Speaking of bridge laws....

Ah, no. it's weight distribution and possibly turning radius, ( heard that somewhere).

 

It is for the turning radius.

 

King pin to rear axle law is the proper name, it says how far apart your axles can be at maximum, it helps with turning to have the axles closer, but you also get more tailswing, when they are far apart, and this law only applies to trailers over 48 feet.

bridge law says how close your axle can be, for spreading the weight going over bridges!

People are always confusing the two!

 

CA does not have enough "low" bridges for this to be a concern. But yes, the issue you speak of makes a huge difference when you're trying to get a 53 foot trailer with the tandems all the way back under a bridge where the road is U-shaped immediately under it. But it's funny, CA, generally speaking, is more truck friendly than most any other state as far as navigating roads and turns with their relatively new wide[er] roads designed with 75+ foot long truck traffic in mind.

But, I think the true intent of the setting is to spread [gross] weight across a wider span ... but not "too wide". But seem very nit-pickey to me, regardless when you think about it.

http://www.fhwa.dot.gov/reports/tswstudy/TSWpaper.htm

... provides some pretty good information on King pin setting and "bridge laws"

 

Re-examine your statement, and you might come to a better answer.

Yes, spreading it out, helps distribute the weight for bridges better, and the opposite of that is...... closer together you can't load as much legally... or tear up the bridge/roads as much. They don't want trucks maxed out on weight. 73,000 for 5 axles with 40' kingpin setting.
The tail swing is an additional benefit in that the tighter the tandems, the less lead you need for a turn, meaning you can make sharper turns with less real estate with the tandems closer. There are some small streets once you get off the freeway.

 

I find it is easier to keep an eye on my trailer tandems as I go around a corner than it is to watch that trailer corner swinging around...but easiest of all is not going to Calif***ya or pulling shorter trailers.

...and 73K for 5 axles is with 40' spacing between the 1st and 5th axle. A 40' kingpin setting would have 40 feet between the 5th wheel (usually located between the drive axles) and the center of the trailer tandems...so there is actually going to be roughly 44' between the front drive axle and the rear trailer axle...4 axles in 44' allows 71.5K (34K x 2 = is only 68K)...and that still doesn't include the weight on your steer axle.

 

From recent experience I for once had no problem with them moved forward. Some tight turns in East LA.

 

I stand corrected, regards the weight. Thank you. Using the tables and misapplying them