5/16 vs 3/8 chain

[redprospector]

Each 5/16 gr 70 has a WLL of 4700#.

So with 4 of them you should be able to tie down 18,800 lbs of stuff. So yea, they are big enough.

But I would suggest the 3/8 if you plan on using the chain for other things, like using with the tractor to drag logs or whatnot. But if only for transport, the 5/16 should be fine.

If you're going to drag logs, use a dedicated "log" chain. I wouldn't recommend using transport chains for anything other than their intended purpose.

As far as breaking chains, I have broken several, but always pulling logs, loaded trucks, etc.
A chain is only as strong as it's weakest link, inspect your transport chains regularly for cracks, and stretched links.

 

[kennyd]

Here's a simple Chart indicating WLL's of various chains:



Here's a good article on what "WLL" is: http://baprod.com/images/stories/wll_article.pdf

And a good one on why chain breaks: http://baprod.com/images/stories/chain_article.pdf

I also agree with most that 5/16" G70 chain is perfect for most compact tractors.

 

[SPYDERLK]

I have skidding logs. Once with the Kubota, and once with my old dodge. The old dodge, it was momentum that broke it. Was skidding along around 8-10 mph and the butt caught a low-cut stump I didn't see. That dodge also made a 5/16 chain un-flexible by stretching the links and they pinched down on eachother.

The time with the Kubota was also skidding a log. About a 20-24" or so ash top. Chained short and with the 3ph raised to get the butt in the air and have maximum traction. Also had loader on and loaded r1's. So tractor was 4k or so + a good bit of weight transfer and slightly downhill. No jerking. Just an easy pull. Moved about a foot and snap. Got a 3/8" and finished.

I have also broke 3/8" gr70 chain more than once. Twice within a few minutes of each other. But had to get the job done. Was demo-ing an old farm house. All rough cut lumber. The "island" of walls in the center of the house surrounded the cinder block chimney. It was all that was left standing and couldn't get the how close enough to knock it over cause of the basement. So pulling was the only option. Dads ford 4500 (12k lbs) would just spin. I hooked to it with my 5500. Again, no jerking. Just a slow steady pull in 1st gear. Ended up breaking 2 chains before we got it down.

Ok. Those chains did not perform to spec -- particularly the one on the Kub pull. Who made them? Does the chain go over a sharp edge or something? I have the 5/16" short link variety. The Mahindra in 12K# trim wont phase it steady. Im sure I could break them jerking a solid object, but the only way Iv even marred one is hooking 2 together with a grab hook so I could jerk out a 7" tree. Damaged a link slightly but no stretch. I had no idea there was so much variability in the Gr 70 selection. Now Im worried making any general judgement regarding the class.
,,,,larry

 

[LD1]

Perhaps they didn't perform to spec. Both were using grab hooks but only one if the 3 failures was at a hook point. No sharp edges. It was hooked to a clevis.

With the Kubota pull, I have no doubt that I was pulling near 10k drawbar pull. Everything was perfect for traction. Short chain, raised hitch, and maybe a 10 degree downhill in the woods with good footing. It was a gr70, bit in all fairness, it was a 10+ year old chain that has pulled a lot.

The pulls with the BH and 3/8, I think I exceeded the 26k or so rating. We are talking an 18k machine with lits of weight over the pulling tires. No intentional jerk on my part but that dont mean the chain felt some when the tires start spinning and kinda do that little hop thing they do while trying to bite. Certainly not like getting a running start. And kinda like slow motion being in 1st gear, if you can kinda get a visual of what I am saying.

So I think I can attribute the 5/16 breaking due to optimum conditions +old chain. And the 3/8 broke cause it was just too small for a big ole hoe.

Either way, I don't rely on 5/16 if I know I am going to be pulling hard. 3/8 is no big deal for me. And next time I buy some chain, I think I will step up and get some 1/2 for the BH.

Also worth noting that the chain is only tested to 2x wll. And only random same are treated for break strength. So you are really only gaurenteed 2x wll.

