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n2916s · 12-17-2008, 08:39 PM

Was cleaning up the hitch ball today to regrease and noticed some minor spalling. So, I figured I'd run right out and buy a new hitch ball. Then noticed that the existing hitch ball is marked for 6000#. This is not swell as my Sovereign is rated 8600# max (although I've never had it near that).

Anyway, get to the store and discover the 10000 pound hitch balls have a shaft diameter greater than the hole in the hitch body.

So, is there a source for some depleted uranium/tungsten/titanium 10000 hitch ball that will fit or should I take the whole thing to a machine shop and get the hole bored out??

Thanks,

mike

Inland RV Center, In · 12-17-2008, 08:44 PM

Quote:

Originally Posted by n2916s

Was cleaning up the hitch ball today to regrease and noticed some minor spalling. So, I figured I'd run right out and buy a new hitch ball. Then noticed that the existing hitch ball is marked for 6000#. This is not swell as my Sovereign is rated 8600# max (although I've never had it near that).

Anyway, get to the store and discover the 10000 pound hitch balls have a shaft diameter greater than the hole in the hitch body.

So, is there a source for some depleted uranium/tungsten/titanium 10000 hitch ball that will fit or should I take the whole thing to a machine shop and get the hole bored out??

Thanks,

mike

Enlarge the hole.

Andy

CanoeStream · 12-17-2008, 09:07 PM

Quote:

Originally Posted by Inland RV Center, In

Enlarge the hole.

Might that lessen the hitch bar rating? I don't know at all (danger of sticking my foot in it), but were 10,000# ball shanks even available back in the day of some older WD setups?

I just checked an old V5 Shelton hitch bar in my garage (year unknown). It has the larger diameter ball shank.

Anybody know how this evolved and when?

Inland RV Center, In · 12-17-2008, 09:40 PM

Reese ball mounts for over 30 years, all had 1 1/4 inch holes for the ball.

They also provided tight fitting shims, for smaller sized balls.

Andy

**Action** · 12-18-2008, 07:30 AM

I have a two man dril the has an RPM of about 3 and a drill bit that is sized for that shank. I have drilled out two holes on two different hiyches. Let me yell you when it gets to the bottom and the bit catches, it takes everything thing we have to hang on. However when it is done you will feel better about the added capacity.

Goood luck.

>>>>>>>>>>>>>>Action

markdoane · 12-18-2008, 07:43 AM

I'd be reluctant to drill out a hitch head for a larger 1.25" ball shank.

If the hitch head has a 1" hole in it, it was designed around a 6000# hitch ball. How would you know if the rest of the assembly is able to handle the higher stress of a 10,000# load?

On the other hand, if it was designed for a 10,000# load, I wouldn't hesitate to use a lower rated 1" hitch ball with a bushing, like Andy says above.

purman · 12-18-2008, 07:48 AM

The largest 2" ball you can get is a 7500# If it is a 2 5/8 I would get a new hitch that will take the larger diameter shank. Drilling is a option but thats some tough work. Cutting torch would work, But would destroy the metal strength.

**Action** · 12-18-2008, 08:54 AM

My hitch is stamped with the rating and class.

If one uses a 10,000 rated ball on a 6,000 load is there an issue?

The hole that the shank goes into, needs to be a precise fit. Not sure a torch would offer that kind of fit.

>>>>>>>>>>>>>Action

markdoane · 12-18-2008, 09:14 AM

I don't think there is any problem using a 10,000# rated ball for a 6000# load. I think the issue is if you have a 6000# rated ball pulling a 7800# load.

. . . and if you need to drill out a 6000# rated hitchhead to handle a 10,000# ball, I don't think you are automatically uprating the whole hitch assembly to 10,000#.

Bob Thompson · 12-18-2008, 09:42 AM

This topic made me curious so I started checking to see if 2-5/16" balls with 1" shank rated for 10,000 lbs even exist. Sure enough, the first website I went to had one. See: TRAILER HITCH BALLS- 2 5/16" - KMT Trailer Parts

The Stainless Steel appeals to me. See also: http://www.amazon.com/Brinks-3005-04.../dp/B000LS5TQQ

And there must be many more. With hardened steel, it should be possible to make a 1" shank with much more strength than the 10,000 pound rated being sought here!

n2916s · 12-18-2008, 08:09 PM

Thanks Bob - I don't know how I missed those sites... Now all I have is a simple switch out.

Also thanks to all else who helped. This forum is golden!

mike

**Action** · 12-19-2008, 07:37 AM

Markdoane

I believe the man has a possible 8600# load with a 6000# rated ball. Getting a 10,000# ball with a 1" shank is a fix. The next move would be a 10,000# rated ball with a 1.25" shank. All of these balls would be a 2 5/16 dial.

