Registration, Safety, Maintenance & Crossbar Overview | Bulldog Folding Trailers
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Registration, Safety, Maintenance & Crossbar Overview

Trailer Kit Registration

IMPORTANT: A trailer kit is not a motor vehicle and is NOT subject to state motor vehicle registration laws UNTIL it is assembled with intent to haul it on a public road.

Your Bulldog Folding Trailer is eligible for registration only after it has been completely assembled. Trailer registration is typically easy and inexpensive, provided you have all of the proper documentation. In some states, an inspection or notarized signature is required for registration. Please email us at if you have any questions.

Trailer Kit Registration Documents

Once assembled, the trailer must be taken to your local Department of Motor Vehicles (DMV) office in order to verify the vehicle’s identification number (VIN). A receipt or bill-of-sale and a Manufacturer’s Certificate of Origin (MCO) are necessary to complete the registration process.

Bulldog Folding Trailers will mail the following documents to your address:

  1. Receipt or Bill-of-Sale
  2. Manufacturer’s Certificate of Origin (MCO)
  3. Vehicle Identification Number (VIN) Label
  4. Tire Placard

Receipt or Bill-of-Sale

All states require a receipt or bill-of-sale for registration to determine that the trailer was purchased legally and to determine value. Bulldog Folding Trailers or your dealer will provide this to you at the time of your trailer purchase or mail it to your address. In some case, the VIN number is required on the receipt or bill-of-sale. Check with your local DMV office for specific requirements. Please see your Bulldog Folding Trailers dealer or contact us if a receipt is lost, and always keep all necessary documentation in a safe location.

Manufacturer’s Certificate of Origin (MCO)

The MCO is necessary to determine where a trailer comes from and that it meets all required U.S. Department of Transportation (DOT) safety standards. The MCO confirms the date of manufacture and the VIN number of each trailer. Your MCO will be sent to your address. Be sure to keep the MCO in a safe place and contact us at if it becomes lost and must be replaced.

On the front of the MCO under the section; NAME OF DISTRIBUTOR, DEALER, ETC., you will see the name of the Bulldog Folding Trailers Dealer that you purchased the trailer from. On the back side of the MCO under the section; DISTRIBUTION-DEALER ASSIGNMENT NUMBER 1, the Bulldog Folding Trailers Dealer will have entered your name and address; dealer name; dealer license number (if required); dealer signature; date; and finally, the state and county. There is a section for a Notary Public signature if required by your local DMV.

Some DMV clerks may ask for the dealer section to be filled in as if transferring title of an assembled motor vehicle. This section does NOT apply to a self assembled trailer kit and we or the dealer who sells Trailer Kits are NOT required to have a motor vehicle dealer license in order to sell them.

Vehicle Identification Number (VIN) Label

Bulldog Folding Trailers will also mail you a VIN number label. This adhesive label contains tire and loading information as well as the VIN number of the trailer. This label should be fixed to the tongue of the trailer after registration.

Tire placard

The placard is an adhesive label lists the vehicle manufacturer’s cold inflation for front, rear, and spare tires, along with the tire size designation, indicated by the headings “size” or “original tire size” and “spare” or “spare tire” for the tires installed at the time of first purchase for purposes other than resale. This label should be affixed next to the VIN Label.

Information for Local Motor Vehicle Departments


Safety and Maintenance

Towing Vehicle Capacity

The maximum vehicle towing capacity is the entire trailer weight including the load. Bulldog Folding Trailers has been carefully designed to not exceed a typical compact vehicle’s tow capacity (usually a minimum of 1000 lbs.). This allows nearly any properly licensed vehicle (from compacts to large SUVs) to safely tow the trailer. We do advise that you check your vehicle specifications for more specific information.

Hitch Capacity

Hitches are rated for gross trailer weight (GTW) and tongue weight (TW). The gross trailer weight is the total weight of the trailer including the load. Trailer tongue weight (TW) is the amount of downward weight on the tongue. The tongue weight should be 10 to 15% of the total trailer weight. The Bulldog Folding Trailer has been outfitted with a Class II 2” ball hitch which can handle nearly ten times more than its rated GTW and TW. It is always recommended that the vehicle’s hitch be installed by a professional reputable shop.