 

[dragoneggs]

Thanks for the replies regarding 'how you broke your chains' and some of the analysis behind it. I wasn't trying to say that 3/8in is overkill or implying anything other than true curiosity. I have always used 5/16in grade 70 but I don't do any 'heavy duty' work. Weekend warrior, Small tractor and all! What I don't like is having something that is overkill to the point that it is cumbersome. Maybe being an aerospace engineer has taught me to be efficient and not carry more weight than necessary. That said, I appreciate having a generous factor of safety (won't 'fly' for aerospace design) so you can use and abuse with less care. Still interested in 'broken' chain stories! :laughing:

 

[HHR]

I don't think 5/16 chain would hold up in this anchor drop maneuver, but 3/8 may be just the ticket.
http://youtu.be/qd5MqjvhW9c

 

[TomSeller]

. I have always used 5/16in grade 70 but I don't do any 'heavy duty' work. Weekend warrior, Small tractor and all! What I don't like is having something that is overkill to the point that it is cumbersome. :

Same here.

 

[dragoneggs]

I don't think 5/16 chain would hold up in this anchor drop maneuver, but 3/8 may be just the ticket.
http://youtu.be/qd5MqjvhW9c

Ha ha... good thing I have tipped a few before watching this crap. But I did like the chain arrest idea.

 

[Happy Gilmore]

Not sure if this table is of any help. Federal Motor Carrier Safety Administration guidelines below



Part 393
PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION
< 392 | 395 >

ｧ 393.108: How is the working load limit of a tiedown, or the load restraining value of a friction mat, determined?

(a) The working load limit (WLL) of a tiedown, associated connector or attachment mechanism is the lowest working load limit of any of its components (including tensioner), or the working load limit of the anchor points to which it is attached, whichever is less.
(b) The working load limits of tiedowns may be determined by using either the tiedown manufacturer's markings or by using the tables in this section. The working load limits listed in the tables are to be used when the tiedown material is not marked by the manufacturer with the working load limit. Tiedown materials which are marked by the manufacturer with working load limits that differ from the tables, shall be considered to have a working load limit equal to the value for which they are marked.
(c) Synthetic cordage (e.g., nylon, polypropylene, polyester) which is not marked or labeled to enable identification of its composition or working load limit shall be considered to have a working load limit equal to that for polypropylene fiber rope.
(d) Welded steel chain which is not marked or labeled to enable identification of its grade or working load limit shall be considered to have a working load limit equal to that for grade 30 proof coil chain.
(e)(1) Wire rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit equal to one-fourth of the nominal strength listed in the Wire Rope Users Manual.
(2) Wire which is not marked or labeled to enable identification of its construction type shall be considered to have a working load limit equal to that for 6 ﾗ 37, fiber core wire rope.
(f) Manila rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit based on its diameter as provided in the tables of working load limits.
(g) Friction mats which are not marked or rated by the manufacturer shall be considered to provide resistance to horizontal movement equal to 50 percent of the weight placed on the mat.

Part 393
PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION
< 392 | 395 >

ｧ 393.108: How is the working load limit of a tiedown, or the load restraining value of a friction mat, determined?

(a) The working load limit (WLL) of a tiedown, associated connector or attachment mechanism is the lowest working load limit of any of its components (including tensioner), or the working load limit of the anchor points to which it is attached, whichever is less.
(b) The working load limits of tiedowns may be determined by using either the tiedown manufacturer's markings or by using the tables in this section. The working load limits listed in the tables are to be used when the tiedown material is not marked by the manufacturer with the working load limit. Tiedown materials which are marked by the manufacturer with working load limits that differ from the tables, shall be considered to have a working load limit equal to the value for which they are marked.
(c) Synthetic cordage (e.g., nylon, polypropylene, polyester) which is not marked or labeled to enable identification of its composition or working load limit shall be considered to have a working load limit equal to that for polypropylene fiber rope.
(d) Welded steel chain which is not marked or labeled to enable identification of its grade or working load limit shall be considered to have a working load limit equal to that for grade 30 proof coil chain.
(e)(1) Wire rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit equal to one-fourth of the nominal strength listed in the Wire Rope Users Manual.
(2) Wire which is not marked or labeled to enable identification of its construction type shall be considered to have a working load limit equal to that for 6 ﾗ 37, fiber core wire rope.
(f) Manila rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit based on its diameter as provided in the tables of working load limits.
(g) Friction mats which are not marked or rated by the manufacturer shall be considered to provide resistance to horizontal movement equal to 50 percent of the weight placed on the mat.

