Tire Spacing ????

[tvman44]

I have seen a couple of tire spacing questions, but want to know if any one has ever checked with a manufacturer as to the minimum spacing between 2 tires on a tandem (dual) axle trailer.  Right now I have 3 1/4" between the tires on our 5er and was thinking of getting a slightly larger tire that would cut the spacing down to about 2".  That would get me about another 724 lbs carrying capacity for a pair of tires.

 

[DieselJay]

it is not so much the size of the tire, but what the tire is rated,most trailer tires are rated D & E  E being the better, so going to just a bigger size tire may not achieve what you are looking for ,I would check out the ratings of the tire. And don't forget the axle is rated for a certain weight so if you have a 6 lug wheel you have 5000 pound axle, and if you have a 8 lug , you have a 6000 pound axle, be careful how much weight you add to your axles if you overload them you will be burning up bearings quickly. just my 2 cents

 

[tvman44]

Axles are 5,200 lbs, rims are 6,400 lbs for two, plenty of clearance all the way around except for maybe between the tires.  I would gain an additional 724 lbs capacity from the tires.

 

[kjansen]

I have 8 lug axles, but they are 7,000 # axles.

 

[Gary RV_Wizard]

I wouldn't think that 2" would be a problem, but can't find any info that supports that opinion. Seems to me there is almost zero tire movement for & aft - it's all up and down motion. I've seen tires so close you could hardly get a hand between them, but can't say for a fact that those tires never rubbed. But if its a rare event, maybe not worth worrying over anyway?

One caveat: if the space is small, you can't use a locking wheel chock.

 

[glockholiday]

I'd run that setup.

I've heard people say that if they're too close then if one blows it will take the other with it. I think we all know that when a tire blows anything within 10 feet is fair game so whats an inch or two.

 

[catblaster]

Depending on how your springs are set up the can be movement for and aft as the spring loads and unloads. An example is a set up that is where the springs are fixed at the front and rear and has a rocker in the middle with shackles. Each axle will move half of the difference of the springs length between loaded and unloaded. If the spring is low load with a high arc then it will move much more than a heavy spring with a low arc. The loaded measurement is increased as the vehicle moves and the spring is impacted with road conditions.

If each spring is fixed at its front with slippers on the rear the same amount of movement occures but each axle moves to the rear instead of towards each other in the above example.

Best answer is to keep the same diameter tire and increase the load rating instead.

 

[billmac]

I have a 2005 Cardinal with tandem axles and the spacing is only about 1 or 2 inches.  It is my understanding that on my trailer the E rating truck tire was an option that ate up the previous clearance.  I have owned the trailer for nearly 10 years and the closeness has not been a problem.  Like one person said, anything within 10ft is in jeopardy if the tire explodes. 

FYI.  I recently replaced all my bolts and shackles.  My old stuff was a problem waiting to happen.  I went with wet bolts and lifetime bushings.  The shackles are now super heavy duty. 

 

[John From Detroit]

Not the vehicle maker but rather the tire makers often DO state minimum spacing requirements or recommendations on the tire's web page.

I have seen them for Michelin (The only one I checked)  but I am fairly sure they all will have them.

If the tires are too close, air can not properly circulate, heat rises and you get the problme Ford caused with it's Explorers some years ago (Sidewall failure of the tire)

 

[Ned]

Spacing requirements are for dual wheels, the OP is asking about tandem axle spacing, an entirely different question.

 

[FastEagle]

Here is some information from Dexter axles. Other axle manufacturers may have different clearances. Item #24 on this list answers the question about clearances between tires for Dexter axles.

http://www.dexteraxle.com/running_gear_tips

FastEagle

 

[John From Detroit]

Spacing requirements are for dual wheels, the OP is asking about tandem axle spacing, an entirely different question.

An Dual axles, an inch is as good as a mile,, So long as they do not touch, should not be a problem.

 

[Gary RV_Wizard]

From the Dexter Axle tips that FastEagle posted:

Tip #24:  Axles should be spaced far enough apart to allow a minimum of 1" clearance between the tires. More space would be required if tire chains are to be used.

 

[tvman44]

Gary, that is the kind of answer I was looking for.  My reason for wanting to go with bigger tires was not to be able to carry more weight but I would like more reserve capacity in my tires.

 

[Mopar1973Man]

Still don't understand why you have to increase size of the tire? Most all ST tire sizes allow for Load Range C, D, E, F and G. Like Right now I could go up another Load range on my RV without changing the tire size at all. The F and G load range might be a bit more tricky but I know the C, D and E are common and shouldn't require a size change.

 

[tvman44]

I am running LT225/75R16E currently with a max capacity of 2,680lbs, the LT245/75R16E I am considering have a max capacity of 3,042 lbs. giving me a 362 lbs increase per tire or 724 lbs per axle.  What I now have is adequate I would just like more reserve capacity.  Load range E is the heaviest in my size.  I originally had ST225/75R15D but I changed to get away from the funky chinese ST tires that were wearing in a crazy pattern for American made LT tires and so glad I did.