Checklist Before Use

  1. Tires are properly inflated. DO Not over inflate the tires.
  2. Trailer lighting is working properly.
  3. Hitch and tongue free of deformities and defects.
  4. The trailer is setting level with the tow vehicle.
  5. Trailer ball should be lightly greased.
  6. Safety chains should be long enough for tight turns.
  7. Safety chains should be crossed in case of a hitch or coupler failure.
  8. Safety chains should not touch the ground.
  9. Lighting hookup wire should be long enough for tight turns.
  10. Lighting hookup should not touch the ground
  11. Check that all nuts and bolts are properly tightened.


Wheel Alignment

It is very important to have the trailer wheels aligned correctly or the tires can suffer premature excessive wear. The wheels should be aligned according to the procedure in the Operating Instructions included with each trailer and checked regularly or before long trips. if you have any questions regarding the wheel alignment procedure, please contact us at

Bulldog Folding Trailers will not be responsible for premature tire wear due to improper wheel alignment.

Tire Inflation

It is very important not to over inflate the tires. over inflated tires will bulge in the center of the tread and wear out prematurely. The PSI will vary based on the load, but for lighter loads such as kayaks, the tires should be inflated to 30 PSI. Heavier loads will require a higher PSI, but generally not higher than 35 PSI.

Wheel Bearing Maintenance

Trailer wheel bearings should be greased every six months and before long trips. Check them during long trips by feeling the hub for excessive heat. Caution: If the bearing is adjusted too tight or is low on grease it can get excessively hot! A hot bearing needs immediate attention. Grease or proper adjustment will normally ease the problem, but bearing replacement may be necessary.

Bearing Replacement

  1. Remove dust cap, cotter pin, nut, and washer. Pull hub off spindle.
  2. Use a hammer and a mild steel bar to drive out old inner cups.
  3. Use a solvent such as kerosene to clean the hub, nut, washer and spindle. All dirt and old grease must be removed.
  4. Inspect inside the hub where the cups seat and the spindle for scoring, pitting, bending, dents, thread or other damage. Pay close attention to the raised rear surface of the spindle where the grease seal grips. If it is scored or pitted the grease seal may leak.
  5. File off nicks or burrs using a fine file or emory cloth, then wipe away any filings, then re-clean with solvent.
  6. Coat the spindle and the inside of the hub lightly with grease.
  7. Use the mild steel bar to drive the new cups in to the hub until they are solidly seated. Do not damage the cup surfaces.
  8. Pack both bearings with grease forcing grease inside the cage in-between all the rollers starting at the large end until grease shows at the small end.
  9. Install the packed rear bearing in the hub.
  10. Install the grease seal. Don’t hammer directly on the seal. Use a block of wood. Take care to drive the seal in straight. Seal should be flush to the outside surface of the hub.
  11. Fill the hub, in behind the seal, with grease then slide the hub over the spindle being careful not to damage the seal against the spindle. Pack the hub full of grease.
  12. Install the packed outer bearing and cup then pack more grease into any voids and install the washer and nut.
  13. While turning the hub, use a 12” wrench to tighten the nut until the hub begins to bind indicating that all the bearing parts are sealed properly.
  14. Back off the nut about ¼ turn, as needed, until you have between .001” to .007” of end play.
  15. Warning: Failure to back off the nut to allow end play may cause the bearings to overheat and fail creating a risk of serious bodily harm.
  16. Lock the nut in place using a new cotter pin.
  17. Re-check end play. Install the dust cap.

Trailer Tires

Bulldog Folding Trailers use 4.80-12 or 4.80-8 tires. This tire is capable of safely maintaining any posted speed limit in the United States. The documentation package delivered with every trailer includes tire information and a warranty card. The warranty card should be filled out and sent back. This will allow Bulldog Folding Trailers to contact you in case of a tire recall.