Tables to ｧ393.108

[Working Load Limits (WLL), Chain]

Size mm (inches) WLL in kg (pounds)
Grade 30 proof coil Grade 43 high test Grade 70 transport Grade 80 alloy Grade 100 alloy
1. 7 (1⁄4) 580 (1,300) 1,180 (2,600) 1,430 (3,150) 1,570 (3,500) 1,950 (4,300)
2. 8 (5⁄16) 860 (1,900) 1,770 (3,900) 2,130 (4,700) 2,000 (4,500) 2,600 (5,700)
3. 10 (3⁄8) 1,200 (2,650) 2,450 (5,400) 2,990 (6,600) 3,200 (7,100) 4,000 (8,800)
4. 11 (7⁄16) 1,680 (3,700) 3,270 (7,200) 3,970 (8,750)
5. 13 (1⁄2) 2,030 (4,500) 4,170 (9,200) 5,130 (11,300) 5,400 (12,000) 6,800 (15,000)
6. 16 (5⁄8) 3,130 (6,900) 5,910 (13,000) 7,170 (15,800) 8,200 (18,100) 10,300 (22,600)
Chain Mark Examples:
Example 1 3 4 7 8 10
Example 2 30 43 70 80 100
Example 3 300 430 700 800 1000

Synthetic Webbing

Width mm (inches) WLL kg (pounds)
45 (13⁄4) 790 (1,750)
50 (2) 910 (2,000)
75 (3) 1,360 (3,000)
100 (4) 1,810 (4,000)

Wire Rope (6 ﾗ 37, Fiber Core)

Diameter mm (inches) WLL kg (pounds)
7 (1⁄4) 640 (1,400)
8 (5⁄16) 950 (2,100)
10 (3⁄8) 1,360 (3,000)
11 (7⁄16) 1,860 (4,100)
13 (1⁄2) 2,400 (5,300)
16 (5⁄8) 3,770 (8,300)
20 (3⁄4) 4,940 (10,900)
22 (7⁄8) 7,300 (16,100)
25 (1) 9,480 (20,900)

Manila Rope

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 90 (205)
11 (7⁄16) 120 (265)
13 (1⁄2) 150 (315)
16 (5⁄8) 210 (465)
20 (3⁄4) 290 (640)
25 (1) 480 (1,050)

Polypropylene Fiber Rope WLL (3-Strand and 8-Strand Constructions)

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 180 (400)
11 (7⁄16) 240 (525)
13 (1⁄2) 280 (625)
16 (5⁄8) 420 (925)
20 (3⁄4) 580 (1,275)
25 (1) 950 (2,100)

Polyester Fiber Rope WLL (3-Strand and 8-Strand Constructions)

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 250 (555)
11 (7⁄16) 340 (750)
13 (1⁄2) 440 (960)
16 (5⁄8) 680 (1,500)
20 (3⁄4) 850 (1,880)
25 (1) 1,500 (3,300)

Nylon Rope

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 130 (278)
11 (7⁄16) 190 (410)
13 (1⁄2) 240 (525)
16 (5⁄8) 420 (935)
20 (3⁄4) 640 (1,420)
25 (1) 1,140 (2,520)

Double Braided Nylon Rope

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 150 (336)
11 (7⁄16) 230 (502)
13 (1⁄2) 300 (655)
16 (5⁄8) 510 (1,130)
20 (3⁄4) 830 (1,840)
25 (1) 1,470 (3,250)

