50mm x 3.5t High Shoulder Towball

$69.95 inc GST

SKU: CM290-HT25-62mm Category:


50mm High Shoulder Towball

50mm high shoulder tow balls suit Al-ko, Ark and Hyland Hitch off-road couplings.

Additionally, the tow ball has high corrosive characteristics similar to hot-dip galvanising.

Super zinc ™ is a triple-layered deposit and is the same colour as conventional blue zinc. SA-5 ™ zinc plating is a deeper coloured iridescent green and gold than conventional gold zinc. Both of these specialized deposits provide outstanding corrosion protection, far superior to conventional zinc.

Many balls on the market are manufactured in China or internationally, and it is unusual to find Australian made goods.

Couplemate is proud to manufacture this product in-house for you, adding to the number of products in our Australian Made range.Australian Made

Importantly, our tow balls are tested, whereas there is no procedure for testing imported tow balls.

In our opinion, the Couplemate high tensile tow balls are the best on the market and an excellent investment

What specifications are available?

  • 25mm Shoulder.
  • 62mm Thread length.
  • 22mm diameter UNF thread to suit most tow bars.
  • 4140 High tensile steel

The high shoulder allows great articulation of off-road couplings over standard equipment.

Standard tow balls can touch and put a lot of force on the edge of the receiver bar and may cause coupling, tow ball and chassis damage.

Why it is necessary to test tow balls

Couplemate tow balls have been tested to comply with AS4771.2 where balls are examined to 85kN and held at 85kN for not less than 10 sec. Watch this interesting video. Watch the computer monitor in the background.

What is 85kN?

85kN is the force applied to the ball during testing (85kN = 8.667 tonne).

Therefore, 3.5t tow balls must be tested to satisfy the Australian Standard and to a min standard of (8667.59kg).


tow ball in Manufacture

Couplemate Towballs in Manufacture

High Tensile 25mm High Shoulder Tow Ball

Couplemate manufacture 3500kg extended shoulder tow balls in Australia. Thank you for your support.

A standard shank tow ball shoulder is approximately 12.5mm. This size shank fits all highway couplings except some off-road couplings.

Offroad couplings can foul the tow bar tongue when towing through gullies or river beds on an angle.

Couplemate developed a high tensile tow ball to allow the full rating of 3500kg. A much higher rating is achievable due to the grade of high tensile used.

Galvanising and Plating

Galvanising and plating is a big issue when talking about “but will it be strong enough?”

There has been a fair amount of research on galvanising and spring weakness due to the galvanising process.

Will galvanising or plating affect my product strength?

Yes, strength tests can reduce the product rating by up to 0.4%, however, the tolerance we would take notice of is 1%. In effect, there is no negligible effect on product load rating. Click this link to read our article on galvanising.

How can I be sure my ball rating will not be affected by galvanising?

A good question deserves the right answer.

After plating, Couplemate tests tow balls to AS 4177.2—2004.

Also required as part of testing is a certificate that the coupling balls have undergone a de-embrittlement process.

American Tow Balls

Couplemate manufacturers American tow balls (2″ and 2 5/16″) and rates them to 3.5t.

Tow Ball Scales

Coupling weight is critical to ensure your rig running true and braking correctly. Too much ball weight overload your tow vehicle and make it overrun its braking ability.

Tow weight ball scales help identify how much weight you should move back onto your trailer axles thereby lightening the load on your tow bar.

The correct weight and a level chassis play a huge role in effective and efficient towing.

Couplemate Tow Ball Weight Scale

Couplemate guarantees tow balls for life against faulty manufacture. If your Couplemate high tensile tow ball fails you for any reason, we will replace it.

Couplemate Trailer Parts sells only the best quality 50mm x 3.5t High Shoulder Towball and caravan spare parts throughout Australia.

Customers are welcome to either pickup or take advantage of our low freight rates. Express shipping to Melbourne, Sydney, Brisbane, Perth, Adelaide, Darwin, and Hobart.

We also ship products to New Zealand via Australia Post Air Express.

© Steve Wotherspoon June 10, 2014. Images and text may be copied, provided a link back to the copied page and the source is displayed where the content or image is located.

Additional information

Weight 2 kg
Dimensions 10 × 5 × 5 cm


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