Tires and Dynamic vs Static Loads

[srschang]

Lots of debate on here about rear tires - SRW vs DRW, E rated vs 19.5.... But what about the front tires on a pickup with a heavy camper. The door sticker states the maximum load on the front and rear axles. Most truck campers add little to no weight to the front axle when the truck is sitting on the scale not moving. But what load is on the front tires during hard / emergency braking? Especially with a higher basement camper?

How about duallys with a heavy/tall camper. When braking hard, would a couple thousand additional pounds be put on the front axle?

Never heard of anyone having a front tire blowout while hauling a camper, so maybe I'm not thinking about this right.

Scott

[Kayteg1]

The basic knowledge about tires is that they take short overloads just fine.
Any tires will carry 3-5 times nominal load when rolling.
It is combination of overload and heat who destroys the tires.
Overload = more flex= higher temperatures.

[billtex]

srschang wrote:
I thought it was something like that. When we were shopping for our camper, we stopped at a popular dealer in the northeast. He had recently bought a new Ford F350 SRW for a general shop truck and to deliver campers. He said he even used it to deliver double slide campers, he just slapped a pair of 19.5s on the back and loaded the camper up. Never mentioned changing the tires on the front, so I guess no need to worry about the weight transferring to the fronts.

Scott

Unless that was a 2WD truck (highly unlikely in the NE) I think he was pulling your leg. Or he paid a LOT of attention to matching tire diameters...

[Grit_dog]

From engineering understanding and a few years of hauling a camper under my belt, I'd say it's virtually impossible to put as great of a dynamic load on a front tire as it is a rear tire under a camper.
I don't even air up the fronts any more than whatever is in them for bob tailing around and never felt a bit of issue even during hard braking, cornering, evasive maneuvers.
Or to look at it another way, if the fronts saw anywhere near what the rears did, the front springs would need to be much heavier just for normal driving to keep from bottoming out.

[srschang]

I thought it was something like that. When we were shopping for our camper, we stopped at a popular dealer in the northeast. He had recently bought a new Ford F350 SRW for a general shop truck and to deliver campers. He said he even used it to deliver double slide campers, he just slapped a pair of 19.5s on the back and loaded the camper up. Never mentioned changing the tires on the front, so I guess no need to worry about the weight transferring to the fronts.

Scott

[mkirsch]

valhalla360 wrote:
The manufacturers already figured this out long ago.

Exactly. They figured it out, so you don't have to worry about it.

Otherwise we would have tires blowing every time we hit the brakes, or hit a pot hole, or went around a corner a little too fast...

[valhalla360]

Load ratings are listed as static loads because it's hard to measure dynamic loads...and will confuse most people because clearly their pickup doesn't weigh 30-40,000lb.

But ratings assume dynamic loads that the static loads generate when they are converted to dynamic.

The manufacturers already figured this out long ago.

This is why I find it funny when people freak out about someone only blocking a single tire on a dually MH to level it for the night...guess what the dynamic loads when that tire hits a nasty pothole are far higher than double the normal static load on the tire. As long as you pull up onto the block slowly keeping the dynamic loads minimal, there is no real risk.

[billtex]

Well on a SRW the front tires should have same LR as rear tires. So if you are already carrying the camper on your rear tires safely any dynamic loading on the (lightly loaded) front tires would be well with load capacity.
Certainly you could have a failure (road hazard?) on any tire.