How to Determine Compatible Replacement Trailer Hubs

Question:

I have a 50 year old trailer that I use to haul fire wood. It has a 4 bolt hole hub, 8 inch wheel and I want to increase the hauling capacity. maybe changing the hub, and wheels. Would a 5 bolt hub, most likely fit the same spindle?

asked by: Larry S

Expert Reply:

A trailer's weight carrying capacity is a function of all the parts used to construct it. These include the trailer's frame, axle, suspension, hubs, wheels and tires. Each of these individual components will have its own weight rating. A trailer's weight capacity rating will generally be that of the lowest-rated component part used to construct it, that of the weakest link in the chain, so to speak.

Trailers usually have a sticker or plate that indicates the trailer's weight capacity (the same sticker that has the trailer VIN). Axles too usually have a label of some type that tells you the amount of weight the individual axle can handle. Hubs too are rated to match an axle's capacity. And trailer wheels and trailer tires are likewise rated for weight handling.

IF your "weakest link" were indeed your hubs you could replace them with higher-rated ones so long as you can find new hubs that use the very same set of bearings as the original hubs. This is the one way you can ensure that a new hub will fit on your spindles. Both the inner and outer bearing part numbers must match between the two hubs.

Please refer to the linked photo that shows the usual appearance and location of bearing numbers. If you can obtain your inner and outer bearing numbers you can search our site for hubs with your preferred wheel bolt pattern using the hub page I linked for you.

First, click on your axle weight rating. Then click on your hub style (hub only, hub with drum or hub with rotor - for disc brakes). Then select the bolt pattern you want and your wheel size. You can then check for a hub that uses the same bearings as your existing one.

If part numbers are not available on your bearings you can measure the spindle and hubs using a precision caliper. You need to take measurements to the nearest thousandth, such as 1.234-inches. These dimensions can be used to identify a compatible bearing and therefore allow you to find a compatible hub.

Do note that a trailer that is a half-century old may pose a challenge for finding compatible hubs. In the event that no hubs are available we can still help you with a complete axle/hub kit. The linked page for axles will allow you to review these kits which are offered with and without brakes.

expert reply by: Adam R