5th wheel tires and axles

[tuffr2]

There are however a dually set-up on the old Newmar up-scale 5th wheels. I believe the Mountain Aire Newmar 5th wheel came with 2 axles, each axle had 4 tires.

[Racklefratz]

Originally Posted by RustyJC

These 17.5 inch trailer tires are for "high cube" trailers, car haulers, etc. that need a very low load floor. Most of them use dual wheels. Their application for 5th wheel RVs is not their intended market - we are the outlier.

When Newmar was in the 5th wheel business, they built their heavier 5th wheels with duallies, but that required a narrower frame section and larger wheel wells.

Rusty

That's pretty amazing. I've never even heard the term "load floor" before, so that's where I am regarding tire sophistication.

But, suffice it to say that the numbers for "single" vs "dual" are higher, so it appears that the load carrying safety margin I have by virtue of the G114s on my trailer is even better than I thought. I could learn to like that.

[RustyJC]

A "high cube" trailer is built with an interior that has the maximum cubic feet of cargo space possible. Since the ceiling height is pretty well fixed due to trailer height limitations, the other way to get more interior space is to lower the floor. With these smaller 17.5" tires (versus, let's say, 22.5" tires), the load floor (the floor of the trailer on which the load is carried) can be 5" lower, everything else being equal.

Rusty

[FastEagle]

Originally Posted by Eric_ So Cal

Hello All. Brand new member and first post. I was hoping someone could help me out. I have a 08 Keystone Everest 343b which I bought new. I have had tons of problems with tires- fortunately have caught them before any blow outs. They lasted me about a year each ( have always replaced 4 at a time). Didn't know about the china bombs until finally researching and will be finally getting rid of them. The trailer says its dry weight is 11650 with 2370 for loading which makes it 14020. The china bombs are 3520 (235/80-R16) a tire but I want to go with the LT tires the same size which are 3042. When computing the weight the tires are carrying the tire shop told me I don't use the 14020, rather subtract the hitch weight (2020) from the total and that's what is on the tires. Is this true? I have 6k axles so I am thinking it is and will be able to get the xps ribs or duravis r250 which wouldn't give me any wiggle room with weight. Any help would be greatly appreciated

I'm pretty familiar with all of the Everest specs and I'm pretty sure yours has 6000# axles fitted with OE ST235/80R16E tires. I'm also sure that any information you get about going to a lower load capacity tire is incorrect.

The minimum load capacity for tires fitted to your trailer is found on its certification label. That label is displayed on the left forward external portion of your trailer.

The interpretation many use to support their claim to go with a lower load capacity tire is found in 571.110 & 571.120 regulations. Unfortunately for those wishing to use those minimum standards is the fact they are not intended for individual use. They establish minimum standards for vehicle manufacturers. The vehicle's certification label depicts the minimum standard for that vehicle.

Here is one of many places where the industry standards can be found.

Cooper Tire US - Load Capacity

There are a lot of name brand 16" LRG tires to select from but almost all of them are from "off shore" manufacturers.

FastEagle

[danojeno]

Even though the ST tires you are looking at have a higher weight rating, on 6k axles, the LT tires will give you the wiggle room you are looking for. I would take RIBs with 1lb to spare vs STs with 1k to spare any day.

[mhs4771]

I will just add this comment: While going to 17.5 wheels and tires is a great idea, it would be total over Kill on 6K axles. Staying with 16" with G tires would give you the "Wiggle room" you're looking for, BUT (seems there's always a But) you need to check your current rims to see if they will handle the 110 PSI of the Gs.

[RustyJC]

Originally Posted by mhs4771

I will just add this comment: While going to 17.5 wheels and tires is a great idea, it would be total over Kill on 6K axles

When it comes to tire capacity on 5th wheels, I subscribe to the Stroker McGurk (an old cartoon character in Hot Rod magazine back in the '50s and '60s) philosophy: If some's good, more's better and too much is just enough.

Rusty

[Racklefratz]

Originally Posted by RustyJC

If some's good, more's better and too much is just enough.

That's been my philosophy as well. The last thing I ever want to have to deal with on the road is tire issues, especially the explosive kind, having already tasted that exquisite pleasure once with the left front tire of our prior Class A, a 40' diesel pusher. That event ruined a planned reunion and took months to resolve, at considerable expense. So when I became aware we were rolling on Carriage OEM China-bombs, I quickly upgraded to LR H Goodyears on 17.5" wheels.

