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In general, the longer the trailer, the easier it is to back up. You will have to pay a bit more attention when turning, going forward but you'll quickly get used to it. Probably the biggest thing when I went from single to double axle is hooking up the trailer to the hitch. With a single axle, it's pretty easy to nudge the coupler five or six inches or more one way or the other. With the double axle, you better be within an inch or two - or have Superman helping you hook up.

I've found the double axle trailer to be much harder on wheel bearings, as well. I think it's because of the side pressure put on them when turning sharp. You'll be surprised the first time you see your tires so stressed east and west it looks like they are about to pop off the rims. Has to be hard on wheel bearings designed to roll straight forward or backward. Just keep a watchful eye out for them.

Double is definitely easier but as BN said harder on trailer on sharp turns / reverses etc. I have looked back at my tires before and thought "that cant be good" lol. The ball bearings are designed for it though.

I have to differ with you about the bearings being designed for "turning". My guess is they are "somewhat" designed to withstand the rigors of turning but since the exact same bearings are used on single axle trailers, either they are "overkill" on single axles or under designed on double axles. That torque put on them when your wheels are cranked sideways is either pushing them in or out and not against the race of the bearing. The pressure is on the flange and end of the rollers. Sure it withstands the abuse time and again, but I bet if you turned your rig in a tight circle and let it circle for 50 or 100 miles, something would give. Of course that 50 or 100 miles is a lifetime for most trailers so good enough.
I put over 500 miles each week of the season on my trailer which is more than many put on in a year. Bearing failures have accelerated since I went to a double axle. In fact, I can't remember ever having a bearing go out on my single axle trailers. I watch them like a hawk, keep 'em greased, oiled, packed, cleaned up, checked daily and still have problems to the point I keep a new spare axle and replacement hubs at home so if I have a bearing go out and it screws up the spindle, I can swap out the whole axle and have new hubs installed in a couple hours.

I dont argue the fact the dual axle trailers will take more bearing thrust load than a single because of the centerline moment created by the adjacent axle. There is no doubt about that. Tapered roller bearings can handle immense thrust loading I would suspect higher end trailers use even further upgraded bearings for these applications.

I know you put a ton of miles on your trailer Mike, but am surprised to hear you have so many bearing issues. Perhaps investigate upgraded bearings that are designed for higher thrust loads? I havent messed with bearings on a technical level since I was designing machinery for the mills - and that was 15 years ago. It was always about perceived life expectancy vs. cost and I am sure trailer mfg's do the same thing, minimize the cost for what they think will "work".

Sorry about hijacking your thread OMT, but the chance to learn a few more things is there. The trailer under my searunner is a trailmaster trailer. Never owned one before so I can't speak for or against them. I know that like BN my trailer is going to get tested. 575 miles for one round trip to the lake. I try to be diligent in bearing care also. Last year I suffered a bearing failure despite my efforts. Things happen like that. I blamed some of it on the Lucas Red and Tacky grease I started to use. I switched back to Lubriplate Marine grease. I never had problems using that sticky white grease. Do you guys have a favorite?

It is very important not to mix lubrication types especially in hi speed applications such as a wheel bearing. Sometimes it does not matter and sometimes there are unintended consequences by two different compounds reacting to each other.

I am lucky because my trailer has Vault Hybrid Oil Hubs. Completely sealed and no maintenance.......until one fails that is. So far so good.

In my defense it was a complete repack of the bearings using the red grease. It lasted 2 trips up then one failed. I don't know what went wrong but all the remaining grease on the hub was like tar. I was so happy I am a friend of Flo and had good towing and boat insurance that day. The rider was 28 dollars and the tow bill was near a grand.

Sounds like you did everything right Don. Maybe just unlucky and had a bad bearing. I remember that day - really sucks to go down with that much of a drive ahead of you........ugh