Hard Lesson Learned

Susan wrote:

My company marks the side of the trailers, in feet, so we can easily tell how many feet the center of the 5th axle is from the kingpin. Much easier to know you're compliant with bridge laws.

I'm glad to see it explained.

Bridge law? I think you meant kingpin law.

The federal bridge law formula (for example) for 80,000 pounds gross weight is 51' from the rear most axle of the tandems to the front steer axle of the tractor is the minimum legal distance for a 5 axle trailer. As the weight is less, the minimum allowable distance decreases. Relatively speaking; for a 53' trailer and a condo-sleeper, the one hole (tandems set all the way to the front of the rails, closest to the cab) is about at the 54'-55' mark. All but impossible to be non-compliant with bridge law for a 53' tractor and trailer combination. However in the one hole, many northeast states will cite for excessive overhang. You can be in compliance with bridge laws and be non-compliant with kingpin setting law.

Where bridge law becomes more critical and enforced is with highly dense, heavy loads in a short trailer, such as 45,000 pounds of gravel in a 30' dump. Typically this type of trailer is a tri-axle configuration because bridge law goes by max weight per axle and distance between each axle and/or a set of axles. It's complicated.

Bridge law was far more relevant when there was greater restriction in overall legal length, 1980s during the COE (cab over) era when 40' and 45' trailers were SOP, and 80,000 pounds gross combination weight was legal.

In addition not all companies mark their trailers like you mentioned, because kingpin law varies from state to state. Walmart does not mark 41' on center, but they do mark maximum hole settings by state that's relevant to kingpin setting law (not bridge law) on the side of each trailer above the tandem area. The maximum hole setting is furtherest from the kingpin to the rear of the trailer.

To be specific; in PA and NJ (where I spend the majority of my time) I can work with the 6-11 holes (I'll push to 12 if need-be) to comply with kingpin law, and get the load legal on the tandems and drives.

Each state's kingpin law is different and some states like Maryland, New Jersey and Connecticut are very strict, known to use a tape measure for overhang infractions. This is why I originally posed the question to Unholychaos: "what states are you routed through?"

In my profile photo gallery I have two images relevant to state kingpin law. With a laptop it shoukd be readable, probably not with a phone though. For you Swifties, this information is in the drivers handbook and quick notes binder.

Can you elaborate on the overhang? Specifically with regard to 53' van trailers. I'm aware of the bridge laws (with regard to axle weights) and king pin laws (I'm under the impression that restricting the distance from king pin to rear axle is in attempt to control and manage the turning radius of trucks)

I haven't found any consistent information about why I shouldn't/can't run with the tandems all the way forward? If the weight permits I usually have them as far forward as possible. Is that also a problem in some states??

Four states are of concern for overhang enforcement (that I know of) PA, NJ, MD and CT. MD DOT will use a tape measure, very strict.

As follows; Trailers in excess of 48' require no more than 41' spacing from kingpin to center of either the tandem or rear axle, and can have no more than 35% of that same distance as overhang measured from the center of the tandem to the end of the trailer.

35% of 41' is 14.35' from the center of the tandem to the rear edge of the bumper.

I would not run in any of those 4 states with the tandems set all the way forward.

Remember sliding the tandem accomplishes two things; legal weight on the drives and tandems is rule 1. Rule two is weight balance. If sliding all the way forward towards the front puts a lot of weight behind the tandems, your truck will handle poorly. As an example 11.5k on the steers, 28k on the drives and 32k on the tandems could occur with the tandems set to the very front of the rails on a cubed out load. Legal yes, balanced no.

Susan replied:

GTown, it is real complicated which is one reason my employer marks ALL equipment with length markings. It can get crazy so it just helps in standardizing.

To be clear, for a 53' tractor and trailer not exceeding 80,000 pounds, it's virtually impossible to be noncompliant with federal bridge law. State kingpin setting law and bridge law is not the same and not interchangeable terms.

I agree, many companies do mark their trailers for nominal kingpin settings with the distance measured from kingpin to the mark. Many times 41' is marked with a vusable downward pointing arrow, also will see 40, 43, 45. But, you need to understand the kingpin laws in each state for the marks to mean anything and/or help a driver to get legal. That said; 41' is definitely the predominant number. However some states use diagram 1, like Maryland and measure to the center of the rear axle, while others use diagram 2, like PA and NJ measuring to the center point of the tandem subframe. In PA and NJ I can legally run with tandems set about 2' further to the rear than I can in MD. The oddball is CA, 40' using diagram 1 (tough).

Of the states I run, Maryland is the most strict. On occasion I get a first-stop Maryland run that doesn't comply with their law so the trailer is re-docked and either reworked or the last pallet comes off. I run only one vendor backhaul from MD, bagged sugar from Domino; typically in the 37-38k range so I am able to legally scale that.

More than half the states have no kingpin law; others do and it can vary even in adjoining states; like MD and PA, OH (no KP law) and PA, etc.

