Motorcycles by design are unable to carry copious amounts of luggage or cargo. Sidecars increase loading capacity and distribution of weight, but there is nothing better than a well manufactured trailer to alternatively load a motorcycle. The main problem with loading the back-seat of a motorcycle is improper weight distribution, wear and tear, and handling problems. With proper technique, design, and loading a trailer can be added to most motorcycles.
A quick perusal through most owners manuals will provide the famous words “Vehicle not manufactured for use with a sidecar or trailer” ” use of a sidecar/trailer can/will void warranty”. Obviously the addition of any accessory to a motorcycle must use caution, the manufacturers place these warning for reasons. The selection of a trailer would be an entire article by itself, what we will deal with here is the operation and techniques of trailering.
The hitch on the motorcycle should be sturdy (connected at least to four points on the bike). Hitches should not be connected to moving suspension components, swing-arms, shock-absorbers, or drive shafts for the obvious reasons. There should be no movement in the hitch. Hitch height should be at hub-level of the rear wheel. The distance between the rear wheel and the hitch should allow the rear wheel to move up and down unimpeded, but it should not be an excessive distance from the hub.
The best designs of trailers use the largest tire height possible and high speed bearings in the wheels. Beware the use of cheap lawn and garden tires on trailers. These types of tires are made soft and compliant so as not to damage lawns and are in no way recommended for highway use.
Trailers come in all shapes and sizes. A trailer should contain the following design features. A hitch assembly rated at a significant value higher than the gross vehicle weight of the trailer (total weight of the trailer). The trailer should have an axle width to tongue length of around 1 to 3 approximately. A significantly shorter trailer tongue will not track behind the motorcycle correctly, and a significantly longer trailer tongue will create cornering problems. There should be enough overhang to the rear of the trailer of the cargo area to allow proper loading. However, it should not be so great of overhang as to possibly drag the curb when leaving your favorite gas-stop.
A trailer is an alternative method of loading gear. A motorcycle has particular design characteristics that are being modified to allow the operator to carry more gear. As the operator you will have to decide how much is enough. A trailer is not a “blank check” to bring everything. Some simple rules for loading trailers is to take everything you would put on or in the bike and put it in the trailer instead. This is true alternative loading. Of course if you look down at the wide open maw of the emptiness of the trailer and start filling remember; the trailer total weight should be distributed over the axles so that the tongue weight is about 10 – 20 percent of the total weight of the trailer. Figure the total allowance of weight for the bike by looking in your owners manual. Add all the gear weight on the bike including passengers and riders. Don’t forget to add the tongue weight of the trailer. If you are in the positive and not overweight your doing good. If the amounts are over start shedding gear. Motorcycles are very finicky on how much weight they are moving.
Remember all of the weight (trailer, motorcycle, rider) is still going to be stopped by those same brakes, and accelerated by the same drive train. Depending on the weight of the trailer you choose to tow, all of the components on the motorcycle are going to wear a lot faster. Brakes and tires may be the most effected component on the motorcycle. Proper loading is going be the most important part of trailering because its going to effect every other part of the handling of the motorcycle.
When starting out and stopping a trailer you want to be as straight as possible. The degree of difference at the hitch between the trailer and motorcycle is going to create side forces on the motorcycle as it begins to move. The resistance to moving of the trailer will pull the bike over in the direction the trailer is. For an example if the motorcyclist stops with the trailer “kicked out” to the right the motorcycle will be pulled to the right as it begins to move forward. With the motorcycle and trailer in line the resistance will not effect balance. If the hitch is to high, and is mounted significantly over the level of the hub a lever of force will be created when starting out lightening the front wheel of the motorcycle. The resistance of the trailer creates this effect and steering wobble is usually the result. The effect of the trailer on the bike can be very slight or so severe a hazardous riding condition will result. No matter how well the trailer or bike is setup and designed the trailer will have some of these effects.
