stuff4sale09 Posted January 17 Share Posted January 17 (edited) A little bit confused and need a bit of guidance, to start my tire size is 275/70R22.5 , the only tire I can find with a max load 6940 with PSI of 125 is Goodyear G670, all other tire brands that has 275/70R22.5 has a max load 6940 with a PSI of either 130 or 131 psi. The Accuride rims I have state 125 max psi cold, as pictured, is there any unforeseen problem that could arise using any other brand tire that has max load 6940 with a 130+ psi on the rims. thank you all in advance for your expert knowledge and advice. Edited January 17 by stuff4sale09 Better pic Link to comment Share on other sites More sharing options...
JDCrow Posted January 17 Share Posted January 17 After weighing your corners I’ll doubt you’ll ever have enough weight to hit max load. I fall in the 100psi range on the tire charts after weighing the coach. 2 Link to comment Share on other sites More sharing options...
Tom Cherry Posted January 17 Share Posted January 17 20 minutes ago, stuff4sale09 said: A little bit confused and need a bit of guidance, to start my tire size is 275/70R22.5 , the only tire I can find with a max load 6940 with PSI of 125 is Goodyear G670, all other tire brands that has 275/70R22.5 has a max load 6940 with a PSI of either 130 or 131 psi. The Accuride rims I have state 125 max psi cold, as pictured, is there any unforeseen problem that could arise using any other brand tire that has max load 6940 with a 130+ psi on the rims. thank you all in advance for your expert knowledge and advice. Couple of things…. First….you can ONLY USE the PSI for the 6,500 pound FRONT axle. It is rated at 13,000. So, theoretically, that is the limit. Second…..you will only need 115 PSI in front to get the max front axle weight of 6500….that will give you 6510 Pounds…. SO….good to go as the max pressure is 125. If one side is OVERWEIGHT and exceeds 6,500….time to shed some weight or rebalance as you can damage that side of the front axle. NOTE…..you need to specify or include the load range. That tire only comes, per the screen shot, in LR H. That is ON THE TIRE PLACARD inside the MH. Final COMMENT. That GY tire has a bad, and well deserved, reputation…..or the consensus here. Purchase at your own peril. There are alternatives. Toyo seems to be the top brand now, but other brands also are being used. Personally, I have Toyo’s but in a pinch, would have purchase Bridgestone. Still some discussions and negative comments about Michelin and side wall checkering. If you want the full story….use the search box. TIRES and then click on the Everywhere….choose topics. It may overwhelm, but scroll and read. If you want a specific brand or size as part of the search then add Goodyear or such. You might try 275/70….or the entire size…. But members are inconsistent in the exact nomenclature of the size….so 275/70, I think will narrow it down but give you information. Link to comment Share on other sites More sharing options...
stuff4sale09 Posted January 17 Author Share Posted January 17 Thank you Tom and JDCrow, this is where I get a bit confused Tom, so for the same weight Goodyear vs Michelin just saying (Toyo I do not see steer / all position tires in my size) goodyear would be 115 psi @ 6510 and the Michelin , continental, firestone etc. would be at a 120 psi for the same 6510# weight, not that i am ever close to max load, just don’t want to purchase the wrong set (6) tires and regret it. again thank you in advance for everyone’s expertise and experience. I am learning. Link to comment Share on other sites More sharing options...
JDCrow Posted January 17 Share Posted January 17 I’m confused I guess. If you are not hitting max load, ever, then you concerned that you are overloading your wheels if you buy a tire that requires more psi than the wheel is rated to handle, even if you don’t hit the 125 psi on the wheel because you will only need 100-110 psi to carry the actual load that you have loaded on your coach? Link to comment Share on other sites More sharing options...
Jetjockey Posted January 17 Share Posted January 17 (edited) So how do you compensate for the tires that are running in the sunshine. Those pressure will be higher no matter what the ambient temp. I suppose ideally set tire pressure with all tires cold and out of the sun.. I generally do so in an enclosed building. But do notice pressures will vary a lot between the sunny and shady site of my motorhome. Edited January 17 by Jetjockey Link to comment Share on other sites More sharing options...
stuff4sale09 Posted January 17 Author Share Posted January 17 My concern is getting a more harsh ride with a higher psi for the same weight as per tire MFG weight / psi chart. But i may have found my answer thanks to all reply’s , the Bridgstone R205ED 275/70R22.5 tire has a max weight of 7000# at 120 psi. Just have to do a little more research On this tire. Hope they are a good tire and will work. another question is there any location i am in Ocala, Florida area that i can get 4 corner weight, maybe someone knows of. again thanks for all info. Link to comment Share on other sites More sharing options...
