a light boat, that would be ok wouldn't it?????

 

[109jb]

Re: Question about leaf springs on trailer

If I understand you right, the springs you are looking at are rated at 1500 and 2000 pounds respectively. Remember that the rating of a spring is for a single spring, so since you have 2 springs then you double the spring rating. 1500 pound springs would be good for a 3000 pound loaded trailer. I would choose these over the 2000 pound springs (4000 pound trailer).

The book weight of my boat is about the same weight as yours and I have 1500 pound springs (3000 total). I understand what you are saying about the loaded weight of your boat, but if you have a family and ever take it on vacation it will have a whole lot more load than that. When we go on vacation with the boat it winds up being loaded with bikes, luggage, coolers...... All this stuff adds up quick. Add to this that many older boats (I don't know if yours is new or old) are carying a bunch of excess weight in the form of waterlogged foam. I'm currently rebuilding my boat and would estimate that I had at least a couple hundred pounds of extra weight in waterlogged foam. Having said that, if you get the 1500 pound springs you will be good for a 3000 pound load and it sounds like that would give you a bit of reserve for this kind of stuff.

Finally to answer your question about using springs lower than the axle rating. No problem. Even though the axle is 3500 pounds there is no problem putting the 1500 pounds springs on. All that happens is that instead of the axle limiting the amount of load the trailer can carry, now the springs are the limiting factor.

 

[maverick974]

Re: Question about leaf springs on trailer

That sounds good to me. Besides, I don't have a big family. My wife passed away a couple of years ago so it's just me and my 16 year old daughter.
The boat is a 1984 Bayliner bass boat and it has NO floatation at all. Kind of bothers me about that boat but there is none whatsoever.
Anyway, the reason I'm thinking of going with the lower rated springs is financial only. The 1500 lb springs are cheaper but if it would be better overall, I'd go witht he heavier springs. I'm glad to hear it would be no problem with the lighter springs. I'm guessing that the lower rated springs won't make any difference with the height of the trailer (tires hitting the fenders). If you think it will, then I'll get the heavier springs but if not, I'll go with the lighter ones.
Off topic....... is there any way to put floatation in this boat without tearing it all up??? Just curious......
Thanks again.

 

[Tvmrfixxit]

Re: Question about leaf springs on trailer

HTV, which drawing below is how you say the spring won't flex?? I have labeled them configuration 1 and configuration 2.

Good Lord configuration 2 is correct for loaded springs!
get the bigger 1750# springs so it wont hit the fenders! or at least get some that have more arc in them, you can find some that are 3.5-5" arc if you look hard enough.
get out on the water and fish, at least your motor runs. I wish mine only had a spring problem right now.