Help me size my chain

[Count Fred]

I have a hi-lift with an off-road kit. Having just performed a pulling operation on my FZJ80 without the ability to reset, I need some chain.

The options are:

G70 5/16 with a WLL (working load limit) of 4700lbs and MBS (minimum breaking strength) of 18800

G70 3/8 with a WLL of 6600lbs and MBS of 26400

The hi-lift is rated at 4660lbs, the top clamp will bend or break at 5000lbs and the shear pin at 7000lbs.

The 5/16 is rated above the jack's rating, but not above the shear pin (what you'd like to break first). Neither however is the 3/8. The top clamp appears to be the weak point, which is not ideal, but better than it being mid-length on the chain. The 5/16 is rated below the top clamp, but will break above it. The 3/8 is rated above it.

Personally, I don't think I'm strong enough to get that much force on the hi-lift. I don't know what the actual leverage is though. But I'm looking for other people's thoughts as to whether the 3/8 chain extra weight and bulk are worth it.

I am also unsure as to what this means in the hi-lift manual: "When used as a winch, the top clamp-clevis will support up to 5,000 lbs. (2273 kg). Going over
this limit will result in the top clamp-clevis bending or breaking." The item is not stamped or otherwise labelled with a WLL, so is this really a MBS, or just a WAG (wild-*** guess).

So which is ok? 5/16 or 3/8?

Cheers,
JFS III

 

[spencyg]

I have a 30' length of 5/16" G70 in my rig without any concern for standard recoveries...and I'm pushing 8000lb+. For your rig, I wouldn't hessitate to run 5/16" recovery chain. Remember, chain has a specific usage (no shock loading), so my recommendation only applies when you're using the chain properly (no running starts with a recovery vehicle!!). You should also carry a 30' 3" strap with loops on each end, appropriately sized shackles, tree strap, etc.

Spence

 

[I Leak Oil]

If I were buying it I'd get the 3/8" chain. More versitile in more situations. If your plan is to ONLY use the 5/16" for your hi-lift you'll probably be O.K. but plan for the future and get the 3/8".

 

[Count Fred]

A running start with a hi-lift? You're funny! Having just done a flat-ground pull of an unstuck (but non-running) vehicle I hate to think about what a workout extracting a vehicle might be. Slow but steady I hope.

Yeah, I have some straps in my collection, snatch straps, tow straps, and tree straps. Had to use those to pull a roofing boom truck up a construction site once. Much fun that was.

Cheers,
JFS III

 

[rovingowl]

a 20' 3/8 grade 70 chain weighs roughly 31.5 lbs compared to a 20' length of 5/16 weighing 21.5 lbs. this is with clevis hooks installed. both are heavy and cumbersome. i recently opted for the 3/8 chain under the adage of "better to have it and not need it, than to need it and not have it".

 

[IggyB]

I have some in both sizes. Nothing wrong with 5/16" as long as no shock is applied. I do however like the extra safety factor of 3/8".

Kind of like the shackles, big ones and little ones. Big ones fit trucks and little ones fit the tiny tow loops on stuck Honda's.

 

[adventurebuddies]

I have had this same dilems. 5/16 g70 chains is commonly available with grab hooks as a kit. Even Home Depot carries it for about $35. Great price. I haven't bought it because I'd like the extra safety factor of the 3/8 - just can't find it anywhere other than $100 from offroad supply sites. Any retailers that carry 3/8 for less than $50 with the grab hooks?

 

[Count Fred]

NAPA through SCC has a low weight same WLL 20' strech of 3/8 and 5/16 chain with clevis grab hooks. Part numbers are H3275-5620 for the 3/8 and H3275-5220 for the 5/16. I asked about the 3/8 today and was quoted $60. Not quite $50, but sounded like a good deal. The weight is 30lbs for the 3/8 and 22lbs for the 5/16.

 

[rovingowl]

here's where i got mine

http://www.1st-chainsupply.com/chain/gr70_binderchain_38.htm

 

[Stumpalump]

I'd use the thin chain to save weight.

 

[IggyB]

I'd use the thin chain to save weight.

I've been thinking of using pretzels tied together with silly string :coffeedrink:

 

[I Leak Oil]

I've been thinking of using pretzels tied together with silly string :coffeedrink:

My friends to the north are always thinking! Just a little trick I picked up recently though...use the salted pretzels...the extra salt in the bottom of the bag can be used to melt the ice during the winter or entice a couple horses to pull you out.:ylsmoke:

 

[Count Fred]

I've been thinking of using pretzels tied together with silly string :coffeedrink:

If you can find pretzels and silly string rated with the appropriate WLL, go for it.

JFS III