# rule of thumb for log weight



## MidGAOutdoor (Apr 7, 2011)

whats the best way to figure log weight in the filed where one wouldn't have access to the woodweb log weight calculator. I am about to upgrade trailer axles and don't want to bust the frame. frame is 5 inch channel with 3 inch channel cross members. wanting to upgrade to 2 6K axles from 2 #3500 axles


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## woodnthings (Jan 24, 2009)

*I think you have 2 separate issues*

You are doubling the axle capacity at 12,000 lbs on a frame designed for 7000 lb axles. You may be better off to just upgrade to a heavier trailer than to start replacing axles. Sell this one and get a bigger capacity one. Hitch components like the rating capacity, tongue weight and ball size will also have to get larger. Brakes are another issue and a controller.

http://www.forestryforum.com/calcs/log_weight.htm

As far as field estimates, just use this calculator and run a bunch of examples based on the length of the trailer bed. For example "Live Oak is the heaviest on the chart at 75, a 10 ft log 20" diameter estimates to be 1,659 lbs. Use the same dimensions for Maple, Pine, Alder, etc. and you will have a rough estimate of weights for that length and diameter.


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## 44260 (Aug 29, 2013)

Woodnthings is 100% correct on the trailer. You can put heavier axles under the trailer but if the frame work is only rated for 7,000 pounds then the frame will start cracking with pulling 12,000 pound loads. The type of hitch is also a consideration. I don't know what kind of truck you are pulling the trailer with, but I would seriously look into a goose neck trailer.


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## hwebb99 (Nov 27, 2012)

I can tell how close to how heavy my trailer is loaded by looking at it. If you are using the same machine to load logs you can make a fairly accurate guess by how the machine behaves. This is assuming your machines lift capacity isn't much greater than the log weight. This forklift with a 7,500 pound capacity effortlessly lifted this 40 inch diameter 11 feet long log which doesn't leave me much to guess from. What you are trying to do is a bad idea. The trailer frame was designed to carry 7,000 pounds. Upgrading your truck engine to a semi engine that can produce over 1,000 foot pounds of toque doesn't mean you can now tow like a semi.


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## Allen Tomaszek (Dec 11, 2010)

One thing that might help is to make yourself a chart you can take with you to the field. It would take a couple hours at most to just sit at the woodweb calculator and plug in some values to make a simple chart. I'd plug in 12", 16", 20" and 24" for diameters or whatever you run into the most. Then plug in 8', 10' and 12' for lengths. Then just choose the species you run into the most.

I agree with the rest of the posters on the trailer mods. Safety first in this line of work.


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## Allen Tomaszek (Dec 11, 2010)

I forgot... When I'm guessing in the field I use this rule... an 8' long 20" diameter hardwood log is about 1000lbs. Cherry and Walnut are around 900lbs and hard maple or white oak are around 1100lbs according to the calculators.


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## FishFactory (Nov 8, 2013)

After a few loads you should be able to judge fairly well. I can usually look at the tires on my trailer and be able to tell roughly how much weight I have on it. I am not always using the same machine to load logs. Its also fairly easy to tell when you get behind the wheel and feel how the trailer reacts when you start moving.


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