Driveway strength

[RV Pirate]

Bunch of years...gee, you mean it didn't last forever??

[Bob Denman]

Yup! I agree...

[Dbadger777]

We have always parked our RV in the Driveway. I re-bared it and had them add fiberglass fibers to the mix. It had held up great until the day a neighbor went crazy and started shooting out his front window. The police asked me if they could park their communications vehicle in my driveway. I said yes. It was a huge converted greyhound bus. Really cracked one side of the driveway. The swat armored vehicle ran over the corner with the drain tile and crushed that. No compensation, because I had given them permission.
Not exactly RV related, but my kids still talk about that day.

[Pete'sMH]

ALWAYS impressed with the knowledge base associated with this forum! As with many things the answer is “it depends”. Not quite sure what I’m going to do going forward but it probably includes parking in the street most of the time. And buying snap pads or similar. And if I ever get into a position where I can build a place for my machine I’m going to overbuild the base. Thank you cyber friends.

[Bob Denman]

Good luck; with how all of this works out...

[SuperD]

Without knowing exactly how your driveway was constructed it’s impossible to predict whether or not you will have cracking. RV tires are large and spread the weight over a wide area which reduces psi on the concrete, tire pressure has little effect on the contact patch, but it still depends on how your driveway was constructed.

Most HOA’s allow parking an RV for loading and unloading, usually 3-4 days before and after. My HOA is very strict, 4 days max before and after, then I’ll get a warning letter after some busy body reports me, those go in my paper shredder.

[Chance]

Originally Posted by SuperD

....cut..... tire pressure has little effect on the contact patch, ....cut......

Contact patch has a lot to do with air pressure. As you deflate a tire to a lower pressure, it flattens down, and the area against the road increases significantly. This imbalance of area and pressure at each tire is what creates the forces that support the RV.

By the way, this isn't limited to RVs. It applies to cars or bikes too, and also helps to explain why higher tire pressure leads to harsher ride -- although that's a different subject altogether.

[Bob Denman]

Your point about the contact patches is spot on.
I wonder if there's a way to do a comparison between the different sizes of them?
The RV on it's tires
The RV on it's levelers
(Or stabilizers and tires)
The RV on it's levelers, with Snap-Pads or some other type of pad under them.

[JamieGeek]

Its also why 4x4'ers "air down" when on loose soil: to increase the contact patch so they ride on top of the sand/soil instead of digging down.

[Bob Denman]

But if we'd "air down" in the same manner: the results wouldn't be pretty!
They can often go as low a 3 or 4 psi, and have the tire bead screwed to the rims.

[Chance]

Seriously, it wouldn't help to any significant level in my opinion.

Total tire load is still the same, and is determined by vehicle weight, not tire pressure. And because tire pressure will always remain relatively low compared to concrete strength in compression, I seriously doubt that spreading the load over a few extra square inches will matter. As I mentioned before, it's how these tire loads somehow convert to tension in the large driveway slab that will crack it.

Was thinking back how concentrated tire loads on forklifts in industry were way higher, and didn't necessarily cause concrete cracks. The biggest problem we had was at edges of expansion joints, where concrete would chip off.

[Bob Denman]

Anything that you can do to increase the surface of the area putting the load tot he ground will help...
it all depends on how much larger you can make the footprint.

When they put enough rubber under Bigfoot: it would float!


http://www.thorforums.com/forums/att...1&d=1518720772

[JamieGeek]

I think this guy has more surface area in its "treads":

[Bob Denman]

Yup!
Those treads are about the best way to spread the ground pressure of a load out...

But then they also offer insurmountable driveability problems...

[SuperD]

Originally Posted by Chance

Contact patch has a lot to do with air pressure. As you deflate a tire to a lower pressure, it flattens down, and the area against the road increases significantly. This imbalance of area and pressure at each tire is what creates the forces that support the RV.

By the way, this isn't limited to RVs. It applies to cars or bikes too, and also helps to explain why higher tire pressure leads to harsher ride -- although that's a different subject altogether.

I totally agree the contact patch increase at lower pressures but I believe the effect would be negligible, perhaps 10-15% at the most with street tires which have stiffer sidewalls. Seriously, would anyone lower the pressure in their tires before pulling in their driveway, then pull out, stop and air their tires again? I certainly wouldn’t!!!

As a diehard 4 wheeler years ago I regularly lowered air pressure in my tires but to soften the tread and allow it to conform to irregular rocks and terrain.

[Bob Denman]

Originally Posted by SuperD

I totally agree the contact patch increase at lower pressures but I believe the effect would be negligible, perhaps 10-15% at the most with street tires which have stiffer sidewalls. Seriously, would anyone lower the pressure in their tires before pulling in their driveway, then pull out, stop and air their tires again? I certainly wouldn’t!!!

How about putting down your levelers or stabilizers, and having them help to shoulder the load?
They should certainly increase the contact patch by a pretty decent amount.

[Chance]

All the BS makes my head hurt.

Too bad it's impossible to have a serious discussion about anything.

[Bob Denman]

What exactly are you referring to?

Since you can't easily improve the strength of the driveway: it makes sense to try and reduce the ground pressure of the rig.

[Laco]

Had a friend some years ago, that had a very large, 45 foot, Prevost, weighed in the neighborhood of 60,000 pounds or better. Drove to his daughters, parked in her driveway, shut down, the front shuttered, and dropped about 18 inches or so as the driveway gave way.

[captmetal]

Originally Posted by Dbadger777

We have always parked our RV in the Driveway. I re-bared it and had them add fiberglass fibers to the mix. It had held up great until the day a neighbor went crazy and started shooting out his front window. The police asked me if they could park their communications vehicle in my driveway. I said yes. It was a huge converted greyhound bus. Really cracked one side of the driveway. The swat armored vehicle ran over the corner with the drain tile and crushed that. No compensation, because I had given them permission.
Not exactly RV related, but my kids still talk about that day.

finish the story, what happened to the neighbor, all the details