Single vs double sheer

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kgrabber

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So I've been reading a lot of suspension threads and see a lot of concern about running double shear. I understand double shear is stronger but, My question is why does everyone want everything built double shear? Is single shear that week? And how are front shackle perches single shear in the batwings. I'm looking at running single shear 1/2" rod ends on hairpins. is this strong enough for a Chevy tudor Coach with low HP V8?
 
A pin or bolt held in double shear can transfer twice the force as the same pin or bolt held in single shear. (It's really that simple.)

A clevis attached to a single batwing is double shear... at least at the clevis... unless I misunderstood the question.

Heim ends should be held in double shear, wherever possible. I would think 1/2'' ends way too small, especially in single shear...

.
 
Single shear also has the problem of bending.

The way I see it, unless there is reason to go single shear like part removal or confined space, go double and be done with it. If you're already fabricating, how much more work is it?
 
Tie rod ends are typically in single shear. The taperd end usually is 1/2" on the end and about 5/8" at the joint end. The threaded shank is usually 5/8" or 11/16". That should give you some guideline for sizing for single shear.
 
Whether you single shear or double shear depends on the amount of side load applied to the part in question.
Shackles mounted to batwings, have as much side load as they do push and pull load and have little chance of bending the bolt connecting them. The weight it carries is also not as much as you'd think. This may be one of those areas where double shear is near impossible.
Rear end mounts have a lot of shear applied while under throttle and braking so double shear is preferred.
Shocks have very little load so single shear is adequate.
Coil over shocks carry the load of the vehicle and should be double shear.
It really depends on the application as to whether single or double shear is used.
 
Thank you all for the Insight I know double shear is best I'm just having a hard time making everything fit between the frame and steering arm swing, and still have room for suspension travel laterally. I will now stop procrastinating and rebuild the needed brackets.
 
Here's a little teaser but it's been a slow build. I will start a build thread when I get back to working on it.
 

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The way people talk about it you'd think anything mounted single shear, or any fixing using less than grade 8 bolts etc, are going to fail just rolling your car out of the garage.

I was once lectured about the dangers of welding together two piece of steel that are different thickness's, due to stress risers, localised cracking etc etc. Guy told me I HAD to use exactly the same gauge steel to patch a hole in a chassis rail or it would fail and kill me, basically.... :rolleyes:

The principal is correct, but the practical effects in the real world are totally ridiculous! Unless it is an F1 car.

If I think my car might needs a grade 8 bolt to survive in some fitting, I make the bolt 50% bigger! Doesn't really matter what grade it is then.

If I think 1/8" steel bracket may be marginal, I'll use 1/4".
 
King Herald said:
The way people talk about it you'd think anything mounted single shear, or any fixing using less than grade 8 bolts etc, are going to fail just rolling your car out of the garage.

I was once lectured about the dangers of welding together two piece of steel that are different thickness's, due to stress risers, localized cracking etc etc. Guy told me I HAD to use exactly the same gauge steel to patch a hole in a chassis rail or it would fail and kill me, basically.... :rolleyes:

The principal is correct, but the practical effects in the real world are totally ridiculous! Unless it is an F1 car.

If I think my car might needs a grade 8 bolt to survive in some fitting, I make the bolt 50% bigger! Doesn't really matter what grade it is then.

If I think 1/8" steel bracket may be marginal, I'll use 1/4".
Click to expand...
[cl
I use grade 8 bolts in everything, for the simple reason that I buy them by the pound.
I don't have anyone mixing them up with the different grades either;)
Grade 2 $1.99 lb.
Grade 5 $2.99 lb.
Grade 8 $3.99 lb.
When building a hot rod the difference in total cost is minimal :)
Besides they look cool in the bolt bins :cool: [ddd
 
http://www.speedwaymotors.com/Coil-Over-Shock-Mount-Support,3332.html
Here's a single shear rear coil over mount that Speedway Motors sells. Not the preferred method but I suspect hundreds, if not thousands of hot rods have the the rear end hung this way.
My Renault has the rear faux coil overs mounted in single shear with 1/2" bolts. I'm hoping the car is light enough that this arrangement is satisfactory.
(You have to click the Speedway link above then open the lower middle picture on left to see how the mount is installed).
 
Old Iron said:
[cl
I use grade 8 bolts in everything, for the simple reason that I buy them by the pound.
I don't have anyone mixing them up with the different grades either;)
Grade 2 $1.99 lb.
Grade 5 $2.99 lb.
Grade 8 $3.99 lb.
When building a hot rod the difference in total cost is minimal :)
Besides they look cool in the bolt bins :cool: [ddd
Click to expand...

...care to divulge the name of the source?
 
I'm not sure about the exact prices but I buy bolts of all kinds from Tractor Supply by the pound too. Beats the heck out of paying top money for single pieces. Usually I'll count out what i need for projects then just top off a bag of same style pieces to round out to pounds, then I always have spares in the shop.
 

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