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DMichael
05-11-2020, 10:53 AM
Replacing tires on a 3725RL. Tire company trying to sell me an N rated tire... not RV specific. Is this normal?

dieselguy
05-11-2020, 11:51 AM
I dunno what tire you are specifically talking about. The N rating I'm familiar with is for "speed" not application. Beyond that you'll find a lively discussion brewing for people that go with ST "trailer tires" and others that go with LT "light truck tires". If you have a light enough trailer as I do ... LT tires fill the requirement. I as others have been running them to get away from China Bomb ST's for many years without issue. Goodyear 614's and Sailun 637's are good trailer tires as well.

mlh
05-11-2020, 12:40 PM
Get a set of Sailum tires. You can’t go wrong. In years past about the only thing we could get were ST tires made in China hence China Bombs. You understand where the phrase came from. Not only did the tire blow out it took the side of your camper with it. Now more people are using H rated tires and tires are much less problematic. The Sailum have a great reputation and good price, get em.
Lynwood

DQDick
05-11-2020, 07:28 PM
:horse: Stick with Sailuns or 614's and you'll be fine.

Jeff Myers
05-12-2020, 06:42 AM
Just installed new Sailun 637 on our rig. I have been hard pressed to find anything negative about them. Fair price, and dependability are both there. Safe travels!

1retired06
05-12-2020, 07:15 AM
On our second set of Sailun tires. Highly recommend them. Who was the manufacturer of the tires the dealer recommended?

BuilderBob
05-12-2020, 12:27 PM
You can,t go wrong with the Sailun tires at all look at reviews.

DMichael
05-12-2020, 03:49 PM
Thanks for the help!

CruzinMooses
05-12-2020, 08:09 PM
The title says it all, I will pay more for a tire not maid in China....

PSFORD99
05-13-2020, 07:28 AM
The title says it all, I will pay more for a tire not maid in China....

I understand your sentiments on made in China, but you can't buy a better fifth wheel tire then a Sailun. Its unfortunate thats where it is made, but its a quality tire that many run on their fifth wheels. Anyone thats taken the time ,and educated themselves on tires know about Sailuns .

mhs4771
05-13-2020, 08:08 AM
Search and you can find loads of Goodyear tire failures, myself for one, but you will be hard pressed to find a Sailun failure other than one or two road hazard failures.

CalandLinda
05-13-2020, 12:07 PM
Replacing tires on a 3725RL. Tire company trying to sell me an N rated tire... not RV specific. Is this normal?

Remember the most important thing. Insure the new tires have a load capacity equal to or greater than the OE tires.

I'm guessing your OE tires are ST235/80R16 LRE. That designated size is also built with an all steel casing and at least a half dozen manufacturers provide them with a LRG.

As a full time, high mileage user I'm not fond of mail order tires. But, I don't recommend brands so search around.

PSFORD99
05-13-2020, 12:22 PM
Remember the most important thing. Insure the new tires have a load capacity equal to or greater than the OE tires.

I'm guessing your OE tires are ST235/80R16 LRE. That designated size is also built with an all steel casing and at least a half dozen manufacturers provide them with a LRG.

As a full time, high mileage user I'm not fond of mail order tires. But, I don't recommend brands so search around.


I ordered a set of 5 Sailuns online, and I agree not fond of that at all. First set was from SimpleTire , the date of manufacturing was too old for me. I sent them back. Next set from Walmart were okay, and actually a bit cheaper .

I will say SimpleTire was easy to work with,, and returned the tires without a problem. There was two options either have them picked up from your home or take them to the shipper. I chose to take them to the shipper, and get the process started instead of waiting a day or two for them to be picked up.

PSFORD99
05-13-2020, 12:24 PM
Search and you can find loads of Goodyear tire failures, myself for one, but you will be hard pressed to find a Sailun failure other than one or two road hazard failures.

I was a victim of a road hazard ,and one that reported here on the forum. Yes I will stick to Sailuns. Not a fan of Goodyear .

