Couplemate Trailer Parts
Couplemate Trailer Parts

Galvanised Trailer Parts are being phased out!

Galvanised trailer parts are being phased out by many Chinese manufacturers. The Government has imposed a galvanising tax. Simple as that!

Gone are the hot-dipped galvanising methods that were used in many parts processes.

Hot-dipped galvanising trailer parts whilst still very popular is being replaced by ElectroGal® or a Mechanical Galvanising process.

Technology evolution is paving the way for ElectroGal® process to completely replace hot-dipped galvanising.

Vibration Fatigue is often to blame on hot-dipped galvanising and the stresses that occur in the process. The same vibration fatigue leads to disastrous consequences for boat trailers.

Hot Dipped Galvanising

Let me explain, hot dipped galvanising can be loosely summarised by the following processes.

  • Product cleaned by dipping in an acid bath to remove rust and debris.
  • The basket containing products are then washed to remove the acid.
  • Pickling, rinsing, fluxing solution.
  • A hot tub of galvanised zinc is prepared into which a basket of product is immersed.
  • The parts undergo inspection whilst hot with any slag removed.
  • In some cases, parts are put into a cooling oven to de-embrittle over several hours.

galvanised trailear

Hot-dip galvanization is a form of galvanization. It is the process of coating iron, steel or aluminium with a layer of zinc by immersing the metal in a bath of molten zinc at a temperature of around 860 °F (460 °C).

When exposed to the atmosphere, the pure zinc (Zn) reacts with oxygen (O2) to form zinc oxide (ZnO). As a result, it further reacts with carbon dioxide (CO2) to form zinc carbonate (ZnCO3. The result is a dull grey, fairly strong material that stops further corrosion in many circumstances.

This hot dipped process is cumbersome but the only method of rust proofing that has been available until ElectroGal® arrived.

ElectroGal® Video

ElectroGal® is a mechanical process that bonds a fine coating onto any product. Bonding allows bolt and nut threads to be better coated.

Couplemate uses the ElectroGal® for u-bolts, nylocks and washers.  We found fewer problems with nuts fitting thread using the ElectroGal® process.

Examples of Galvanised trailer parts are

  • Single Axle Trailer.
  • Tandem Trailers.
  • Tie down rails.
  • Galvanised box trailers.
  • Camper Trailer.
  • Tradesman Trailers.
  • Cage Trailers.
  • Tandem box.
  • Flat Top trailers.
  • Hot dipped galvanised trailers

Technical Aspects of ElectroGal®

The next video deal with the technical aspect of ElectroGal® bolts and nuts versus hot dipped galvanised nuts and bolts.

.We have learnt that the hot dipped process adds thicker, uncontrolled coating to thread and the inside of nuts.

The inside of nuts is actually re-machined to remove zinc. This enables the nut to be tightened on the thread without stripping the thread. Nevertheless, no matter how careful operators are, bad threading remains a problem.

Watch the video for other problems.

Caravan and Trailer Problems

The video clearly shows how badly galvanised nut and bolts will not tension correctly.

Image a rough road and vibration fatigue. What is the effect on u-bolts?

  1. Why U-bolts may be the Major Cause of Accidents
  2. Caravanning Problems caused by Stretching U-Bolts

Finally, I hope this series of videos and new technology helps to explain the variety of products available for purchase.

In conclusion, should think about replacing your boat trailer standard and heavy duty ubolts, purchase them here.

