Tire pressure according to the manual

Bearcatrp

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BX1880
Mar 28, 2023
344
161
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Minnesota
The book calls for 17 PSI for front tires. The sidewall of tire states max 38 PSI. Got my class II delivered today, 15 yards of it. With 17 PSI, a half bucket load flattens my tires to the rim. So I bumped the air up to 30 PSI. Works fine now. But am I going to regret this down the road?
 

GrizBota

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L3830HST/LA724, B2601/LA435/RCK54-32, RCR1872, CDI 66”grapple, pallet forks
Apr 26, 2023
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Oregon
Interestingly enough, when I researched this with my Kubota owners manuals a while ago, I got nowhere too. The tractor manual provides tire pressures with no mention of adjustments for FEL work. The manual for the FEL provides the same tire pressures as the tractor manual, again with no mention of adjustments for the FEL being loaded. I have two Kubota tractors and four owners manuals, same result in both cases.

My thought process suggests to me that an increase in front tire pressure would be warranted when the FEL is installed, since the load on the front tires is increased, at least to the point the rear counter weight isn’t lifting the front of the tractor off the ground. Myself, I do increase the front tire pressure about 5 psi when the FEL is installed.
 

Bearcatrp

Active member

Equipment
BX1880
Mar 28, 2023
344
161
43
Minnesota
Interestingly enough, when I researched this with my Kubota owners manuals a while ago, I got nowhere too. The tractor manual provides tire pressures with no mention of adjustments for FEL work. The manual for the FEL provides the same tire pressures as the tractor manual, again with no mention of adjustments for the FEL being loaded. I have two Kubota tractors and four owners manuals, same result in both cases.

My thought process suggests to me that an increase in front tire pressure would be warranted when the FEL is installed, since the load on the front tires is increased, at least to the point the rear counter weight isn’t lifting the front of the tractor off the ground. Myself, I do increase the front tire pressure about 5 psi when the FEL is installed.
Am hoping Kubota considered the loader when they selected tires for this tractor. I went through both manuals a few times and there was nothing for adjustment when using the loader. I have turf tires on my tractor.
 

The Evil Twin

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L2501, LA526, LP Box Blade, EA dual lid grapple
Jul 19, 2022
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So counterweight may be part of the problem, but tire pressure is certainly too low. I missed the 17 psi part.
Obviously you have a different unit, but my manual says anywhere from 23-30 psi. However, there is a note that says to inflate to max when using a loader.
 

GreensvilleJay

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BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
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Greensville,Ontario,Canada
Read the tire sidewall and use THAT number,it's the ONE that counts !
That number will allow you to run max weight on the tires,again a sidewall rating.

The 17 is probably for someone cutting grass.....with stock tires.
 

Bearcatrp

Active member

Equipment
BX1880
Mar 28, 2023
344
161
43
Minnesota
So counterweight may be part of the problem, but tire pressure is certainly too low. I missed the 17 psi part.
Obviously you have a different unit, but my manual says anywhere from 23-30 psi. However, there is a note that says to inflate to max when using a loader.
My manual for both tractor and loader does not adjust for when using loader.
 

Bearcatrp

Active member

Equipment
BX1880
Mar 28, 2023
344
161
43
Minnesota
Read the tire sidewall and use THAT number,it's the ONE that counts !
That number will allow you to run max weight on the tires,again a sidewall rating.

The 17 is probably for someone cutting grass.....with stock tires.
Was thinking that but wasn't sure if I risk a blow out. With 30 lbs, seems good when I get a load in the bucket but thinking 35 lb may be better. Thanks for all the replies. Will send a message to Kubota to see what they say.
 

The Evil Twin

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L2501, LA526, LP Box Blade, EA dual lid grapple
Jul 19, 2022
2,247
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Virginia
My manual for both tractor and loader does not adjust for when using loader.
I understand that. What was implied by my post was to just air them up to max and call it a day. Or close to it. It's not going to hurt anything but the ride quality when you are unloaded. You aren't going to have a blow out or anything like that.
 
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Henro

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B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
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North of Pittsburgh PA
Well, you know that you need more air pressure with your current set up when doing loader work.

If the lower pressure worked otherwise, just lower the pressure back to what you were using previously after completing what you are doing now, then take your time to figure out what you need to do long term.

In my case I got my front tires foam filled, since they were so prone to getting punctures anyway. No need to worry about air pressure now...for the last 19 years or so
 

North Idaho Wolfman

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You can safely run the tires at max PSI.

When looking at the PSI specs in the manual, also look at the PLY's they state the tire is, but the ply count is much lower than what you have.
A 4 ply tire takes different PSI than a 6 ply tire!
 
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GrizBota

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L3830HST/LA724, B2601/LA435/RCK54-32, RCR1872, CDI 66”grapple, pallet forks
Apr 26, 2023
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Oregon
It’s interesting that Kubota doesn’t address this matter in their fairly detailed owners manuals. They do list all the OEM tire options a specific model of tractor could have been ordered with, as well as the recommended pressure (sans FEL considerations). Sometimes the ply rating is mentioned in the tire size in the manual.

It’s curious Kubota leaves us to our own devices on this consideration.

Add 5 or 10 psi
Inflate to maximum load carrying capacity pressure
Foam fill
Inflate until the tire isn’t flat when the FEL has a bucket full.

Pick one? Someone’s probably right.
 
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GrizBota

Well-known member

Equipment
L3830HST/LA724, B2601/LA435/RCK54-32, RCR1872, CDI 66”grapple, pallet forks
Apr 26, 2023
1,020
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113
Oregon
I bumped it up to 35 PSI. Seems to be ok for now. Thanks for everyones replies.
The manual calls for 21 psi in front on my L3830. I usually have them set at 25 psi. If I run the loader a bunch, I’ll bump it to 30 psi. The max pressure on the sidewall of the tire is 34 psi. R1 s with 6 ply rating.