Steel Strapping

Width ﾗ thickness mm (inches) WLL kg (pounds)
31.7 ﾗ .74 (11⁄4 ﾗ 0.029) 540 (1,190)
31.7 ﾗ .79 (11⁄4 ﾗ 0.031) 540 (1,190)
31.7 ﾗ .89 (11⁄4 ﾗ 0.035) 540 (1,190)
31.7 ﾗ 1.12 (11⁄4 ﾗ 0.044) 770 (1,690)
31.7 ﾗ 1.27 (11⁄4 ﾗ 0.05) 770 (1,690)
31.7 ﾗ 1.5 (11⁄4 ﾗ 0.057) 870 (1,925)
50.8 ﾗ 1.12 (2 ﾗ 0.044) 1,200 (2,650)
50.8 ﾗ 1.27 (2 ﾗ 0.05) 1,200 (2,650)

 

[dragoneggs]

Not sure if this table is of any help. Federal Motor Carrier Safety Administration guidelines below



Part 393
PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION
< 392 | 395 >

ｧ 393.108: How is the working load limit of a tiedown, or the load restraining value of a friction mat, determined?

(a) The working load limit (WLL) of a tiedown, associated connector or attachment mechanism is the lowest working load limit of any of its components (including tensioner), or the working load limit of the anchor points to which it is attached, whichever is less.
(b) The working load limits of tiedowns may be determined by using either the tiedown manufacturer's markings or by using the tables in this section. The working load limits listed in the tables are to be used when the tiedown material is not marked by the manufacturer with the working load limit. Tiedown materials which are marked by the manufacturer with working load limits that differ from the tables, shall be considered to have a working load limit equal to the value for which they are marked.
(c) Synthetic cordage (e.g., nylon, polypropylene, polyester) which is not marked or labeled to enable identification of its composition or working load limit shall be considered to have a working load limit equal to that for polypropylene fiber rope.
(d) Welded steel chain which is not marked or labeled to enable identification of its grade or working load limit shall be considered to have a working load limit equal to that for grade 30 proof coil chain.
(e)(1) Wire rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit equal to one-fourth of the nominal strength listed in the Wire Rope Users Manual.
(2) Wire which is not marked or labeled to enable identification of its construction type shall be considered to have a working load limit equal to that for 6 ï¾— 37, fiber core wire rope.
(f) Manila rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit based on its diameter as provided in the tables of working load limits.
(g) Friction mats which are not marked or rated by the manufacturer shall be considered to provide resistance to horizontal movement equal to 50 percent of the weight placed on the mat.

Part 393
PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION
< 392 | 395 >

ｧ 393.108: How is the working load limit of a tiedown, or the load restraining value of a friction mat, determined?

(a) The working load limit (WLL) of a tiedown, associated connector or attachment mechanism is the lowest working load limit of any of its components (including tensioner), or the working load limit of the anchor points to which it is attached, whichever is less.
(b) The working load limits of tiedowns may be determined by using either the tiedown manufacturer's markings or by using the tables in this section. The working load limits listed in the tables are to be used when the tiedown material is not marked by the manufacturer with the working load limit. Tiedown materials which are marked by the manufacturer with working load limits that differ from the tables, shall be considered to have a working load limit equal to the value for which they are marked.
(c) Synthetic cordage (e.g., nylon, polypropylene, polyester) which is not marked or labeled to enable identification of its composition or working load limit shall be considered to have a working load limit equal to that for polypropylene fiber rope.
(d) Welded steel chain which is not marked or labeled to enable identification of its grade or working load limit shall be considered to have a working load limit equal to that for grade 30 proof coil chain.
(e)(1) Wire rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit equal to one-fourth of the nominal strength listed in the Wire Rope Users Manual.
(2) Wire which is not marked or labeled to enable identification of its construction type shall be considered to have a working load limit equal to that for 6 ï¾— 37, fiber core wire rope.
(f) Manila rope which is not marked by the manufacturer with a working load limit shall be considered to have a working load limit based on its diameter as provided in the tables of working load limits.
(g) Friction mats which are not marked or rated by the manufacturer shall be considered to provide resistance to horizontal movement equal to 50 percent of the weight placed on the mat.

