Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
 
Old 08-20-2022, 10:23 AM   #1
New Member
 
Join Date: Apr 2019
Location: Eagle River, AK
Posts: 5
Year: 2001
Coachwork: Thomas
Chassis: FS65
Engine: CAT 3126E, 2000series
Rated Cap: 16
Tire Pressure?

My bus has a GVWR of 25500 lbs but I’m only at 14000 right now. I don’t think I’ll be able to build it out much more than 18000 so I’m looking to soften the ride a bit. Has anyone seen a good chart for tire pressure vs load capacity? Riding on Mastertrack M-Trac 255/70R22.5 but cant find much information on them. Maybe there’s a generic chart or rule of thumb though?

shortbusak is offline   Reply With Quote
Old 08-20-2022, 10:28 AM   #2
Bus Crazy
 
TheHubbardBus's Avatar
 
Join Date: Apr 2019
Location: SW USA
Posts: 2,064
Year: 2003
Coachwork: IC / Amtran
Chassis: CE300
Engine: International T444e
Rated Cap: 23
All of the big 4 tire manufacturers Ive researched provide that info in their annual commercial tire catalogs. I'm not familiar with your brand but if you Google for their commercial catalog, that might be the easiest way. If not, contact them or a distributor directly.
__________________
Go away. 'Baitin.

Our Build: Mr. Beefy
TheHubbardBus is offline   Reply With Quote
Old 08-20-2022, 10:51 AM   #3
Bus Crazy
 
turf's Avatar
 
Join Date: Apr 2013
Location: Colorado
Posts: 2,382
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
i run my 22.5's in the 90 psi range.

theyre rated to 110, but like hubbard mentions, their chart says i can run less at my weight.

with the cost of diesel, i'll probably fill the tires up back over 100 for better rolling. i'm not convinced tire pressure made much ride difference.
__________________
.
Turfmobile Build Thread
turf is offline   Reply With Quote
Old 08-20-2022, 01:18 PM   #4
Bus Crazy
 
TheHubbardBus's Avatar
 
Join Date: Apr 2019
Location: SW USA
Posts: 2,064
Year: 2003
Coachwork: IC / Amtran
Chassis: CE300
Engine: International T444e
Rated Cap: 23
I haven't spent much time experimenting, but with our bus still mostly gutted, I had a similar initial impression, Turf. Between the 90 or so set when they were mounted, and the 110 I'm keeping them at now while it mostly just sits (my attempt to prevent flat spotting), I didn't notice much if any improvement in ride quality. Now replacing the shocks... That was huge.
__________________
Go away. 'Baitin.

Our Build: Mr. Beefy
TheHubbardBus is offline   Reply With Quote
Old 08-20-2022, 01:31 PM   #5
Skoolie
 
tlzimmerman's Avatar
 
Join Date: Jul 2020
Location: Kansas
Posts: 143
Year: 1996
Coachwork: Thomas
Chassis: Ford B
Engine: 5.9 Cummins 12v
Rated Cap: 60
Run them at 90 or 100. That's where they are designed to be. I don't think you will see much difference in ride quality going less and you could compromise the sidewall over time.

Blowouts in big tires can cause serious damage.

Just one man's opinion.
tlzimmerman is offline   Reply With Quote
Old 08-20-2022, 01:32 PM   #6
Bus Crazy
 
Join Date: May 2018
Location: topeka kansas
Posts: 1,794
Year: 1954
Coachwork: wayne
Chassis: old f500- new 2005 f-450
Engine: cummins 12 valve
Rated Cap: 20? five rows of 4?
10r22.5

Rear axle 5,800 lbs. that is within the load limit of ONE tire! I run 60 psi. Summer heat 100 degrees and tread/ carcass temperature is below 125. Road surface temperature around 135. This off the charts! I played with pressure quite a bit over a 800 mile first trip to arrive at these pressures. Front tires at maximum pressure 110 psi. Front axle near full load at 10,800 lbs.

