Originally Posted by whiterhino
Did a quick search. Found the state police inspection sheet. Look in section D. States brakes on all wheels if 5500 pounds. I haven't found the actual law.
I also found several rv and boat sites that state brakes are required over 3000 pounds.
As far as the tire size, I would go with the 15". Keep in mind that the actual trailer deck height is only 1" higher with a 2" taller tire. I have had my share of trailer tire issues over the years. Personally I don't like radials because of the sway. They are also visually harder to determine if they are low on tire pressure when doing a simple walk around inspection during fuel stops. I never get anthing but "D" rated bias now.
And like the other guys said, larger tire equals slower revolutions and cooler bearings.
just my .02
In the Michigan Vehicle Code, it states:
(1) Brake equipment shall be required as follows:
(d) A new motor vehicle, trailer, or semitrailer sold in this state and operated upon the highways shall be equipped with brakes on all wheels, except a motorcycle or moped, and except that a semitrailer, pole trailer, or trailer of less than 3,000 pounds gross weight need not be equipped with brakes if the gross weight of a trailer or pole trailer, no part of the load of which rests upon the towing vehicle, does not exceed 40% of the gross weight of the towing vehicle, and if the gross weight of the towing vehicle and the gross weight of a semitrailer or pole trailer, part of the load of which rests upon the towing vehicle, does not exceed 40% of the gross weight of the towing vehicle when connected to the semitrailer or pole trailer. This subdivision shall not apply to a trailer or semitrailer owned by a farmer and used exclusively in connection with the farming operations of the farmer and not used for hire.
Gross weight being defined as:
257.19 “Gross weight” defined.
“Gross weight” means the weight of a vehicle without load plus the weight of any load thereon.
So, what that means is that EMPTY you don't need brakes on most flatbed, which weigh in around 1500-2000 lbs unloaded. But when you've got a 4x4 up there your trailer gross weight is ~5000-7000 lbs, which is usually more than 40% of your tow vehicle, which for most of us is ~7000-12000 lbs.
So, even the baddest Dodge 3500 out today, which has a gross vehicile weight rating of 12200 lbs can't legally tow a stock TJ on an average trailer without 4 wheel trailer brakes. Bu tit can tow that trailer empty with no brakes.