jadatis
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Re: TPMS - Tire Pressure Increase
That is what I forgot in post before yours, external factors like sunshine on tire, exaustpipe pointed at tire, severe braking, etc. When descending the mountains, and using the brakes to often, the heat of brakes, transported trough the rimms to tire inside, can rise it to boiling point of water, 100 degr C/212 degr F, with the pressure rising to 87.3psi dry and 101psi wet is more then 50% pressure rising from 65 psi at 65 degr F. Then still dont let out air, a healty tire can stand that pressure, and tire material mayby still wont go overheated, because low speed and lesser deflection, so lesser heatproduction. If you still think it scary on a hot day, you better use lower speed then lower the pressure ( wich you never must do, not warm, not cold).938Views0likes0CommentsRe: TPMS - Tire Pressure Increase
I used my made tirepresure/temperature-calculator for wet and dry gascompound. 65psi at 65 degr F. measured rising to 81 psi, means a temperature in tire of 170 degr F. if dry gascompound, and 149 degr F. If enaugh water in tire, like with normal air filled. So if filled with Nitrogen 25% pressure rising is to much, but if filled with normal air, on a hot day its OK. I once estimated that on a hot day of 100 degr F. the temp in tire is allowed to rise to 160 degr F, on a 70 degr F day driving 140 degr F in tire max.gives rising to 76.4psi dry and 78.9psi wet is about 20% rising. Then tire-material wont go over its critical temperature of by me estimated 300 degr F. And not overheating any part of tire-material is main goal of tirepressure determination. So never blead down a hot tire, as already written, even dont anticipate on " to high pressure by filling lower cold pressure. And I want to go a bit further, but" tirespecialists" dont agree with me. Let the cold pressure flow with ambiënt temperature, so dont lower it to determined best at 100 degr F. ambiënt temperature, even if above maxloadpressure of tire, yours 65psi. The tire needs the higher pressure to give lesser heatproduction, because cooling down is also lesser, because of lesser temperature-differences between tire-material and air in and out tire.943Views0likes0CommentsRe: 2019 coleman 264RL tire pressure?
Mayby I should have written in my post about the chaktest, that I also am not a fan of it, but if you use it, mind the things I wrote. For the pressure buildup test, percentage allowed higher is more for low pressure like 35 psi, then for high pressure, like 110 psi, if calculated for the load and speed. And the pressure buildup represents a certain temperature of the gascompound in tire. I estimated that at 70 degr F outside, and driving with pressure calculated for referencespeed of tire, temperature in tire is allowed max 140 degrF, with no external factor. In 100 degr F outside, inside tire 160 degr F. With that you can calculate the pressure-rising. Made spreadsheet for it, in wich also for when enaugh water in tire.891Views0likes0CommentsRe: 2019 coleman 264RL tire pressure?
A radial tire stays within a large range with total width on the ground. So if you found the pressure, beginning high, at wich chalk wears even, you have still a small surface-length on the ground. Then when keep lowering, at a certain pressure, sides chalk begin wearing off. At the lowest pressure, at wich chalk still wears even, the surface_length is larger, so larger surface on ground so best contact. But then mayby at higher speed tire overheats. So for safety of tires, you have to begin high, and stop lowering pressure, when chalk wears even.892Views0likes0CommentsRe: 2019 coleman 264RL tire pressure?
Grit dog wrote: ^Thats TMI for the OP. He found the max psi rating on the tire. That’s good enough for him…. And you are overcomplicating it. Then those pressure/loadcapacity lists for ST are also overcomplicating, and going even as low as 25 psi and no reserve and given per tire. My list makes it allready a bitt less complicated, because given per axle and maximum reserve build in, so topicstarter dont need to do pre-calculations. Wenn ever TS determined the axleloads acurately, it will most likely come to 65 psi, but then he knows its not a pressure determined in the blue. Airstream TT's have as exeption to the rule, in general comfortable reserves in the tires the GAWR's and comfortable reserve in the GAWR'S to the GVWR. Then often popped rivets when using the max of tire, Most other brands have yust enaugh loadcapacity to law for the GAWR's. So most TT brands need the max of tire or even more. Do then an upgrade of tires is a good idea.891Views0likes0CommentsRe: 2019 coleman 264RL tire pressure?
