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wjbusguy
Active Member
United States
42 Posts |
 Posted - 07/30/2013 : 1:34:08 PM
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What are you guys running for tire pressures front and rear? Almost all of our buses are 77 passenger conventional front engined buses with 11R/22.5 tires.
Mike |
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bus a groove
Senior Member
70 Posts |
Posted - 07/30/2013 : 3:50:04 PM
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| We have Conventionals and transit style buses. All of our buses we run 100psi in the rear and 100 in the front. Its pretty standard |
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partsman_ba
Administrator
United States
377 Posts |
Posted - 07/30/2013 : 4:30:56 PM
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| We run 120 psi front; 80 in the rears on short buses (conventional and transit) and 100 on full sized transits. |
"Growing old is mandatory. Growing up is optional." |
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bwest
Administrator
United States
3820 Posts |
Posted - 07/30/2013 : 5:40:32 PM
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On the 11R tires we run 100 psi all around. We run country roads with a serious crown and I tried a lower pressure on the inside but I didn't see much of a difference in wear.
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Bryan |
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jadatis
New Member
1 Posts |
Posted - 07/31/2013 : 07:16:41 AM
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Registered to this forum to give you an answer, not a busdriver.
Live in Holland and got hold of the formula that is used for tire-pressure calculation for radial tires.
What you need from tires is the "maximum load xxxx lbs AT yyy psi" written on the sidewall.
yyy is called the reference pressure and is lower then the maximum pressure.
So you are alowed to go higher then yyy . This is done for more load at lower speed.
From the bus you need the GAWR's ( Gross Axle Weight Ratings), mostly on a plate somewhere on the bus. The bus is made so that if 77 persons in it the GAWR's are not exededs, if they did it right.
Because you dont drive all the time with 77 persons, you could determine the lowest possible weight by using the empty weight and weight division, and I can put it in another spreadsheet of mine only in Dutch to see what the axle weights can get.
Also need the axle configuration like back tandem-axle and or twintwheel axle.
If you have all the data you can fill it in in my , MotorhomeRVtirepressurecalculator, or give the details here and I will do it for you. Then you can doo with using the GAWR with reserve of 0% , whenever you realy have 77 persons in it yust drive slower.
Then see if the empty weight with say 5 persons is above 85% of the weight you calculate the pressure for, this is the border below wich discomfort begins by bouncing ( determent by me trough reactions so discussable, for Traveltrailers I use 80% before screws come loose from wood.
Next link is to a map on my public map of skydrive, that belongs to my hotmail.com adress with same username as here( so combine yourselfes, spamm machines cant this way).
Download a spreadsheet first by RIGHTclicking on it then choose Download of the dropdownbox.
Dont use the top 2 possibilitys, first cant handle some things I used in the speadsheets, and second asks you to log in with your hotmail acount.
https://skydrive.live.com/?cid=a526e0eee092e6dc#cid=A526E0EEE092E6DC&id=A526E0EEE092E6DC%21793
So succes and greatings from Holland
Peter |
Edited by - jadatis on 07/31/2013 07:22:14 AM |
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Farmridge
Senior Member
51 Posts |
Posted - 08/01/2013 : 05:13:20 AM
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We use Firestone/Bridgestone tires, mostly 11r's and we set our air pressure according to their load data chart. The majority of ours run 85 in the front and 80 in the rear. Our tire wear is wonderful now, most are worn even and not just in the center.
http://www.trucktires.com/firestone/us_eng/load/databooks_pdf/F_MediumLightTruckDataBook.pdf
That link is for firestone. Every manufacture has one, you just have to ask. I just replace a set of rears on a rural route bus and got 98,000 miles out of them in 6 years.
You will also notice a smoother ride too. |
If you can't handle the answer, don't ask the question |
Edited by - Farmridge on 08/01/2013 05:14:07 AM |
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wlanphier
New Member
5 Posts |
Posted - 08/08/2013 : 7:56:57 PM
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| Not sure on the pressures but I just had a firestone tech come to my district and suggest taking the buses across the scale. He believes that our 105 psi is to high and would extend life by dropping significantly. I would contact a rep from your tire manufacturer. |
Edited by - wlanphier on 08/08/2013 7:57:41 PM |
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Fastback
Top Member
1500 Posts |
Posted - 08/09/2013 : 06:34:24 AM
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| We make sure to run 100-105 psi front in our front engine transits and have "Catseyes" on the rears of all our buses that show underinflated if we drop below 90 psi. |
Why yes, the ORIGinal CHARGER is a Fastback |
Edited by - Fastback on 08/09/2013 06:36:10 AM |
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bbassett
New Member
7 Posts |
Posted - 10/24/2013 : 07:26:12 AM
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quote:
Originally posted by Farmridge
We use Firestone/Bridgestone tires, mostly 11r's and we set our air pressure according to their load data chart. The majority of ours run 85 in the front and 80 in the rear. Our tire wear is wonderful now, most are worn even and not just in the center.
http://www.trucktires.com/firestone/us_eng/load/databooks_pdf/F_MediumLightTruckDataBook.pdf
That link is for firestone. Every manufacture has one, you just have to ask. I just replace a set of rears on a rural route bus and got 98,000 miles out of them in 6 years.
