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Old 09-08-2022, 02:03 PM   #41
Tireman9
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Originally Posted by edeman View Post
Thank you bsmith0404.
Could you recommend a TPMS for my trailer tires, I have done some research on some of the different systems, but haven't chosen the system I want to purchase yet. This will be my first purchase of a TPMS.



Check out the length of warranty. I an in year 4 of the only direct comparison of two different brand TPMS and find no meaningful performance difference in warning of pressure loss.
I have been publishing the performance numbers on my RV Tire Safety blog
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Old 09-08-2022, 04:11 PM   #42
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Agree that Trailer King tires are garbage. Just had one blowouts and another failed steal belt issue within past 300 miles with 2 yr old original Trailer Kings w 5K miles on them. Local tire dealer used to carry Trailer King but quit doing so after a month due to too many problems. Upgraded to from Trailer King 10 ply to Carlisle 14 ply commercial grade for peace of mind.

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Old 09-08-2022, 06:48 PM   #43
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I'd like to point out, nothing that hasn't been said before, but in a way I think anyone can understand. Apples to oranges.

Many people think about tire pressure the same way they do about their car. First off car tires run up to 35psi and come in many sizes and profiles. Manufacturers recommend pressures according to the car's characteristics.
Car tires have a more flexible side wall in order to keep the tread flat during maneuvers. Cars have a steering axle and drive axle, (sometimes the same).
And them's the apples.

Trailers Do Not have a steering or drive axle. The main function of a trailer tire is "load bearing." Trailer tires have stiff sidewalls not made to flex much. They are bearing a load and not steering or driving the trailer. Running trailer tires to soft induces unwanted flex which can lead to excessive heat and premature failure.
Trailer tires are made to run at their maximum inflation. Example would be, any trailer in North America that uses load range C tires, the manufacturers stick will list the pressure at 45psi. None of them will list 42psi or anything but 45psi. If the trailer uses load range D tires they all will list the pressure as 65psi. It will Never be anything but 65psi...period.
If you upgrade to load range E they should run at 80psi...nothing else. The Goodyear load range E tires I upgraded too even list the pressure in Big numbers on the side of the tire...80psi. Trailer tires have a different function than car tires. They're pressure is not adjusted to the trailer. They only run at one pressure.
And them's the oranges.
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Old 09-08-2022, 11:20 PM   #44
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Originally Posted by edeman View Post
Hello everyone,
I have a 2017 Keystone Springdale 5th wheel SG253 about 10K or so weight.
Currently my tire size on the trailer are ST225/75R15 Load range D (65) and I need to purchase new tires. Would it be better to purchase Load Range E or stay with LR D.

Thank you.
This thread is getting a lot of "IMO" answers, so I have come back to page 1 for my mathematical answer.

According to the specs I found for your trailer I have determined that the trailer's certified axles are 4400# and that the vehicle certification label will list the GAWRs at that value. I'm just using past Keystone procedures to come to that axle load capacity. However, if my assumption is correct the ST225/75R15 LRD tires with a maximum load capacity of 2540# provide more than 15% in load capacity reserves. So, is it really necessary to increase the tires load range from "D" to "E"?

Math used; GVWR 10300# minus published tongue weight of 1500# = 8800# divided by 2 = 4400# on each axel.
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Old 09-08-2022, 11:56 PM   #45
jadatis
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Using the data gathered in post above #44, thanks for that.
Filled in in my made spreadsheet for calculating tirepressure for TT, 1500lbs tongeweight is 14.6%.
Then using 2540lbs maxload as given for D load
AT 65 psi.
It gives 63psi advice, with 11% reserve added so using 90% of the loadcapacity belonging to 63 psi.

But then I lowered the maxload by 6 LI steps, to give the tires a deflection LT would need for 99mph.
Gave 75psi advice, is maximum pressure without trembling screws loose. But above 65psi.

This indicates that upgrade to LRD is wise to laws of nature.

Filled that in and gave not 6LI corrected, 69psi.
And corrected for max pressure without "bumping", 82psi.

So I would do the upgrade and use 80psi, if real weights are as given in above post.
And thats the bear along the road, determining the real weights is the most tricky part in it all.

Then if you use this LRE AT 80psi, and check the tires every year on aging signs, cover for sunlight, when standing, they might last upto 10 years of use.
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Old 09-09-2022, 08:18 AM   #46
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Wow! The last 2 post gave me a headache with all the calculations!
As said again & again & again, they are trailer tires designed for weight carrying NOT a good ride or fuel mileage.
If using the original size tire inflate it to the recommended pressures posted on the rv tag. If you've upgraded size or load rating inflate to the pressures stamped into the sidewall. It's that simple, NO math required!
Also I wouldn't recommend 10 year old tires on ANY rv regardless of brand or tread appearance, that's just asking for trouble. If they aren't showing cracking you might get 5 years, if lucky. Rv tires age out LONG before they wear out.
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Old 09-09-2022, 08:46 AM   #47
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Originally Posted by travelin texans View Post
Wow! The last 2 post gave me a headache with all the calculations!
As said again & again & again, they are trailer tires designed for weight carrying NOT a good ride or fuel mileage.
If using the original size tire inflate it to the recommended pressures posted on the rv tag. If you've upgraded size or load rating inflate to the pressures stamped into the sidewall. It's that simple, NO math required!
Also I wouldn't recommend 10 year old tires on ANY rv regardless of brand or tread appearance, that's just asking for trouble. If they aren't showing cracking you might get 5 years, if lucky. Rv tires age out LONG before they wear out.
Danny, since you have chosen to restate the same guidance that has already been posted several times in this thread, I suspect you will soon see a rebuttal. LRE=80PSI. Got it. This thread has been beaten to death and should be allowed a quiet burial. OP (after tons of confusion) as received the answer he was looking for I guess.
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Old 09-09-2022, 09:19 AM   #48
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Calculating as in post # 44 and #45 is the only safe way, and I hope topicstarter apreciates it.

