14" to 15" Tires

[1joedoug]

I'm wondering if 15" new tires are better than the 14" tires on my '03 Casita 17 SD? What are the pros/cons of 15" as opposed to the 14"s on now? I have the high-lift axel but would have to buy new wheels.

Any suggestions/recommendations are certainly appreciated. And thanks to all that respond.

[Joe & Cherie]

Its just my opinion, but I think its a great upgrade! Those 14" C rated are marginal for that Casita 17 SD weight. I like margin in my design - especially in tires. When we had a 17 Casita SD (and also our current EggCamper), I switched them out from 14's C rated to 225/75/R15 Maxxis M8008 D rated. I also upgraded to aluminun rims just for the bling, and dont forget the high pressure valve stems! Dont upgrade the tires/wheels and cheap out on weak valve stems. Just the piece of mind of that upgrade was worth it!

By the way - I see this is your first post - Welcome!!!

[Jon in AZ]

15's are much easier to find in stock if you need one in a hurry on the road somewhere, too.

And I'll second the welcome!

[Daniel A.]

Timely post as I'm looking to change from 14" to 15" on my Bigfoot this spring I had a lift kit put in last fall for improved clearance and its time for new tires anyway.

[Sparky0]

Here's a thread about my conversion from 13" to 15" on a 2005 Trillium.

http://www.fiberglassrv.com/forums/f...els-82440.html

So glad i did it.

Cheers

[ehoepner]

The 14 inch tires are running at maximum capacity all the time.

The 15 inch tires can be purchased in a load range D which can carry a much higher load which in creases the durability and life span of the tires. Plus the bearings last longer because they are turning slower.

[wvorih]

Being an old tire engineer I would like to make a comment. Tires marked ST (ST235/85R16) for trailer use are engineered and tested to a lower standard than tires marked Light Truck, LT (LT235/85R15) or passenger tires for that matter.

*Convince yourself of that fact by reading the words on the side of trailer tires "For Trailer Use Only". Since trailers do not carry passengers, the manufacturer of trailer tires has less liability when a tire fails than when a light truck or passenger tire fails.

Now look at that construction description on the sidewall. An LT tire will usually say, 3 tread plies, 2 steel 1 nylon. A radial ST tire will not have the nylon ply. The nylon cap ply is there to make sure that the tire stays together in case of a separation failure.

People talk about ST tires being more stable. Stability is a function of air pressure. More air is better. Right up to the maximum pressure listed on the sidewalk. In fact you can go even 5 psi more than the max listed because that higher pressure is recommended in the tables for vehicles traveling continuously at high speed.

Considering the above, it is always better to use an LT tire instead of an ST tire and LT tires are usually cheaper because they are made and sold in greater volumes.

For small trailers if you can't find a suitable LT tire, use a passenger tire instead of ST if you can find one that can carry the load.

[Glenn Baglo]

So, it's your theory William, that tire companies deliberately design an inferior tire and call it Special Trailer to deceive customers.

[wvorih]

Good comment Glenn. Manufactures in general try to serve their customers (trailer manufacturers in this case) with the lowest cost products that meet the customers requirements. Trailers do not carry people and so their tires can be made cheaper and do the job.
I illustrated this last point by mentioning the nylon cap ply that is now almost 100% used in passenger and light truck tires. This extra ply, over the 2 steel tread plies was implemented over the last 20 years to solve the problem of tires on the back axles having catastrophic failures and vehicle rollovers often due to under inflation. Remember those Ford Explorers and other SUVs rolling over? Now if the tire fails, it stays in one piece and the vehicle rarely rolls over.

In my experience the cheapest tire construction I ever saw was the high ply rating 14 inch bias tires used on mobile homes. The plies had a very thin coating of rubber and very thin tread depth. The trailers had a dozen wheels on each side so the risk of a vehicle problem from a blow out was low. And blowouts they had.
Another point of interest is that in Europe they drive a high speed even with trailers and the trailers use passenger tires that are speed rated.
Please let me know if you find an ST tire with a nylon ply over the steel belts. A sidewalk photo of the construction would be nice.

[Captleemo]

Wvorih
Thanks for the educational post. Heres a website that has a lot of useful info on tire sizes. https://tiresize.com/height-calculator/

[Joe Romas]

William.
Glad you approve of my new Good Year Endurance ST tires.
How about 2 plies of Nylon?
Here's a picture of my 205/75R15 D rated side wall you asked for
It says 2 Polyester + 2 Steel + 2 Nylon, N speed rating. (87 MPH)
https://www.goodyear.com/en-US/tires...ce/sizes-specs

They are made in the US
To the original poster, this is the size Casita is putting on new high axle trailers.
My "Bling" are Sendel T02 80 psi rated rims
Joe

[Joe & Cherie]

Originally Posted by Joe Romas

My "Bling" are Sendel T02 80 psi rated rims
Joe

Same wheels I have! I researched and most were much lower psi. These were the only ones that were 80psi! And they look good too!

[Tom Trostel]

If you wish to stay with 14", there are some better options than any ST. Mounted on my trailer are Maxxis Bravo UE-168 in size 185R14C. They have a load rating of 1874 lbs.@ 65 psi and a speed rating of R (106 mph). They are light truck tires with 2 polyester, 2 steel and 2 nylon belts. They are made in Taiwan. They can be had in size 205R14 with a load rating of 2270 lbs. I've been very happy with these tires. The main "con" is they can be difficult to find and buy. Amazon lists them.

https://www.amazon.com/MAXXIS-UE-168...70_&dpSrc=srch

[k0wtz]

joe I like those rims


bob

[wvorih]

Joe, Thanks for that photo and info on your tires. They sound like serious tires.
And look great on those rims!

[wvorih]

Tom, your tire, *185R14C, does not have the letters LT as a prefix because that size is a European size. For tires listed by the ETRTO, European Tyre and Rim Technical Organisation, the suffix "C" means commercial use including trucks and buses. The LT prefix is for metric sizes listed by TRA,
The Tire and Rim Association, Inc
Which is the USA tire standards organization. The two designations are for practicle purposes the same. I thought this little technical fact might be of interest. There are a few other tire sanctioning bodies but these two are the most important.

[Joe Romas]

Originally Posted by k0wtz

joe I like those rims


bob

When they arrived I was very impressed by their weight and construction
According to what I could find they are only 0.3 pound lighter then steel rims.
My GY endurance 205/75R15 "D" tires are rated at 2150 pounds each at 65 PSI.

I talked to Sendel and these rims can be balanced both "hub centric" and "Lug centric" eliminating what can be a hassle. I got the tires at Discount tire and specified only stick on weights on the inside only period. The installer really didn't want to do it that way.
I shudder to think of them pounding on conventional weights on my brand new rims.
My 2017 GMC Sierra came from the factory that way

[k0wtz]

I have owned cadilacs and lincolns it irratates me to no end to take the car in for either new tires or balancing come out after paying and see pound on weights on the outside of a 2k set of rims.

what are those guys thinking?

bob

[Joe Romas]

Bob

I stand outside the service door, out of the shop area and watch and am not afraid to let them know when I see them getting out the pound on weights

Joe

[Captleemo]

I bought a set of tires once at Discount Tire and I specified that the weights be on the inside of the rim. When they were done I noticed that the weights were on the outside of the rim so I complained to the manager and he had them re balance the tires as specified on the signed purchase agreement.