Spacers...

[brian_bp]

Spacer versus nuts or washers
There's no way I would go without a full plate spacer. Personal gut feel, when I imagine the bending stresses involved... and I've never heard of a competition car which needs an adapter (racers mix and match stuff all the time) using just nuts or washers.

Alignment
Caster means nothing to a wheel which doesn't steer.
Camber is usually positive (top out) just so it doesn't go negative under load (more stable when positive, more responsive when negative, performance cars are always negative, street vehicles often positive)
Toe should almost never be toe-out, for stability and wear. I agree that toe-in with a trailer - if deliberate - is probably there so that drag and braking force doesn't cause toe-out

Hub Fit
While cars and modern trucks generally locate the wheel with the centre hole fitting nicely to the hub (the hub-centred or hub-centric design), trailer axles normally just depend on the studs/bolts - they are bolt-centric, and have clearance between the centre hole and the hub. The hub usually doesn't even have a nicely machined area to fit a wheel's centre hole (which is probably why they're bolt-centric - it's cheaper)

Studs versus Bolts
Studs are used to make the vehicle easier to work on and tolerant of more wheel changes (no threads in the hub getting messed up); wheel bolts are cheaper. VW Rabbits have bolts... enough said. Dexter offers their hubs both ways, and also offers conversion studs to screw into the tapped holes of a hub which was built for use with bolts. Get long ones and convert from bolts to studs while providing enough stud length for the adapters at the same time.

[dahoon]

Dean,

Here are a few of the spacers that I found in my catalogs.

Trans-Dapt part number 4082 priced around $20. This is 3/8" thick

Baer Brakes part number 2000010 for Billet Aluminum priced around $75. This is 1/2" thick.

Mr. Gasket part number 2372 is priced around $27. This is 7/16" thick.

There are available at any local auto parts store.

Hope this helps,
Mike

[Dean in Eureka, CA]

Mike,
Thanks for the info, but...
I need 5 x 4.25".

[Sierrajack]

The wheel spacers are easy to find as any good wheel shop should have them. Check on line. They have to be a "full" spacer so you do in fact have complete clamping force on the wheel and on the hub. You must replace your wheel or hub studs with a 1/2" longer stud however. Always TORQUE the nuts regardless and then check them periodically. I recommend the use of anti seize on the threads (lightly) to prevent the nuts from rusting to the studs. If you have tow in/out problems, I would take the trailer to a good alignment shop to have the axle straightened. Don't worry about the "flame wrench" this is how the Ford trucks with the I-Beams are done as long as the front end mechanic doesn't heat the tube to a cherry red. They will chain down the trailer, heat the tube and pull with a come-a-long until the readings are zero. Some positive camber is okay, maybe 1/4 degree but no more. Front end alignments are done camber, caster, toe in that order. You won't have caster so have the tech check the camber then the toe. It's very important that a trailer track straight or you run the risk of premature tire wear problems and more importantly, stability problems at speed. Too much tow in will cause the trailer to be squirrely and unpredictable. I usually shop around for alignment shops and generally pick the independants because they usually have some "'ol boy" who's been there for awhile and really knows how to do things right. If you have some knowledge about camber, caster, toe and can speak it with some knowledge, the mechanics have a tendency to give you more credibility and will listen and suspect you are an expert!! I can ALWAYS baffle the kids at the franchise tire shops and get them to scratch their butts. While you're at it, pack your wheel bearings with a good grade of synthetic grease and NEVER rely on "bearing buddies". See, you got me started and all those years of being a mechanic and race car engineer come back to haunt me - again!!!
Good luck, any questions - let me know.

[Sierrajack]

Dean,
One aspect I forgot to mention is ACKERMAN. This is a desirable effect for an automobile when turning but not on a trailer. Simply it means one wheel leading the other or axle out of square. You might want to check that the axle is perfectly square in the frame. Usually you will have evidence of "out-of-square" with one tire wearing on the inside and the other wearing on the outside.
Yes, short track stock cars DO have a great deal of off set on the right side of the car to aid in turning the corner and loading more weight to the left side. We used about 3" of spacers which was a very desirable and common practice. A full spacer places all the dynamics of loading fully around the circumference of the wheel/hub assembly. Please DO NOT use washers. A passenger car type suspension can not tolerate much wheel offset due to the short arch the wheel travels which places a load on the inner wheel bearing. However, adding spacers to a trailer is okay (within reason) because the actual pivot point of the wheel is 48" away or so, as it travels up and down. thereby not placing horrendous loads on the bearings. Some terms used for this action is called "polar moments" or where upper and lower control arm points intersect if a line where drawn through them to the inside of the car. How's that for confusing-eh?

[roger-c]

I found 1/2" spacers at ezaccessory.com They are 19.99 on sale for the pair

Roger C.