Wheel width and rating on a '77 Excella

[JimGolden]

OK, this has probably been beat to death, but I spent an hour and a half searching and couldn't find the answer...

How wide are the rims on my '77 Excella and what load rating tire are they rated for?

It's got load range D tires on it now (from PO) and my best measurestimate is 7" wide on the rim. Are these correct?

How wide a tire will fit on a 7" rim? Can you put a 265 on one? I am unconcerned about the wheel wells, as that is all going to be redone (along with the frame). I'm mainly wondering how big a tire will fit on a 7" wide rim, and if my rims are 7" wide. I used to run 265/75-15 tires on my Suburban (as well as 31x10.50's), but I had 8" wide rims. Would a 265 fit on a 7" rim? Are my rims 7"? Are they suitable for load range D tires?

I'm getting ready to fabricate a brand new frame and will be getting new axles, brakes, the whole shebang. The wheel well size is of no importance as I will change that to fit whatever size wheel/tire I decide to go with. I'm toying with the idea of going to 16" wheels, and possibly even 17" to match my truck, and 8-lug wheels (along with load range E tires). However, I got to wondering if a 31x10.50 truck tire would work on the Alcoa rims I already have. What do you all think?

What I'm really looking hard at is the BF Goodrich Commercial T/A 265/75-16 which has a rating of over 3000lbs. Overkill is a good thing. My truck uses a 265 series 17" wheel. Whichever I go with, the new suspension will be sprung accordingly to work with whatever tires I go with. But, I thought there might be a last ditch chance to save the original wheels.

But if not, no biggie. My utility trailer would look a lot nicer with the 5-slot mags on it than the white wheels on there now

The Alcoa 8-lug wheels look awfully nice!

[3Ms75Argosy]

I think you'll end up squishing the tirewalls together, getting a squirmy ride. I have 255/70/16's on 16x8 for my van (could be 10's but I can't remember). 7's would be too narrow.

I have the commercial trail t/a's - love them!
Marc

[Beginner]

Jim
The original tire on your trailer was probally a 700-15 8 ply(load range D).
The rim width is probally 6 inches.
Go to this web site

Car Bibles : The Wheel and Tyre Bible

and scroll down about half way down and you will see how wheels are measured.

Here is where I get in trouble.

It is my contention that heat caused by speed is what is making the ST tires fail (belts seperate and slip).
What is needed is a more heat resistant tire, not one rated to carry more weight. Heat is generated by the sidewalls flexing as the wheels roll down the highway. The faster you go the more the sidewals flex in a given amount of time and the more heat is generated.
ST tires are speed rated at 65 MPH only.
The Goodrich Commercial T/A that I went to is a LT225/75R16 Load Range D (LRD) with a speed rating of Q(99mph).
The Commercial TA in LT225/75R16 LRD All Season (2335 LBS for a total of 9340 LBS on a trailer that groses at 8200) is the same outside diameter as the 700-15 that came on my trailer from Airstream and the same width as the ST 225/75R15 LRD, thus clearance is not a problem.
The wheels that I went to are the Eagle Alloy Wheel

Eagle Alloy Wheels Series 058

Model 0589 - 7766, with an +8mm offset which was the same offset as the original airstream wheels that came on my trailer. They are rated at 3040 lbs.

According to mfg specs I'm covered.
I'm not the only one running these Commercial T/As in this size and none of us have had a moments problem yet.
Beginner

[JimGolden]

Marc,

Thanks for the reply amigo. I'll take that endorsement of BF Goodrich products. I used to routinely exceed 140mph on their tires (on a T-Bird SC) and really like their stuff. I'm kind of brand loyal

Beginner,

Sharp looking wheel. It looks a lot like the Alcoa that I saw and liked. I checked out your link and see what you mean...I was measuring 7" wide along the outside of the rim. If you go on the inside, it is more than likely a 6" rim. No can do on a 265.

So, it looks like I'll be going at least to a 16" anyway. And if I'm going new wheels, I might as well go 8" wide. Then I can run a 265 Commercial T/A, which will give me over 12,000lbs of capacity for an 8500lb trailer.

But they say you lose 30% of the tires in three years, so that's .7 * 12,000 = 8400lbs = just about right. But the LT tires have the 15% extra margin built in, so I'll be OK.

There, see, I just talked myself into 8-lug 8" wide rims for the 265 series E rated tires on my new disk brake equipped axles with the Towbrake E over H linear actuator unit....

Man, who said vintage trailers were cheap....he lied!!!!!!!!!!!!!!!!!!

[Excella CM]

Ours had Michelin heavy duty traier tires put on by the previous owner. Thee are no longer made, and I haven't found anything as butch that will fit a 15" rim. If you can go to 16", then you have a choice of all the truck tires with heavier load ratings. The Excella puts about a ton on each tire which is marginal for the 15" tires that I have found.

[Beginner]

Jim
Be careful. More isn't always better.
Before you buy any tire or rim take your finished trailer and have it weighed, preferrable at a CAT scale (wonderful folks).
Then determine what you need.
My Excella (as built) max weight is 8200 lbs(800+7400). Tongue weight is 800 lbs/Axle weights 7400 lbs (as measured at CAT Scale)at 3200 lbs/axle(1600 lbs/wheel).
Commercial T/A LT225/75R16 Load Range D (LRD) Speed Rating of (Q99 mph) (Max WT 2335) works out to 4670 lbs capacity/axle.
I'm sitting at 3200 lbs per axle.
This means that the tires have a load of 68% of their full capacity (32% safety factor, (plenty)).
As I said before, the problem with the ST (Speed Rating 65 mph) tires is that they cannot stand up to our present day driving habits. They have plenty of capacity, they just cannot stand the heat caused by 65 mph + on hot Interstate highways.
Also, If you go to a higher weight rated tire the trailer shell will suffer. Cracks will appear and other problems will surface (reference Andy of Inland RV's remarks on LRE tires).
The hardest most grueling part of an airplanes life is the trip from the runway to the loading area/tarmac and back to the runway on those hard little tires.
I played with the idea of going to 8 lug wheels because then the wheels would be interchangeable with the TV but there wasn't enought money.
Oh well.
Beginner