• Announcements

    • Site Upgrade   11/18/2017

      The Forums will be down, Friday, November 24th starting 8 AM PST for upgrade.We'll probably be down until 1PM PST, but it might be longer. I'm doing a major forum software upgrade, so I expect the forums to operate somewhat differently when we come back online. 

wheel help

5 posts in this topic

Posted

Hey guys, I have a really dumb question for you guys.  It's going to take me a bit to get to it, so here goes.  I live in Massachusetts, which as far as I can tell will allow a truck to gross 73k with 3 axles.  And as far as I can tell this would require an 18- 20k front axle and most likely 58k rears.  Now in order to achieve this I believe you would have to run 11x24.5 or 12x24.5 tires.  Does this sound correct?  Now for the hard part, what are my options for these?  I currently have a few dump trucks coming down the pipe and am trying to line up some parts and get my ideas figured out before I start, so I can make sure things play nice together.  

Thanks for the help.

Share this post


Link to post
Share on other sites

Posted

This may or may not help Chris, but by federal regulations the maximum weight is 80,000 pounds for a regular 5 axle tractor trailer with a breakdown like this:

Steering axle=12,000 lbs

Tandem drive axles=34,000 lbs

Trailer tandem axles=34,000 lbs

Trailer tandem spread axles=40,000 lbs but total GVWR (gross vehicle weight rating) still cannot exceed 80,000 lbs

That is the rules for federal interstate over the road trucks, but there are also state regulations that muddy the waters so to speak, but the max I would say a three axle truck could weigh would be more around the 50,000 lb range with a steering axle with wider "float" tires, which I believe may raise the max steer axle weight to 17,000 lbs. Other than the wider float steering tires, tire size doesn't have a difference in the allowable weights. The common size for wheels today are 22.5 rims, though 24.5 are still used, but the biggest difference is the sidewall height, which is why the tires for 22.5 rims are commonly called "Lo Pros" because of a lower sidewall profile than the "tall rubber" 24.5s. 

You could still build a dump truck with three axles, but at least most in my area in the WV, OH, and PA region near Pittsburgh hauling coal usually have at least one liftable "tag" axle and more commonly two or three tags, making them 5 or 6 axle trucks. 

5 axle

6 axle

The lift axles add 17,000 lbs to the gross weight, so one added to a 3 axle dump truck with a steering axle with the wider float steer tires (like the 5 axle Peterbilt has) would give the truck a 68,000 lb GVWR. 

Hopefully this helps you some, but those are the easiest examples using the federal guidelines. Everything can vary state to state, and permits to haul heavier can throw everything out the window! :lol:

Share this post


Link to post
Share on other sites

Posted

Thank you for the reply, I know that my state's laws vary a bit from the norm.  I found this online...

 

In general, circumstances under which a special permit is required are as follows:

A motor vehicle or vehicle combination requires a special permit if the vehicles weight exceeds the following maximum vehicle weight:Motor vehicle with two axles - 46,000 lbs.Vehicle or vehicle combination with three axles - 73,000 lbs.Vehicle or vehicle combination with four or more axles - 87,000 lbs.Vehicle or vehicle combination with five or more axles - 99,000 lbs....

 

Someone told me that there was a difference in the manufacurers' ratings on the 22.5's and the 24.5's but I don't honestly know about that.  I guess that's the starting point of my question.

Share this post


Link to post
Share on other sites

Posted

Thank you for the reply, I know that my state's laws vary a bit from the norm.  I found this online...

 

In general, circumstances under which a special permit is required are as follows:

A motor vehicle or vehicle combination requires a special permit if the vehicles weight exceeds the following maximum vehicle weight:Motor vehicle with two axles - 46,000 lbs.Vehicle or vehicle combination with three axles - 73,000 lbs.Vehicle or vehicle combination with four or more axles - 87,000 lbs.Vehicle or vehicle combination with five or more axles - 99,000 lbs....

 

Someone told me that there was a difference in the manufacurers' ratings on the 22.5's and the 24.5's but I don't honestly know about that.  I guess that's the starting point of my question.

You're welcome Chris, and what you found online was exactly what I meant by permits making all the federal guidelines go out the window! 

As for the wheel size being a factor, I don't know able that either but since you did mention the manufacture rating, it could have an influence in the GAWR (gross axle weight rating) and the GVWR that the truck as the manufacture equipped it, but that still doesn't make a difference in the state or federal guidelines for allowable weights. The manufacture specs are different depending on how the truck is equipped, a vocational truck such as a dump truck, garbage truck, or a tractor built for heavy hauling is built with much heavier duty components than an over the road truck would be.  

Share this post


Link to post
Share on other sites

Posted (edited)

And should you really decide to run yourself into a mental abyss on this whole issue, do a little digging into what is called "bridge formulas".  Especially in California and Florida in the 1970's and 1980's.  While it is still "bad" even today, it is nothing like it was. Remember...no computers or smart phones to do the math.  Inmates running the asylum utilized more logic.  

I am convinced it was a mandated apprenticeship for once intelligent minds brainwashed and drugged into desiring employment with the IRS writing US tax code.  "Let us see just how complex you can make this.  Pay is based on word count and ensuring the inability of the common man to every truly be compliant no matter how hard he tries too."

Tragic....

Peace. 

Edited by olsbooks

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now