PTO Shear Pins

[kbushnz]

Hi Yah All
As part of my mid mount winch I need to put in the shear point.
Not sure what size to aim for.
Don't want a situation of breaking a rope before the shear pin goes.
Did a search on the forum with differing results.
So here is a quick poll on what size shear pins people are running.
You can choose two options. Size and material spec.
Also any comments on why would be good.

Thanks

[kbushnz]

Well interesting results thus far.
5mm seems the common size.
I am going to start with 4mm and work my way up.
Thinking about using some R clips as they are made of spring steel and re strength sit between 4.6 and 8.8.
And come in sizes from 4mm to 6mm.
Time will tell.

[mudlva]

Well interesting results thus far.
5mm seems the common size.
I am going to start with 4mm and work my way up.
Thinking about using some R clips as they are made of spring steel and re strength sit between 4.6 and 8.8.
And come in sizes from 4mm to 6mm.
Time will tell.

no no no

r clips will collect crap and then pull out

bolt and nylock for where you are putting it as you only want to get underneath when she breaks and then you will not have to worry about the nulock as it wont be there

you need to build it maintanance free as you dont want to be doing maintanance to it on the track

[mudlva]

oh yes im running 6mm HT in my bj74 had to do a mod to make it fit but worth the effort

its pulled many a treee over for my whilst doing firewood recovery for folks and friends so im pretty sold on the 6mm version

personally i would rather the rope break then the pin as you can always resplice the rope on the track but getting underneath to do a pin whilst sitting in a hole dont sound all that attractive to me

again just my thoughts

[taz01]

in my nissan size 8mm 8.8 grade with nylock

[Beer_Cruiser]

I had a 4mm cap screw in mine when I got it.
When that sheared Ive been using Pasload nails. Some nails last some shear straight away.
Im going to mod to 5mm cap screw and try that.
edit is Toyota pto

[kbushnz]

personally i would rather the rope break then the pin as you can always resplice the rope on the track but getting underneath to do a pin whilst sitting in a hole dont sound all that attractive to me

Hmmm I know what you are saying, but I would rather a pin shear when I am hanging off a bank....
Don't like the sudden fall to earth, backwards, not a issues just pulling thru bogs.

I have a cunning plan to have a trap door in the floor above the shear point to allow easier access.
Seen all the others having to lay down in the mud.....yum yum....

Keep the comments comming.... Then I can use everyone's real world experiences.

[mudmike]

I use a 4mm cap screw with nylock nut. now I have a tight fit on the shaft don't break many, only done one winching, and that was pulling out a safari well stuck and me tied to 2 other trucks. Had no problems so not going to change in a hurry. used to break a few from impacts on the drive shaft with the factory drive that is a very loose fit on the shaft.
Start small and go bigger if its an issue, be easier to drill out later than start to big.
You still got the other winch to save you if it breaks anyway.
my 2 cents
Mike

[Twodiffs]

Nissan pto's have 2 shear pins...I've got a HT hex key bolt and nyloc nut where the shear pin WAS closest to the gearbox and the standard shear pin closest to the winch.
That way if I do break a pin then it's the one thats easiest to get to.

[coxsy]

oh on your back in the pouring rain semi head down found out didn't have right tools with me highlifted the truck up and pushed it sideway to get it moving again

[Sadam_Husain]

Wont really affect Calvin's setup but the difficulty with the Toyota pto's is there isnt enough meat on the coupling to drill the shear pin size out much more from 4mm without modifying the coupling, theres a huge difference between the Nissan Coupling/Shear pins and the Toyota ones

[yael]

Nissan pto's have 2 shear pins...I've got a HT hex key bolt and nyloc nut where the shear pin WAS closest to the gearbox and the standard shear pin closest to the winch.
That way if I do break a pin then it's the one thats easiest to get to.

Great minds think alike, I did the same on my old MQ 8.8 HT bolt on the PTO drive with a nyloc nut and a Genuine Nissan sheer pin at the winch its self, I gave it alot of abuse and never broke a single Sheer pin.

