LT vs ST's - Canadian Tires cries "Illegal!".
I replaced all 4 tires on my 35' horse trailer in the last 2 weeks - Canadian Tire had some excellent LT tires that were on 50% off "end of line liquidation" discount and the price was too hard to res...
Forum Discussion
spud1957 wrote:BFL13 wrote:PrivatePilot wrote:
Gary, read the entire thread. If Canadian Tire ..........
The only legal requirement is that the tires are capable of carrying the weight for the application they are being used for, AKA they must be rated to carry the weight the axle they're to be attached to is rated for. In my case the tires are each rated for just under 2700 pounds each and are mounted on an axle rated to carry less than that, therefore they are well within their legal required ratings.
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When did it become law that the tires have to be rated "to carry the weight of the axle" using the axle's weight "rating" as stated above?
It is true that the tires have to carry the load put on them, but that has nothing to do with the axle rating. In fact the GAWR can be based on the tires max load limit while the axle is rated to carry much more.
When you go on the scales and get your "axle weight" that is to get the load on the tires. Nothing to do with "axle weight rating"
Our truck has a rear axle rated at over 10,000 lbs. But the RGAWR is 6,084 lbs, which is what the two E tires can take at 80psi as singles.
Meanwhile our trailer has a pair of 5,200 lb axles but its GAWR is 8,600 lbs, which is max for four C tires at 50 lbs.
If I put stronger tires on the vehicle it would not change its legal GAWR. There are other components involved such as the springs. GVWR also involves the frame strength and I think, the stopping the brakes can do. If you modify your truck AFAIK you can go through a process to get its weight ratings legally changed, but otherwise its legal ratings stay the same.
BFL13, not sure if this is what you are disputing but this is taken from Transport Canada's CMVS110 definitions:
GAWR: Gross Axle Weight Rating, in kilograms, means the value specified by the vehicle manufacturer as the
load-carrying capacity of a single axle system, as measured at the tire-ground interfaces. “The GAWR shall not
exceed the rated load carrying capacity of, but not limited to, the tires, rims, suspension, axle mounting hardware
and axles.”
So it looks like it says, the axle rating cannot be greater than the tire's rating (among other components). Not sure if you meant to say your rear axle is rated for 10,000lbs or did you mean to say GVWR? You have a 3/4 ton so your rear axle is rated at 6084. From a Transport Canada perspective, your rear axle is rated at 6084 by GM, per your door label. So your tires' load capacity has to be equal or greater than 6084.
The "axle rating" is for the axle itself as its own chunk of metal. It is not the same thing as your "axle weight rating" for when on the scales. Your "axle weight" on the scales must not be more than the GAWR.
Read the rule again. The "axle system" sets the GAWR and one of the components will be the "weakest" and the GAWR is taken from what the weakest component can do. Look at your tires and see the "max load at xx PSI for a single. Your GAWR will be twice that weight. The tires are what sets the actual GAWR.
The trailer is designed so the axle systems can carry the designed weight. They choose an axle (Dexter 5200 lb rating ones, eg) and how strong to make the frame etc, then they need tires, so they choose a tire so four and the pin can carry the weight at trailer GVWR. Once they have the tire, they make the trailer GAWR equal to its rating times the number of tires. I don't know any trailers that have GAWR less than what their tires can hold because the axle is the weakest component, but I suppose it could happen.
The trailer's GVWR may be more than its GAWR where the pin is expected to carry some of the weight. The truck's two GAWRs total more than the truck's GVWR so that is different.
Yes the truck axle is rated for over 10,000 lbs. If the truck were a Diesel that axle would be rated at over 11,000 same as a 1-ton's. ( I have no idea why the axle is rated for so much more than what the tires can do)
The trailer has two Dexter 5200s so the total there is 10,400. But GAWR is 8,600. Newer Komforts with those same 5200s came with Ds instead of Cs like ours. The GAWR on the newer ones with the Ds is 10,160--which is four Ds worth. Still not 10,400 though. I just put Ds on ours but its official GAWR is still 8,600.
Be silly to put Es on it, since the new weak component would then be the axles still rated for 10,400.
