Space Between Dually Tires

[JWalker]

Looking at a tire change here shortly. Currently have 235/80/17. Thinking about switching to 265/70/17. There seems to be a lot more options for an aggressive tread pattern in that size. My concern is the tire width. The tires are almost the same diameter, but are 1.25" wider. This would leave only about .5" of space between tires. How much space is required for tire flex and heat dissipation? Thanks for the help.

Jamie

 

[jnbhobe]

Jamie will it be .5 loaded or unloaded

 

[hoefler]

I installed 245/75R17 on my dually Rams. The 265 is too wide. 1/2 an inch is not enough space under full load. If the side walls touch while loaded, you will overheat the side walls and possibly causing a blowout.

 

[priorguy]

If you know a good reputable tire guy like I do he'll have the knowledge needed to answer your question. Tim at Prior Tire has always helped me out. But he's up here in Canada and probably of little use to you, but I'm sure there's someone in your area with a small shop like his. He's a third generation tire guy so I think he's got a bit of rubber in his veins.

 

[mattpopp]

As long as the side walls never touch under every application that you use your pickup for then you are fine. 1/4" is enough as long as they never touch on a constant travel.

Alot of people will run a 1/2" or so spacer between the duals to give more clearance. Though some frown against because they think its unsafe. Which it is safe.


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[JWalker]

Jamie will it be .5 loaded or unloaded

According to my calculations, it would be .5" unloaded, so I think tire flex is going to be an issue.

 

[JWalker]

Alot of people will run a 1/2" or so spacer between the duals to give more clearance. Though some frown against because they think its unsafe. Which it is safe.


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The option of spacers was discussed. I have read several cons about this, but I have heard from several about not having any issues at all. Not sure.

 

[hoefler]

Spacers change where the load is carried by the hub and bearings, can cause bearing failure or stud failure.

 

[mattpopp]

Spacers change where the load is carried by the hub and bearings, can cause bearing failure or stud failure.

With the exception of cement roads, most all if not every other type of surfaced road is not flat. The crowns in the road cause a difference in loads on a set of duals. So with that in mind it is common for the center of the load on a set of duals to be constantly shifting.

1/2" spacer will have ill effect on the bearings. Studs only fail when not torqued properly. The clamping force from 8-9/16" studs at 60% yield is enormous. Again, they will only fail if they are not torqued properly.


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[hoefler]

With the exception of cement roads, most all if not every other type of surfaced road is not flat. The crowns in the road cause a difference in loads on a set of duals. So with that in mind it is common for the center of the load on a set of duals to be constantly shifting.

1/2" spacer will have ill effect on the bearings. Studs only fail when not torqued properly. The clamping force from 8-9/16" studs at 60% yield is enormous. Again, they will only fail if they are not torqued properly.


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That is true for hub centered wheels, wheels that fit the hub tightly ( and sometimes very difficult to remove ) and only use the studs for clamping and to keep from spinning. Wheels that do not fit the hub tightly, the load is carried by the studs as well as clamping.

 

[mattpopp]

They're called Hub Piloted. Rim is supported by a 4.75" Hub. But I don't understand what you are or are not suggesting!

 

[Garypowell]

Another factor not mentioned yet is that tire load capability is always lower in dually applications. The reason given is heat dissipation. I would think as you move the tires closer together this would only get worse making the tires more and more vulnerable to blow outs.

 

[hoefler]

On some makes, and especially if they have after market wheels, the wheels are not hub piloted or hub supported, the studs carry 100% of the load.