Air pressure

[NCL4701]

What about when the operator has an Empty Bucket …while traveling empty back-and-forth from the source?

While that practice (max tire mfr statement) is unlikely to cause much issue….. I disagree with the ”need “to use max pressure “per the sidewall”…. as when empty it will cause excess wear on the center of the tread area…while doing nothing beneficial for the tire when carrying a load….(in-fact, will cause excess wear on the center of the tread during load-carrying ops as well.)

The Tractor Mfr’r and FEL Mfr’r both Know the maximum rated lifting capacity of that tractor, it’s front axle, And the loader. The front tire pressure recommended by the tractor/loader combo is what should be utilized….as that is what will meet the needs of that lifting capacity.

The one on the tire sidewall probably won’t hurt anything…except the Tire… …. but it’s not necessary to stress the wheel, the tire, or the equipt by doing so…

If not using the loader for some extended period of time, taking it off for mowing, etc. and it’s off long enough in the operator’s subjective opinion it’s worth their time and effort reducing tire pressure during the loader’s disuse and increasing pressure when back to using the loader (as in jyoutz example of varying the tire pressure in his truck tires depending on use), I completely agree. Varying tire pressure to fit the task at hand makes perfect sense.

If you, or anyone else, wishes to run front tires on your tractor/loader at less than maximum allowed by manufacturer while using the loader, my only suggestion is to check the load capacity of the front tires at whatever pressure you want to run them (if you can’t find a chart online, a query to the tire manufacturer should clear that up for you quickly); then do a little math to figure out how much weight you’re actually putting on the front tires with the full bucket of rock or whatever else you have on the loader (don’t forget to calculate the weight transfer from/to rear axle which is dependent on rear ballasting because if/when the “back end gets light” that weight went to the front axle rather than disappear); add in safety factor of your choice unless you only operate on flat pavement; make sure you’re not overloading the tires at your selected pressure.

That or load it up, look at the front tires, and if the sidewalls are mushed out too far, add some air. Either way, most of the time you’re going to end up at or near max rated pressure on the fronts with a fully loaded loader. As with most things, YMMV.

Edit: And we’re discussing tractor tires. Over inflation causing excessive tread wear in the center is certainly applicable for a relatively flat tread such as a road tire where it can create a slightly rounded profile, but a R4 or R1 is higher in the center by design.

 

[GeoHorn]

Sooo… I went out to my M4700 which has it’s original OEM tires and the front tires have on the sidewalls “32 psi… Max” No weight rating is noted. (Bridgestones - Japan)

And the rear tires have “Do not exceed…. (blank) psi at (blank) max load” and then just-below that “(Blank) MPH max speed” (Firestones - U.S.)

The Operators Manual shows the following:

 

[NCL4701]

Sooo… I went out to my M4700 which has it’s original OEM tires and the front tires have on the sidewalls “32 psi… Max” No weight rating is noted. (Bridgestones - Japan)

And the rear tires have “Do not exceed…. (blank) psi at (blank) max load” and then just-below that “(Blank) MPH max speed” (Firestones - U.S.)

The Operators Manual shows the following:

View attachment 123868

View attachment 123867

Thanks for looking it up in the OM and making my point so I didn’t have to…

 

[DustyRusty]

Beautiful!
Do you still have it?

Yes, it is in its winter slumber mode right now. Will come out of hibernation in April.

 

[NCL4701]

So far as wearing out the center of the tread due to over inflation…

This front tire is running 45psi (max per sidewall)

This rear tire is running 15psi…

See how the tread profile of one is rounded and the other isn’t?

Yeah, me neither. We’re not discussing passenger car tires.

But… your machine, your rules.

 

[GeoHorn]

Thanks for looking it up in the OM and making my point so I didn’t have to… View attachment 123869

Yes …BUT….the Max pressure.. AS SHOWN IN THE OPERTORS MANUAL….is 29 psi….. NOT the Max Pressure as shown on the SideWall.

 

[fried1765]

Yes, it is in its winter slumber mode right now. Will come out of hibernation in April.

Kinda like my L48 TLB, my Ford 1920 FEL, and my 8N.......all in "winter slumber mode right now"

 

[GeoHorn]

So far as wearing out the center of the tread due to over inflation…

This front tire is running 45psi (max per sidewall)
View attachment 123870
This rear tire is running 15psi…

View attachment 123871
See how the tread profile of one is rounded and the other isn’t?

Yeah, me neither. We’re not discussing passenger car tires.

But… your machine, your rules.

Sorry my friend…but clearly there IS a Crown (rounded tread) evident…. Although ..Agreed….the tread IS also designed to provide maximum traction contact… with whatever psi is used.

 

[NCL4701]

Sorry my friend…but clearly there IS a Crown (rounded tread) evident…. Although ..Agreed….the tread IS also designed to provide maximum traction contact… with whatever psi is used.

Obviously there’s a crown in both the high pressure tire and low pressure tire. That’s the way they’re designed, both R4 and R1, but you already know that so I really shouldn’t have to say it.

