Tow Ball Wear

[PaulT]

Do tow balls ever wear out? I tow a fairly heavy caravan and also a large plant trailer and am wondering if I should be checking the ball - but what size should it be?

 

[Damian]

Yes, towballs do wear out but if looked after it would take a considerable time to do so.
The standard size is 50mm and the lower wear limit is 49mm.
If towing using a non stabiliser hitch then a grease towball is a must.
If towing with a stabiliser hitch, then a clean towball is a MUST

 

[ProfJohnL]

Just to add to Damian's comment,

European Directive 94/20/EC sets out the standard for the common 50mm tow ball ( see fig 2) it details size and surface finish.

Where a friction stabiliser hitch is to be used, it must not be lubricated in any way. The friction pads are designed to be the sacrificial component and should not cause excess wear on the ball hitch. If you are using an ALKO friction stabiliser it needs a special ball hitch with a longer support other wise it may not safely couple to a standard ball.

 

[Hutch]

Prof the Alko Towball doesn't have a longer neck its a deeper one to allow for the pitching, but we are still going the same way.

 

[ProfJohnL]

Prof the Alko Towball doesn't have a longer neck its a deeper one to allow for the pitching, but we are still going the same way.

My mistake thankyou. The narrower neck makes it look longer, PJL

 

[JTQ]

I had one wear badly oval but over many years hauling trailers; this was pre the friction stabiliser hitches.
What I found out trying to buy a replacement was the first one I purchased was made below the then DIN standard of a 50 mm h13 tolerance sphere! [h13 on 50mm is +0, -0.39].
Armed with a good tool-room micrometer I found most balls at several different retailers also were new below the new condition tolerance and not all spherical, even. The one I got was an original Land Rover item [it was by far the best I found.]

 

[PaulT]

Just to add to Damian's comment,

European Directive 94/20/EC sets out the standard for the common 50mm tow ball ( see fig 2) it details size and surface finish.

Where a friction stabiliser hitch is to be used, it must not be lubricated in any way. The friction pads are designed to be the sacrificial component and should not cause excess wear on the ball hitch. If you are using an ALKO friction stabiliser it needs a special ball hitch with a longer support other wise it may not safely couple to a standard ball.

I always go the grease/no gease proceedure depending which trailer I'm towing. I've noticed on previous postings, various comments about needing a special AlKo tow ball when using an AlKo hitch. I use the standard Volvo detachable tow bar and never had any trouble. Perhaps Volvo make them to suit AlKo tow hitches!

 

[Hutch]

The detachable towball are of the swan neck design so therefore have the clearance for the alko hitches.

 

[WoodlandsCamper]

See pictures here for comparison of ball types.

 

[Woodentop]

Prof the Alko Towball doesn't have a longer neck its a deeper one to allow for the pitching, but we are still going the same way.

Neither of you are answering quite correctly. The Al-Ko ball stands off the mount further - i.e. away from the car backwards - to ensure that the large friction head and cover does not foul the bumper when turning corners (more about turning than pitching.)

 

[JTQ]

Prof the Alko Towball doesn't have a longer neck its a deeper one to allow for the pitching, but we are still going the same way.

Neither of you are answering quite correctly. The Al-Ko ball stands off the mount further - i.e. away from the car backwards - to ensure that the large friction head and cover does not foul the bumper when turning corners (more about turning than pitching.)

That is but one feature where they differ from a "standard" ball.
The neck affords the extra roll clearance the head bulk requires.
In my experience, all the swan-neck type I have encountered have both the horizontal and neck clearances Al-Ko requires.