Changing Load C to Load D tires, can I use my rims?

[animas]

Changing tires to Load D from C, do I have to change my rim?
Just bought a Super Lite 5th (8528 IKWS), have the Trail Express Load C in 225/75/15. Going to the Maxxis 8008, same size but in a load D. The C's max inflation is 50psi, while the new tires in Load D call for 65.

So my Sumic 5 bolt wheels (15x6JJ) have 50 psi checked on the trailer sticker on the outside of the trailier. So I am hoping they can handle the higher pressure. I didn't go with Load E's, as I knew that the wheels probably couldn't handle 80psi.

I'm not going to call the dealer, as too much of the info I have received is plain wrong!

[Ashley]

The wheels will be fine and would even be fine with the Load range E tires.
I personally would run the 65 psi in the Load D Tires and I am speaking from the experience of having been in the tire business for over twenty five years.

[offroad]

I upgraded to LRD Marathons, and am running 65psi with no issues on our Rockwood. It also has Sumec wheel's on it, and I could not find any markings on the wheel that indicated a psi rating.

[animas]

Originally Posted by offroad

I upgraded to LRD Marathons, and am running 65psi with no issues on our Rockwood. It also has Sumec wheel's on it, and I could not find any markings on the wheel that indicated a psi rating.

I am assuming you had Load C tires and upgraded to Load D's?
Can one assume that if a tire calls for a max psi of 65, that it is a Load D tire?

[offroad]

Originally Posted by animas

I am assuming you had Load C tires and upgraded to Load D's?
Can one assume that if a tire calls for a max psi of 65, that it is a Load D tire?

Yes our trailer came with LR C tires from FR, they went to the lake once before I removed them.

ST225/75R15 LRC tires are rated for 2150lbs of load each at 50psi.
ST225/75R15 LRD tires are rated for 2540lbs of load each at 65psi.

The chart at the top of this pdf shows ST tires.
Follow the chart to the right for ST225/75R15 tires and note the 50psi and 65psi columns.

ST load range C tires are 6 ply rated, LRD tires are 8 ply rated, and LRE tires are 10 ply rated. Ply ratings

Trailer tires best practices

[HONDAMAN174]

Ashley- a question for you then. I recently did the same thing of upgrading from c's to d's. Inflated to 60 psi. Trailer loaded 7500 lbs. Had a WICKED sway problem both to and from a short camping trip- DW (who was following) thought for sure I was going to lose it on more than one occassion. Anyhow, read a pressure chart (from different tire manufacture) that I could lower my pressures back down to about 50 and still be at/above capacity. Pulled fine after that.

So...do you think having the tires at the higher pressure was giving it a little too much "rebound spring"?


2014 Stealth Evo 2850 "Woodstock"
2011 Toyota Tundra Rock Crawler TRD 5.7 "Clifford"

[Airdale]

Originally Posted by animas

Changing tires to Load D from C, do I have to change my rim?
Just bought a Super Lite 5th (8528 IKWS), have the Trail Express Load C in 225/75/15. Going to the Maxxis 8008, same size but in a load D. The C's max inflation is 50psi, while the new tires in Load D call for 65.

So my Sumic 5 bolt wheels (15x6JJ) have 50 psi checked on the trailer sticker on the outside of the trailier. So I am hoping they can handle the higher pressure. I didn't go with Load E's, as I knew that the wheels probably couldn't handle 80psi.

I'm not going to call the dealer, as too much of the info I have received is plain wrong!

If you have any doubt about your rim specs you should call the rim manufacturer. They are the only ones that have to give you the correct answer. Look on the rim to get the PN/SN.

Rims can take whatever air pressure is required to get to the maximum load capacity of the rim.

Rims are certified by ASE not the DOT.

Airdale

[animas]

Great comments and advice...thank you everyone!

[Ashley]

Originally Posted by HONDAMAN174

Ashley- a question for you then. I recently did the same thing of upgrading from c's to d's. Inflated to 60 psi. Trailer loaded 7500 lbs. Had a WICKED sway problem both to and from a short camping trip- DW (who was following) thought for sure I was going to lose it on more than one occassion. Anyhow, read a pressure chart (from different tire manufacture) that I could lower my pressures back down to about 50 and still be at/above capacity. Pulled fine after that.

So...do you think having the tires at the higher pressure was giving it a little too much "rebound spring"?


2014 Stealth Evo 2850 "Woodstock"
2011 Toyota Tundra Rock Crawler TRD 5.7 "Clifford"

Hondaman174,
What you described definitely could/would be from over inflation, that is why a maximum rated pressure is just that. The maximum rated pressure a tire can handle is not always the best pressure to run at which you figured out the only way you can sometimes, Trial and Error.

