Why 73,280 lbs?

[Anonymous-0]

Around here the weight limit of the roads is 73,280 pounds most of the year. Why in the world did they pick a strange number like that? Why not 74k or something. Does 73,280 convert into a round number in another unit? I've always been curious.

 

[the tractor vet]

That was what it was for years in most states then along come the new age of trucking when everybody wanted to haul more for less and most places went to 80000 but some stayed at the 73280 on there back roads . To know all the goofy laws on the books ya have to be a New York attorney . This is how they get the little guy when he is out of state. It is all about the almighty buck.

 

[RodinNS]

Dunno. It's an odd number in metric too at 33309.09 KG... It's an awful low number too. We can take 27500 on a tandem here so long as it's got super singles on the front. Normal weights here are 9500 per axle on the drives, 9500 on the trailer axles and 5500 to 8500 on the front axle. I don't do any heavy trailer work so I'm not right up on those rules, but as far as I know most of our secondary roads are only tandem trailer roads. Tridems are supposed to stay on the highways, or else they have to carry their third axle in the cluster while on secondary roads. They can't scale on the third axle. Super B's will go to 62500 on the main highways. These figures are all in KG, so multiply by 2.2 for the #'s...

Rod

 

[Anonymous-0]

I did some quick digging, and that number seems to have come from the 1956 Federal Highway Act that establised it as the maximum GVW on Interstates (except for a bunch of exceptions...)

It also established 18,000# single axle, 32,000# tandem axle limits.

One hopes that somewhere some engineer did the calculations based on the maximum axle weights, maximum allowed trailer length, maximum speed limits to come up with that number.

Of course, it was Congress that had to pass the law and we can only imagine the back scratching going on.

 

[Donnie Baker]

Let me guess you live in Illinois? They was one of the last states to go to 80,000lbs. on their highways and I think they keep the lower number on the other roads as a revenue enhancement scheme. I gotta go that d*ckhead Randy won't even give me a break on Sunday

 

[jpl]

yep, i hauled steel out of pittsburg for 12 years starting about 1967, it was 73280 in pa and you always snuck out to ohio with bigger load cause ohio was 80,000. the 73280 already had tolerance in it, so you better not be over the 73280, they watched preety good and used grain scales and whatever they could use. remember 53 cents per 100wt pitts to cols ohio. that was good money being as fuel was a lot cheaper than today.

 

[Anonymous-0]

Thats a very good question. I never really thought about it.

 

[Leland]

Wheel base has a lot to do with it as well and thickness of pavement ,but in ILL with a 26' dump I can only scale 73280 due to bridge laws but with a 39' dump I can max out to 80 .I guess they are worried about stressing roads and bridges from not having weight spread out enough .

 

[Anonymous-0]

What I don,t understand is you have so much weight on 5 axles spreading it out still put that much weight on each tire. bridge law I never understood

 

[thejdman01]

What i could never figure out is why they allow 18k on a single axle (like say on a front) 2 tires, and allow 34k oon a tandem (8 tires). Talk about stress on a road etc. I realize they want the weight spread out disntance wise but I never understood why they would allow 18k on 2 tires and 34k on 8 tires. Some roads have a 16k lb axle weight limit in il so you have to run 16 on the front, 32 on yoru tandems to gross 80. Whey would they want /allow 16k on 2 tires and 32k on 8?

 

[fixerupper]

In Iowa the front axle wt is 12000 lb. Jim

 

[Anonymous-0]

The 18k on single axle is for duals, like a drive axle or trailer, or super-singles.
Look closely at a typical truck tire, it will be rated by the maker at around 6100-6500# when used as single, around 5400# each when used as duals.
Also, most states, think even the interstates, limit load to 500# per inch tread width. Used to be 600# in some states. This is why some dumps & transit mixers use super-singles on steering. Extra tread width give extra capacity.
Normal steering axle is rated to 13000# by the maker, unless special ordered.

 

[Doc Larry]

I haven't driven for many years but the Colorado limit was 76000, not 73280, when I was driving, and since has been increased to 80,000. I guess states back east had a lower limit.

 

[RodinNS]

You can carry 18 on a steering axle 'here'. Again, that's on super singles, and with tolerance I think its actually more like 18,7 'here'.
I don't believe there are any restrictions as to how a tractor is loaded here so long as the gross for the combination is not exceeded, and the axle limits are not exceeded. A super B would be able to carry a lot more based on it's axle ratings here than they actually allow due to a maximum gross... but I don't think they're too picky about how it's on there. A standard tractor here will have a 12 front and 40 rears though the heavy spec trucks for logging often have 14,6 or 16 fronts and 46 rears. The 18 and 20 fronts are mostly reserved for tandem straight trucks which can go to 60,700 including tolerance on 3 axles...

Rod

 

[Leland]

it's all psyhics

 

[Anonymous-0]

Matter of fact I do live in Illinois. I've been pondering moving out of here someday, too.

 

[Walt Davies]

We must have some real crazy laws here in Oregon, I see trailers with 3 and even 4 axles on them. Some of them the axles are spread out along the trailer like 6 to 8 ft. between them. Boy I wonder what its like in a sharp turn with these rigs. We have very few State police less than 200 for the whole state. the last three dumacrat Governors cut them way back I rarely see a scales open anymore.
I guess it wide open to haul what ever you want now.
There was an Accident on I-5 just south of Salem a couple months ago and they had to get a State Trooper out of bed to go to it.
Makes one wonder what's next. We also have 3 trailers on I-5 and then they have to drop one when going into Cal. or Wash. Ever watch one of those going down the road looks like a big snake.
Walt