Farnbacher got the Willwood hitch kit for my CS to use in the One Lap of America, including the beefy bumper supports. Those seem fine, but I wasn't happy with the hitch itself.


There are two problems with the hitch, IMHO. The first is that the piece you attach the safety chains to is the MALE part of the receiver. So if your pin were to come out or break, your trailer is leaving you. There is room, I think, to put them on the female half of the hitch. It'll be a pain to get them in there (a little bit) and you'll want chains with some kind of decent but small clip, but I think it's possible.


The bigger problem we had was that after about 2500 miles of pulling the trailer, the pin hole started wallowing out. Now, I do admit we were going pretty hard with it, but I still just think the outer and inner tube material wall thickness should be larger. The pin was perfect with no wear, but the tube (particularly the inner and "male" part) was wearing badly, mostly in the direction of "pull" on top and "push" on the bottom.

I honestly don't think it was acceleration and braking doing this as much as it was up and down vibration. The two parts do not fit together with very small tolerance and will wiggle. Now, my trailer was on the high end of the range. They rate it at 750 pounds and 60 pounds of tongue weight. I was at just under 650 pounds and put the tongue weight at 50 pounds to start. It rattled badly at about 60MPH, so I upped the tongue weight to about 57 pounds. I was using Longacre kart scale platforms which I believe to be very accurate for all measurements.

Now, one problem with this scenario is I *think* the tongue weight needs to be more than the hitch is really rated for for a 650 pound load, but I didn't want to exceed it. The other problem is I *think* air was affecting my tongue weight fairly badly at anything over 60MPH and may have been taking all that weight off, but I really have no good way to know that.

What I do know is that with the original setup it didn't seem to be vibrating much at all and wasn't seeming to do it with any regular frequency early in the trip. By late in the trip it was vibrating badly. What's worse is the pin they provide has no positive mechanism to lock in the hole other than one of those spring loaded balls on the bottom and a heavy keychain-like ring on the top. It needs to have a beefier top piece and a hole for a cotter pin on the bottom at the very least.

I would like to see a thicker wall for the female tubing. I would like to see solid bar for the male piece rather than tubing at all. A better pin should be standard. And I really think the safety chain catches should be on the female side.

All that said, when I rolled the stupid trailer (yes, that was me being stupid and just screwing up badly), what happened? The coupler on the trailer ripped off the ball and the safety chains DID hold the trailer to the car. That's even though as it torqued over it DID rotate the trailer hitch mount some before it ripped off the ball. The hitch did better than I thought it would, so I shouldn't complain TOO much, obviously.

I'll be having my own hitch custom made that addresses these problems from here, but I thought folks might be interested in what I found with it.


--Donnie

Donnie - sorry you've had problems. I've had the same hitch system since September of last year. Pulls my little aluminum trailer great and I've had no problems.

I agree with your assessment of the chains. The pin I use to hold the male & female together has holes in it to accept a cotter pin. That seemed like a good solution making the risk of the pin coming out much less.

Anyway, here's some pix of my rig. The tennis ball keeps the license plate from getting wedged in front of the coupler thing (handle/lock on top) in a turn. As they say in the beer commercial, Brilliant!

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I had no idea one could put a trailer on this car. That just extended the usefulness by a lot in my book!

Caygirl, any idea what your trailer weighs and how much tongue weight? Also, how many miles has it been used and at what speeds and road conditions are you generally under?

Obviously my experience was 2500 miles in four days or so on some really bad interstates at some fairly high speeds. We generally kept it to no more than nine over the speed limit, but that could mean running near 80 for long periods of time on really bumpy roads. Also, it should be mentioned that I have much stiffer shocks and springs on my car than a stock car would have, which would have contributed greatly to the extra fatigue.

I'm sure my situation isn't normal as it sounds like there are a lot of happy customers with the product. I doubt my problems were due to any difference in my particular hitch versus anyone elses, either. I just think I took it to the edges of what it can handle and then some, and most importantly really wanted people to know they should definitely address that pin.


--Donnie

My trailer weighs about 600 - 700 lbs loaded with a tongue weight of 65-70 lbs. I only carry one set of wheels & tires (lightweight Enkei's/RA1s). They sit in the very back of the trailer. Most of the tongue weight is the spare that sits there. The only heavy things in the middle section of the trailer are my jack, tool box, and easy-up shade. There's a ton of other stuff in there (from zip ties to glass cleaner) but mostly lightweight.

I have about 5,000 highway miles on it. The weekend after I got it, it made a trip to Topeka, KS for the SCCA Solo Nationals. After that, there's been countless weekend trips from where I live in East TX to the tracks and AX/Time trails in the Dallas area. Mostly good roads.

Interesting. Makes me think the aero of my trailer may have taken the tongue weight off allowing more vibration and thus the accelerated wear. Something for folks to keep in mind, certainly.


--Donnie

I saw a trailer and hitch yesterday at Streets that seemed to deal with two of your problems. The safety chains wewre hooked to loops screwed into the bumper. One used the Porsche tow hitch mount, and the other to a similar hole drilled and tapped on the other side. The receiver box appeared quite sturdy to the eye, and the male part was solid, as is the case with most trailers hitches. Other design aspects seemed well thought out. The owner built it for himself, and now makes them available to others. He also built his trailer, which had a lock down rack for four wheels and a large storage box for whatever. Call Mike Furnish (805) 657 3754.
Marty

I have towed my Harbor Freight trailer for over 3000 miles with no problems. However, I do not cruise much over the speed limit (75-80) on smooth roads. I only have about 20 pounds of tongue weight and the trailer tracks fine. I am sure the aerodynamic loads and bouncing may make for negative tongue weight. On smooth roads, you forget it's back there, On rough concrete Interstates, the bouncing dirves me crazy. My trailer is lined with rubber diamond-plate floor mat just to keep the tools from pounding through the aluminum bed. I have no idea of the ideal tongue waight to overall weight and wonder why trailers don't have shock absorbers. Anyone know?

Mike Foxtrot

Because you generally don't need them. I've seen trailers with them, but it's rare. The torsion bar trailers really do have shock absorbers, just not the typical type...you've got a bar that twists acting like a spring, but there's also some portion of rubber bushing in there that helps dampen, too. The trailer I pulled with my Cayman has that. As long as you load it to at least 60% of the axle capacity, they ride way better than the Harbor Freight type with elliptical springs. Under that amount of weight and they are about the same (since I assume you never actually twist the bar enough to have the rubber affect it).

Rubber used to basically be elastic enough that it was considered a spring. In recent years we've developed rubber compounds that have much more in the way of dampening properties, which is cool.


--Donnie

Conventional wisdom on trailer tongue weight is 10% of total weight, minimum.

My little trailer has a swing axle. It's a sweet little custom trailer.

In fact, you could expand that to "conventional wisdom is 10-15% is the range you really want to be in."

That's all well and good, but when your hitch is rated for 750 pounds total and 60 pounds of tongue weight, you have a problem as soon as your trailer ends up at 650 pounds. Maybe the answer here is "don't do that." Perhaps they should have just rated it 60/600 if you can't go over 60, I don't know.


--Donnie

I've got a couple of good photos of Mikes trailer if you would like to post them here.

email me at garybarnhill@sbcglobal.net and I'll email photos to you for posting.

I have your DVD ready from SOW. Will you be at the Concours on Saturday, I'll bring it instead of mailing
Gary Barnhill