When a tire is overinflated it tends to "Crown Out", meaning the Face of the tire that contacts the road surface is bulging out more in the middle so to speak. This will cause the feeling you had due to less "Good" contact with the road. Think about it this way, a constantly overinflated tire will wear faster in the middle tread of the tire, a constantly under inflated tire will wear faster on the outer edges of the tire, just to help you understand the principal of how air pressure changes the shape of the face of the tire.

With that in mind though, remember this, the less air pressure you run, the more sidewall flex you get which translates into heat generation as well as weakening of the steel belts in the sidewalls, and ultimately the "Tire Bombs" everyone likes to speak of. Regardless of what brand tire you have, under inflated tires tend to be the biggest cause of premature tire failure we see, especially the hotter the roads and weather.

So try to find that happy medium where you get the best ride and handling, but are also running the most air pressure within the rated specifications of course. There is not one perfect answer that fits every situation, that is why us learning from each other is so important.

Oh yeah, one last thing. I have even found over the years different tires, based on their construction, will "Crown" more or less at the same exact air pressure. So, just because one particular tire felt the way it did at 60 psi, you might find another brand performed just fine at that same pressure.

Ashley

[Rsharrer]

After 11,000 plus miles I just changed out the factory installed Trail Express tires on our 8289WS. Found that three of them had split along the edge, near the rim, and on the inside. They were only nineteen months old. Would not have discovered this had I not taken one off to have a nail hole patched. Upgraded to the "D" rated ST tire. My Sumec wheels are made in China and have the maximum load rating marked on the inside of the rim at 2150 lbs (C rated). I could find nothing that recommended against mounting 65psi tires on these rims. One other thing, although out of warranty, I did appeal to Forest River and they provided a partial compensation to me. I have had a couple of warranty issues and this company has always done the right thing. Couldn't be happier with their produce or with their customer service.

[Rockwoodjoe]

Where do we find the Marathon lrd tires. I have Westlake 205/75 14 load C on my 2015 Rockwood 2703WS from the factory. I have checked some local dealers and Tire Rack and no one has these Marathon D's I for a 14" rim. Also thinking of upgrading the tires on my 2013 F-150. Any recommendations and where to find them.

[Lloydg]

Originally Posted by Rockwoodjoe

Where do we find the Marathon lrd tires. I have Westlake 205/75 14 load C on my 2015 Rockwood 2703WS from the factory. I have checked some local dealers and Tire Rack and no one has these Marathon D's I for a 14" rim. Also thinking of upgrading the tires on my 2013 F-150. Any recommendations and where to find them.

It doesn't look like Goodyear makes a Load D in a 14" rim. See the Goodyear link and click on Marathon to see their sizes. I checked Maxis too and they don't make a 14" Load range D either. Sorry
Goodyear RV Tires – Tire Selector

[Rockwoodjoe]

Thank you Lloydg. Just not what I wanted to hear.

[jawga]

hankook makes a D range tire (couldnt find the kuhmos)for a 14" its a 195r14 euro specwhich is the same as a 205/75r14. we just swapped ours and it made a huge difference

[Taranwanderer]

Originally Posted by Rockwoodjoe

Thank you Lloydg. Just not what I wanted to hear.

I hate to say it Joe, but if you upgrade to 15 inch rims you will have a much better selection of tires, load ranges, and brands--assuming you have the room to run a larger rim. I know, not the news you wanted to hear.

[HONDAMAN174]

Kumho does make a 195r14 in their 857 line. Ran it on my High Wall and loved it.

Also think about a tire pressure monitor. Different opinions on if they help on blowouts but I prefer to know if a tire is going down slowly.


2014 Stealth Evo 2850 "Woodstock"
2011 Toyota Tundra Rock Crawler TRD 5.7 "Clifford"

[Safe man]

You give me hopes with forrest river co. I will call them again and see if they will, can help on my wolf pup, bought it brand new. It has negative camber where the tires, original, wear out in 1000 miles. It's the second set of tires too.

[Rockwoodjoe]

I found D range tires on Etrailer.com. Size st205-75-14 for $106.95. Never heard of Kenda or Karrier brand. They must be Chinese. Maybe they come with eggroll.

[Road-King]

Originally Posted by Road-King

When I had my Windjammer, I went from load "C" to "D" tires. I had the same question as the OP. I contacted LionsHead the supplier of my rims. They told me that my rims were rated for 50 psi, but if I went to a metal valve stem, I could go up to 80 psi. The rubber valve stems was the reason for the 50 psi limit. I had the fancy 15" aluminum rims.

From a old post

[Airdale]

Probably the best upgrade for the ST205/75R14C tire is the ST215/75R14C tire. You wont have to change rims and you pick-up 110# of extra load capacity per tire. The 215 is about a half inch wider and taller than the 205.

Airdale