Long Trips

[ViperRon]

brakes

For brakes on the trailer you may be able to fabricate hydrolic. I have a trailer that I made with a hydrolic mechnism that basically uses the force of weight pushing on the hitch ball to engage the brakes. The complicated part is getting something light weight for the wheels that is cheap. Maybee some small disc brakes from a moped would work. I only suggest this because I have driven with electric brakes and also with this hydrolic brake setup. I do prefeer the control from the hydrolic system. If you want to consider this I may be able to find the drawings of the hitch part to send to you so you have a design.

[Rasputin]

One must keep the weight in front of the axle more than what is behind the axle in any case. While the tongue weight is important the percentage front to back is more imperative. If it is wrong the trailer will sway and cause the bike to become unstable. Oh yeah and do not exceed the braking power under any circumstances.

[DiverRay]

Scott,
You are correct for the tires, but wrong on the total weight capacity of the bike. When you bought a "tour package" from Yamaha, it came with new front and rear springs/shocks. The total weight limit of the bike was up to 1250lbs, IIRC. The limit WAS the tires of the times, but they seemed to have a higher load limit, due to Honda using the 17" on the goldwing.
I can't find my '78 book now, but once I do I'll post the specs for the tour kit. I know my bike in '78 was 820lbs WITHOUT me, on a truck scale. I was over 1100lbs ALL the time, and it never gave me any problems.

[3Phase]

Thanks, Ray!

I have put XJ air shocks on the back but I did measure the front fork springs when I changed the seals and the fluid.

The fork springs on my '80G are stock, no extra beef there. The air adjustment is supposed to handle different loads without changing springs and the GVWR should be marked accordingly. I haven't run the numbers for any other year/model bikes but the weight distribution should be pretty close and, of course, the tire LI/SR numbers would be on the sidewall of the tires.

I made the first set of calculations that I mis-posted so I would know whether or not it was safe to carry my buddy's kids out in the desert at >100*F. It was close enough that I did unload the luggage and fairing even though all of the kids are still under 120 lbs but it was better to know than to guess.


I did discover that the LI/SR rating for tires is not necessarily accurate. Like everything else: it depends! Here's a link to a small 10MB PDF:-

DOT HS-810-561, February 2006: The Pneumatic Tire.

================================

Contents

Chapter 1: An Overview of Tire .......................... 1
by B. E. Lindemuth
13136 Doylestown Road, Rittman, OH 44270

Chapter 2: Mechanical Properties of Rubber ................. 28
by A. N. Gent
Polymer Science 3909, The University of Akron, Akron OH 44325-3909

Chapter 3: Tire Cords and Cord-to-Rubber Bonding ........... 80
by E. T. McDonel
10867 Fitzwater Road, Brecksville, OH 44141-1115

Chapter 4: Mechanics of Cord-Rubber Composite Materials ... 105
by M. C. Assaad and T. G. Ebbott
Technical Center, The Goodyear Tire & Rubber Company, Akron OH 44316 and J. D. Walter Civil and Mechanical Engineering Depts., The University of Akron, Akron OH 44325-3905

Chapter 5: Tire Load Capacity ............................ 186
by S. M. Padula
Michelin North America, One Parkway South, P.O. Box 19001, Greenville SC 29602

Chapter 6: Tire Stress Analysis .......................... 206
by M. J. Trinko
4426 Provens Drive, Green OH 44319

Chapter 7: Contact Patch (Footprint) Phenomena .... 231
by M. G. Pottinger
1465 North Hametown Road, Akron OH 44333

Chapter 8: Forces and Moments .......................... 286
by M. G. Pottinger
1465 North Hametown Road, Akron OH 44333

Chapter 9: Tire Noise and Vibration ............... 364
by K. D. Marshall Ohio Dynamics, 1830 East Boston Road, Cleveland OH 44147
iv

Chapter 10: Waves in Rotating Tires .............. 408
by D. M. Turner
Swithuns Gate, Ostlings Lane, Bathford, Bath BA1 7RW, UNITED KINGDOM

Chapter 11: Rubber Friction and Tire Traction .... 421
by K. A. Grosch
Uelenbender Weg 22, 52159 Roetgen, GERMANY

Chapter 12: Rolling Resistance ....................... 475
by T. J. LaClair
Michelin North America, One Parkway South, P.O. Box 19001, Greenville SC 29602

Chapter 13: Rubber Abrasion and Tire Wear ...... 533
by K. A. Grosch
Uelenbender Weg 22, 52159 Roetgen, GERMANY

Chapter 14: Tire Properties That Affect Vehicle Steady-State Handling Behavior .. 594
by J. D. Walter
Civil and Mechanical Engineering Depts., The University of Akron, Akron OH 44325-3905

Chapter 15: Introduction to Tire Safety, Durability and Failure Analysis ... 612
by J. D. Gardner and B. J. Queiser
Bridgestone Americas Holding, Inc., 1200 Firestone Parkway, Akron OH 44317

