8 inch trailer wheels

I hear very mixed reviews for pros and cons of trailing with 8 inch wheels on the highway. My intended use is limited highway and wondering if it is a wise choice or should I bite the bullet and spend more cash for 12 inch wheels

What is the load you will be carrying
and what is the mileage you’ll be traveling in a year?

If it was me, I would go with the 12".

And knowing what I know from experience with small trailer wheels I would also keep a spare set of bearings.

jack L

8 inch wheels
Carrying light load of either (1) 15 foot canoe or possibly (4) bikes.

Don’t anticipate more than 500 miles per year with 1-2 trips of 150 miles each way

What are the pros?
I cannot think of any Pros for highway towing with 8" wheels. The cons are obvious. With 8" wheels your bearings turn about 1250 times in a mile, while with 12" wheels only 940. That is about 25% less with the 12". A friend has 8" wheels on a boat trailer and likes them because it makes the boat easier to load and unload on unimproved launches being lower. But he has a set of 14" wheels and tires for when he hauls the boat from Massachusetts to Florida just to reduce the bearing failure. Just one bearing failure on a deserted section of highway late at night will convince you that you should have paid the extra for the larger wheels and tires. Another plus is that the tires when replacing them cost about the same.

light load low miles

– Last Updated: Sep-01-14 7:34 PM EST –

I wouldn't be concerned. I've trailered a 14ft aluminum boat over the road weighing easily 4 times the weight you will haul with 8" wheels. My present boat weights more like 2500lb with engine and gear, that has 13" wheels. The main thing is keep the bearings greased. Most trailer wheel failure is caused from bad or non existent maintenance.

8" wheels
I did the same thing. I used 8" wheels locally, and would put the 12" wheels on for long trips.

get 12in wheels put bearing buddies on them . Grease before every trip and forget about it. A little bit of care goes a long way.

Bearing Basics

– Last Updated: Sep-01-14 6:28 PM EST –

Your second statement, "a little bit of grease goes a long way" is absolutely true. If that grease is clean, the bearings will normally last a really long time, just as you say. Think about how often you re-grease the wheel bearings on your car. Most people have never done this in their life, on any car, not even people who put 300,000 miles on them. The bearings for tiny trailer wheels can't be expected to last that long without attention, but they aren't bound to fail after a few short trips either.

Your first statement, "grease before every trip and forget about it" not only contradicts your other statement, it's not even remotely possible to follow that advice. Grease takes up space, and once the spring-loaded piston of the Bearing Buddy has been loaded, the hub is completely filled with grease, and it won't take many extra squirts to push the piston against the stops. Once the limit of piston travel has been reached, all you'll accomplish by adding more grease is to shove the excess out through the seals, possibly wrecking them in the process (whether or not you wreck the seals will depend on whether the seal's lip faces in or out - and chances are that you don't know which is the case in your situation). You could even cause the Bearing Buddy to pop off the hub (by the same principle as a hydraulic jack because that's a lot of surface area for the grease to push against).

Most of the hype about trailer bearings comes about because people neglect them, and in the case of regular boat trailers, it may not take a long period of neglect because the grease easily gets contaminated with water and dirt, and seaweed wrapped around the axle is pretty good at destroying the seals. The OP has a trailer that might see 500 miles per year. That's virtually nothing. My bet is that the bearings will last a mighty long time, and that he only needs to check the condition of the grease once in a great while. Advising the use of larger wheels is reasonable, but using 8-inch wheels won't be the worst thing ever, and advising that bearings need "new" grease every time you turn around is not based on reason.

Finally, think about the real purpose of a Bearing Buddy. It is not to make it possible to add new grease when the hub is already chock-full of clean grease. With standard boat-trailer hubs, air inside the hub will contract when the hub is suddenly cooled by being submerged in water, and that contraction creates a vacuum which sucks water in through the seals. A Bearing Buddy will keep a slight amount of pressure inside the hub, and the spring-loaded piston simply "takes up the slack" when contraction of air in the hub occurs, preventing the water-entry problem. On trailers that aren't backed into the water for launching boats, a Bearing Buddy is just a convenience feature that allows you to avoid the need for getting your hands dirty once every few years. It adds nothing to bearing life that can't be accomplished with occasional checks of the old-fashioned kind. So, should you add grease before every trip, just because you can? Absolutely not.

I yield to your expertise

I think the follow-up ? should be…
Are you thinking of buying a Harbor Freight trailer? If so, the bearings that come with it are notorious for failure. You can purchase higher quality bearings to install as you assemble the trailer if this is the scenerio. I have a trailer with 13 inch wheels with a lubrication system that literally forces the grease to the inside of the hub and forces the older grease out towords the outside. The new grease displaces the old grease. The brand name is Dexter. It isn’t submersible though…

Guideboatguy, thanks!
I’ve learned a lot just from this post, much appreciated. I’ve not owned a trailer, am looking at buying one (a used ~7 yo 5’x8’ utility, w/ a homemade kayak rack) soon for our growing fleet, and this thread has been helpful.

