Wheel well protection modification question

[roadglide]

I was doing some research and found Something John JRTHM posted four years ago tire exploding ripping of 16 gauge fenders. I used EPDM the stuff that goes on rubber roof. I applied it with a paint brush and sealed all the cracks edges with silicone came back a few hours later the stuff is amazing tough to where I could not scrape it off. There it is EPDM rubber roof coating has another use .

[flybouy]

In the early 1970's I was driving my now DW's fathers Econoline passenger van back from Main with 5 of us aboard. Just prior to the trip he bought 4 new steel belted tires (Goodyear if I recall). Anyway transiting near Boston humming along at about 70 m.p.h., the right rear tire decided to let the tread casing go it's own way. Luckily there was 3 travel lanes and 2 shoulders as I think I used every inch of pavement.

Seeing the incredible amount of damage that tire inflicted was just as scary. The fender, fender liner, and about a foot of the rear bumper were twisted in a basketball sized clump. I can't imagine anything shy of some sort of ballistic material surviving those forces.

[JRTJH]

I've seen a "blown tire" (tread separation) twist a 1/2" black iron propane pipe into what looked like a pretzel. When you think about the way a wheelwell is constructed, the "luan/Styrofoam/luan" floor sits on top of thin outriggers which are used to support the 1x1 aluminum square tubing that holds the end of the flooring and provides a place for Keystone to attach the J-wrap and molding.

The ENTIRE structure can easily be "removed from the trailer" by a 12 year old with a 2 pound rubber mallet... Expecting something "screwed to that structure" to withstand more forces then the "actual trailer structure" is "wishing beyond hopeful reality"....

You can screw 3/8" armor plate to the plywood and outriggers. The first time a tire tread "breaks loose and starts flapping, if it catches your armor plate, it'll just make a bigger hammer to tear up more stuff before you can get the trailer stopped....

What I'm trying to say is, "Don't "armorplate your wheelwells" because if you have a tread separation, all that armorplate is going to be ripped away from the 1/8" luan that you screwed it to."

The "functional purpose for attaching something that's permanently waterproof and will withstand road debris" is to protect against the probability of towing during rain. You can't "armorplate the trailer and keep it an "ultralite"... Every pound you add is a pound more your truck has to tow and a pound less you can take along as cargo...

[sourdough]

Originally Posted by JRTJH

I've seen a "blown tire" (tread separation) twist a 1/2" black iron propane pipe into what looked like a pretzel. When you think about the way a wheelwell is constructed, the "luan/Styrofoam/luan" floor sits on top of thin outriggers which are used to support the 1x1 aluminum square tubing that holds the end of the flooring and provides a place for Keystone to attach the J-wrap and molding.

The ENTIRE structure can easily be "removed from the trailer" by a 12 year old with a 2 pound rubber mallet... Expecting something "screwed to that structure" to withstand more forces then the "actual trailer structure" is "wishing beyond hopeful reality"....

You can screw 3/8" armor plate to the plywood and outriggers. The first time a tire tread "breaks loose and starts flapping, if it catches your armor plate, it'll just make a bigger hammer to tear up more stuff before you can get the trailer stopped....

What I'm trying to say is, "Don't "armorplate your wheelwells" because if you have a tread separation, all that armorplate is going to be ripped away from the 1/8" luan that you screwed it to."

The "functional purpose for attaching something that's permanently waterproof and will withstand road debris" is to protect against the probability of towing during rain. You can't "armorplate the trailer and keep it an "ultralite"... Every pound you add is a pound more your truck has to tow and a pound less you can take along as cargo...

I would add that "ever pound" you add to any exterior surface (thin luan, foam, fiberglass etc.) is a pound it was never designed to have stuck on it in the first place. Reference back to trying to adhere something to the Darco….it can't hold itself on much less anything stuck to it.

[Big 417]

Originally Posted by sourdough

I would add that "ever pound" you add to any exterior surface (thin luan, foam, fiberglass etc.) is a pound it was never designed to have stuck on it in the first place. Reference back to trying to adhere something to the Darco….it can't hold itself on much less anything stuck to it.

Well said gents. I am a carpenter, and I can tell you sandwiching several layers of "water tight" layers is never a good idea. The better you seal a layer to the next, the greater the chance of moisture and condensation. Your layers of luan will rot under those layers of tin.

Add some light agent to help with road water. Our fuzion was sprayed with keystones "mouse proofing", which is basically undercoating. That added a nice seal for us on this unit.

[Tireman9]

April 24 I wrote an article on my blog on the idea of trying to contain the force of a tire failure.


some things to consider.
- Even without considering the forces of parts of a tire flailing around at 65 mph how about just considering the force of the tire inflation. That force is enough to support the load on that tire. Will you be building a structure that is strong enough to support that load? If you think so, would you be willing to jack up your RV using the "shield" you are building as the contact point for your floor jack?
If not then why would you consider that "shield" sufficient to contain that force PLUS the hammering of the tire tread and belts hitting your shield at 65 mph.
I cover how tire companies "contain" failing tires by building steel structures around the test wheel. If you want to build a structure strong enough, then I would not waste you time with sheet metal and wood screws. Price out the steel grating. Suggest you start by checking out 15W2 grating with 1-1/2x3/16 bar. This weighs about 10# per sq ft You will need to cover the entire wheel well. This grating needs to be welded to a steel structure that is welded or bolted with 3/8" Gr5 bolts spaced no more than every 4" to 3/8" plate brackets bolted/welded to your steel frame. You also need 4"x4" backing plates to your frame as I am thinking your frame material is less than 1/8" thick. Plates should be at least 4"x4". This is the kind of structure used in roll cage construction.


Will the above prevent all damage? Maybe not given that tire safety cages constructed of 2" dia 1/8" wall steel tubing still get bent and damaged when a stationary tire lets go.


IMO it is better to take the actions to prevent a tire failure in the first place.

[firestation12]

Good points expressed of why you shouldn’t try to bulletproof the wheel wells. As stated in post #7, the OP only intended To create a better water resistive barrier. I guess the takeaway might be, do your best to enhance the Darcor, but don't get carried away because it might amplify the damage from a catastrophic tire failure.

[Ccrew]

May have missed a couple layers in the flooring. In my 2018 there was a layer of thin ( think shoebox) cardboard. It’s actually the wicking in that layer that separates the bottom layer of 2mm Luan. Top layer of Luan is 4mm. So in mine from top down it was:
Linoleum
4mm Luan
Cardboard
1.5” Styrofoam
Cardboard
2mm Luan
Darco.

Floor “joists” were on 4’ centers and they conveniently missed them when lag bolting with 3” self tappers the floor to the joists.
Never so happy to see an RV go away.

[gregrc75]

if the idea is to just waterproof it, what could one use? What about the peel and stick ice and water shield you would normally apply under your roof shingles on your home?

[geeman]

Originally Posted by chuckster57

You should be okay with all the adhesives your using. BTW its not dicor. Dicor is what is used on the seams on the roof, what you have underneath is DARCO fabric. No big deal, but if someone else were to read this I wouldn't want them looking for the wrong stuff.

Spray on bed liner probably wouldn't provide the protection against frame/Floor damage in the case of a tire blowout.

Guesssing... Neither would thin aluminum sheeting with screws for flying belts to catch. Some but no fail proof. I would just spray a couple good coats if I was concerned. Last thing you want is moisture to get above the sheeting either if screws or seems happen to leak.

[Customer1]

If just concerned with water resistance, spray automotive undercoating/rustproofing.

On a side note, I always spray all my frame-ground connections. The stuff is fairly durable.