no need to say more
http://www.th.gov.bc.ca/cvse/vehicle_inspections/PDF/MV3230.pdf
yep they just came out with the brakes on the tow vehicle law
..brakes needed when towed vehicle is over 4409# or over 40% of GVW of motorhome.
First off, I am not trying to start a large debate.
I have concerns about all the supplemental brake systems on the market - some more than others. In FMCA seminars, the representatives have been unable to satisfy those concerns.
What are my concerns?
1. Over or under braking of the tow car. If the tow car is over braked, it is going to wear out its brakes trying to slow the coach. Under braked, it is not effectively doing anything. On cars, extensive development testing is done so that the front and rear tires would skid at the same vehicle deceleration rate (approximately 35 ft/sec/sec.). Antilock helps this situation in panic stops. But you also want the front and rear brakes to share in the deceleration BEFORE wheel skid.
So, how would a supplemental brake supplier size their components so that it would not over or under brake? They would have to encompass the towed vehicle's master cylinder size, wheel cylinder sizes, brake pedal ratio, brake lining friction characteristics, ... Oh yes, they would also have to design their product for all the variety of TOWING vehicles.
The supplemental brake suppliers cannot do this effectively. They need to compromise or GUESS!
2. Those designs that operate the brake pedal may be damaging to the car. Most cars are designed with vacuum power brakes. They are not designed to operate the brake pedal under a manual type condition (without vacuum) continuously. Large pedal forces required to stop a vehicle, will eventually fatigue the front of dash (mounting point of the brake pedal bracket). Do you think that the supplemental brake supplier evaluated this condition?
3. Were the supplemental brakes designed for potential failure modes. Nick's product problems demonstrate the potential reliability concerns. This, is even before the product is used extensively, to show any durability problems.
4. My last concern is the cost of the supplemental brake system. IF they worked effectively, reliably, and were durable, they may be worth the expense.
Having experience in brake design, I have, "design a supplemental brake system", on my To Do list. But, it is not high on the list.
At this point, I rely on the fact that I am operating a coach and towed vehicle below the gross combined weight, and probably less than the GVW, gross vehicle weight, of the coach. Also, I use a jake brake extensively.
Ed Roelle
Flint, MI
ED, I use the M & G air system it mounts between the booster and the master cylinder and so far I like it works off my coach air brakes only draw backs it can not be adjusted from the drivers area like the wireless models and you can not take it from vehicle to vehicle but it's simple like me and cost around 650.00
The M & G is one of the nicest/cleanest units out there. Concern 2 is completely eliminated.
Unfortunately, they do not have a unit for every tow car.
Ed Roelle
Flint, MI
We also use the M&G on our Grand Cherokee. It is fed from our tag axle brake air supply. More air pressure to the tag alxee brakes=stronger Toad brake application. No muss-no Fuss when we arrive. Paula hops in the Cherokee, puts transfer case in 2WD while I disconnect the hitch, air hose, lights, and break-away cable. Takes about 2 minutes. Jack
PS: Removing the break-away pin from the switch on the car is a good anti-theft device.
maybe the Moderator could put this as a sticky???? I don't recall any other state or province's regulations being posted [maybe they have I just don't recall].
BC revised this regulation some years ago from 1500 KGs to 2000 KGs to be closer to the NORM, making all regulations much closer to each other.
Les R
Quote from: lesrMC9 on March 30, 2008, 04:08:12 PM
maybe the Moderator could put this as a sticky???? I don't recall any other state or province's regulations being posted [maybe they have I just don't recall].
BC revised this regulation some years ago from 1500 KGs to 2000 KGs to be closer to the NORM, making all regulations much closer to each other.
Les R
I have already copied it to the
HELP boardRichard
Some of my thoughts (Oh, that hurts) on supplemental braking.
First of all the whole idea of supplemental comes from some fool trying to tow his Hummer behind a Winnebago which was overloaded when it left the factory. For most of us the towed is probably 10-15% of GVW and not an issue. If you are driving a 50,000# conversion, that's a different story.
If you are going to add brakes then I have a couple of ideas for your consideration.
The first is to have an electric vacuum pump on the towed and keep the anti-locks powered up. That way you could significantly reduce the pressure on the pedal assembly. In the old days, you could not leave the ignition on without the engine running because it would burn up points and coils. I don't know that it would do any harm on today's cars. You would have to keep the towed's battery charged from the bus.
I like Fred Hobe's home built system myself.
http://users.cwnet.com/~thall/fredhobe3.htm
The second idea is to use the standard "pedal pusher" but limit it's operation to panic stops, either by using a protection type valve so the towed brakes are not applied at all until the bus braking pressure is high enough (whatever that number is) or by a pendulum type decelerometer such as is used in electric trailer brakes.
Len
for ye who are FMCA members the January issue has "RV Regulations" and can be seen via the web in PDF, but you have to be a member to see them online.
It gives DL type, length, height, width, combined length and speed limit for each state and province and territory
also posted on other BB