You will also notice a smoother ride too.
We run Bridgestone tires also but we onlt get 40,000 miles on a set on our front engine 77 passenger Internationals. What model of Bridgestone are you using?
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BJ Henderson
Advanced Member
USA
280 Posts |
Posted - 10/24/2013 : 10:29:16 AM
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| Each bus has a label on it for proper tire inflation. We adjust for road conditions, but very little. If the alignment is good, tire wear in minimal. |
CMTT,CMAT,CMBT |
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bwest
Administrator
United States
3820 Posts |
Posted - 08/20/2018 : 10:09:50 AM
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| I hate to bring up an old topic but I'm wondering if any of you have a different opinion than above? Been almost 15 years since this topic was last commented on but it is still something we need to get right. I'm currently running 85 front 70 rear. I'm thinking about bumping to 85 rear and staying at 85 front. |
Bryan |
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kummins
Active Member
41 Posts |
Posted - 08/20/2018 : 10:36:07 AM
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the vehicle manufacturer recommendations are based on the tires supplied at that time on the assembly line.
each tire brand/manufacturer has optimal tire pressures for each composition & size.
i'd trust the tire manufacturer over the vehicle manufacturer.
found this link from the nhtsa, there's a pdf that can be downloaded, it's for 1998 thru 2005 schoolbus recalls
https://icsw.nhtsa.gov/people/injury/buses/1998_2005SchoolBus_Recalls/ |
Edited by - kummins on 08/20/2018 10:57:05 AM |
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RonF
Top Member
867 Posts |
Posted - 08/20/2018 : 11:27:47 AM
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quote:
Originally posted by kummins
the vehicle manufacturer recommendations are based on the tires supplied at that time on the assembly line.
each tire brand/manufacturer has optimal tire pressures for each composition & size.
i'd trust the tire manufacturer over the vehicle manufacturer.
found this link from the nhtsa, there's a pdf that can be downloaded, it's for 1998 thru 2005 schoolbus recalls
https://icsw.nhtsa.gov/people/injury/buses/1998_2005SchoolBus_Recalls/
I use to run 85 all the way around on my 72's and I came up with this from Firestones load data chart. However since Firestone switched to the FS 561's, the 85 psi was causing an abnormal wear issue. The tire was wearing the second rib our on either the inside or outside of the tire. The Firestone enginneer came and looked and said yes the pressure is correct for our axle weight and tire, but to bump the pressure up to 100-105 and try that. I have not had anymore wear issue out of those tire. I am currently testing the FS560 plus tires at 105. If the centers are wearing out we will adjust down from there.
The other reason we switched from the 561 to the 560 is because the 560 is 1 inch narrower the the 561. With the 561 we had rub issues with the drag links on certain buses.
We still run 85 on the rears of all of our buses based on the axle weight and are recording perfect wear with some great 32nd per mile. Of course wear will depend from bus to bus. |
US Army retired CMBT |
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aaronwilmoth80911
Top Member
538 Posts |
Posted - 08/20/2018 : 1:44:03 PM
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| We run ours at 85 all the way around. We have run into a few issues with fronts wearing goofy, but our tire people haven't said anything about the pressures causing issues. Most issues have come from Goodyears, but we run primarily Michelins. |
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RonF
Top Member
867 Posts |
Posted - 08/21/2018 : 03:47:39 AM
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quote:
Originally posted by aaronwilmoth80911
We run ours at 85 all the way around. We have run into a few issues with fronts wearing goofy, but our tire people haven't said anything about the pressures causing issues. Most issues have come from Goodyears, but we run primarily Michelins.
It sounds like the same issue I was having with Firestone. I have a picture of a private school bus with a Goodyear G661 HSA with the same goofy pattern as Firestone. |
US Army retired CMBT |
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aaronwilmoth80911
Top Member
538 Posts |
Posted - 08/21/2018 : 08:15:55 AM
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| Ron it has been 661s that have been troublesome for us too. Weird low spots on the outer tread. Switched tires to Michelins and problem hasn't come back. |
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RonF
Top Member
867 Posts |
Posted - 08/21/2018 : 10:59:53 AM
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quote:
Originally posted by aaronwilmoth80911
Ron it has been 661s that have been troublesome for us too. Weird low spots on the outer tread. Switched tires to Michelins and problem hasn't come back.