Same thought process occurred when it turned out our Cameo's brakes were FUBAR. They never were right from the factory, and when finally opened for diagnosis, only one was operational, the rest being either polluted with grease everywhere and/or internal wiring ripped apart from faulty installation. I wanted to have nothing more to do with electric brakes and leave us open to more of their design frailties, so I elected to get electric/hydraulic disc brakes installed on new 8K axles. Drum brakes may be OK for farm equipment, but the automotive industry switched to disc brakes over 40 years ago.

Moral again: For the really important stuff, too much is just enough.

[taken]

Aside from suggesting you go to load range G tires as opposed to ST, I'd offer this. Many tire failures out there aren't just from the cheap tires that come on our RV's. They are from misaligned axles causing scrubbing even when traveling in a straight line. The Correct Track system can be had for $325 at RV Wholesalers. It's a simple bolt on system that allows you to align you axles. Correct Track - Alignment & Safety

[garbonz]

To be completely clear. You SUBTRACT the hitch weight from the dry weight and then add the contents (some of which will be on the pin, not the trailer tires) to get the approximate trailer weight on the tires, so You are within capacity on what you got.

However, It is best is go to a CAT scale and weigh the rig to make sure. CAT scales are all over the place. It also will help determine if you are within the payload capacity of your truck.

Stay with ST tires of a load range that works for your situation, and inflate to the max pressure that is on the sidewall.

nuff said

[Racklefratz]

Originally Posted by garbonz

Stay with ST tires of a load range that works for your situation, and inflate to the max pressure that is on the sidewall.
nuff said

I do not "inflate to the max pressure on the sidewall, and made a conscious decision not to do that.

Max inflation pressure guarantees the trailer frame and contents will get the harshest ride possible. My Goodyear G114 tires are so far above any load my trailer will ever place on them I inflate to the pressure from the tire loading chart from Goodyear that most closely matches loaded CAT scale weights. YMMV

[glennwest]

Originally Posted by Racklefratz

I do not "inflate to the max pressure on the sidewall, and made a conscious decision not to do that.

Max inflation pressure guarantees the trailer frame and contents will get the harshest ride possible. My Goodyear G114 tires are so far above any load my trailer will ever place on them I inflate to the pressure from the tire loading chart from Goodyear that most closely matches loaded CAT scale weights. YMMV

Do you know your individual wheel weights? Many units the kitchen side is heavy. Cat scale gives you axle weight. While 1 tire could be under inflated while other over. I always air mine to max 110 on the DRV.

[Racklefratz]

Originally Posted by glennwest

Do you know your individual wheel weights? Many units the kitchen side is heavy. Cat scale gives you axle weight. While 1 tire could be under inflated while other over. I always air mine to max 110 on the DRV.

I should have said earlier that "I use an inflation pressure from the load chart matching the weights PLUS A COMFORTABLE MARGIN.

The load capacity of each of my G114s at 115 psi is 4,495 lbs/tire. The average "CAT" weight with the trailer loaded is about 3,000 lbs/tire. Even WITH some uneven tire loading, the excess capacity of the tires is far above that average weight figure - enough that I'm simply not worried about load variances. It's the main reason I bought these tires, as opposed to others that are available. Max inflation for these tires is 125 psi, which supports 4,805 lbs/tire. Inflating them to that pressure would just be silly, IMO.

I understand that weights of individual wheels is nice-to-know information, but in the 16 years we owned our 40' diesel class A with its 26,000 lb gross weight, a single tire pressure worked for us, and I'm not losing sleep over not having individual wheel weights.

[jeffreyj]

I own a 05 Keystone Challenger which was like a sister trailer of the Everest. My trailer came with Tacoma LT tires on it and also on the id tag outside was also listed with LT tires 235/85-16 tires. I got 8 years on those tires and just replaced with Michelin Lt MS2 tires and show no wear at all yet and have 6 trips on them. I suggest you also check shackle bolts for wear and loosness. I had several loose shackle bolts and worn out leaf spring bushings. I replaced them with a wet bolt kit also a egua flex center egualizer and new upgraded leaf springs. Went with a 6 leaf 3300 lb leafs versus the 4 leaf 3000 lb ones due to springs were sagging and now I have no sign of wear on the new tires.