3 leaves3000lb vs. 4 leaves3500lb?

I Fish

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Jan 28, 2011
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It's time to replace my worn out slipper springs. Given their dimensions, they are 3 leaves and 3000 lb (2x1500). I'm not sure how to tell the axle rating, but was wondering if I replaced them with 4 leave 3500lb springs, would it make much difference in the ride? It's an 18' riveted aluminum boat, and the trailer is a custom made bunk trailer. I just don't want the trailer to beat the rivets loose. I'm just thinking about the 3500lb springs because I have added some weight, and this might help the springs longevity. Any opinions?
 

dingbat

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Nov 20, 2001
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Re: 3 leaves3000lb vs. 4 leaves3500lb?

It's time to replace my worn out slipper springs. Given their dimensions, they are 3 leaves and 3000 lb (2x1500). I'm not sure how to tell the axle rating, but was wondering if I replaced them with 4 leave 3500lb springs, would it make much difference in the ride? It's an 18' riveted aluminum boat, and the trailer is a custom made bunk trailer. I just don't want the trailer to beat the rivets loose. I'm just thinking about the 3500lb springs because I have added some weight, and this might help the springs longevity. Any opinions?

Capacity over and above your axle rating buys you nothing and in fact can be detrimental by increasing the shock reaching your boat.
 
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agallant80

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Re: 3 leaves3000lb vs. 4 leaves3500lb?

I would think that increasing the capacity of the springs would make it less forgiving therefor making the boat bounce around more. When the trailer and boat bounces around more there will be more energy when things go clunk. I would stick with what the factory has put on there.
 

limitout

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Re: 3 leaves3000lb vs. 4 leaves3500lb?

as mentioned above, if the springs are too strong then they don't have enough give and instead of flexing as they should and you will bend the spindles or the axle instead
 
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Elkhornsun

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Nov 21, 2012
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Re: 3 leaves3000lb vs. 4 leaves3500lb?

Go to a shop that repairs trailers and ask for their advice. Not unusual to have the springs fatigue over time and lose their arch. Spring shops can tell you whether it is better to rearch the original springs or add an additional leaf. I have gone both ways and gotten good results.

The leaf springs are designed to support the boat load but that is not an indication of the axle and wheel bearing load capacity. Tires are another limiting factor and usually the they are the primary load limitation for a trailer or vehicle. The trailer should have a plate with a maximum load rating and that is what I would go by and not the springs and not the tires.
 

I Fish

Petty Officer 2nd Class
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Jan 28, 2011
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Re: 3 leaves3000lb vs. 4 leaves3500lb?

I guess maybe didn't explain myself properly in my original post. Although you'd never guess it, the trailer is a true custom "homemade", as in, the guy built it from scratch in his shop. He even bought the spindles and fabbed the axle, so, no manufacturer plate or ratings. By checking the bearing numbers, the spindles are rated either 5000 or 6000lbs.. Like the rest of the trailer, they're way overkill. Long story short, I went with the heavier 3500 lb, 4 leaf springs. I used it Saturday, and now, I wished I'd have done it a long time ago. Thanks for everyone's replies.
 
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limitout

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Re: 3 leaves3000lb vs. 4 leaves3500lb?

well glad you are happy with it.

the "unknown" factor is how heavy the trailer itself is so most people are thinking of a generic production weight trailer and yours may be twice or more heavier then that.

its a moot point now but the fewer leafs the more flex and softer ride the boat will have so its "usually" better to go with less springs (but not lighter weight ratings) for lighter boats when a huge weight load isn't requiring that support.

just remember what you may think is a much better rock solid smoother ride now, is only because the boat is now absorbing the majority of the road shock now instead of the springs which is what happens when you see it bouncing.

bouncing is not a bad thing (within reason) and usually means the suspension is cushioning the ride and doing its job while the trailer not bouncing is a very very bad thing and usually means the suspension is NOT cushioning the ride and NOT doing its job
 
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