Can I Put Larger Wheels and Tires On My Harbor Freight Trailer By Replacing the Hubs?

Question:

Hello, I know youve had a lot of questions about these trailers. I would like to put new hubs on this trailer that would allow me to run larger wheels/tires for interstate driving. The original wheels are 12inch and on a recent trip a bearing got dry. The trailer has less than 1000 miles on it. I think the 14 or 15inch wheel would help with this. I know the stems are 1, can you give your thoughts on this?

asked by: John M

Helpful Expert Reply:

I don't think that your wheel size (or lack thereof) has anything to do with the bearings on your HF trailer drying out as much as it is likely that the seal blew out from overfilling the grease or poor installation. This isn't uncommon when dealing with "bargain" brands and upgrading components is a good way to get a more reliable trailer. You could replace the hubs on the trailer with hubs that are able to handle a larger wheel/tire combo- but you may run into trouble with clearance to the frame and fenders and larger wheels, so that should be considered when deciding on how big to go (more on that at the bottom).

I would actually recommend replacing the entire axle and hubs with a better axle like the Dexter Trailer Axle with Idler Hub # 20545I-ST-60-15 which has a capacity of 2000-lbs and can handle wheels from 12" up to 15". This is a 60" long axle with 48" from spring center to spring center (which should be the measurements on your existing axle-you'll want to measure to be sure). Going with this setup would give you the ability to upgrade your wheels if you determine that you've got enough clearance to do so and provide you with a high quality Dexter axle, hubs and bearings that are going to stand up to use much better than the existing axle with regular maintenance. This is going to be a bit more expensive than just replacing hubs, but still a very reasonable price for a complete axle setup.

If you wanted to just upgrade the hubs, that's still an option, but in order to provide you with the correct replacement parts you'll need to determine what size bearings are in your old hubs. You can do this by pulling out the bearings and checking the numbers on the backs or by measuring the inner/outer diameters on the bearings (you could also just measure the spindle once you take your old hubs off). I've linked an article about trailer hub bearings and spindles that show how to measure everything- you'll need a digital calipers in order to do this accurately.

While you're removing the hubs to find which bearings this axle uses, I would recommend measuring the space between your tires and fenders, as well as the tires and the frame of the trailer so that you've got an idea of how much tire you can add to this trailer without causing issues with contacting those components.

Once you've gotten all of these measurements I can help you pick out an axle, hubs and wheel/tire combos that will work for your trailer.

I've linked an article on trailer bearings and how to measure, as well as a picture that shows exactly how/where to measure.