I posted that picture on the School bus mechanics Facebook page. |
US Army retired CMBT |
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eddo
Advanced Member
USA
311 Posts |
Posted - 08/22/2018 : 09:13:47 AM
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I learned a while ago that I always get weird wear from Goodyears. Both on IH's, and vans.
I stay as far away from them as I can. |
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Black Smoke Customs
New Member
USA
4 Posts |
Posted - 08/22/2018 : 6:45:35 PM
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| In my experience, under-inflation and excessive age cause more failures than anything else. Make sure that your following the tire requirements from the Mfg. of the equipment before you start playing with the pressure. Just for reference on a standard 12R22.5 in a 16 ply rating on a 84 pax Thomas or Bluebird I prefer 110 on the front and 105 in the rear. But if your running the wrong tire for the equipment your just begging for trouble. |
Yes I am looking for a job, PM me for a copy of my resume. 20 plus years bus and 34 years as a Mechanic. Currently the Lead in a Federal shop. |
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1Dieselman
Active Member
28 Posts |
Posted - 08/23/2018 : 10:29:17 AM
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| We used to run 110 front and rear but about two years ago decided to drop to 85. Wear pattern and ride have both been better. We don't run re-treads or tire's older than 5 years. Drive tire's are BFG DR444, steer tire's are Michelin XZE2 |
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bwest
Administrator
United States
3820 Posts |
Posted - 08/29/2018 : 05:44:21 AM
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| I tend to agree with kummins. This is exactly the discussion (argument) that was going on when Ford Explorers were blowing tires and rolling over. Ended a near century long relationship between Firestone and Ford. The manufacturer of the tires know best. As we are all well aware, technology changes at a breakneck pace. That's no different with tires. Newe manufacturing processes and material come along quickly. That cannot be reflected in the owner's manual (unless you are looking at it online and it's updated I gess) |
Bryan |
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RonF
Top Member
867 Posts |
Posted - 08/29/2018 : 09:09:07 AM
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quote:
Originally posted by bwest
I tend to agree with kummins. This is exactly the discussion (argument) that was going on when Ford Explorers were blowing tires and rolling over. Ended a near century long relationship between Firestone and Ford. The manufacturer of the tires know best. As we are all well aware, technology changes at a breakneck pace. That's no different with tires. Newe manufacturing processes and material come along quickly. That cannot be reflected in the owner's manual (unless you are looking at it online and it's updated I gess)
https://commercial.firestone.com/content/dam/bcs-sites/firestone/TBR/load-inflation-tables/mar2015/FS_TBR_load-inflation-tables_web_2014.pdf |
US Army retired CMBT |
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kummins
Active Member
41 Posts |
Posted - 08/29/2018 : 10:18:49 AM
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quote:
Originally posted by bwest
I tend to agree with kummins. This is exactly the discussion (argument) that was going on when Ford Explorers were blowing tires and rolling over. Ended a near century long relationship between Firestone and Ford. The manufacturer of the tires know best. As we are all well aware, technology changes at a breakneck pace. That's no different with tires. Newe manufacturing processes and material come along quickly. That cannot be reflected in the owner's manual (unless you are looking at it online and it's updated I gess)
vehicle manufacturers want & need their customers/clients to feel a smooth comfy ride, so they tend to lean towards under inflation of tires, just like in racing where the crew chief says "take out a pound on left front" to get more grip/speed , even when goodyear tells them absolutely not because the tire will explode! |
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bwest
Administrator
United States
3820 Posts |
Posted - 08/30/2018 : 07:19:07 AM
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quote:
Originally posted by RonF
quote:
Originally posted by bwest
I tend to agree with kummins. This is exactly the discussion (argument) that was going on when Ford Explorers were blowing tires and rolling over. Ended a near century long relationship between Firestone and Ford. The manufacturer of the tires know best. As we are all well aware, technology changes at a breakneck pace. That's no different with tires. Newe manufacturing processes and material come along quickly. That cannot be reflected in the owner's manual (unless you are looking at it online and it's updated I gess)
https://commercial.firestone.com/content/dam/bcs-sites/firestone/TBR/load-inflation-tables/mar2015/FS_TBR_load-inflation-tables_web_2014.pdf
Yep, I've got the same document. |
Bryan |
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Topic |
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Tire Pressure?
