Ace

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_114.jpg

Bookshelf

Cooper makes a 255/85 tire also. The only thing keeping me away from these tires is the fact that it is not a regularly stocked or available tire, if I tear one up on the road or something it could be tough to find a replacement. Forget about the M-55's, I called every tire dealer that carried toyo in the Chicago area and even the regional warehouses don't stock any size. Thats more of a wilderness/heavy duty off road tire. I have also read that they'll hurt fuel mileage also.

Diesel_Dawg

Bookshelf - Do you know the load range of the 255/85 Coopers?

Thanks,
C. D. Hunter

Bookshelf

Almost positive they're D range. I ran across them on Cooper's website.

G1625S

Dang! How about unloaded or lightly loaded? I was really looking forward to putting 255's on next time around.

Diesel_Dawg

Thank you sir!

BearKiller

Find me an exact rim width for the 1st. Gen DRW wheels.

Get me the measurement between two wheels from bead-seat to bead-seat, as installed side-by-side; this measurement can be taken from two wheels simply stacked atop each other in the manner they would be if bolted on.


I can take those measurements and calculate just how close the sidewalls will be loaded and empty.

I would like to know myself.


I do know this: on later model trucks, Ford, Dodge, or GMC, the wheel mounting surface is farther from the leaf-springs and the rim spacing is greater by about an inch, thereby making a mile more space between dual tires.

The catch is that the later model wheels will hit the springs on older trucks.


One remedy is to use a late-model rim on the outside and the older model inside, maintaining spring clearance on the inside and gaining half the advantage of the late-model spacing; BUT, a slick-faced hub-centric Ford rim has to be swapped in place of the coined Dodge rim for the inner wheel, unless a machinist has made provision for the late-model wheel to coincide with the "coins", all of this considering that the selected rims are hub-centric, or machined to be, to the 1st Gen. Dodge hub.....confused yet ??.

bandit1trucking

I just went back to the 255/85 R 16 BFG mud terrains on my '96. They are close when empty (my empty truck weighs more than a lot of people call loaded) and they will rub loaded (with a backhoe). but I've never had a problem. I've ran them since '91 on different dually's, and I'll not change again unless I find something better. I can usually get about 80,000 miles out of a set of them. We tried the cheap route last time, and went with 235/75 r 16 Cooper st's... I'll never buy another cooper tire. Blew the sidewall out on one at about 10,000 miles, and the rest are junk at less than 20,000. Didn't save enough money on the set to make up for the difference. I also noticed that the coopers must have really weak sidewalls, as you went down the road rocking and swaying really bad on rough roads. I tried Coopers on another truck about 8 yrs ago, but was convinced by the tire guy that they had improved them. They have not. I also wasn't too happy when I went to pick the truck up, and found it had 235/75's on it. He could have called me and said "hey cooper doesn't have a 255/85 in that tire, instead of just installing the smaller ones.

BearKiller

Another way to look at it :

Over-all inflated width of a Toyo M-55 255-85-16 LR-E = 10.4"

O.A.W. of a 7.50-16 = 8.3"

O.A.W. of a 235-85-16 = 9.3"

The 7.50 and the 235 are exactly the same height at 32".

The 255 is 33.3" tall, a gain of 1.3", which doesn't sound like much, but will look like a foot when mounted on a truck.



If you currently have 7.50s on your truck, the 255s will be closer to each other by 2.1", meaning that much less space between the tires.

If you currently have 235s, the 255s will be closer by 1.1".


To get a good idea of this, rip a length of wood, either 1.1" or 2.1" wide, and place this against one of the rear tires, taking note of the remaining gap (or lack thereof).

If the stick will not even slide between the tires, then the bigger tires will lay hard against each other.



It is un-real what I see people do all the time; not a day passes that some redneck don't come in the shop with an old DRW truck with a set of P265-75-16s on the rear wheels, these being common as dirt in the used tire racks, therefore cheap; when you take the lug-nuts off, the tires will shoot apart like springs; we have learned to inflate them after bolting up.


We also see a lot of "way-to-fat" tires on "dished-the-wrong-way" wheels mounted on various trailers, the tires always polishing the sheet-metal behind them, and these guys can't seem to understand why they keep blowing tires.

BearKiller

I am a bit confused; by "st" are you meaning "special trailer" service tires ??

Were these on a truck or trailer ??


I didn't know anyone made a 235-75-16 tire, I see 235-85-16 and 235-80-16, but never 235-75-16.

Thanks.

archer2

Here's a 255/85/16 next to a BFG 285/75/16. I found that in the "slush ruts" the BFG's are prone to uncommanded lane changinghttps://www.dieseltruckresource.com/forums/images/smilies/shocked.gif
, therefore I use with the skinnier MT's in the winter.

https://www.dieseltruckresource.com/...1&d=1196699552
IM000360.jpgFG 285/7https://www.dieseltruckresource.com/forums/attachment.php?attachmentid=17406&stc=1&d=11966996 34
IM000361.jpg5/16

MoparMarv

Thanks for the great side by side shot of the tires. It looks like the 255/85 is a touch taller than the 285/75. I think I'm going to give the BFG's a shot since they are more avalible than the Toyo M55's in my area. I'm willing to try the D rated tires since the truck is empty more often than not. Who know maybe in the next 3 months they will come out with a different 255/85 tire and I have some time to think about it.

bandit1trucking

Sorry about that. They were Cooper Discoverer s/t., and I could very well be wrong on the size. I'll have to check and see what size they were, if the guys brought the old ones back from the tire store. I have a set of the Discoverer STT's on the '99, and they seem like a better tire, but it isn't loaded nearly as heavy, and hasn't been hooked to a trailer at all since they were installed. We also had a set of the s/t's on the '03 (17" wheels), and they lasted about 30,000 miles before they were worn out.

On a side note, I was probably thinking of the 235/75's because we used to run them on some of the work trucks, but I think they might have been Hercules tires...(terra trac).

bandit1trucking

Here are some pics of the 255/85 BFG mud terrains on my truck.

Bookshelf

Thats a BFG 255/85 mud terrain? The tread looks different than the tires below on the dually.