Ski Bum Truck V2.0, F450 Rough Road RV
- Thread starter java
- Start date
Have you ever had any issues with frame flex? If I remeber right your box is bolted on top of the chassis. So no pivot points or anything to allow the camper body to flex?
Is it a non issue if you aren't lifting tires off the ground? Any concerns over stress fractures?
My bus has an aluminum frame bolted to the truck chassis. Wondering your thoughts with what you have experienced.
Is it a non issue if you aren't lifting tires off the ground? Any concerns over stress fractures?
My bus has an aluminum frame bolted to the truck chassis. Wondering your thoughts with what you have experienced.
java
Expedition Leader
That is correct, its old school truck style, 2x4 on top of the frame rail, and U bolts and a a few locating bolts to hold them together.
The floor on mine is 2x2.5 (IIRC) square tube, on 24" centers, with a 3/16" thick plate for the floor. It makes it VERY stiff back there. To the point I don't think the rear frame section flexes much at all. I was a little concerned about it, but the box has shown no signs of issues yet, I am more concerned with the frame at the back of the cab. It definitely flexes right there. Lifting tires on a truck this big takes some real trying.... I have had it all twisted up, and in reality it just would feel way too tippy to get into a situation of lifting a tire I think. I thought I was going to flop it once. I literally just stopped and got out of the truck for a couple mins.... The rear springs on mine move pretty well too.
Buckstopper
Adventurer
Yikes! Those are the same tires as my Fuso. I need to give mine a close look.Went to do brakes. Found this.....
Ideas? Still holding 80 psi. Never aired down....
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Buckstopper
java
Expedition Leader
Oddly the fronts are fine? They are a older tires. 7yrs from mfg date now.
I do!
My thinking is perhaps the beadlock ring inside did something weird with the bead of the tire and concentrated the stress right there? I'll pop this one open soon.
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Ozrockrat
Expedition Leader
Check the bead profile matches the rim profile. There are a couple of different types. The 365/80R20 that we’re on my yellow truck were MPT and the 395/85R20 are MVT). MPT tires cannot be fitted to MVT rims. MPT rims are not as easy to find as MVT.
Also check that the beadlock insert is not spreading and pushing on the inside of the tire above the lip of the bead.
Also check that the beadlock insert is not spreading and pushing on the inside of the tire above the lip of the bead.
RAM5500 CAMPERTHING
OG Portal Member #183
This is my guess
java
Expedition Leader
That's what I have been hearing.... Looking into it.
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Alloy
Well-known member
From someone else who bought the same wheel/tires, here is the insert. Could the height/thickness of the insert be causing the tire to flex further into the sidewall instead of down towards the bead more?
Bead locks fix the bead abd increase the flex in the sidewall .....more flex = more chance of cracking. More chance of it happening on short sidewall high load tires. Also if the tires are run below mfg recommended pressure for weight.
Usually the bead rotate/twists on edge of the wheel which causes rim flange wear. Rim flange wear is the cause of aluminum wheels being scrapped / TIG welded /machined on commercial trucks. Knew a guy that had 20-30 wheel he wanted me to weld but it was mind numbing. I'd had enough after doing 1.
An example, not my welding.
