towball life span

[runnerphil]

Hi all,

How long should a tow ball last? I have been using the same one for the last 9 years. It's not looking worn, but what is the life span for a towball?

Cheers.

 

[RogerL]

Before hitch-type stabilisers were used, I'd have said almost indefinitely if properly greased. The wear/friction occurs during turns and over undulations which are of small angle and little force. Acceleration and braking are forces on the towball, not movement.

However hitch-type stabilisers do cause wear because of the lack of lubrication as well as the high frictional forces of the pads. An annual inspection is obviously desirable and replacement if any significant wear is noted.

 

[JTQ]

I have not the wear details to hand but a Land Rover towball I purchased with the vehicle in 1988 was found to be worn well below the specified tolerance, by I recall about 2000/2001. I have to admit I towed a great mileage; more than 50% of the usage of the two Defenders it was fitted on, so probably more than 50k miles. This was without a ball hitch friction stabiliser, and using Moly Disulfide grease. Wear was very localised and was realised when the trailer I was towing unexpectedly became detached on a bumpy gravel track. I measured the wear with a micrometer and it was very significant, as I said I have not the actual wear info to hand. I also found that many towballs offered for sale were at the minimum tolerance.

 

[Lutz]

The wear must be really significant for the towball to be out of tolerance (unless it was close to bottom tolerance already when bought). Unless I'm mistaken (I'm not at home at the moment, so I can't check) the tolerance on the diameter of a 50mm towball is -0.64mm, which is quite a lot.

 

[JTQ]

From what I can access at the moment the Ball tolerance is 50.0 +0 -.39mm ALKO Document via

http://www.nationalcaravan.co.uk/images/resources/alko_towball_guide_final_rev1.pdf
This is just 15 thous of an inch diametrically or opposing wear patches of 7.5 thou. And that was what happened it wore egg shape.

 

[Lutz]

Sounds about right, yes. What I probably had in mind was a minimum diameter of 49.64 not a tolerance of -0.64. That would just about stack up with the tolerance of -0.39 that you found on the AlKo technical information sheet (won't argue about the difference of 0.03).

 

[gary]

I've just measured an old ball at 49.74mm which is the same all the way round, it's lost the zinc coating but other than that I would say it's therefore unworn.

I also measured a 10 year old Alko hitch and it's closed and locked maximum clearance is a shade under 42mm, this would suggest to me that a ball would not need measuring to see it was worn so much it would come off!!

Put another way, I towed 1000's of miles with a 2" hitch on a 50mm ball a difference of nigh on 2mm, bit noisy sometimes but never came off.

 

[ProfJohnL]

I think it is near on impossible to a life span in years on a tow ball, it depends on the quality of the surface whether or how much its hardened, and of course how much wear it has suffered.

The important feature is it wear pattern and that can only be checked with a caliper of micrometer.

 

[ProfJohnL]

In addition to my note above, wear usually occures of both surfaces that rub together, so if you have substantial wear on teh ball, then you shoudl also consider teh possibility of wear inside the hitch, Sadly the hitch surface being out of sight can sometimes mean out of mind.

 

[Lutz]

Unless subjected to abuse such as frequent towing with substantial amounts of grit embedded in a greased towball, both the towball and the coupling should last the life of the vehicle and caravan.

 

[nick_374224697]

Guys, come on...it's Christmas, surely there's more to life??? Why not shell our a tenner every three years or so and save yourselves the heartache of micromeasuring your towballs??

Not meant as a nasty but more a slightly less serious look at our great hobby.Merry Christmas all..

 

[Lutz]

Replacing the towball every three years or so is really going over the top a bit, even if they aren't that expensive.

 

[gavin_5121842]

Guys, come on...it's Christmas, surely there's more to life??? Why not shell our a tenner every three years or so and save yourselves the heartache of micromeasuring your towballs??

Not meant as a nasty but more a slightly less serious look at our great hobby.Merry Christmas all..

I've never measured any of my balls!

 

[VIP2006]

Replacing the towball every three years or so is really going over the top a bit, even if they aren't that expensive.

Having printed off the AL-KO Guide to towballs which states that the diameter of the ball must be 50mm (+0/- 0.39mm) and meet EEC Directive 94/20 (Din47058) and a detachable tow ball for my car is around

 

[Surfer]

As a matter of interest, could a tow ball or even a tow bar suffer from metal fatigue?

 

[Lutz]

Replacing the towball every three years or so is really going over the top a bit, even if they aren't that expensive.

Your thoroughness is to be commended, Shiraz, but I doubt whether you will find any measurable wear of the towball even after several seasons unless you get grit into it.

 

[Lutz]

Theoretically, yes, although I have never heard of such a case as the EU Directive which all towbars have to fulfil, specifies relatively stringent minimum durability requirements.

I do know of cases, however, where vehicle underbody structures have failed in the area where the towbar is bolted and this is not covered by EU requirements.

 

[hgv dave]

i must agree with nick and im not sure but i dont think that they cost a tenner...the only advice i can give is if in doubt change it.....it will give you peace of mind and wont cost that much

 

[Lutz]

If you have a detachable towbar with a specific towball to suit the respective socket, you probably wouldn't think of replacing that during the life of the car. It therefore seems a bit illogical to replace a bolt-on towball just because they are relatively inexpensive. After all, both types of towball are probably made of the same steel and should wear equally well.

 

[Terry_5112949]

A standard 50mm tow ball in the 2006 Towsure catalogue is

 

[Lutz]

Fair enough, but a replacement for a detachable towball will probably cost 10 times that much so one would think twice about replacing that unless it is seriously damaged. If this applies to detachable ones, it also applies to bolt-on ones.

 

[Lutz]

Fair enough, but a replacement for a detachable towball will probably cost 10 times that much so one would think twice about replacing that unless it is seriously damaged. If this applies to detachable ones, it also applies to bolt-on ones.

Besides, some towbars have fixed, i.e. welded, towballs that you can only replace as a complete unit.

Having to change the towball is even less likely than having to replace a brake drum or disc and they also have steel surfaces subject to wear.

 

[bertie1]

My car is fitted with a Brink towbar, with detachable towball. According to the ad in the C.C.mag., and I quote: "That's the unique, lifetime warranty we provide for our entire range of fixed and detachable towbars.

As I am not aware of "detachable towbars", can I assume they mean "detachable towball". In this case, they obviously would not expect any significant wear on the tow ball due to stabiliser friction pads, or the warranty could be an expensive one.

One thing that does intrigue me is that they say not to lubricate the socket into which the towballis located, but to remove any rust with a fine emerycloth.

Now, to my mind rust is oxidised steel, which is material removed. So I grease this location point, and wipe off the grease prior to fitting the towball.

Obviously, I never grease the towball itself. When not in use, it is stored off the car, and the ball end is wrapped in clingfilm to prevent rust.