CFDFireman90
05-13-2020, 02:06 PM
Just received 4 new Sailuns. Having them mounted and balanced tomorrow. Wow, those are heavy tires. Speaks volumes on the quality.

Fishin2dMax
05-13-2020, 02:31 PM
After two years using the OEM tires, I felt we were pushing it, so I ordered the Sailuns (for improved safety) and went a little larger profile (265/85 R/16) to help raise the 5'er up a little more and level with truck. In monitoring daily pricing from Simpletire.com, the price of the tire can change as much as $50 each in one day? One day it was listed at $127.65 and next $176.00 and hasn't gone below $160 for a week. Called them and tried to get better pricing, but they were not willing to go lower than $155 with healthcare professional discount. I was so frustrated trying to wait and time my purchase for the lower price, that I just ordered from Amazon at $142.60 FET tax included. Tires were delivered in 2 days and were sent from Simpletire.com ? Date codes all 6 months old - reasonable considering tires had to be imported from China. Local tire shop was blown away and very impressed with how thick and heavy the tires where. Hope to have the same good experience as everyone else with Sailuns.

Dam Worker
05-13-2020, 03:12 PM
Sailun tires on my unit for probably around four years, same size as OEM junk that Keystone installed. Do a search on here for Sailun and you can see when the fun really started pertaining to quality tires. Back then there was a lot of support for the Goodyear’s G614’s if I remember the model number correctly. They were way better than the Trail Kings or other AKA China bombs. They still had a fair number of blowouts with Goodyear standing by their tires most of the time at least for a replacement tire, maybe not so much for help on repair of the fifth wheel. I did a lot of research and could not find any blowouts with Sailun on a fifth wheel. I did find one blowout on the Sailun when a guy put them on his DRW truck but they were not rated for DRW back then and were strictly a Trailer Tire. I can’t blame them for that blowout. One Sailun tire By itself will probably weigh about as much as the cheap tire and rim does together. I have never looked back on my decision and really have no fear of a blowout.
Happy and safe roads to you.

Tom Marty

Dave10
05-17-2020, 01:39 PM
Replacing tires on a 3725RL. Tire company trying to sell me an N rated tire... not RV specific. Is this normal? I would find a dealer that knows something about tires. BTY Sailin, Maxxis, Good Year, and other reputable brands make great trailer tires. It does not matter if they are made in China or not if the mfg meets ISO manufacturing standards. I don't recommend China Mfg tire for political reasons.

RRman
05-17-2020, 03:42 PM
I run Bridgsetone Duravis R250 and Michelin XPS Ribs currently. They cost around or at least $200 - $300
Got tired of less than $200 Tire performance...
Maybe I'm getting what I pay for - only one PUNCTURE failure to date on these tire in the last 5 years...

Leyland
05-17-2020, 04:31 PM
Don’t want to hijack this thread but I have saluns on my 3791 RD. How often should I replace them. Time will get them before Mileage does .

Byron B
05-17-2020, 04:35 PM
We took delivery our our new (to us) 2019 legacy 3121RL. I was happiest about all of the upgrades when I saw the Sailun tires. One thing I did not need to fix, repair or replace.

Anatnom
05-17-2020, 05:47 PM
My Montana came with Goodyear Marathon tires. After three years of light use and maybe a couple thousand miles I got ready and took off on a Sunday afternoon on a holiday weekend. Boom ! one tire went and I had a spare so I Am all set. A couple hours later and Boom ! another tire and no spare so had road service come out with a new tire after a few hours of waiting I was on my way. Got to just south of Knoxville and Boom! a third tire all on the same side of my camper. I got it replaced and went back to the fellas shop bought a couple more tires for the other side while back at his shop. Good year Endurance tire is much stronger that the first tires and they are made in the USA. Higher speed rating (to 75 mph). I didnít get my spare changed. yet but I will. Had the left side of my camper fixed and that took a couple months to get parts and such. I think they. are much better tires. I like the USA tires. I have a 3900FB

Erikksen
05-18-2020, 06:25 AM
I donít have mileage experience but when my 2 year old China bomb exploded on the high way to flagstaff in the mountains at night I rolled in the next morning and replaced all 4 with Goodyear endurance. The sidewalls were very stiff compared to any trailer tire I have seen in the past. Only a year and a half on them so far but only a couple thousand miles. Will update later when miles go up. These are E rated ST tires on a 2016 362RD.

