295 or 305

[Hpimichael02]

Hey guys I don't know what to go with, I want 33's or close to but I'm
Not sure f I wanna go 295/75/16 or 305/70/16, I was leaning toward 305's cause I do mostly sand trails and mud,

What do you think , I'm going bfg or knock off brand MT tire

[Trail X]

I guess it depends on if you need the flotation. I honestly doubt you'll notice much difference between that extra half-inch of width. between the 295 and 305s.

By the way, welcome to the site.

[Zero]

1. Take a look at the retread tires. There is a thread on here about treadwright.

2. If you go with the slightly narrower tire, you can save your self some stress cause u will have to cut less of the body to avoid rubbing issues when turning.

[johnburgelin]

For arguments sake, I'm going with 285's which have been proven to work well with quite a few people on this site. 265 is the most common size, but 285's are plenty big for our trucks I believe. 305 is a big honkin' tire

[irishboy02]

For arguments sake, I'm going with 285's which have been proven to work well with quite a few people on this site. 265 is the most common size, but 285's are plenty big for our trucks I believe. 305 is a big honkin' tire

Im at 33x12.5

[HARDTRAILZ]

I can attest that 305 is a lot of tire. I have not seen many 295 width tires. What tires are you looking at.

[Hpimichael02]

Either bfg at or knockoff my tire, a 305 is 12" wide and 32.8 tall, 295s are 11.3 wide and 33.8 tall , it comes down to what's more important, floating on top of sand of additional ride height

[Hpimichael02]

I have 265's but they look small lol

[The Roadie]

After breaking lotsa stuff, I'm additionally concerned about tire/rim combined WEIGHT.

[glfredrick]

I'd be concerned with the overall leverage arm length with tires that large. Bigger diameter, longer lever against the axle shafts. There is a point of no return for what the stock sized axles can handle, torque wise. Roadie's concern over rotating mass is also worth considering.

From some tests JP Magazine ran on common off-road axle shafts, these breaking numbers are commonly posted:

JP magazine did an axle test in their November issue and heres what they said.....
1: A stock D44 axle broke at 35* of twist and 3500 ft.lb
2: A 4340 chromoly hardened shaft broke @ 35* of twist and 4500 ft.lb
3: A 35 spline D60 shaft broke @ 30* twist and 8100 ft.lb
4: A 4340 chromoly D60 shaft broke @ 130* twist and 10,500 ft. lbs

Here is another set of figures (calculated by Bobby Long, who is behind the Longfield and RCV axles):

Product................................ft-lbs....degrees

Yukon 4340 Dana 60 35 spline............12,000.....130
Stock Dana 60 35 spline..................6,500......35

Yukon 4340 Dana 44 30 spline.............5,800......35
Stock Dana 44 30 spline..................5,000......35

Yukon 4340 Birf Elim 30 spline...........5,000......50 (ear failure)

Longfield 4340 30 spline used............8,500.....175 (shaft failure)
Longfield 4340 27 spline.................6,500......75
Stock Toyota Birf........................4,200......45
Profield Birf............................3,500......30

Toyota Front Inner axle, 27 sp Stock.....5,000......45
Toyota Front Inner axle, 27 sp 4340 Pig..?,???......??
Toyota Front Inner axle, 27 sp 4340 Long.?,???......??
Toyota Front Inner axle, 27 sp 300M......7,000......??
Toyota Front Inner axle, 30 sp 4340......?,???......??

Toyota Rear Axle Shaft, Stock............6,500.....110
Toyota Rear Axle Shaft, Superior 4340....7,600.....160
Toyota Rear Axle Shaft, PIG 4340.........?,???......??

Toyota T-case output shaft, Stock........2,500......65
Toyota T-case output, AllPro 8620 .......2,500......60
Toyota T-case output, Marlin Treated ....2,500......10 ?
Toyota T-case output, Longfield Treated..2,500......20 ?
Toyota T-case output, Longfield Treated..3,000......48 ?
Toyota T-case output, Longfield 4340.....4,000......25

Warn Locking Hub (for Toyota axle).......5,000

Toyota Hub Gear, Stock...................5,800
Toyota Hub Gear, Longfield Treated.......6,800
Toyota Hub Gear, Longfield 4340..........7,500

Toyota Drive Flange, Stock...............6,000
Toyota Drive Flange, Longfield 4340......7,500 (broke 6 - 5/16" bolts)

The front axle shafts on the TrailVoy platform are smaller than the Toyota Birfield stock axles, breaking point 3500 ft. lbs. and 30* twist.

Here is the formula for determining the ft. lbs. of torque on an axle:

Engine’s maximum net torque
X first gear ratio
X transfer case low-range ratio
X axle ratio
X “real world” ratio of 0.85 (real world factors in issues like used parts, steering while applying torque, etc.)

If an engine puts out 200 ft lbs torque, multiplied by a 2.50 first gear ratio, multiplied by a 2.50 t-case ratio, multiplied by a 3.73 gear ratio times the .85 "real world ration" (all numbers are less than typical I-6 Trailvoy outputs) you get: 3963 ft. lbs. A typical TB would likely output about 6500 ft. lbs to the axles (300 eng, 2.75 1st, 3.67 t-case, 3.73 gears, .85 fudge).