I would hope the hitch and hitch head have a rating to take the existing load since he has been towing it with the underated ball. The ball alone does not make the tow rating. And that was not what I was inferring by going to a larger rated ball in my first post. However I personally feel better when the proper equipment for the job is being used in my tow set up rather than underated components.

>>>>>>>>>>>Action

markdoane · 12-19-2008, 10:14 AM

I agree.

I think it's a weakness in the tow hitch rating system that the hitch receiver has a rating, the ball has a rating, the coupler has a rating, but the only component that doesn't have a stamped rating is the drawbar and ballmount.

Without any way to know the drawbar rating, I would use the diameter of the ball shank opening as a guide. Generally and historically, Class III have 1" holes and and Class IV hitches have 1.25" holes.

I'm not writing a rule here, just stating my personal opinion. We don't even know what kind of drawbar Mike is using, or even if it is a WD hitch.

Bob Thompson · 12-19-2008, 11:15 AM

I think in this instance, the ball is the least likely item of the hitch system to fail! The math suggests the ball is much stronger than the rating and much stronger than is needed. A 1" shank has a cross sectional area of .785 sq. inches. Most common structural steel has a modulus of elasticity of 36ksi or 36,000 pounds per square inch, therefore:
.785 x 36,000= 28,260 pounds or 2.8 times the rating for a 10,000 lb. rated ball with a 1" shank. Keep in mind, this is with basic common structural steel.

As I mentioned in a earlier post, if it is high strength steel which has a modulus of elasticity of at least 50,000 lbs./ sq. inch, then the ball would be at least 3.92 times the strength of it's rated capacity.

This knowledge does raise the question, how often do hitches fail? And, when they do fail, what item in the assembly is the usual cause for the failure? I'll go out on a limb and bet the receiver hitch mounted to the truck is usually the weakest link! I say this because it seems the vertical end plates which extend upwards to attach to the truck frame lack enough stiffening due to the need to provide space for the spare tire. In other words, the end plates could have excessive flex which would eventually lead to failure of the attaching welds and then the hitch itself.

markdoane · 12-19-2008, 11:27 AM

Quote:

Originally Posted by Bob Thompson

I think in this instance, the ball is the least likely item of the hitch system to fail! The math suggests the ball is much stronger than the rating and much stronger than is needed. A 1" shank has a cross sectional area of .785 sq. inches. Most common structural steel has a modulus of elasticity of 36ksi or 36,000 pounds per square inch, therefore:
.785 x 36,000= 28,260 pounds or 2.8 times the rating for a 10,000 lb. rated ball with a 1" shank. Keep in mind, this is with basic common structural steel. . . (snip)

Except in this instance, Bob, it would fail the SAE standard, which requires 3X the rating, or 30,000lbs.

And it still doesn't answer my question: what is the rating of the ballmount it's attached to?

Bob Thompson · 12-19-2008, 11:37 AM

Now you have me curious again. Where can I find this 3X SAE standard so I can read more! Most structural steel has a safety factor of between 1.4 and 1.7 depending on where it is used in an assembly.

Aside from that, 50 ksi (high strength structural) steel would easily meet any 3X SAE standard with a strength of 39,250 pounds or a 3.9 safety factory. Grade 8 steel would have a modulus of elasticity of between 120,000 and 150,000 pounds per square inch or in this case, a safety factor of at least 9.4 . You get the idea.

markdoane · 12-19-2008, 11:45 AM

Bob,

I agree you can find hitch balls with 1" shanks that meet the SAE standards. Whether they are high strength steel or forged, I don't know. Iknow they're out there.

But it does explain why the standard, made out of 36k steel, hitch balls that you find in the bargain bin at Menards are only rated for 6000#.

It also backs up my reasoning for having a rating on the hitch head or drawbar. If you can put a 10,000# rated ball with a 1" shank on a cheap Class III drawbar, doesn't mean the whole shebang is now worth 10,000#.

markdoane · 12-19-2008, 11:47 AM

. . . and the SAE standard is J684, section 6.5.2, and table 2.

Bob Thompson · 12-19-2008, 05:48 PM

Yep, there it is, SAE Standard J684 for Trailer Hitches, Couplings, and Safety chains, In Table 2 under Class 4 hitches (and only under Class 4 hitches) it does have a requirement that hitch balls be able to withstand horizontal thrusts equal to the weight of the trailer x 3. For us, that would mean the rating of the hitch assembly. For Class 4 hitches, common 36ksi steel won't work for balls with a 1" shank but high strength 50 ksi steel will.