Q & A Icon

How To Determine the Weight Capacity For a Trailer Axle


How can I determine the weight rating for the axle on my heavy duty in appearance utility trailer?


Expert Reply:

The trailer will have a plate or sticker on it that will list the VIN number. The weight rating of the axle should be listed on that same plate or sticker. Also, the axle could have a tag or plate on it that will list the weight capacity.

You can also tell the weight capacity of the axle by measuring the diameter of the axle. Here is a list that will show the axle weight capacity based on the axle diameter:

Typical Axle Diameters Based on Axle Capacity
- 1,000-lb - 2,000-lb Axles: 1-1/2 inch - 1-3/4 inch diameter
- 3,500-lb Axles: 2-3/8 inch diameter
- 6,000-lb - 7,200-lb Axles: 3 inch diameter
- 8,000-lb Axles: 3-1/2 inch diameter
- 9,000-lb Axles: 4 inch diameter
- 10,000-lb Or more axles: 5 inch diameter

Those suggestions would be the easiest way to find the weight capacity on your trailer axle. If you cannot determine the weight capacity using the above suggestions the next step would be to measure bolt pattern on the hub, size of brakes, and bearing part numbers. With this information we could narrow it down to what size axle you have on your trailer.

I am sending a link to a FAQ page that has information on trailer suspensions.

expert reply by:
Jeff D

Product Page this Question was Asked From

Follow up Questions


I am looking for replacement axle bearings for a 2011 rockwood roo 19 foot. i measured the spindles: inner bearing Spindle diameter: 1.4170 inch outer bearing spindle diameter: 1.0625 what is the bearing kit to buy and what is the weight rating of the axle. its a torsion axle. thank you

Etrailer Expert
Reply from Chris R.

The outer bearing measurement you took on the spindle matches up to the L44649 bearing, but we don't quite have a match for that inner bearing dimension. I recommend verifying that measurement - if you get something closer to 1.378", then you have the very common 3,500 pound axle setup. For a replacement bearing kit part # BK2-100 will work perfectly.

Rick S.

Hello I purchased a trailer that does not have a tag on it to identify the capacity. The axle is 1.75" square tubing and the bearing shaft is 1.0" diameter. Your thoughts on the capacity?

Etrailer Expert
Reply from Chris R.

I really wish I could offer some insight here but it's really hard to even guess at a capacity based on those dimensions. Is there any way to get in touch with the trailer manufacturer or seller?


Bought used trailer. No stickers or plate with info. 6 x 12 utility trailer, double axels 3” diameter. Breaks on one axel. By your estimated load rating of 6k to 7200#. Is that total or per axel? Thanks

Etrailer Expert
Reply from Chris R.

A 3" diameter axle typically has a higher 6,000 pound to 7,200 pound rating - this would be PER axle, so a total capacity of of 12K to 14.4K on your trailer. I worry about making this assumption though as going just by axle diameter isn't always 100 percent accurate. Does the seller have any information with regards to its capacity or is there any info listed in the paperwork?

Reply from George

@ChrisR No info was available. A, what you see is what you get deal. There is a number on the frame. Has stout tires; 800 x 14.5

Etrailer Expert
Reply from Chris R.

@George I gotcha. I wish I could offer some clearer insight here. What are you planning on using the trailer for? Do you think you'd even be coming close to that estimated capacity?


How about rectangle shaped axles? Any measurements/ratings for those?

Etrailer Expert
Reply from Chris R.

Square/rectangle axles are harder to distinguish in terms of weight capacity. Your best option will be to simply look for the main axle tag that actually lists this information. If possible, you can also contact the trailer manufacturer with the VIN and they should be able to help you out.

Kevin O.

My question is Im looking to buy ce smith trailer hub kit , i have a 2006 tracker trail star trailer for my tracker boat which is a pt 175 Im trying to figure out which axle load to get? Any recommendations?

Etrailer Expert
Reply from Chris R.

The axle capacity should hopefully be listed with a tag/sticker on the axle itself. Along with the proper rating, it's also important to check the inner and outer bearing numbers used on your existing hub to ensure the replacement will fit. The numbers will be printed inside the bearings themselves. If you can tell me these numbers I can definitely recommend the correct replacement assembly.

Reply from Rick K.

@ChrisR I been given an old boat trailer which has old 5 star looking hub/wheel assemble and looking to switch to the newer trailer hub style tires. Just wondering what hub assembly I would need. Axle is 3" Seal Diam - 1.93" Inner Bearing - 1.38" Outer Bearing - 1.25" Old inner bearing # L68149 I cannot find the outer smaller bearing # Seal# 19219 Length from shoulder of seal to beginning of threads 3" I have pictures if needed

Etrailer Expert
Reply from Jon G.

@RickK Are you talking about a design like the part # 8-174-5UC3 ? We have the hub and drum # 8-407-5UC3-EZ which has matching bearing measurements to what you mentioned but the seal doesn't match and we don't have one that does. The other thing is that this has a 6 on 5-1/2" bolt pattern as opposed to a 5 bolt pattern. If your boat trailer is old enough you might need to swap out your axle(s) so that you can use hub and drums that are current.

Q & A Icon

Similar Expert Q&A Pages

See More Q&A Expert Answers >>