Our front axles are equivalent to #2 below. Our rears are equivalent to #3/4 below.

Here are additional axle strengths by size of the axle shaft:

Size (inches)
Material Yield--Torque (lbs-ft) Note
1.00 1040 carbon steel 2,657.3 1
1.10 1040 carbon steel 3,639.8 2
1.125 1040 carbon steel 3,787.5 3
1.16 1040 carbon steel 4,160.8 4
1.25 1040 carbon steel 5,184.5 5
1.28 1040 carbon steel 5,571.4 6
1.28 4340 chrome moly 9,147.4 7
1.31 1040 carbon steel 6,044.1 8
1.31 1340 mang-steel 6,473.1 9
1.31 4340 chrome moly 9,923.5 10
1.32 1040 carbon steel 6,121.6 11
1.37 1040 carbon steel 6,828.4 12
1.37 1340 chrome moly 11,211.2 13
1.50 1040 carbon steel 8,966.2 14
1.50 4340 chrome moly 14,721.2 15

Notes:
1. Old Jeeps, Dana 23 and 41, as well as old Land Rover series rigs.
2. The necked-down section on GM 28 and 30-spline front axle shafts and 30-spline Dana axles. Also a close approximation of the old Jeep Dana 25 and 27.
3. The OE stub axle of Dana 44 and GM 10-bolt front axles.
4. Dana 30 and 35 front and rear 27-spline axles used on Jeeps and Ford Rangers and Bronco II. The 1.20-inch, 28-spline Ford 8.8 on many small Fords is just slightly stronger. Mitsubishi trucks and SUVs are slightly stronger.
5. Jeep AMC 20 rear 29-spline and AMG Hummer IFS/IRS (not CVs). Newer Nissan trucks and SUVs similar.
6. The GM 10-bolt front or rear 28-spline axle.
7. A 28-spline in 4340.
8. An OE type 30-spline axle, to include Dana 44 in many rigs, most Toyota axles, GM 10 and 12-bolt axles, small axle Dana 60 light duty full-floaters.
9. A slight upgrade in material on a 30-spline axle.
10. A 30-spline axle in 4340.
11. The 31-spline Ford 8.8 OE axle. Old Nissan Patrol similar.
12. An OE 33-spline axle similar to those used in the GM semi-float 14-bolt.
13. A 33-spline axle in 4340.
14. An OE 35-spline axle as found in a front or rear Dana 60 or a 30-spline, 1.5-inch, 14-bolt full-float axle, a Ford 10.25 Sterling full-floater, or a Dana 70.
15. As in number 14 above, but in 4340 alloy.

[KE7WOX]

I think rotating mass and diameter would be more of a concern than the lever arm by itself, which you would only be pushing out a little bit. Obviously it will multiply things, but I have a feeling that the tire diameter/weight

I went from a ~34 lb, ~29.5" tire to a 52 lb, 31.7" tire, and I'm still small compared to other people, my brain is not in condition of doing any sort of math right now (or operate a calculator for that matter), but it seems like this will have a larger effect when you are running larger tires (we've all heard of the Dana 35, famous for handling tires up to... 31")

As of now I believe the only one here who has damaged an axle is the roadie, and we all know how much he abuses that Envoy (I think that at least 1/4 of Jeep owners who claim to be real off-roaders would not do what he does).


Last post of the night, as I just wrote 1/4" of Jeep owners. Obviously my brain is not working

[Hpimichael02]

Good point on the axles , mark is running 315's I think and bill your running what 285's? Now

[KE7WOX]

I'm running 265s, but most of the 33" crew is running 285s

[Philberto]

255/85/16 FTW... my next tire.

[fishsticks]

255/85/16 FTW... my next tire.

This.

[The Roadie]

This.

Can anybody tell this old fart what "This." means? A year ago it seemed to be people would post "word" as a response and I didn't get that either.

Heck, I'm just catching up to "FTW".

[Philberto]

It would just be "I agree with this." I'm rather fond of the usage, much more so than "word."

Besides, "word to your moms" is so much better


But seriously, 255/85 saves you on fuel consumption, wear/tear, weight, and gives you a 33" tire. Only downside is fewer choices and availability in tires.

[MrSmithsTB]

It would just be "I agree with this." I'm rather fond of the usage, much more so than "word."

Besides, "word to your moms" is so much better


But seriously, 255/85 saves you on fuel consumption, wear/tear, weight, and gives you a 33" tire. Only downside is fewer choices and availability in tires.

Truth. I personally prefer the little extra width the 285 provides, and I don't mind the fuel consumption. Anything wear/tear wise will need to be replaced eventually anyway, and 285s leave you open to way more options. But lets face it, we didn't go this direction with our vehicles to save money.

[Trail X]

I've posted this before... but it's a good overview of tire width selection:
http://expeditionwest.com/research/whit ... _rev1.html

[Saxis]

I'm going with 265. The majority of my time in 4x4 is spent in beach sand or sloppy mud, and I think this size will be plenty good.