| Author | Message | ||
| Bob Baldwin (Bob4106)
Registered Member Username: Bob4106 Post Number: 184 Registered: 10-2004 Posted From: 24.74.180.20  Rating: N/A |
The 4106 weighed in at 26600 LBS Front axle 9300 Rear axle 17300 Looking at the Firestone tire chart looks, like my tire pressure should be 70 PSI. The chart is on page 61. Have to down load the PDF file. This doesn't sound right to me. My tires are 12R22.5 16 PR T575 Radial load range H. Any Help on this would be great. http://www.firestonetrucktires.com/us_eng/load/index.asp (Message edited by bob4106 on October 21, 2009) | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1727 Registered: 12-2000 Posted From: 76.71.101.218  Rating: N/A |
Trust the Force, Luke... Try it and see, you aren't carrying a load of folks and baggage anymore. happy coaching! buswarrior | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 437 Registered: 10-2003 Posted From: 66.165.176.62  Rating: N/A |
Is there a downside to running a higher pressure than needed other than ride harshness? Now that I think about it in automotive you might get an uneaven treadwear but don't know if that is the same with these tires | ||
| Dan West (Utahclaimjumper)
Registered Member Username: Utahclaimjumper Post Number: 207 Registered: 1-2005 Posted From: 208.66.38.60 Rating: N/A |
Why evan accept the harsh ride if not needed.>>>Dan | ||
| John and Barb Tesser (Bigrigger)
Registered Member Username: Bigrigger Post Number: 270 Registered: 9-2007 Posted From: 24.183.21.246  Rating: N/A |
Better mileage with more air pressure. Did you make it to Rosine Dan? | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 178 Registered: 11-2003 Posted From: 70.192.220.154 Rating: N/A |
less chance of running them under inflated and having a blow out too. | ||
| NH BIll (Nh_wanderer)
Registered Member Username: Nh_wanderer Post Number: 26 Registered: 11-2008 Posted From: 24.62.162.30  Rating: N/A |
When it comes to tires, there seems to be as many different opinions as there are tires. I recently went through tire replacement. Read some stuff, spoke with a number of commercial tire guys. I came away from that exercise with the idea tires should be run close to their rated PSI for safety, tire life and mileage factors. I run 11R 22.5s and have 115psi in the steers and 100psi on the drives. Front axle 13K, rear 23K loaded. The following is a link to videos produced by Michelin. To me they were informative. Somewhere in there, it is stated that in the commercial tire business a tire that is running less than 20% of its rated pressure is considered to be flat and dangerous. http://www.michelinrvtires.com/michelinrv/toolbox/videos-demos.jsp NH Bill | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 298 Registered: 12-2000 Posted From: 72.187.35.208  Rating: N/A |
The video actually said that a tire running 20% below the recommended pressure for the load, in Bob's case 70 psi. Unless the wheels were weighed individually, I think I would add 5-600 lbs. to the scale weight for unbalance. In other words, the 9300 lbs. front axle might just be 4000 on one side and 5300 on the other or even worse. Both sides must be inflated for the highest load. Commercial interests run with the max pressure because they don't know from one trip to another what the load will be. For Bob's rig, I think I would run 75-80 psi. | ||
| Bob Baldwin (Bob4106)
Registered Member Username: Bob4106 Post Number: 185 Registered: 10-2004 Posted From: 24.74.180.20 Rating: N/A |
Thanks Len They are at 100 psi now. I was thinking 80-85 psi. | ||
| Cullen Newsom (Cullennewsom)
Registered Member Username: Cullennewsom Post Number: 158 Registered: 2-2009 Posted From: 129.7.52.191  Rating: N/A |
Monitor the temperature closely? | ||
| NH BIll (Nh_wanderer)
Registered Member Username: Nh_wanderer Post Number: 27 Registered: 11-2008 Posted From: 24.62.162.30 Rating: N/A |
"The video actually said that a tire running 20% below the recommended pressure for the load, in Bob's case 70 psi." Len, Thanks for picking up on this and the clarification! NH Bill | ||
| JC Alacoque (Jc_alacoque)
Registered Member Username: Jc_alacoque Post Number: 84 Registered: 7-2006 Posted From: 72.45.68.242 Rating: N/A |
Mine weighs 22000lbs. Long story short: the charts call for 70lbs of tire press. I run 80 and it is great. The hockey team's 102D3 has to be 105lbs on the steers, 85 drives and 75 tags per MCI manual and plaque in the stair well. And that is for 40000lbs GVWR. The tire shop always puts 110lbs in them though... so I get adjust them when I get home. JC | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 1024 Registered: 11-2005 Posted From: 209.142.172.156  Rating: N/A |
My 4104 probably is 3-4000 lbs lighter than the 4106. It is a very modest conversion with no really heavy stuff inside. I run 90 in front and 85 rear. The way to tell if your pressures are correct is to note the tire wear. Wear in center, too much air. Wear on edges, not enough. However, most of us never wear out tires so ride and driveability are probably more important. | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 134 Registered: 1-2006 Posted From: 66.218.33.156 Rating: N/A |
I've talked to many tire manufacturing reps, and ALL have said to follow the tire inflation tables for best tire performance period. Any non educated tire buster at a tire store that tells you to run maximum tire pressure is just trying to cover his butt and is also talking out of it. I went to the tire inflation table, and your tire even at 70psi is going to give you 9880lbs front and 19120lbs rear-which is 580lbs over in the front and almost 2000lbs over on the rears. Use the 70psi and you won't believe the difference in ride. If you have a question about it-drive for two hours at freeway speeds and then stop and feel the tires to see if they are running hot-they will be warm, but shouldn't be hot. Good Luck, TomC | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1005 Registered: 10-2006 Posted From: 66.82.162.21  Rating: N/A |
Some folks will run the tires at a much higher pressure than the table to reduce rolling resistance. Below about 55mph RR is at least as important as air resistance.Above 55 its still number 2 factor for fuel burn. Those modern low pro , very low rolling resistance (under 100 is good) are really expensive for a bus camper at 10,000 miles a year. So the trade off , on the slab , is a slightly crappier ride for better slightly fuel mileage. Just what IS 1/2 MPG worth yo you? FF |