galvanised trailer

Couplemate U-Bolts

Round U-Bolts


Square U-Bolts





Part Number
1 ½” (39mm)½” (13mm)4″ (100mm)U39R4GH
1 ½” (39mm)½” (13mm)4½” (112mm)U39R45GH
1 ½” (39mm)½” (13mm)5″ (125mm)U39R5GH
1 ½” (39mm)½” (13mm)5½” (137mm)U39R55GH
1 ¾” (45mm)½” (13mm)4″ (100mm)U45R4GH
1 ¾” (45mm)½” (13mm)4½” (112mm)U45R45GH
1 ¾” (45mm)½” (13mm)5″ (125mm)U45R5GH
1 ¾” (45mm)½” (13mm)5½” (137mm)U45R55GH
1 ¾” (45mm)½” (13mm)6″ (150mm)U45R6GH
1 ¾” (45mm)½” (13mm)6½”(162mm)U45R65GH
2″ (50mm)½” (13mm)4″ (100mm)U50R4GH
2″ (50mm)½” (13mm)4½” (112mm)U50R45GH
2″ (50mm)½” (13mm)5″ (125mm)U50R5GH
2″ (50mm)½” (13mm)5½” (137mm)U50R55GH
2″ (50mm)½” (13mm)6″ (150mm)U50R6GH
2″ (50mm)½” (13mm)6½”(162mm)U50R65GH
2″ (50mm)½” (13mm)7″ (175mm)U50R7GH
2 ⅓” (60mm)½” (13mm)5″ (125mm)U60R5GH
2 ⅓” (60mm)½” (13mm)6″ (150mm)U60R6GH
2 ⅓” (60mm)½” (13mm)7″ (175mm)U60R7GH
2 ½” (65mm)½” (13mm)5″ (125mm)U65R5GH
2 ½” (65mm)½” (13mm)6″ (150mm)U65R6GH
2 ½” (65mm)½” (13mm)7″ (175mm)U65R7GH
1 ½” (40mm)½” (13mm)4″ (100mm)U40S4GH
1 ½” (40mm)½” (13mm)4½” (112mm)U40S45GH
1 ½” (40mm)½” (13mm)5″ (125mm)U40S5GH
1 ½” (40mm)½” (13mm)5½” (137mm)U40S55GH
1 ½” (40mm)½” (13mm)6″ (150mm)U40S6GH
1 ¾” (45mm)½” (13mm)4″ (100mm)U45S4GH
1 ¾” (45mm)½” (13mm)4½” (112mm)U45S45GH
1 ¾” (45mm)½” (13mm)5″ (125mm)U45S5GH
1 ¾” (45mm)½” (13mm)5½” (137mm)U45S55GH
1 ¾” (45mm)½” (13mm)6″ (150mm)U45S6GH
1 ¾” (45mm)½” (13mm)6½”(165mm)U45S65GH
1 ¾” (45mm)½” (13mm)7″ (175mm)U45S7GH
2″ (50mm)½” (13mm)3″ (75mm)U50S3GH
2″ (50mm)½” (13mm)4″ (100mm)U50S4GH
2″ (50mm)½” (13mm)4½” (112mm)U50S45GH
2″ (50mm)½” (13mm)5″ (125mm)U50S5GH
2″ (50mm)½” (13mm)5½” (137mm)U50S55GH
2″ (50mm)½” (13mm)6″ (150mm)U50S6GH
2″ (50mm)½” (13mm)6½”(165mm)U50S65GH
2″ (50mm)½” (13mm)7″ (175mm)U50S7GH
2″ (50mm)½” (13mm)8″ (200mm)U50S8GH
2″ (50mm)½” (13mm)10″ (250mm)U50S10GH
2 ¼” (56mm)½” (13mm)4½” (112mm)U56S45GH
2 ¼” (56mm)½” (13mm)5″ (125mm)U56S5GH
2 ¼” (56mm)½” (13mm)5½” (137mm)U56S55GH
2 ¼” (56mm)½” (13mm)6½”(165mm)U56S65GH
3″ (75mm)½” (13mm)3″ (75mm)U75S75GH
3″ (75mm)½” (13mm)4″ (100mm)U75S100GH
3″ (75mm)½” (13mm)5″ (125mm)U75S125GH
3″ (75mm)½” (13mm)6″ (150mm)U75S150GH
3″ (75mm)½” (13mm)7″ (175mm)U75S175GH
3 ¼” (82mm)½” (13mm)4 ¾” (120mm)U80S120GH
4″ (100mm)½” (13mm)3″ (75mm)U100S75GH
4″ (100mm)½” (13mm)4″ (100mm)U100S100GH
4″ (100mm)½” (13mm)5″ (125mm)U100S125GH
4″ (100mm)½” (13mm)8″ (200mm)U100S200GH
1 ¾” (45mm)⅝” (16mm)6″ (150mm)CM600GH
2″ (50mm)⅝” (16mm)6″ (150mm)CM602GH
2 ⅓” (60mm)⅝” (16mm)7″ (175mm)CM604GH
1 ¾” (45mm)⅝” (16mm)6″ (150mm)CM601GH
2″ (50mm)⅝” (16mm)7″ (175mm)CM603-7GH
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