Tom Cherry Posted January 17 Share Posted January 17 Comments on the posts….You set the Tire Pressure from the Manufacturer’s specs for the correct weight on the axle. There is a sequel to “Gone with the Wind” about how ro weigh and such and calculate in every owner’s manual. Thus, the OP should NOT exceed 115 PSI. Lower if his axle corners are lower than the 6,500 max rating. AS AN ASIDE. Need the corner weights. The largest one should NOT exceed 6,500 Pounds. You set the SAME TP in BOTH UPFRONT TIRES….based on the heaviest loaded corner…but do not exceed 6,500. Don’t have a rule of thumb…but you, driver, and passenger(s) have to be in the MH when weighed. If there is a gross difference then rebalance. What is Gross…depends….maybe 500 pounds and you DW has enough canned food in a front bay for a nuclear Holicost……it dpends… Second….inflation. Temperature. JJ, you are correct. You set the COLD pressure at “ambient”. Most define that at “sunrise”….before the sun gets up and you get radiant heating. Some say temp compensated in winter for 65 or 70 degF. i usually set mine and then drive. If in frigid NC heading to Florida in winter….i set for when we leave and don’t mess with them….as we are coming home. Great delta T or altitude changes require some common sense and adjustment. That’s it Link to comment Share on other sites More sharing options...
Scotty Hutto Posted January 17 Share Posted January 17 Robert, Not to further confuse, but to provide additional info… My 2006 Diplomat is on the same chassis (Roadmaster RR8R) and same length as your Knight. Our coaches are essentially twins, with the Dip have a few more bells and whistles (and therefore a little heavier) You might consider going with a slightly larger tire. This will allow you to run a few lbs less pressure and have a slightly smoother ride (don’t expect too much of a difference). I run Toyo M154 tires size P295/75R22.5 at 105 psi, based on weighing my coach. The considerations are ensuring the 295’s don’t rub (they won’t) and a few more $$ per tire. It’s pretty common to run 295s on a RR8R chassis. Hope that helps… Link to comment Share on other sites More sharing options...
Tom Cherry Posted January 17 Share Posted January 17 1 hour ago, stuff4sale09 said: Thank you Tom and JDCrow, this is where I get a bit confused Tom, so for the same weight Goodyear vs Michelin just saying (Toyo I do not see steer / all position tires in my size) goodyear would be 115 psi @ 6510 and the Michelin , continental, firestone etc. would be at a 120 psi for the same 6510# weight, not that i am ever close to max load, just don’t want to purchase the wrong set (6) tires and regret it. again thank you in advance for everyone’s expertise and experience. I am learning. OK….Toyo might NOT make that tire in a LRH. Note the placard…it has an “H”. OK, they make the M320 which is a “J” LR rating. That would be a bit harsher….I would not recommend it…. I recall that this has been discussed before. You run maybe 5 PSI less but never below 90 PSI (some like 95) in any tire. Folks have said that Hankook (sp) is a good tire. ODDS ARE….speculation, that if the other brands are showing 120, then that is a 14 ply LRG tire….again not the way to go. OK…had to keep searching. There was a tire uograde in some models. If you look at the 2011 Knight, they went to a 275/80R22.5(presumed LRH) tire per the sales brochure. Your speedometer might be off a smidge…but i think that would work. Find a tire this size and compare, in a LRH. You can get revs per mile from most vendor’s sites… Link to comment Share on other sites More sharing options...