CT Wanderer
05-18-2020, 07:04 AM
I replaced my OEM tires (3 yrs old) with Goodyear Endurance ST235/85R16, one size bigger. They have an increased load capacity over the OEM tires and a better speed rating (87 MPH). The OEM speed rating was 65 MPH. I have 2 years and 10,000 miles on them. They hold pressure well as I've never had to add air to any of them. So far I'm extremely pleased with their performance. I also like that they are made in the US.

Anatnom
05-18-2020, 07:50 AM
Goodyears that came on my Montana only lasted a short while before their tires failed. I believe they were Marathon tires. New Goodyear Endurance tires are made in the USA and a much better tire. Not real expensive but when compared to the original tires they are in a new league. Certainly like the USA built tires and so much stronger side walls.

PSFORD99
05-18-2020, 08:00 AM
Donít want to hijack this thread but I have saluns on my 3791 RD. How often should I replace them. Time will get them before Mileage does .


Some say 5 ,some say 6 years. I will run my Sailuns for 6 years.

PSFORD99
05-18-2020, 08:14 AM
Goodyears that came on my Montana only lasted a short while before there tire failures. I believe they were Marathon tires. New Goodyear Endurance tires are made in the USA and a much better tire. Not real expensive but when competent to original tires they are in a new league. Certainly like the USA built tires and so much stronger side walls.


I am hoping the Goodyear Endurance prove out to be a quality tire. I have a hard time with their weight rating for an E rated 16" tire, one of them is rated higher then the Goodyear G614 that is a G rated tire at 3750, which is 235/85/16. That same size in the Endurance is 3640 , but an E rated tire. The next size up is 255/85/16 is 4080 ,still E rated tire.

Over the years the G614 has had its issues, I like to buy a US made tire, but it won't be the G614. The Endurance have been out now about three years , lets hope they prove to be a better tire then their big brother .

CalandLinda
05-18-2020, 10:57 AM
I am hoping the Goodyear Endurance prove out to be a quality tire. I have a hard time with their weight rating for an E rated 16" tire, one of them is rated higher then the Goodyear G614 that is a G rated tire at 3750, which is 235/85/16. That same size in the Endurance is 3640 , but an E rated tire. The next size up is 255/85/16 is 4080 ,still E rated tire.


There is a major size difference to consider when contemplating the use of the GY ST255/85R16 LRE tire. It is over 33 tall and requires a minimum rim width of 6.5".

The GY LT235/85R16 LRG does not provide the necessary load capacity for fitment on vehicle certified 7000# axles when complying with the RVIA 10% minimum load capacity reserve recommendation.

mazboy
05-18-2020, 11:04 AM
I'd get out of that dealer's store quickly...their tires are NOT 'N' rated. They don't know what they're talking about.

CalandLinda
05-18-2020, 11:57 AM
I'd get out of that dealer's store quickly...their tires are NOT 'N' rated. They don't know what they're talking about.

According to this GY Endurance chart they are all speed rated "N".

https://www.goodyearrvtires.com/tire-selector.aspx

PSFORD99
05-18-2020, 06:54 PM
There is a major size difference to consider when contemplating the use of the GY ST255/85R16 LRE tire. It is over 33 tall and requires a minimum rim width of 6.5".

The GY LT235/85R16 LRG does not provide the necessary load capacity for fitment on vehicle certified 7000# axles when complying with the RVIA 10% minimum load capacity reserve recommendation.