You’ve been running your machines for I don’t know how many hours, but I suspect quite a lot. Whatever you’re doing apparently works for you. By all means, carry on.

Past that, this has reached the end of constructive discourse. You can have the last word if you wish. With respect, I’m out of this one.

 

[Lil Foot]

I run my tractor tires at the sidewall recommended max pressure. Any excess wear from running at that pressure will not be an issue in my lifetime. (it never sees pavement)
My place is fairly rocky and a rock puncture could be an issue in my lifetime.
It was twice on my old set of tires running 15 & 18 psi as the PO did.
If it rides rougher at max pressure, it is not noticeable nor a big deal for me as little as I use the tractor.
Maybe if I was on it all day every day or used it commercially....

 

[InTheWoods]

Worth noting that the OP asked about the REAR tires, not the front. The answer is 14 psi.

 

[GeoHorn]

Worth noting that the OP asked about the REAR tires, not the front. The answer is 14 psi.

View attachment 123914

Yes…maintain the “maximum pressure” in the front tires if using a loader…. That “maximum pressure is the Max pressure listed in the Tractor Owner Manual Chart…..NOT the Max pressure on the sidewall…

 

[InTheWoods]

...and if you're NOT using a loader, what pressure would you put in the fronts?

BTW, In my case (B7510 w/ 23x8.50x12 fronts) the sidewall MAX is 35 PSI and the chart in the owners manual is exactly the same. IOW, for the FRONTS I run the max sidewall rated pressure. NOT the case for the rears, which again, are the topic of this thread.

 

[Kubota Newbie]

AG tire manufacturers all publish load inflation tables for their tires. For the best combination of ride, load capacity, traction, and tire life, inflate to the lowest pressure in the chart for the expected tire load including bolt-on ballast. This may very well mean that you "should" change that pressure occasionally if doing different tasks although most people don't and just over inflate.
Operation on extremely steep slopes and liquid ballast will require adjustment of the recommended pressure.
This all requires a little math and thought about what you do with the tractor. Keep in mind that it's the operating load you are interested in. For example, for front tires on a loader tractor you have to add the weight of the loader and the weight of the typical operating load. That can vary greatly (dry round bales, wet wrap round bales, scooping gravel, etc.). On the other hand, in the case of say a 4 bottom mounted plow, the operating load doesn't include the weight of the plow because you're interested in the tractive efficiency of the tire and the plow is not supported by the tires when engaged in the soil.
Bottom line - Kubota recs are assumptions based on what they think you might do with the tractor. The tire manufacturers sidewall rating is the maximum inflation pressure. Neither one might be appropriate for your operating conditions. Consult the load charts for the best combination of tire attributes for your situation.
(If your tire manufacturer doesn't have a chart you can be really close by using someone else's. Just abide by the same tire type, ply rating and carcass type (radial/bias)).

 

[GreensvilleJay]

The problem with using the rating in the book, is you don't KNOW what make/model tires were used for that chart or the operating conditions.

Reminds me of the constant myth on TV where the cops find the bad guy using the tire tracks left at the murder scene.

I'd like to have an onboard air compressor to adjust for road vs offroad but instead ,just buy tires/rims every 3 years.

 

[WFM]

I just put on new R1's on the front of my tractor. Thinking of this thread when the local mechanic that changed them said the max pressure on the sidewall is 54 psi , I put in 50 psi he said. You can adjust that to what you want. I dug out the owners Manuel and it list my front tires the 7.2-16 the Manuel says 6 ply, the tires are 8 ply that came on the tractor. But in the Note: it says when using a FEL maintain Maximum Pressure. Seems simple.

 

[phoenix]

Wow! This is a great forum. I joined today to understand a front tire problem I'm having with my L3130.

I am thinking of CHANGING my front tires on my L3130 from AG to Industrial. I keep rolling the tires enough to break the bead and wind up with a flat. Plus the tires mash out under heavy load. NO, I'm not abusing my machine. Not pushing the limit. The 7.00-16 tires just seem too small, capacity doesn't match the LA723 loader and they have very little area over which the load is distributed. Max load is listed at 1,100 lbs.

I have rolled the bead half a dozen times. All but one when I had the loader and either forks or bucket mounted. Once when blowing snow with LA274A front mount. With either combination to total weight of the tractor and implements is about 4,600 lbs. The tractor bare weighs about 3,300 lbs. If I assume(!!!) the weight distribution is about 60% rear and 40% front that make the front end load about 1,300 lbs naked. Each set of implements adds about 1,400 lbs that I believe is more like 60% front or 840 lb. That puts the weight on the front tires at a total of about 2,200 lbs. A max load for a pair of tires with 1,100 capacity each. If I pick up even just half of the bucket's max capacity load at half-lift, that's another 300 lbson the front end and now beyond the rating molded into the tire. Full bucket of pea stone or loam and the front tires mash out to something pretty nasty looking.

Changing just the fronts is not recommended on 4WD tractors. Would cost $900. All 4 tires (and required rims) would be $3,100.

I will appreciate any other comments on problems/issues/suggestions concerning the AG front tires in light rural use.