Both trailers I’ve had used 8" wheels

– Last Updated: Sep-02-14 12:10 AM EST –

The first trailer, which I used for about 10 years, was a modified snowmobile trailer with 8" wheels. The one I have now is a Trailex kayak trailer that also uses 8" wheels. No problems with the wheels on either trailer, including a 5200-mile round trip with the snowmobile trailer, a 1500-mile moving trip with the kayak trailer, and lots of shorter runs with both. They each had/have fittings for easy lubing with a grease gun.

There are two things you should watch for when using small wheels in general:

1. Grease the proper amount, when needed.
2. Keep the tires inflated to a reasonable pressure. Sorry, but 10 psi on small tires is asking for trouble! If you're doing that to soften the ride for the boats, you need to change the suspension.

Actually, the above advice applies to all wheels anyway!

Both trailers had fittings for easy greasing. You DON'T need to grease frequently; in fact, you can do harm by stuffing too much grease in there. With Bearing Buddies, just pull off the cover, push down on the metal spring-loaded plate, and see if it goes down and back up. If it's too low, the plate will bottom out. If it doesn't need any grease added, the plate will be fairly high. If it's in between those two conditions, add a few squirts from the grease gun.

You don't need to fanatically, frequently, open up the thing to look at it. What I did and still do is, right after towing it, FEEL whether the rims (not the tires) heat up and SEE if any grease has leaked out. If the wheels stay clean and the rims don't overheat, your grease is doing its job. On a long road trip, just check these on your fuel stops. Takes less than a minute and no tools. On my long road trips, I stopped checking them at each fuel stop because there was nothing wrong; I still checked them a couple of times each day, though.

For the kind of duty you described, the 8" wheels should be fine. There IS an advantage to the little wheels: they cost less and are less attractive to thieves. There is also a strange disadvantage to them: some tire shops will not balance them. Supposedly, you CAN have them balanced at places that sell (drumroll) 8" tires.

Harbor Frieght trailer bearings
From what I’ve been told about these trailers and bearings ( my stepson owns one of the li9ttle kit trailers from there that he tows behind his motorcycle as do many people in that community)it’s not the bearing quality that is so low as to cause failure but the grease. The grease is like Vaseline, just pull the wheels and grease with a quality wheel bearing grease and they go as well as any other bearing. The trailers are light and made for light loads as well, I believe they are rated for 1000lb gross weight ( the kit trailer , can’t speak for the pre built ones if they have those)…

Goes without saying…
Using Buddy Bearings and NOT submersing the wheels in saltwater or any water if possible is prudent.

I have lots of miles on 8" tires.

The trick is if you carry a spare tire and set of bearings you will never need them.

Installing a spare set of bearings

– Last Updated: Sep-02-14 9:18 AM EST –

How does the average person install the outer races when replacing bearings on the side of the road? You can knock the old ones out with a hammer and punch, but installing new races without a press is iffy at best (odds are really good that they'll end up with slight deformities near the edges). As you say, you probably won't ever need them, but what's the plan if you do? Do you carry a bunch of clean rags and spare grease too?

One other advantage of 12" wheels
Dear Larry,

One other advantage of a trailer with 12" wheels is the increased ground clearance and the greater ability to travel rough and rutted roads.

If you are often traveling dirt and gravel roads to launch and recover your boats that can be a big advantage.

While you probably won’t damage your trailer frame or the boats you are hauling it is quite easy to bottom out and damage or lose your license plate and/or damage the trailer lights.


Tim Murphy AKA Goobs

15" inch wheels
Do yourself a favor and get a high quality trailer with 15" wheels. One factor that will cause bearing failure is heat. Heat is caused by excessive speed, which is what goes on with small wheels. Even in the best of environments, bearings will not last forever, but generally in the larger wheels they will probably last a very long time with reasonable maintenance.

diminishing returns

– Last Updated: Sep-02-14 10:54 AM EST –

One would think at some point, the greater mass of the larger wheel, and the resultant greater wear or load on the bearings, would offset the reduced wear from using a bigger wheel. This is why guys who drive trucks with 22" rims are not very bright.

My first car had 13" wheels. Never replaced a wheel bearing.

I had a car with 13-inch rims too. I drove it for almost 200,000 miles, and though I did re-grease the wheel bearings a few times over that time span, plenty of other people would not have and still would have had a good chance of the bearings lasting.

Another problem with 15-inch wheels, is that any trailer axle having hubs that will accept 15-inch wheels will be very heavy-duty. It won’t be practical to put such an axle on a light trailer with light springs, so most likely this would mean using a heavy-duty trailer. There’s no reason to subject bikes and boats to the ride-quality of an essentially unloaded heavy-duty trailer.

As far as heat reduction goes, note from Pikabike’s post that properly lubricated (and properly adjusted) bearings don’t get hot, not even on 8-inch rims. Speed of rotation isn’t the whole story, since there are other bearings with long lifespans that spin many times faster than those on trailer wheels.

that’d be my concern
…with a 15" wheel, agree about this aspect.