[jakwoo39]

i had a 6mm HT bolt in mine with a nyloc nut. (still bloody broke on me though). but my shear point is right at the winch so its really easy to change on the go

[lincooln]

forgive me if this seems to be a stupid comment/question

But is tensile strength not the strength of stretching it not shearing? Like a tow-ball, strong when tight but snaps easy if loose? aren't bolts used to hold things in place with friction, they have a low shear value? So a proper shear pin of the same size will be stronger than the HT bolt?

Just getting confused so hopefully someone can clear it up for me?

cheers
Lincoln

[kbushnz]

Shear strength is approx 60% of tensile strenght.
Each metal type, mild, grade 4.6 or 8.8 all have different tensile strengths.
And also shear stregths.
Shear is the load it takes break it sideways rather than pulling it long ways.
The bigger the diameter bolt or grade, the harder it is to shear.

Proper shear pins tend to be soft so they dont damage the holes when they shear and some have rebates cut in them to fail in a particular spot.

Sure others will have some words of wisdom

[lincooln]

sweet cheers dude, that helps to clear things up in my head

[playingInTheDitch]

bit of a side note: has anyone heard of someone putting a pto winch on a terrano?

[mudlva]

bit of a side note: has anyone heard of someone putting a pto winch on a terrano?

ptos can only fit if there is a output on either the gearbox or the transfur box to generate the require power for the winch

at a guess the terrano is missing this important output location

[playingInTheDitch]

thanks thought that might be the case

[JONO250]

have been running 8.8 bolts in a nissan pto, and stripped the gear in my winch before the shear pin broke, would reccomend putting a proper shear pin in.

[Mud Hog]

have been running 8.8 bolts in a nissan pto, and stripped the gear in my winch before the shear pin broke, would reccomend putting a proper shear pin in.

That's why you just have one bolt (rear one hard to accesses in mud, water) and the shear pin in the front shaft. Trail gear do brass gears reasonably priced.

[Sadam_Husain]

have been running 8.8 bolts in a nissan pto, and stripped the gear in my winch before the shear pin broke, would reccomend putting a proper shear pin in.

its all a bit subjective as to how and why it stripped and how hard you may or may not have been winching, I use a 8.8 bolt in my Saf winch on my cruiser but I know when my winch is working hard and loading up and just back off a bit and spend an extra 30 or 60 seconds winching a bit slower and a bit lower geared than bust something and spend all day working out how I'm going to get myself out

[Madaz]

have been running 8.8 bolts in a nissan pto, and stripped the gear in my winch before the shear pin broke, would reccomend putting a proper shear pin in.

its all a bit subjective as to how and why it stripped and how hard you may or may not have been winching, I use a 8.8 bolt in my Saf winch on my cruiser but I know when my winch is working hard and loading up and just back off a bit and spend an extra 30 or 60 seconds winching a bit slower and a bit lower geared than bust something and spend all day working out how I'm going to get myself out

You will never break a shear pin with that rope you use

Or should I say, used to use

[Sadam_Husain]

have been running 8.8 bolts in a nissan pto, and stripped the gear in my winch before the shear pin broke, would reccomend putting a proper shear pin in.

its all a bit subjective as to how and why it stripped and how hard you may or may not have been winching, I use a 8.8 bolt in my Saf winch on my cruiser but I know when my winch is working hard and loading up and just back off a bit and spend an extra 30 or 60 seconds winching a bit slower and a bit lower geared than bust something and spend all day working out how I'm going to get myself out

You will never break a shear pin with that rope you use

Or should I say, used to use

so long as the trees are in the right place and the pricks up the back havent got my 5m tree trunk protector 8m of rope works just fine

[kbushnz]

Finally broke my first pin in my new pto setup. Didnt help chosing the wrong tree and pulling myself into the bank. Live and learn. Good lesson for my winch boy.
Going to move upto 5mm ht bolt. And need to learn when to back off and go slower, apparenty the winch / pto chatters when working too hard.

[coxsy]

have to get my son to knock up two more for me broke two, one driving off with pto still in gear,
other a dumb winch