I am not sure I follow you on the Goodyear G614's you are saying they are not rated high enough for some of these Montana fifth wheels, they have been the choice of many for years.

If not mistaken some of the Montana fifth wheels at one time came with the Sailun S637's , and could upgrade to the Goodyear G614, IMO not an upgrade ,but they were more expensive.

Montana Man
05-18-2020, 08:07 PM
I would find a dealer that knows something about tires. BTY Sailin, Maxxis, Good Year, and other reputable brands make great trailer tires. It does not matter if they are made in China or not if the mfg meets ISO manufacturing standards. I don't recommend China Mfg tire for political reasons.

Just for understanding, ISO doesn't set manufacturing standards. The manufacturer sets their own standards. ISO merely certifies that the manufacturer adheres to consistency that they set for themselves.

I don't like China making most of what we use. However, if they adhere to using quality materials, processes, and quality control, a desirable product can be successfully produced. Just because something is made in the USA doesn't mean it is high quality.

Carl n Susan
05-18-2020, 09:17 PM
I am not sure I follow you on the Goodyear G614's you are saying they are not rated high enough for some of these Montana fifth wheels, they have been the choice of many for years.

You are correct, they used to be an extra cost option on Montanas. Then RVIA (or somebody) moved the goal posts. No longer do the tires just have to exceed the axle rating, they have to exceed it by 10%. So a 7,000 lb. rated axle needs tire capacity of 7,700 / 2 lbs (i.e. each tire rated at 3850 lbs). The GY G614 is a Load Range 126 or 3748 lb. tire, just short of the 10% requirement. Hence the Sailuns became the standard.

DebNJim B
05-19-2020, 07:04 AM
Search and you can find loads of Goodyear tire failures, myself for one, but you will be hard pressed to find a Sailun failure other than one or two road hazard failures.

My 2018 3731FL came with Sailuns and I had never heard of them. There was a GY option for $1800, didn't bite on that.

This past year I had what turned out to be a bent axel and it wore the inside off one tire. Didn't see it until it was really bad. got the axel replaced and put the spare on. The worn tire was showing steel belt on the inside but was still holding 110 lbs. The only drawback to Sailun is they are heavy as all get out because they are steel all around.

PSFORD99
05-19-2020, 07:49 AM
You are correct, they used to be an extra cost option on Montanas. Then RVIA (or somebody) moved the goal posts. No longer do the tires just have to exceed the axle rating, they have to exceed it by 10%. So a 7,000 lb. rated axle needs tire capacity of 7,700 / 2 lbs (i.e. each tire rated at 3850 lbs). The GY G614 is a Load Range 126 or 3748 lb. tire, just short of the 10% requirement. Hence the Sailuns became the standard.


Thanks. Thats interesting. I am surprised , that kind of leaves the G614, and all but the one Endurance with a weight rating thats doesn't meet the ratings set for 7K axles.

If some remember at one time the Sailuns were an LT tire, and 3750, they changed to an ST, and increase in weight ratings.

Last2Die
05-19-2020, 08:00 AM
Search and you can find loads of Goodyear tire failures, myself for one, but you will be hard pressed to find a Sailun failure other than one or two road hazard failures.

or badly aligned axles from the factory that ruin brand new sailun tires....:facepalm:

PSFORD99
05-19-2020, 08:03 AM
or badly aligned axles from the factory that ruin brand new sailun tires....:facepalm:

They were not Sailuns ,but a good friend had bad alignment on his new Montana ,didn't take long to ruin the OE tires, not out much, got it realigned ,and put the new Sailuns on .

CFDFireman90
05-19-2020, 10:47 AM
I have seen recommendations of 5-7 years. I think there are a lot of variables that can come in to play. One of the biggest being exposure to sun. I just put on new Sailuns, I immediately bought tire cover for when it is stored or parked for long periods. After spending $700 Iím going to protect that investment.