Tom Cherry Posted January 17 Share Posted January 17 1 hour ago, Scotty Hutto said: Robert, Not to further confuse, but to provide additional info… My 2006 Diplomat is on the same chassis (Roadmaster RR8R) and same length as your Knight. Our coaches are essentially twins, with the Dip have a few more bells and whistles (and therefore a little heavier) You might consider going with a slightly larger tire. This will allow you to run a few lbs less pressure and have a slightly smoother ride (don’t expect too much of a difference). I run Toyo M154 tires size P295/75R22.5 at 105 psi, based on weighing my coach. The considerations are ensuring the 295’s don’t rub (they won’t) and a few more $$ per tire. It’s pretty common to run 295s on a RR8R chassis. Hope that helps… OK....from the TECHNICAL SPECS... Toyo M320 275/75R22.5 545 REVS per Mile; Inflated WIDTH 10.8", Inflated HEIGHT 38.1"; 32,700 REVS (60 X 545) in an HOUR at 60 MPH. Toyo M154 295/75R22.5 514 REVS per Mile; Inflated WIDTH 11.1" Inflated HEIGHT 40.4" Driving 60 MPH (speedometer reading) in an hour... Divide 32,700 by 514 = 63.6 MPH ACTUAL SPEED.... or 6% INCREASE. Bottom Line... The ECM Parameters can be changed to reflect a different size. I THINK that you have to put in the new size and REVS per mile. SO, that will adjust the Speedometer and recalibrate it. If the ECM is recalibrated....then the odometer will also be "recalibrated.... OTHERWISE (no Recalibration), you would MULTIPLY your MILES TRAVELED by 1.06 as you are going further by driving the SAME SPEED on the Speedometer... In THEORY, you should (May? Probably?) see an increase of 4 - 6% in the REAL economy....but you MUST adjust the MILES by the difference in the REV's mile. The MH will sit approximately 1 - 1 3/16 " HIGHER as the tires are larger. The Ride Height is the DISTANCE between the Air Bag Mounting Plates....so there will be NO adjustment there as it is a function of the air bags...but you will find the front step is an inch or so higher for entrance and exit... NOW, that assumes an equal amount of "sag" or the bottom side of the tire being wider and flatter. Your results may vary... Assuming they are good tires as I run the different model (M144?) in 295/80. I could NOT seen any deterioration in ride quality....one always THINKS that new tires ($$ SPENT) is an improvement. I drove about 4,500 miles back from Sacramento, CA to Raleigh, NC via a little trip up to Seattle and then on to Elkhart with the new tires. Great. NO ISSUES...would buy again. I have been on climbs and descents and in the mountains with them also. Link to comment Share on other sites More sharing options...
stuff4sale09 Posted January 17 Author Share Posted January 17 Thank you all for your knowledge , i guess in the back of my mind i was concerned about going up in tire size , worried about front tire rubbing on fenders, and also rear dual spacing issues. Now with the info i can look into other tire options (sizes), speed odometer readings not an issue, my gps keeps me in check :), she yells at me when i go 5 MPH over speed. Link to comment Share on other sites More sharing options...
Jetjockey Posted January 17 Share Posted January 17 (edited) When you talk of weighing all four corners I understand however, where I live there are a lot of truck scales and I don’t know of a single one that you can weigh individual corners. Partly due to corner post around scale to protect it and the fact the elevation of the surrounding terrain is not exactly the same as the scale platform so the weights were not be actual anyway and probably useless.Follow manufacturers recommendation and monitor the tire pressures with a Tpms might be best . I am not sure varying 500 or even 1000 pounds is critical. also individual tires in a dual configuration can have a lower load rating than that same tire in a single configuration . You can’t load the dual tires up to 2 times their single load rating because you have to have a margin in case one blows and all the load is transferred to the one good tire. That makes higher ply rating with the higher load rating a good thing to have. Many times a tire will blow in a dual situation because one of the tires was low on pressure causing the good tire to carry more load and fail first. Seen it numerous times on my grain semi trucks. I probably would not go down inply rating to get a better ride. There are tires out there that you won’t sacrifice much if any ride at a higher ply rating. They may get more expensive tho. I , like Tom. Set mine drive and monitor pressures. Really all you can do. My 3 cents worth. Edited January 17 by Jetjockey Link to comment Share on other sites More sharing options...