I only gave the end results and conclusion to prevent that headache.

But if these topics give that to you, only remedy is to not read them.

Hope it stays with these 2 offtopic reactions, and not rise to my calculated 23.7 posts oftopic
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Old 09-09-2022, 09:52 AM   #49
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Sorry, post #46, was somewhat on topic.

About the 10 years of use.
In Europe C-tyres ( = LT-tire) are used on traveltrailers and even an ocacional personscartire, but then XL.
IMO nothing wrong with that if maxload is with enaugh reserve for the GAWR.

And why then on a tandemaxle motorhome I already read of 10 years use with zero safety-problems.

If ST treated for tirepressure as LT, so higher pressure, IMO they can last yust as long as LT.

Mind regarding this that laws of nature are the same in US and Europe.

Official institutes advice max use of 6 years, but in discussion the last years to after 5 years of use, every year checked by a profesional, especially on aging signs, and after 10 years of use preventive renewal.
2 years profesional storing after production, can be sold as new, so SOMETIMES after 12 years after DOT date preventive renewal.

If that wont give you a headage.

Sorry for wrong spelling and miswritings
Writing on mobile asks much of fine motorics of this 62 year old man.
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Old 09-09-2022, 12:35 PM   #50
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Here a link about how long tires last from Bridgestone

https://www.bridgestonetire.com/lear...-a-tire-lasts/

OK Bridgestone is the tiremaker deforced from Ford because of the Ford Firestone affaire.
But wil search for other brands in English.
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Old 09-09-2022, 02:27 PM   #51
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Originally Posted by jadatis View Post
Here a link about how long tires last from Bridgestone

https://www.bridgestonetire.com/lear...-a-tire-lasts/

OK Bridgestone is the tiremaker deforced from Ford because of the Ford Firestone affaire.
But wil search for other brands in English.
And that has NOTHING TO DO WITH ST TRAILER TIRES! You have consistently spread incorrect information on air pressures, and now tire service length as it pertains to the subject at hand and the relevance of this forum. Please stop.
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Old 09-09-2022, 03:28 PM   #52
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Quote:
Originally Posted by jadatis View Post
Calculating as in post # 44 and #45 is the only safe way, and I hope topicstarter apreciates it.

I only gave the end results and conclusion to prevent that headache.

But if these topics give that to you, only remedy is to not read them.

Hope it stays with these 2 offtopic reactions, and not rise to my calculated 23.7 posts oftopic
I'll say this then done!
I've stated appropriate safe pressures for ST tires in this country! It requires no multiple weights or a calculator.
If I'm EVER across the pond with my rv I'll give your calculations & inflations a try!
DONE!
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Old 09-10-2022, 03:40 AM   #53
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Then I repeat that laws of nature are the same in Europe and US. And tires in basics are the same all over the world. So if in Europe you need 80psi to be safe for the tires, you also need that pressure in US.

And if in Europe tires on traveltrailers make upto 10 years of use (average 8) its also possible in US.

The bridgestone article might be more directed for LT and tructires, but especially tires for stering axles have higher demands then even tandem axle trailer tires.
The Special in special trailer tires is not that special, sooner a limitation.

In Europe sometimes " for trailer use only" are used, wich claims better the limitation.
Those have 2 loadindex steps higher then same sise and loadrange LT tire, because N speedrated and reference speed also 140kmph/87mph.
St always for 65mph maxload given, even if N speedrated is given.
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Old 09-10-2022, 05:22 AM   #54
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Originally Posted by jadatis View Post
Then I repeat that laws of nature are the same in Europe and US. And tires in basics are the same all over the world. So if in Europe you need 80psi to be safe for the tires, you also need that pressure in US.

And if in Europe tires on traveltrailers make upto 10 years of use (average 8) its also possible in US.

The bridgestone article might be more directed for LT and tructires, but especially tires for stering axles have higher demands then even tandem axle trailer tires.
The Special in special trailer tires is not that special, sooner a limitation.

In Europe sometimes " for trailer use only" are used, wich claims better the limitation.
Those have 2 loadindex steps higher then same sise and loadrange LT tire, because N speedrated and reference speed also 140kmph/87mph.
St always for 65mph maxload given, even if N speedrated is given.
Again, this ain't Europe, you're comparing apples to oranges and your misleading the folks that aren't shaking their heads and dismissing this mess. As you can't take a hint and further disscussion of this type serves no purposeother than to confuse, thread closed.
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