DebNJim B
05-19-2020, 11:26 AM
They were not Sailuns ,but a good friend had bad alignment on his new Montana ,didn't take long to ruin the OE tires, not out much, got it realigned ,and put the new Sailuns on .

I was hoping it was alignment so I could claim it on extended warranty but sadly it was clearly bent, plus I was in the third year so alignment should have shown up and it was only one tire. I'm thinking a bridge transition on the Interstate or nasty pot hole. I haven't been off road.

Joe in Texas
06-02-2020, 12:06 PM
was that a G614?

CalandLinda
06-03-2020, 12:12 AM
Being in the quarantine mode I have oodles of time to ponder tire situations. Iíve been writing about RV trailer tires for about 16 years. I belong to a half dozen trailer forums or those that have trailers. I use other nick names in some of them. I first joined here as FastEagle but was dismissed because I didnít own a Montana. Later when that membership rule was modified we rejoined. We have a 38í Everest which is very similar to the Montana and built by Keystone. Back in its ďhay-dayĒ it was one of the largest Keystone fivers being built.

Anyhow, the original tires on our trailer got me into researching ST tires. Why? Within the first year we lost every one of the OE tires to tread separations. Why? We exceeded their speed restriction & they were always close to being overloaded, in fact we probably always had at least one tire position extremely overloaded. Their speed restriction was 65 MPH. The tires were rated at 3000# and the axles were vehicle certified at 6000#. They were USA built GY Marathons.

The ST235/80R16 LRE has been manufactured with three different maximum load capacities; 3420#, 3500# and 3520#. The GY Marathons and the new GY Endurance in that designated size and load range has a maximum load capacity of 3420# at 80 PSI. Itís always been a problem tire for Keystone or others that want (ed) to use them on 7000# axles. Keystone, like all other trailer manufacturers, quickly found-out that they would have to recall any of those GY tires installed on 7000# vehicle certified axles.

That brings me to ANATNOMís situation. Because trailer manufacturers have the authority to set GAWR values, they solved their GY LRE Marathon tires on 7000# axles by devaluating the axles to 6750# and certified them at that value. Still they didnít have hardly any load capacity reserves and would surely fail earlier than expected, especially when operating at the certified GAWRs maximum load capacity.

Fast forward. RVIA, with all their wisdom, mandated a minimum tire load capacity reserve recommendation (10%) for all participation members Ė about 98 % of the RV trailer manufacturers.

Bottom line; The minimum acceptable load capacity for vehicle certified 6750# GAWR axles is about 3715#. None of the ST235/80R16 or ST235/85R16 LRE tires qualify.

NOTES: The only tire brand that has not officially increased their ST tire speed ratings to 75 MPH or above is Maxxis. Ė The GY Endurance is not yet going to China. They are moving it from their AL plant to a NC plant.

Joe in Texas
06-03-2020, 06:55 AM
Thank you.....for the numbers and history behind them.

Bottom line- sailun S637 -235/85R16 - is that the tire time buy ? For my 2011 - Montana........

PSFORD99
06-03-2020, 08:04 AM
Thank you.....for the numbers and history behind them.

Bottom line- sailun S637 -235/85R16 - is that the tire time buy ? For my 2011 - Montana........


Its the choice of many on here, including me. IMO you can'y buy a better G rated tire for your fifth wheel. Yes they are made in China, I got grief from my wife buying them, but the bottom line is I wanted the best tire to put on our fifth wheel.

This forum has been pretty civilized as far as where the tire is made, most forums you will get a couple guys who condemn anyone buying Sailuns, and are probably typing away on a computer made in China, while wearing a shirt ,and pants also made in China, but thats how it goes. Good luck on your tire choices

CalandLinda
06-03-2020, 03:12 PM
Thank you.....for the numbers and history behind them.

Bottom line- Sailun S637 -235/85R16 - is that the tire time buy ? For my 2011 - Montana.....

The proper nomenclature for that tire is ST235/85R16. Brands are not linked to tire sizes.