Tom Cherry Posted January 18 Share Posted January 18 1 hour ago, Jetjockey said: When you talk of weighing all four corners I understand however, where I live there are a lot of truck scales and I don’t know of a single one that you can weigh individual corners. Partly due to corner post around scale to protect it and the fact the elevation of the surrounding terrain is not exactly the same as the scale platform so the weights were not be actual anyway and probably useless.Follow manufacturers recommendation and monitor the tire pressures with a Tpms might be best . I am not sure varying 500 or even 1000 pounds is critical. also individual tires in a dual configuration can have a lower load rating than that same tire in a single configuration . You can’t load the dual tires up to 2 times their single load rating because you have to have a margin in case one blows and all the load is transferred to the one good tire. That makes higher ply rating with the higher load rating a good thing to have. Many times a tire will blow in a dual situation because one of the tires was low on pressure causing the good tire to carry more load and fail first. Seen it numerous times on my grain semi trucks. I probably would not go down inply rating to get a better ride. There are tires out there that you won’t sacrifice much if any ride at a higher ply rating. They may get more expensive tho. I , like Tom. Set mine drive and monitor pressures. Really all you can do. My 3 cents worth. Do some more searching. I often find scales that are flush or they only have guard rails on one side. For the interim, get the split weights….at least you will know where you are. Many of us have weighed and know that either the front or rear or maybe both are close. My front is almost 95%, so i run the rated pressure of 115. As to the rears, the refined method is to get the rear and then reduce the INNER TP by 3 PSI. So, if you need 100 for the axle, put 100 in the outers and 97 inside. Once you get to the thermodynamic balance point where the heat from the the tires and the differential is stable and the heat loss to the atmosphere is stable, you will find that the TP’s are uniform across the drive. I have not heard to overfill the rears in case of a blowout. If you do the math, using 3 tires on a 20K axle would kick up the TP drastically. I made that mistake once….after 25 miles, reset to the correct TP. Having a safety factor and overinflating the rears will make you and your passengers look like bobble head dolls. Link to comment Share on other sites More sharing options...
Jetjockey Posted January 18 Share Posted January 18 (edited) . Tire pressure equalization systems are very popuplar for keeping dual tire pressure equal . Common on long haul over the road trucks. Interesting that runs counter to description of the refined method. Where might one find that information for the refined method. I don’t think I suggested overinflating any rears, sure did not mean to imply that. I have split weighed front and back including the tags and set pressure accordingly. It is always a challenge to get consistent repeatablepressure readings with gauges. I have read that a Tpms system is accurate to .1 pound . Don’t know if i believe it. Good thought provoking ideas on this subject. Edited January 18 by Jetjockey Link to comment Share on other sites More sharing options...
Tom Cherry Posted January 18 Share Posted January 18 4 minutes ago, Jetjockey said: . Tire pressure equalization systems are very popuplar for keeping dual tire pressure equal . Common on long haul over the road trucks. Interesting that runs counter to description of the refined method. Where might one find that information for the refined method. I don’t think I suggested overinflating any rears, sure did not mean to imply that. Maybe I misunderstood. The dual equalization systems, as long as they connections are “gooped” up work. However, there is only a 3 PSI differential. Many, and many very experienced, individuals have noted this relationship. Depends on how picky you are. So, set both at the same PSI. Your TPMS will show the results. The equalization systems don’t lend themselves to TPMS hookups. In addition, any “screwed in flexible hose” system is prone to leaks. The consensus here and over the years is to attach a TPMS Sensor directly to the valve stem. Many, like myself, have longer inner valve stems. However, if you have the older “custom” Monaco oblong holes, you can remove the flex hoses and actually screw in a sensor through the enlarged hole. I have “stock” Accuride rims….not the custom. I think that Monaco switched to standard wheels in 2009 as a cost savings….but don’t know about the Dynasty. All I know, my flex hoses were leaking. I got rid of them and could NOT get an extender to work as the spring pressure of the operating rod would NOT depress the valve stem so, the transducer was not reading full pressure. So, I replaced the stems with the Borg Dually kit. That’s my take and experience and the group’s consensus,,,, Link to comment Share on other sites More sharing options...
Jake B Posted January 18 Share Posted January 18 18 hours ago, stuff4sale09 said: My concern is getting a more harsh ride with a higher psi for the same weight as per tire MFG weight / psi chart. But i may have found my answer thanks to all reply’s , the Bridgstone R205ED 275/70R22.5 tire has a max weight of 7000# at 120 psi. Just have to do a little more research On this tire. Hope they are a good tire and will work. another question is there any location i am in Ocala, Florida area that i can get 4 corner weight, maybe someone knows of. again thanks for all info. Escapees Rv Club in Bushnell does 4 corner weighing. Link to comment Share on other sites More sharing options...
dl_racing427 Posted January 18 Share Posted January 18 14 hours ago, Jetjockey said: . Tire pressure equalization systems are very popuplar for keeping dual tire pressure equal . Common on long haul over the road trucks. Interesting that runs counter to description of the refined method. Where might one find that information for the refined method. I don’t think I suggested overinflating any rears, sure did not mean to imply that. I have split weighed front and back including the tags and set pressure accordingly. It is always a challenge to get consistent repeatablepressure readings with gauges. I have read that a Tpms system is accurate to .1 pound . Don’t know if i believe it. Good thought provoking ideas on this subject. No way I believe any TPMS is accurate to 0.1psi. Transducers like that are quite expensive, probably hundreds of dollars each. Low cost transducers like those used in TPMS systems are lucky to be within 2 or 3%, or 3psi error at 100psi, which is plenty close for heavy duty tires. Link to comment Share on other sites More sharing options...