Chapter 16: Non-Destructive Tests and Inspections ......... 641
by J.A. Popio and T. M. Dodson
Smithers Scientific Services, 425 West Market Street, Akron OH 44303-2099

Chapter 17: Tire Standards and Specifications .............. 655
by J. D. Walter
Civil and Mechanical Engineering Depts., The University of Akron, Akron OH 44325-3905

Chapter 18: Tire Materials: Recovery and Re-use ........... 670
by A. I. Isayev and J. S. Oh
Polymer Engineering, The University of Akron, Akron OH 44325-0301

Index .................................................. ................. 693

Okay, the information in the file will tell you a little more than most people would ever want to know about the science behind tire design and testing so after you open it you can cheat and just hit Ctrl-F to search the file for the word "motorcycle" or you can take your time and read all of it.

[cywelchjr]

I do know that if the bike got the Yamaha fairing as a dealer installed option it was supposed to get the same heavier springs that the 81 Venturer got to handle the extra weight of the fairing WITHOUT needing to increase air pressure in the forks. Now as to whether your's was dealer installed or not, that would be the question. I was told my Vetter was dealer installed, but it wouldn't have gotten the heavier springs since it's not a Yamaha part. And with MY weight I wouldn't consider carrying anybody else anyways, the bike is heavy enough with just me on it as is.

[Jerry]

I have been pulling a trailer since the 2000 rally in Missouri, usually no less than a couple thousand miles per year.

First, pulling a trailer is not for everyone, or every bike. Weight is one of the key factors, but as far as the bike's suspension is concerned, you are only dealing with the 15 - 20 percent of the trailer weight that is the tongue weight. On a 200 pound trailer that amounts to only 40 pounds.

Brakes, which have to stop the entire load, are another matter. On my XJ I upgraded to EBC brake pads and SS brake lines. Since the XJ's brake system is linked (rear and front-left calipers coupled through rear brake lever) I didn't have to change my braking habits much. If you are not in the habit of applying rear brakes first, you will have to change the way you break. Use the rear brake first. You are also stopping 160 - 200 pounds more, not that much difference if you are used to riding 2-up, but if you are a solo rider, as I am, you have to get used to the extra inertia / weight of the trailer. I've never had problems with the stock braking system, but it has to be kept in top-notch condition and SS lines don't hurt. (I also have SS lines on my Concours.)

Biggest danger is true of all vehicles that tow; the trailer acts as a big lever, and will try to push/pull your rear tire sideways in anything other than straight-line towing. The hitch is a fulcrum, and the entire weight of the trailer and load puts maximum force on the fulcrum point. Magnifying the effect is that the hitch is behind the rear wheel.

I built my trailer to keep the weight down. I used a tubular steel frame and a car top carrier. Biggest weight is the trailer's axle, which is type 60 heavy tubing. I have thought of going to the torsion axle to save weight, but you have to consider the cost differential. My trailer, which has a 16 cubic foot capacity, weighs about 110 pounds empty with it's spare tire, jack, and lug wrench. (I carry a scissors jack out of an old Honda.) All others I have seen, including Harbor Freight and others, come in at least 70 - 80 pounds heavier with a spare tire and carrier included. To me that was significant.

Before I used the car top carrier I used a soft carrier. However, even with treating the seams, I could never keep things dry. Switching to the car top carrier fixed that. In a similar vein, I started off carrying a cooler, which I soon found to be overkill. I now carry a small soft cooler on the bike's luggage rack which has worked well for years. Capacity is large enough to hold a couple 32 oz Gatoraid bottles and a few small odds and ends.

I run a 140-90-16 Dunlop Elite 3, which gives a slightly larger footprint than the stock 130-90-16.

The other point I took special care with when building the trailer hitch was the height of the hitch point. I had planned to use a swivel hitch just because it is an in-line design, as opposed to a ball hitch being an above-the hitch design. My hitch has the hitch point directly in line with the swing arm when rolling. It also the reason I stayed with 8" tires instead of going to the larger 12" tires; I wanted to keep the trailer's center of gravity low.

There is no doubt that pulling a trailer adds an element of risk to a mode of transport that is already risky. (So does loading all your gear on your bike instead of pulling a trailer.) My personal decision was that the advantages of a trailer outweighed the disadvantages, but that is a decision each person would have to make for themselves after weighing the additional risks. If you decide to tow, make sure you upgrade your tires, brakes, and plan to adopt a trailer-friendly braking technique.

Pulling a trailer is not for everyone. It cuts your gas milage and increases your tire wear. Towing in adverse conditions gets a bit tricky as the trailer wants to push the back end of your bike around. If you ride 2-up and trailer you are probably pushing your bike past safe limits; even towing will put you up to the edge of reasonable safety. Still, in my case I feel it is worth it when I plan to stay in one place for a few days on my trips. I can carry larger - better gear, be more comfortable, save on hotel bills, cook my own food when I want, and camp in remote places where other accommodations may not be available. To me, towing works.