40mm Square Axles to suit Standard Bearings
40mm square axle suits wider small box trailers and boat trailers up to 1000kg.
Axles are measured from the tip of the axle to the tip of the axle. When measuring from the face of the axle, add 100mm to this measurement to get the tip of thread to tip of the thread length.
Standard Bearing Sizes are;
- Inner ID 31.75mm, OD 59.10mm
- Outer ID 19.05mm, OD 45.20mm
- Seal ID 37.5mm, OD 59.10mm
- Dust Cap 45.20mm
Couplemate manufactures 40mm square trailer axles in Wynnum, Queensland. BlueScope or One Steel provides the best axle money can buy. If you can find a better product, please tell me. For more information about why we use quality steel check out my article; Axle Steel for Caravan and Trailer Axles.
Your 40mm square axle may be perfect for your trailer, caravan or camper. If you are towing your rig straight and true, perfect. If not then below are a few tips.
- Too much weight will bend this 39mm Round Axle causing axle flex.
- Axle flex is caused by an overloaded axle. You can read about axle flex and vibration here.
- Axle flex occurs when heavily loaded trailer springs rebound on the highway causing the axle to flex up and down in the middle of the axle.
- Springs to fatigue – fail prematurely under axle flex loading conditions.
- If your load is over 1000kg, you will start to experience axle flex.
- If your axle is 40mm Square and bending, buy a 45mm square axle and update to 1.5t.
- It is not expensive in comparison to replacing springs that have suffered fatigue.
- Rough seal journals can cause a loss of grease through the rear seal.
- Are your tandem tyres wearing unevenly? Here is a link that provides an easy method to test your axles.
- Some suppliers supply non-virgin steel or scrap steel and forge this steel into solid square or round shape for axle production.
- Chinese bearings are the second biggest cause of axle failure. If you plan driving on the highway, use Japanese bearings. The combination of Japanese Bearings and 39mm round Axle will help you significantly with lower maintenance for your rig.
Finally, after having read the above information on axles, I invite you to comment in the review box below. We never get too old to learn.