The official load capacity designator for ST tires is the load range letter system.

PhilandRudee
06-04-2020, 10:40 AM
The proper nomenclature for that tire is ST235/85R16. Brands are not linked to tire sizes.

The official load capacity designator for ST tires is the load range letter system.

I too am getting ready to order the Sailun's to replace the Marathon's on our new to us 2012 3750FL. The Marathons are ST235/80R/16 and wondering if the Sailun ST235/85R/16's would be better than matching the original radius of the Marathons? What are the advantages?

I was going to keep the Marathon for a spare but am questioning myself on that as well. Is the spare tire rim also rated for the increase in PSI?

Thanks,

Phil

CalandLinda
06-04-2020, 03:46 PM
I too am getting ready to order the Sailun's to replace the Marathon's on our new to us 2012 3750FL. The Marathons are ST235/80R/16 and wondering if the Sailun ST235/85R/16's would be better than matching the original radius of the Marathons? What are the advantages?

I was going to keep the Marathon for a spare but am questioning myself on that as well. Is the spare tire rim also rated for the increase in PSI?

Thanks,

Phil

The ST235/80R16 LRG is the best fit because it has the same profile as the Marathons.

The spare tire does not have to be the same size and load range as the running tires. It just has to have a load capacity that equals the load capacity of the vehicle certified GAWRs. It's really an emergency service tire.

Texan
06-04-2020, 03:52 PM
The 235/85/16 tires are slightly taller and wider. You can stay with the same size tire or go to the slightly larger tire. The 80 series are rated at 4080 pounds and the 85 series are rated at 4400 pounds. Either tire is rated for more than your wheels. You should be able to use the same tire for the spare and i would buy 5 tires as the spare marathon is getting old and you may just have another flat if you needed it in an emergency. I would probably just buy the tire that is the cheapest at the time of purchase. Simple Tire varies on the price of these tires day to day. You can't make a wrong decision on either tire.

Fishin2dMax
06-04-2020, 04:20 PM
I recently upgraded to Sailun's a few weeks ago. I decided to go with the taller 85's profile tires instead of the original 80. I also upgraded the spare tire to the taller 85 profile; if not, the diameter of the spare would be different from the other tires. While it probably would still work, I decided not to risk it and change a 2 year old never used spare 80 profile tire to the taller 85 Sailun. My vanilla spare rim was rated for 110 PSI. Be prepared to use a hydraulic jack to mount the spare back up under the trailer - Holy cow that Sailun tire is heavy:eek:! My reasoning for going with the taller tire was to help level my trailer when on the truck. My truck sits tall in the rear and made my trailer sit a higher in the front. While the 85's only raised the trailer a little over 1/2", it was enough to make a difference - trailer looks level now with the truck. One challenge I did run into with the taller tire was rub on a wheel skirt.:facepalm: For some reason, my left side (big slide) tire skirt is offset more to the front of the wheels than on the right side (I suspect this for allowing more access space for the rear gray water dump valve via the front of the wheel skirt). When mounting the 85's, the rear left wheel rubbed the wheel skirt, so I trimmed the inside of wheel skirt (3/8" hardly noticeable). I'm really glad that I made this investment in quality tires; the trailer handles / rides much nicer and I have improved piece of mind when towing.

jeffba
06-04-2020, 06:55 PM
this is a good tread to read at bedtime

DanandBrenda
06-04-2020, 07:36 PM
I'm just wondering about the weight of the Sailun's for the spare tire holder. Is the cable and the rack strong enough to hold it up. I just replaced all 5 of my tires with Sailun's

Carl n Susan
06-04-2020, 08:49 PM
I'm just wondering about the weight of the Sailun's for the spare tire holder. Is the cable and the rack strong enough to hold it up. I just replaced all 5 of my tires with Sailun's
My 2012 has supported a GY G614 and now Sailun G637 (both of which weigh about the same) spare for the last 8 years and 60,000 miles. No problems yet.

