Community Forums

royjeri · 07-23-2011, 04:45 PM

I have 235/80R16 Load Range D on my 5th wheel now but am thinking about upgrading rims and tires to Load Range E 235/80R16. Is there any differences in the outside measurements between the load ranges? I don't have a lot of fender skirt clearance on my Jayco Eagle and only 2 inches between the tires.

LVJ58 · 07-23-2011, 05:11 PM

Shouldn't be any size difference so long as the numbers are the same, it's just the "E" rated tires are capable of carrying more weight.

If you have the tire brand go to the manufacturer's web site and pull up the "Load inflation Table" and it should show the specs on the tires, i.e., diameter, tread width, rim width required, and load weight capabilities at various psi inflation.

Good luck,

royjeri · 07-23-2011, 05:22 PM

Thanks. I've found that info on the LR E but nothing on the D. I'll keep trying. Thanks again.

royjeri · 07-23-2011, 05:27 PM

I finally found the info. You are correct. No differences in diameter or width. Thanks for the help.

Cat320 · 07-23-2011, 06:09 PM

235/80R16s are usually ST tires, while 235/85R16s are usually LT tires. The STs, made in China, have a higher rating, the LTs made in the USA/Japan are truck tires that have lower ratings, but, IMHO, are much better tires. I had a 5th wheel and changed the STs (with a tire losing a tread) for LTs...it was a wise decision, and the load capacity was still within specs for my rig.

royjeri · 07-24-2011, 06:16 AM

Thanks Cat320. I've been thinking about going to LT rather than ST but can't really find anyone who has a strong opinion one way or the other. I've talked to tire dealers and they are reluctant to take a stand.

RustyJC · 07-24-2011, 06:45 AM

Quote:

Originally Posted by royjeri

Thanks Cat320. I've been thinking about going to LT rather than ST but can't really find anyone who has a strong opinion one way or the other. I've talked to tire dealers and they are reluctant to take a stand.

OK, you've found someone. Go with the LT tire. If you can find one of these (Michelin XPS Ribs) that will fit your dimensional restrictions and has the requisite weight rating, you'll not worry about tire failures again. Expand TechSpecs at the bottom of the linked webpage for sizing, dimensional and load capacity information.

Rusty

Ray,IN · 07-24-2011, 11:40 AM

Tire aspect ratio, sidewall to tread width ratio, makes a difference in tire diameter. This tire size comparator is quite helpful in making these decisions. The exact same size tire, in different weight ratings should be the same diameter.

ralper · 07-24-2011, 01:29 PM

Weigh your RV. Put tires on it to carry 125% of that weight.
Forget the nonsense about not needing so much tire because of the weight carried on the hitch.

Cat320 · 07-24-2011, 02:40 PM

Quote:

Originally Posted by ralper

Weigh your RV. Put tires on it to carry 125% of that weight.
Forget the nonsense about not needing so much tire because of the weight carried on the hitch.

My last 5th wheel had a GW of 14k and two axles with GWs of 6k...any way you do the numbers, that's 2k on the truck as pin weight.

Tireman9 · 07-25-2011, 08:37 AM

There are a number of points I don't see mentioned in the thread.
To start with, you didn't provide the complete tire size as molded on your original tires. A complete size might be "LT215/85R16 115R Load Range E"

I have seen no mention of your actual individual axle by axle, side to side loads. While most TT have at least a 5% variation, I have seen a few at more than 18% load variation.

I do not consider an ST235/80R16 LR-E the same as an LT235/80R16 LR-E as they are in fact different "Type" tires and are listed on different sections of Industry Standard tables. Goodyear makes both Load ranges in their Marathon line.

Info on Load Range can be found HERE.

Here is what Goodyear says "Trailer tires are considered a special category in the current global design standards of Tire and Rim. The major difference is that trailer tires are required to carry 10% more load than an equivalent P-metric size tire. LT type tires are actually on a lower formula and would require a significant size or load change to meet the trailer load requirements."

Also ST type tires are rated for a Max operating speed of 65 mph. Exceeding that speed rating can result in tire failure.

A switch of Load Range while staying with the same size will only give you more load capacity if you increase the inflation as it is the air that carries the load, not the tire. Info HERE.

Changing wheels to those that can carry the increased load and inflation to match the new tires is a good plan but what are you going to do about your axles and springs? They also have maximum ratings.
You can find links to most of the tire company web pages HERE

You didn't mention why you were "upgrading" from Load Range D to Load Range E. Was it to give yourself a larger safety factor over the max load capability of your original tires? i.e. You have weighed your TT and know tha actual individual tire loads. You are not exceeding the GVWR or GAWR but due to side to side variation have less than 1% safety factor for one position. A switch to the LR-E would allow you to increase the inflation by the suggested 5 to 10 psi while not exceeding the GAWR.

With more facts we can provide a more informed response.

Tireman9 · 07-25-2011, 08:41 AM

Quote:

Originally Posted by Ray,IN

Tire aspect ratio, sidewall to tread width ratio, makes a difference in tire diameter. This tire size comparator is quite helpful in making these decisions. The exact same size tire, in different weight ratings should be the same diameter.

Interesting info on your link, but not as accurate as info from the tire manufacturer. See the tire-information-links on iRV2 and only use the estimator as a back-up if you can't find the link to your tire company.

hooverbill · 07-25-2011, 12:07 PM

I replaced my Chinese bomb ST235/80R16s with LT235/85R16s. The LTs have a lower capacity, but well within what was needed for my trailer. The big problem, was that I could not find any STs in this size made any where but China. I guess they are out there, but I don't know where. Virtually everybody with large 5th wheels was converting from STs to LTs, some did it with brand new STs, they were just not reliable.

royjeri · 07-25-2011, 03:24 PM

I appreciate all the input. My main intent was to get rid of the China rims and thought I'd upgrade while at it. I have no concerns about overloading because we won't/don't. I have the same setup Cat 320 talked about. I just thought 80psi tires rather than 65psi might be safer and/or a better ride. Probably stick with the ST as it stands now. Thanks again for all your input.