Thread: 50mm tow balls

After a few incidents with attempting to tow a trailer and finding vehicles with 50mm tow balls Ive been left wondering who actually uses them and who just chucks them away and buys a 1" 7/8.

I know some new caravans require them but aod imagine 99% on New Zealand trailers are 1" 7/8, so why do people not throw them in the trash unless they actually need them?

50mm ball is very common
Higher rating for a start.

There are new duofit couplings out that can fit 50mm and 1 7/8" balls
https://trojan.co.nz/Duofit-Coupling...-9b75491e9f30/
https://trojan.co.nz/COUPLING-V2-250...-f1ff6d501f82/
https://trojan.co.nz/Duofit-Override...-69d7ec1488aa/
https://trojan.co.nz/Duofit-Override...-5d3fb3959927/

trailer, boat, caravan, all of mine use 50mm. I think NZ is the only place that uses 1 7/8

I’ve got an 1 7/8 on the car, and a 50mm in the vehicle toolbox
Got caught once with a hire trailer, bloody annoying.

Most tandem axle trailers with a tractor or a digger in the 1.8T range on board should be using a 50 as they are likely to be over 2.5 tonne which is all the 47.5 (1 7/8) can take. A big double float with two hacks is also on the limit for a 47.5. A loaded treble float should be on a 50. Most caravans are light enough for a 47.5 but more often than not, the tow vehicles only have a 750kg towing capacity...

1 7/8” here, likewise most other vehicles I deal with.

Originally Posted by Frogfeatures

I’ve got an 1 7/8 on the car, and a 50mm in the vehicle toolbox
Got caught once with a hire trailer, bloody annoying.

#me too

I just put a 50 mm on the Ute to fit the bike rack for two EBikes, thought shit I’ll have to change the 1-7/8 on the boat trailer. Just as well I checked, the boat already has a 50 mm on it. I then realised I’ve been towing it on the 1-7/8 ball for the past 20 years without incident!!

Brought a vehicle that had a standard 50mm ball from OZ with me several years back. Had a head scratch with the first trailer we tried hitching. Fortunately, as always, the wife wised up.

Originally Posted by Maca49

I just put a 50 mm on the Ute to fit the bike rack for two EBikes, thought shit I’ll have to change the 1-7/8 on the boat trailer. Just as well I checked, the boat already has a 50 mm on it. I then realised I’ve been towing it on the 1-7/8 ball for the past 20 years without incident!!

Just a balls up...

Just fitted a towbar to a vehicle I am using. Also bought a set of interchangeable balls in 1 7/8 and 50mm. Only takes a minute to flip a catch, rotate the ball 90 deg and remove it.....

Both my balls live under the seat in a container so that they are handy when I need them.........although at my age, thats not very often.....

There's more than one size????

Originally Posted by Allgood

Both my balls live under the seat in a container so that they are handy when I need them.........although at my age, thats not very often.....

I suppose that stops them from getting all sweaty on those long trips

Originally Posted by Allgood

Just fitted a towbar to a vehicle I am using. Also bought a set of interchangeable balls in 1 7/8 and 50mm. Only takes a minute to flip a catch, rotate the ball 90 deg and remove it.....

Both my balls live under the seat in a container so that they are handy when I need them.........although at my age, thats not very often.....

be aware if you leave them on without trailer etc attached..they can bounce off....happened to a work wagon.

Originally Posted by cambo

50mm ball is very common
Higher rating for a start.

1 7/8" & 50mm have the same rating. Its not the ball diameter that determines the rating, its the threaded shank size that does that. 3/4" shank is usually 2000kg and the 3500kg is 7/8" or 1" shank. The 7/8" is usually a heat treated steel to increase tensile strength to handle the load.