MacGregorSailors.com

If you have sway just over 65 mph, you have ZERO margin for extreme conditions, like getting caught between two-semis just right.

If I can't get a trailer up to 85-90 mph (a bit at a time, getting a feel for it), with total stability, I don't feel comfortable traveling at 60-65 mph with it. That includes the big Airstream as well, but it does have a Hensley Arrow hitch. That, or a Pullrite hitch are the only two hitches I'd pull a big travel trailer with.

If you've ever had severe sway, you'll never want to experience it again.
--
Moe

My mod is posted. Unfortunately I had an attack of stupidity (they're happening more frequently as I get older) and managed to submit it with the title "hello", so it may not be easy to find in a search. I'll try to get Heath to change the title but he's a busy guy and that could take awhile.

If there are a lot of questions I'll post the answers as Part 2.

Chip,
Just looked at your Hello mod. Are you sure you want to put the invoice on the internet? I would hesitate to post something with half my credit card number on it along with name address and phone number. Plus I don't know if the vendor would be happy broadcasting his fees so explicitily.
But maybe I am just overly cautious these days.

By the way, I finally bought a spare set of bearings for the trailer today, but didn't get the seal because the parts store couldn't cross reference the seal info. If I knew the diameter then they would know which one it was.

http://www.championtrailers.com/bearing ... seals.html

I'm guessing that it is number 8 in the link above (1.72 inch seal ID) but somone had posted saying that some macgegor axles had a SS sleeve on them (SPINDO) that required a larger or special seal.
"
SPINDO SEAL
On an axle which uses a standard seal, the seal rides on the spindle. Since the spindle is steel it can rust and pit. This will wear the seal out rapidly and let grease leak out. The Spindo Seal kit is a stainless ring and a special seal that is used instead of the standard seal. This gives a surface for the seal that will not rust and pit. Macgregor has used Spindo Seal on many of his trailers. I don't know what years he used them but my trailer and many others that I have seen came with them.
When working on the bearings this complicates things because the seal is special and can not be bought in an auto parts store or catalog.(The seal has to be taken out to replace the rear bearing and is not supposed to be reused.) Spindo Seal is Made by UFP (Unique Functional Products) They have a web site http://www.ufpnet.com The kit that is used on Macgregors is #2. The kit consists of two seals, two stainless rings for the seal to ride on and two rubber o-rings which seal the rings to the axle.
"

I'm pretty cautious as well, but it's not half the credit card, it's the last four numbers out of sixteen. Twelve numbers missing, plus the three digit valildation number on the back of the card. If you want to guess the other numbers, that's quite a few possibilities. Notice that card's now expired, too. Nothing else there you can't get by typing my name into "whowhere".

The prices are the same as those posted in the Champion catalog, available off the net.

Chip Hindes wrote:

Frank wrote:Bumping that upwards to 280# (~7.5% of boat/trailer) completely fixed the sway problem.

I've been towing for over thirty years, and with the exception of the Mac owners' manual, nobody considers 7.5% adequate tongue weight. It should be closer to 10%.

Hmmm - NOBODY?? ... that's a pretty emphatic parameter, Chip. I've seen the "spec" to be quoted at 8 to 10%, and I'm just reported my own (somebody's) experience. The rig swayed - now it doesn't, whatsoever. YMMV.

Frank wrote:Hmmm - NOBODY?? ... that's a pretty emphatic parameter, Chip. I've seen the "spec" to be quoted at 8 to 10%,

By what strange math does 7.5% meet the "spec" you've seen quoted of 8-10%?

Nobody.

Chip Hindes wrote:By what strange math does 7.5% meet the "spec" you've seen quoted of 8-10%?

You learned it in 5th or 6th grade. It's called "rounding." More importantly, my posting wasn't intended to restate "ANYBODY'S" recommendation, it was a report of my experience - empirical, get it? Your experience is welcomed here too ... I guess.

Besides, my use of the word "spec" was just my euphemism. Those recommendations are hardly specifications, they're general guidelines. Has engineering rigidity possibly twisted your underpinnings today? Boats, in particular, differ from other trailers in a variety of guidelines because they have a uniquely aerodynamic quality. (I'm sure you've noticed)? Particularly argumentative today - Christmas spirit got ya?

Somebody.

I'm gonna weigh in here on the side of 10% minimum. I've heard of boater's claiming better aerodynamics allow 8%, but I've also later seen some of the same boater's later detailing a terrifying sway experience. Under the right conditions, that can even happen with 10% or more, but it's less probable, and usually less severe when it happens.
--
Moe

Enough splashing in puddles ... don't know what drags me in ... just end up with wet socks 'n shoes!

My trailer wagging was completely eliminated at slightly less tongue weight than commonly quoted guidelines. If you're uncertain about it, go right up to 10% tongue weight. I found that 7 or 8 percent (depends on gear in the boat) completely solved my towing problem while also leaving more cargo capacity in the Expedition.

Other vehicles could undoubtedly behave differently. Is it worth spending a couple of hours (at zero cost) to test the rig with increased tongue weight before spending $1200 on an extra axle, wheels and tires?? ... bet it is to many.

My experience in completely solving a trailer sway problem was without the presumed anti-sway benefits of tandem axles. IMO, that's overkill for our boats regardless of pseudo-engineering assessments to the contrary. Anyhow, mine is just one story (among the 8 million) and my opinion is worth exactly what it costs ... nuttin! Ya gotta go with what makes you comfortable. Cheers!

Frank wrote: You learned it in 5th or 6th grade. It's called "rounding."

Some of us have learned something additional since the 5th grade. Even if we accept the range of 8-10, which appears acceptable to you and the Mac owners' manual, but nobody else, it's just that: the permissible range. You can't round yourself into it. Just like 5th grade math. If passing is 70%, 69.5% is failing.

There's more to this than just trying to meet the mimimum technical limit by whatever means. Those who through extensive experience recommend the limit would tell you that, being a single axle trailer loaded to its limits in every way, the tongue weight on the Mac ought to be at the upper end of the range, not half a percent below the minimum.

Where in anybody's tongue weight "spec" did you see the words: 8% or until the trailer stops wagging at speed, whichever comes first?

The disagreement has nothing to do with one axle versus two. It's purely about tongue weight.

Psuedo-engineering? Making fun and name calling is the last resort of those whose arguments lack technical merit.

Please play nice. I like this thread.

Mark Prouty wrote:

Mark Pouty?

kmclemore wrote:Mark Pouty?

Now that is just plain mean!!

You guys are funny.

Frank.....

Snicker snicker.......


WAs that really Chip???

Tell me it aint so.........lol./......

strange thread this time.......


Or maybe I am just not getting enough sleep....