Tom Cherry Posted January 18 Share Posted January 18 10 minutes ago, dl_racing427 said: No way I believe any TPMS is accurate to 0.1psi. Transducers like that are quite expensive, probably hundreds of dollars each. Low cost transducers like those used in TPMS systems are lucky to be within 2 or 3%, or 3psi error at 100psi, which is plenty close for heavy duty tires. TRIPLE DITTO....as in Pressure Pro, on page 11 of the manual.... https://pressurepro.us/wp-content/uploads/2021/05/PULSE-Users-Manual-01.09.18.pdf Sensor Resolution....as in the values will be displayed in 1.00000 increments, rounded to 1 PSI (LOL) And the accuracy is.... +/- 3 PSI. SO....if you are running, as I am, say 115 in the front....then that could be 118 or 112....PSI as Displayed. BUT, in all fairness, the values, if you scan and sort of mentally record and process WILL show, on the average, if you have a discrepancy between the two front one. And back to my "Many Members do this". If I want 100 PSI in the REAR...I set the OUTER to 100 and the INNER to 97. Once they heat up, they are almost identical....as in the Pressures, due to the differences in the heat from the Differential will be "perfect...." as in all FOUR rears are the same. Don't know about other brands.... Link to comment Share on other sites More sharing options...
bborc2005 Posted January 18 Share Posted January 18 I have a 2007 Knight pdq and did not get four corner weight but weighed front axle and rear. With a full load of fuel and half water 3 of setting in front and everything we take on a three week trip the front came in at 11,850 lbs and the rear came in at 19,450. so I run 110 in the front and 100 in the back. Hope this helps. tie size 275/70 22.5 Link to comment Share on other sites More sharing options...
Tdkkart Posted January 18 Share Posted January 18 5 hours ago, dl_racing427 said: Low cost transducers like those used in TPMS systems are lucky to be within 2 or 3%, or 3psi error at 100psi, which is plenty close for heavy duty tires. Certainly well within the error of a wooden tire knocker, or even a practiced operator of a claw hammer. 1 Link to comment Share on other sites More sharing options...
stuff4sale09 Posted January 18 Author Share Posted January 18 Ok hello again been doing a lot of research, and seen my post has been sidetracked, going in different directions. This was my original issue, and yes i have many 😉 . As you can see in the picture (using Michelin as a example only) 275/70R22.5 LRJ X-multi-Z single 6940# @ 131 psi , Dual 6390# @ 131 psi, this should be a 18 ply tire 275/80R22.5 LRH X-Line Energy-Z Single 7160# @ 120 psi, Dual 6610# @ 120, this should be a 16 ply tire My ACCURIDE rims state max 125 psi, and no i will never overload my rig, would i be better to go with a higher load at a lower psi (275/80) or going with a higher load rating (275/70) that i would not be able to because of the higher psi is more then rather Rims. Again Thank You All. Link to comment Share on other sites More sharing options...
dl_racing427 Posted January 19 Share Posted January 19 18 hours ago, stuff4sale09 said: Ok hello again been doing a lot of research, and seen my post has been sidetracked, going in different directions. This was my original issue, and yes i have many 😉 . As you can see in the picture (using Michelin as a example only) 275/70R22.5 LRJ X-multi-Z single 6940# @ 131 psi , Dual 6390# @ 131 psi, this should be a 18 ply tire 275/80R22.5 LRH X-Line Energy-Z Single 7160# @ 120 psi, Dual 6610# @ 120, this should be a 16 ply tire My ACCURIDE rims state max 125 psi, and no i will never overload my rig, would i be better to go with a higher load at a lower psi (275/80) or going with a higher load rating (275/70) that i would not be able to because of the higher psi is more then rather Rims. Again Thank You All. Either tire will carry the load. You don't need to inflate to the tire's maximum, as your axle is not rated for that weight in the first place. The taller tire MAY cause problems with fender clearance, and will definitely adversely affect your overall gearing and speedometer readings. I'd go with the correct size tire in LRJ, and inflate to the proper pressure for the actual load. Link to comment Share on other sites More sharing options...
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