Texan
06-05-2020, 01:00 AM
I weighed on a digital scale the e-rated tire and the g-rated tire and the g-rated tire weighed twice as much at 63 pounds as the e-rated tire. I've had the g-rated spare for 5 years and i don't think you will have any problem. If you are concerned then you could install a strap across the spare for peace of mind.

CalandLinda
06-05-2020, 02:16 PM
Just maybe the vehicle manufacturer is doing the right thing by using the ST235/80R16 vice the ST235/85R16; because the latter is wider and more susceptible to damages from interplay sheer.

I'd be surprised if they would recommend the 85s over OE 80s.

masterdrago
06-06-2020, 11:01 PM
You are correct, they used to be an extra cost option on Montanas. Then RVIA (or somebody) moved the goal posts. No longer do the tires just have to exceed the axle rating, they have to exceed it by 10%. So a 7,000 lb. rated axle needs tire capacity of 7,700 / 2 lbs (i.e. each tire rated at 3850 lbs). The GY G614 is a Load Range 126 or 3748 lb. tire, just short of the 10% requirement. Hence the Sailuns became the standard. We got our 3791 just when that new RVIA rating changed and it came with the Sailun 637 ST235/80R16 rated at 4050#. My question has always been why are the rims rated at 3750#? When I replace, I want to go with higher rated rims (17.5") and the appropriate tire.

masterdrago
06-06-2020, 11:16 PM
Although they are out of stock, I see Speedy Tire has the best price?!!

PSFORD99
06-07-2020, 09:58 AM
I'm just wondering about the weight of the Sailun's for the spare tire holder. Is the cable and the rack strong enough to hold it up. I just replaced all 5 of my tires with Sailun's


I had several hundred miles on my 2008 Montana without a problem with the cable system, but it did give me concern. If I would kept the fifth wheel I would of done something at the least a ratchet strap for extra support.

With this new fifth wheel it has a slide out rack, no cables, very easy to remove the spare , nearly impossible to lift that Sailun back in place. But no worries about it coming off.

PSFORD99
06-07-2020, 10:02 AM
Although they are out of stock, I see Speedy Tire has the best price?!!


That is a great price, no doubt out of stock :D

CalandLinda
06-07-2020, 01:05 PM
We got our 3791 just when that new RVIA rating changed and it came with the Sailun 637 ST235/80R16 rated at 4050#. My question has always been why are the rims rated at 3750#? When I replace, I want to go with higher rated rims (17.5") and the appropriate tire.

Why? your axles are 7000#. The wheels are far from being over loaded, even at maximum tire inflation of 110 PSI.

Your OE tires provide more than 1000# of load capacity reserves per axle.

Carl n Susan
06-07-2020, 02:25 PM
I think this is a good question. If the tires have to have a 10% reserve capacity, why not the rims they ride on? 3750 lbs doesn't provide a 10% reserve.

CalandLinda
06-08-2020, 07:14 AM
I think this is a good question. If the tires have to have a 10% reserve capacity, why not the rims they ride on? 3750 lbs doesn't provide a 10% reserve.

The result of stresses on rubber is much different than the result of the same stresses on metal.

The guidance we get from the USTMA is; don't exceed a wheel's load capacity or PSI limit.

The 10% load capacity reserves for RV trailer tires is not a binding regulation, it's a recommendation from an organization (RVIA) that has a powerful influence on the RV trailer industry.

PSFORD99
06-08-2020, 10:51 AM
I think this is a good question. If the tires have to have a 10% reserve capacity, why not the rims they ride on? 3750 lbs doesn't provide a 10% reserve.

Just doing the math on rims or tires , I could care less about the 10%. 3750, on the rims ,and 4080 or 4400 on G rated Sailuns, these fifth wheels with 15,500 to 16,500 GVWR rating, and anywhere from 20-25 % on the pin weight are covered nicely . Going to an H rated tire at 4805 ,and 125 psi IMO is a bit of overkill.