Tables to ｧ393.108

[Working Load Limits (WLL), Chain]

Size mm (inches) WLL in kg (pounds)
Grade 30 proof coil Grade 43 high test Grade 70 transport Grade 80 alloy Grade 100 alloy
1. 7 (1⁄4) 580 (1,300) 1,180 (2,600) 1,430 (3,150) 1,570 (3,500) 1,950 (4,300)
2. 8 (5⁄16) 860 (1,900) 1,770 (3,900) 2,130 (4,700) 2,000 (4,500) 2,600 (5,700)
3. 10 (3⁄8) 1,200 (2,650) 2,450 (5,400) 2,990 (6,600) 3,200 (7,100) 4,000 (8,800)
4. 11 (7⁄16) 1,680 (3,700) 3,270 (7,200) 3,970 (8,750)
5. 13 (1⁄2) 2,030 (4,500) 4,170 (9,200) 5,130 (11,300) 5,400 (12,000) 6,800 (15,000)
6. 16 (5⁄8) 3,130 (6,900) 5,910 (13,000) 7,170 (15,800) 8,200 (18,100) 10,300 (22,600)
Chain Mark Examples:
Example 1 3 4 7 8 10
Example 2 30 43 70 80 100
Example 3 300 430 700 800 1000

Synthetic Webbing

Width mm (inches) WLL kg (pounds)
45 (13⁄4) 790 (1,750)
50 (2) 910 (2,000)
75 (3) 1,360 (3,000)
100 (4) 1,810 (4,000)

Wire Rope (6 ï¾— 37, Fiber Core)

Diameter mm (inches) WLL kg (pounds)
7 (1⁄4) 640 (1,400)
8 (5⁄16) 950 (2,100)
10 (3⁄8) 1,360 (3,000)
11 (7⁄16) 1,860 (4,100)
13 (1⁄2) 2,400 (5,300)
16 (5⁄8) 3,770 (8,300)
20 (3⁄4) 4,940 (10,900)
22 (7⁄8) 7,300 (16,100)
25 (1) 9,480 (20,900)

Manila Rope

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 90 (205)
11 (7⁄16) 120 (265)
13 (1⁄2) 150 (315)
16 (5⁄8) 210 (465)
20 (3⁄4) 290 (640)
25 (1) 480 (1,050)

Polypropylene Fiber Rope WLL (3-Strand and 8-Strand Constructions)

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 180 (400)
11 (7⁄16) 240 (525)
13 (1⁄2) 280 (625)
16 (5⁄8) 420 (925)
20 (3⁄4) 580 (1,275)
25 (1) 950 (2,100)

Polyester Fiber Rope WLL (3-Strand and 8-Strand Constructions)

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 250 (555)
11 (7⁄16) 340 (750)
13 (1⁄2) 440 (960)
16 (5⁄8) 680 (1,500)
20 (3⁄4) 850 (1,880)
25 (1) 1,500 (3,300)

Nylon Rope

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 130 (278)
11 (7⁄16) 190 (410)
13 (1⁄2) 240 (525)
16 (5⁄8) 420 (935)
20 (3⁄4) 640 (1,420)
25 (1) 1,140 (2,520)

Double Braided Nylon Rope

Diameter mm (inches) WLL kg (pounds)
10 (3⁄8) 150 (336)
11 (7⁄16) 230 (502)
13 (1⁄2) 300 (655)
16 (5⁄8) 510 (1,130)
20 (3⁄4) 830 (1,840)
25 (1) 1,470 (3,250)

Steel Strapping

Width ï¾— thickness mm (inches) WLL kg (pounds)
31.7 ï¾— .74 (11⁄4 ï¾— 0.029) 540 (1,190)
31.7 ï¾— .79 (11⁄4 ï¾— 0.031) 540 (1,190)
31.7 ï¾— .89 (11⁄4 ï¾— 0.035) 540 (1,190)
31.7 ï¾— 1.12 (11⁄4 ï¾— 0.044) 770 (1,690)
31.7 ï¾— 1.27 (11⁄4 ï¾— 0.05) 770 (1,690)
31.7 ï¾— 1.5 (11⁄4 ï¾— 0.057) 870 (1,925)
50.8 ï¾— 1.12 (2 ï¾— 0.044) 1,200 (2,650)
50.8 ï¾— 1.27 (2 ï¾— 0.05) 1,200 (2,650)

HG, way too much to digest this time of night but thanks for posting this.