Again this is why I asked Unholychaos the question about where he was running with his tandems slid all the way to the rear of his trailer. Run like that in PA and NJ during the M-F workweek...if a scale is open you must go in. No scalepass in either state. So be careful and know each state's law your are routed through.

As a rule of thumb from the front of the rail, I use the 11th (standard spacing, 6" centers) hole, not counting the stop bar, for PA and NJ as my max setting because it places the tandem center point 41' from the kingpin every time. Legal max, shouldn't go past it. Walmart buys trailers from every known manufacturer and they all have the same kingpin setting template on the sides using the numbered hole as the indicator for compliance in every state. Granted that's Walmart and what I know best. No idea if it's standard or their specification.

I have a very good friend who works for Wabash National (20 years). Because Brett's point peaked my curiosity and also my desire to offer accurate advice, I emailed my friend to determine if there are any current standards they follow or is the rail length a custom configured part ordered/spec'd differently for each company. I'll report back once he replies to me.

I have a very good friend who works for Wabash National (20 years). Because Brett's point peaked my curiosity and also my desire to offer accurate advice, I emailed my friend to determine if there are any current standards they follow or is the rail length a custom configured part ordered/spec'd differently for each company. I'll report back once he replies to me.

That's cool! I'll be interested to hear what he says.

Just to clarify my earlier post, I thought I'd put in my comment only because UnholyChaos is a fellow Schneider driver, and since some of the older trailers have a sticker listing the max hole for different states, it's important to know how the holes are being counted. But since the subject came up, the Schneider reference I mentioned has a chart listing the max hole for each state, for 3 different trailer models: 2010 and older Wabash, 2011 Wabash, and 2011 Hyundai, and the the max holes are slightly different for each. I think all later trailers have stickers at 41 and 43 feet, so there's no need to count holes.

That said, I'm also be interested to hear what G Town's friend says. I'm particularly interested in knowing if there is any standard in hole spacing.

Kurt G. asked:

That said, I'm also be interested to hear what G Town's friend says. I'm particularly interested in knowing if there is any standard in hole spacing.

Standard hole spacing is on 6" centers (2 per foot). However there is a non-standard micro-setting; holes are on 4" centers. The newer Hyundai Walmart dry vans are micro-set (3 per foot).

I originally wrote this:

I have a very good friend who works for Wabash National (20 years). Because Brett's point peaked my curiosity and also my desire to offer accurate advice, I emailed my friend to determine if there are any current standards they follow or is the rail length a custom configured part ordered/spec'd differently for each company. I'll report back once he replies to me.

Brett replied:

That's cool! I'll be interested to hear what he says.

As promised...

Unless specified otherwise, the standard offered length is 200" (16' 8"). I checked Great Dane's website and their stock length is also 200". Websites for Hyundai, Stoughten, and Utility do not state a stock length, only all of the lengths available. He went on to add, most of the TL Carriers order the 200" or 216" length, on occasion 228". For those spec'd for 216", many times they also spec. the stop bar be set in the 5th hole (Schneider perhaps?). Regional carriers that typically travel in areas without a kingpin rule, many times order a longer length (makes sense). There is also a school of engineering thought that supports the additional length adds cross bracing thus reducing the twisting that occurs between the floor frame, frame rail (slider rail), and the slider (aka sub frame) itself (which can cause the pins to stick).

With that said, they also offer the frame rail in lengths of 228", 232", 236" and 240" and is matched to specific slider/sub frames. Wabash like many trailer builders also make a 57" van, heavy-haul tri-axles, thus requiring the longer frame rails being offered. For shorter trailers (LT 48'), like P&D , local delivery trailers, other specialized applications; stock rails come in 176" and 184" lengths.

Standard hole spacing for the frame rail is 6" on-center, unless micro spacing is spec'd which is 4" on-center.

For the trailers I know and love; most of the frame rails are 200", set holes spaced 6" on-center. There are however some anomalies; 228" on some of the older reefers and many of the newer Hyundai trailers have the micro set hole spacing.

So to Brett's point, hole counting is not always a fool-proof approach to determine the maximum tandem setting necessary to comply with state kingpin law.

Yeah all our dry van trailers are the 4" ones. That said on those P&G Lima OH loads we pick up, 9 x out of 10 I have to run the toll roads to Carlisle PA and then go south on 81 to Shippensburg. They want us to run I68, but no can do Maryland legally on most those loads. Some of our drivers will, but I sure won't chance it. MD will not play for sure. I've seen them pull out the tape measure. Not on me, but other trucks.

Yeah all our dry van trailers are the 4" ones. That said on those P&G Lima OH loads we pick up, 9 x out of 10 I have to run the toll roads to Carlisle PA and then go south on 81 to Shippensburg. They want us to run I68, but no can do Maryland legally on most those loads. Some of our drivers will, but I sure won't chance it. MD will not play for sure. I've seen them pull out the tape measure. Not on me, but other trucks.

I agree on MD. Very strict. If my second stop is in MD, not a problem, but first with 45k in the box, very difficult to scale legal.