Dry weight then, with 10% (minimum to law) on towbar, would need 45 psi, but you need the weights fully loaded. 1000 lbs lugage is minimum I think, wich brings it already closer to 65 psi. Sorry for the typing errors, editing in this forum leads to lost post for me.510Views0likes0CommentsRe: 2019 coleman 264RL tire pressure?
Then I made a list with on front of psi 90% of 1 axle, and behind thebpsi for the tandem so 4 tires. Single load used, because that is usuall on tandem. Normaly I would substact 6 loadindex steps from ST, because maxload given for 65mph, even if L speedrated given. But found out this is only for the larger sizes, not done for your size. And I have a paper list from Michelin, got it from them 10 years ago, when they did not knew I was the mole. It gives the Agillis 81 R speedrated, 205/70R15 106/104R, so that /75 instead of 70 would explain the 1 loadindexstep higher, and that tire is given maxload for 160kmph/99mph. I once determined by reactions about screws trembling loose, that 80% using of loadcapacity calculated for the pressure, gives a deflection that wont tremble srews loose. So 90% used makes weightdifference possible R/L on the axle. Now you "ONLY" have to determine the axleloads or tandemload 99% acurate,the mist tricky part, and your responcibility, and search back in my made list, and use that pressure. So dont add reserves or devide by 4 or 2, all done for you. If you ever weigh per axle-end, I can make a new list for 95% used of 1 tires loadcapacity for the pressure, in wich you then search the heavyest tire back of the tandem. Then hope the others wont go below 80%. Axleload/cold psi/ Tandemload 1625 lbs/ 25 psi / 3250 lbs 1740 lbs/ 27 psi / 3480 lbs 1855 lbs/ 29 psi / 3710 lbs 1969 lbs/ 31 psi / 3938 lbs 2083 lbs/ 33 psi / 4166 lbs 2197 lbs/ 35 psi / 4394 lbs 2310 lbs/ 37 psi / 4620 lbs 2423 lbs/ 39 psi / 4846 lbs 2535 lbs/ 41 psi / 5071 lbs 2648 lbs/ 43 psi / 5296 lbs 2760 lbs/ 45 psi / 5521 lbs 2872 lbs/ 47 psi / 5744 lbs 2984 lbs/ 49 psi / 5968 lbs 3095 lbs/ 51 psi / 6191 lbs 3206 lbs/ 53 psi / 6413 lbs 3317 lbs/ 55 psi / 6635 lbs 3428 lbs/ 57 psi / 6857 lbs 3539 lbs/ 59 psi / 7078 lbs 3649 lbs/ 61 psi / 7299 lbs 3759 lbs/ 63 psi / 7519 lbs 3870 lbs/ 65 psi / 7740 lbs/ maxloadpressure 3979 lbs/ 67 psi / 7959 lbs 4089 lbs/ 69 psi / 8179 lbs 4199 lbs/ 71 psi / 8398 lbs 4308 lbs/ 73 psi / 8617 lbs 4417 lbs/ 75 psi / 8835 lbs509Views0likes0CommentsRe: 2019 coleman 264RL tire pressure?
ncladfw3 wrote: Thanks for the replies. I got some more information off the tires: - ST205/75/R15 - LH-001 (Maybe a Model# ?) - 8PR 107/102L Load Range D - Max Load Dual 850kg (1870lbs) at 450KPa (65PSI) COLD It is a dual axle travel trailer, 6150lbs dry weight. I'll probably try 65psi. Do you mean by dual axle, 1 axle with 4 tire on it(verry unusuall, but they exist) , or tandem axle so 2 axles with each 2 tires on them. And can you still read the GVWR and GAWR('s) ( Gross Axle/Vehicle Weight Rating)509Views0likes0CommentsRe: 2019 coleman 264RL tire pressure?
Then you should start from the basic data. That is GAWR's and GVWR.but better is to weigh fully loaded(also the persons), per axle, better even per axle-end. Then I can make a customised pressure/loadcapacity list for your tires, with build in reserves and per axle single or dual or per tire given,so you dont need to do precalculations before looking back in officiall lists. The recomended pressure you cant read now, is calculated for GAWR with no reserve. Need from tires next. 1. maximum load or LOADINDEX. 2. kind of tire to determine the maxloadpressure, but if AT xxx psi is given on sidewall, thats what I need. Loadrange is a system to give AT pressure. 3, speedcode, less important. 4. If ST509Views0likes0Comments
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