When stopping a motorcycle trailer combination allow increased room to stop. Only experience will show how much, but the increased weight being stopped of the bike and trailer will require more brake effort over longer distances. When stopping the bike should be kept as upright and straight as possible. The surge of the trailer forward as the bike stops should be directed as straight as possible through the bike. If the bike is leaned over and turning during braking the surge will have a tendency to push the bike over in the opposite direction, or push the rear wheel to the side. This effect can be minimal or severe depending on the amount of braking and the weight of the trailer.
If the hitch is set up wrong another problem can occur. On hitches that are above the rear hub of the motorcycle when braking the weight shift normal to stopping lightens the rear wheel. This effect will be exaggerated even more by a high hitch. Some trailer manufacturers attempt to engineer methods that lessen or do away with this effect by the way their trailers are made.
Another frightening effect can be the front wheel lightening on braking. Excessively heavy trailers on low slung hitches can lighten the front wheel and create a wobble when slowing. A simplification of the problem would be a five hundred pound trailer with fifty to sixty pounds of tongue weight. Most of the weight of the trailer during braking is being transmitted to the hitch. Depending on the degree of difference between the hitch and hub that weight can transmitted in a downward direction on the hitch increasing tongue weight significantly. The effect would be similar to a five hundred pound giant standing on your hitch while you try to balance and stop.
Depending on the weight and design of a trailer in slow speed turns it will tend to pull the bike aside in the direction of the turn. This effect will be dependent on the weight of the trailer and the resistance to rolling. In high-speed (highway turns) the trailer can track on the outside of the turn pulling the bike up-right. This effect is usually minimal but can drastically effect the operation of the motorcycle if the trailer is overloaded.
Obviously the motorcycle trailer combination is going to operate easier if it is properly maintained. Most trailer manufacturers have excellent suggestions on tire inflation, bearing care, and care of hitches. The problem usually lays in the operator not doing the recommended service. Tires fail and so do bearings. The operator is the final inspector for safety when a trailer goes out on the road. Most manufacturers recommend at least seasonal maintenance on bearings and side-wall pressure ratings of tires for fully loaded trailers. As part of your pre-ride inspection of your bike include the trailer and inspect every item just like you do on your bike. Include the hitch assembly depending on the type of hitch check for obvious problems and wear. On hitches try and insure proper lubrication and fit to the bike.
Safety chains should be included on all trailers. We all have heard the excuses for improper safety chains. Some riders state they would rather have the trailer “break away” in case of accident or massive failure. Some riders think that safety chains are not required on motorcycles. Most states require safety chains or cables. If the trailer “breaks away” where is it going to go and who is it going to hurt. Ultimately the rider is responsible for any damage his vehicle or trailer causes.
Safety chains should come in pairs and be attached to the frame of the trailer and motorcycle. Some states allow appropriate cables to substitute for chains, but check your local police for verification. Chains or cables should not drag the ground and should cradle the tongue if the hitch fails. Insure that the chains or cables are long enough to allow the bike to turn.
Trailers allow a motorcyclist to include the extra gear desired and not pile the bike high with everything. A trailer may be the way to entice the significant other to come along, lured by the charms of an opulent camp sight. The trailer allows a motorcyclist to bring “real” luggage when checking into a hotel. With proper technique and set up a trailer allows more flexibility for touring/grocery getting. The signs of shock from check out staff at the local grocer are excellent.
In the USA you have to have DOT approved tires on the trailer. Make sure that the tires are rated for the weight you are going to put on them and at or abouve the speed you plan on going
To the guys on the ZR Bike forum.
You don’t want to add a hitch to the swing arm because it dramatically impacts unsprung weight on the rear tire. Literally it’s like adding a huge weight to the rear suspension system. Second element to adding it to the rear swing arm is that the torque forces are lengthened over the entire length of the trailer and added to one or two tiny hinge points a the swing arm and at the shock mount(s). Finally it is decreasing the feel as in point one, but could cause substantial wear and tear on the shock itself.
Yes, you will find cases of people doing the swing arm install. Yes you will find people who said it works for them and they’ve had no issues. Yes you will find builders who do this kind of swing arm mount. Yes people will say they use it only off road. That doesn’t make it right and it most assuredly can cause issues. Lots of people jump off bungee jump, and sometimes the rope snaps. You take your chances.