William
magnakansas is offline   Reply With Quote
Old 08-20-2022, 01:54 PM   #7
Bus Crazy
 
turf's Avatar
 
Join Date: Apr 2013
Location: Colorado
Posts: 2,382
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
im similar but have not been as brave as william.

front heavy, rear light
i'm 19k lbs - 11 on the front, 8 on the rear

so i should probably go harder on the front, softer on the rear?

softer than 90 makes scared of the sidewall, but idk
__________________
.
Turfmobile Build Thread
turf is offline   Reply With Quote
Old 08-20-2022, 04:02 PM   #8
Bus Crazy
 
s2mikon's Avatar
 
Join Date: Nov 2014
Location: NM USA KD6WJG
Posts: 1,342
Year: 1991
Coachwork: Bluebird
Chassis: All American RE 40 FEET
Engine: Cummins 8.3
Tire manufactures have a chart that gives you the pressure to safely handle the weight put on the tires. To use it you have to know the weight of each axle at each end. Not just the total axle weight. I use that and add 5 pounds. The extra 5 pounds is to give me some head room if I get a nail in a tire. This is all based on cold inflation pressures. Now you can adjust the tire pressure to get the best contact on the ground across the full width of your tire. Over-inflating a tire for a given load puts more load in the center of the tread and under inflating puts more load on the shoulders, and causes the tire casing to overheat. Good tire pressure gauges are a must and I highly recommend a good infrared temperature gun. If you have a tire beginning to overheat you need to know. It is good for so many other things too. Tires generally don’t die, they are killed.
__________________
Why can't I get Ivermectin for my horses?
s2mikon is offline   Reply With Quote
Old 08-20-2022, 10:34 PM   #9
Bus Crazy
 
Join Date: Oct 2020
Location: Near Flagstaff AZ
Posts: 1,951
Year: 1974
Coachwork: Crown
Chassis: "Atomic"
Engine: DD 8V71
Quote:
Originally Posted by s2mikon View Post
Tires generally donít die, they are killed.
There's so much truth in this statement. I've read every (I think) report and study on tire failures, including the very detailed NHTSA-sponsored study done by the University of Michigan (comparing recapped and virgin tire failures) and it's pretty clear that the two leading causes of tire failure are underinflation and road hazards.
rossvtaylor is offline   Reply With Quote
Old 08-20-2022, 11:22 PM   #10
New Member
 
Join Date: Apr 2019
Location: Eagle River, AK
Posts: 5
Year: 2001
Coachwork: Thomas
Chassis: FS65
Engine: CAT 3126E, 2000series
Rated Cap: 16
I havenít had luck finding a chart from this manufacturer yet so figured Iíd see if anyone was familiar with these. No surprise about needing to know the weight on each axel. Thanks for the feedback on the negligible effect on ride comfort. I just drove the Alcan on a very blown front right shock so am looking forward to my next trip on the new ones. I was thinking the correct pressure/load balance in the tires would effect grip and tread wear as well. Iíve seen overinflated do just as much damage and underinflated.
shortbusak is offline   Reply With Quote
Old 08-21-2022, 07:07 PM   #11
Bus Nut
 
Dbacks2k4's Avatar
 
Join Date: Dec 2021
Location: Iowa City, IA
Posts: 645
Year: 2006
Chassis: IC CE300 (PB105)
Engine: DT466e @245hp | Allison 3000PTS
Rated Cap: 66
All our buses have a tag in the front that lists the year, GVWR, etc that also lists the recommended tire size and pressure.

So, I run at 105 psi cold on my fleet. We're usually at about 18000 lbs empty before loading up with intoxicated passengers. All our Tires are 11r22.5 and 75r22.5. It's a happy balance between the different buses





.
Attached Thumbnails
Screenshot_20220821-190354.jpg   Screenshot_20220821-190504.jpg  
Dbacks2k4 is offline   Reply With Quote
Old 08-22-2022, 05:40 AM   #12
Bus Geek
 
musigenesis's Avatar
 
Join Date: Jan 2019
Location: Philadelphia
Posts: 7,013
Year: 2003
Coachwork: International
Chassis: CE 300
Engine: DT466e
Rated Cap: 65C-43A
Quote:
Originally Posted by rossvtaylor View Post
There's so much truth in this statement. I've read every (I think) report and study on tire failures, including the very detailed NHTSA-sponsored study done by the University of Michigan (comparing recapped and virgin tire failures) and it's pretty clear that the two leading causes of tire failure are underinflation and road hazards.
I blew a rear tire a couple of months ago and although my tires were eight years old I fear this happened because they were under-inflated (since I basically never checked the tire pressures). A $2700 lesson if so, although I do feel better having brand-new tires.
__________________
Rusty 87 build thread
musigenesis is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 12:57 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.