Jump to content

Replace 14" tires with 15" tires?


Yarome

Recommended Posts

I've read a number of tire threads over the years, but my mind get's foggy. Is there any real issue with replacing 14" ST's with 15"? Working pressure is currently 50psi and the 15" I'm looking at has a working pressure of 65psi.. so I'm not terribly concerned about the rims.

 

Any major concerns I should be aware of? The main reason I would like to go with 15's is to up the load capacity and move up from 6 ply to 8 ply.

Link to comment
Share on other sites

I had 14" tires on a previous trailer. The load capacity of the tires was very close to maximum so I wanted to go to a tire with more capacity. There was not enough room in the wheel well or between the axles to go to 15" rims and tires. I went from 215/75R to 225/75R for a little greater weight capacity. I still had to cut a little off the wheel well trim to prevent it hitting the tires from time to time. The tires did not wear evenly. I was told by friend that worked maintaining a fleet of commercial trailers that I probably needed to get the axles/wheels realigned for the larger size tires. I found that the commercial rated tires supplied as original equipment on some european vehicles were the exact same diameter and width as the ST215/75/14, were available in Load Range D and were speed rated to something like 100MPH. At the time the Michelin Agilis and Kumho 857 were available. Not sure the Agilis still is available in a Load Range D tire. I bought the Kumho 195R14C Load Range D. I put over 15,000 miles on them before I sold the trailer and they wore evenly and still had plenty of tread.

Link to comment
Share on other sites

Working pressure is currently 50psi and the 15" I'm looking at has a working pressure of 65psi.. so I'm not terribly concerned about the rims.

 

 

You will have to get new wheels to move from 14" to 15" tires, so you can get wheels rated at whatever pressure you decide to use. As long as you have adequate clearance within the wheel wells and between the tires, going from 14" to 15" shouldn't be a problem.

Link to comment
Share on other sites

Your tires might handle the load but sure as there are lil green apples your springs will collapse bringing your two axles towards each other wiping out both tires unless you get stopped super fast. Just unload that trailer and have a sidewalk sale and put the cash towards a bigger trailer if you need to haul that much weight JMHO

 

Jim

Link to comment
Share on other sites

Just unload that trailer and have a sidewalk sale and put the cash towards a bigger trailer if you need to haul that much weight JMHO

 

I wasn't planning on exceeding the max gross weight (6700 Dry + load capacity) of my trailer. I was just looking at a current tire max gross of 6800 pounds and thought I would feel a lot more comfortable riding, potentially, that 6700 gross trailer max on 9500 of tires than I do on the current 6800.

 

Does that make sense?

Link to comment
Share on other sites

Your tires might handle the load but sure as there are lil green apples your springs will collapse bringing your two axles towards each other wiping out both tires unless you get stopped super fast. Just unload that trailer and have a sidewalk sale and put the cash towards a bigger trailer if you need to haul that much weight JMHO

 

Jim

Not sure anyone is talking about overloading the trailer. I know I wasn't. I switched to the D load range tires to have more of a cushion between the actual weight on the tires and their maximum rating. Your statement about the springs and axles collasping is assuming that they are overloaded. I have seen a number of trailers where the suspension and axle ratings are substantially greater than the GVWR of the trailer yet it comes with tires that are rated just over the GVWR or maybe even a little under counting on tongue weight to support some of the load.

Link to comment
Share on other sites

I increased the load rating on my tires on my fifth wheel. Didnt go to a larger rim size but the tire circumference was a bit bigger.

Was no problem doing that.

 

What I would suggest is to check the overall diameter of the 15 " tires and see if you have room for the extra growth in both the wheel well and the distance between the two tires. If it all will fit...go for it. But I would switch at the same time to LT tires. ST tires are junk.

Link to comment
Share on other sites

In deciding whether to go to 15" LT tires, I suggest that you take a very close look at what is actually available, the diameter and the actual maximum weight ratings. When I checked a couple of years ago, there were not all that many choices in 15" LT tires. Most were Load Range C with a weight rating less than the commercial grade metric 14" Load Range D tires and a diameter over 2" larger.

Link to comment
Share on other sites

In deciding whether to go to 15" LT tires, I suggest that you take a very close look at what is actually available, the diameter and the actual maximum weight ratings. When I checked a couple of years ago, there were not all that many choices in 15" LT tires. Most were Load Range C with a weight rating less than the commercial grade metric 14" Load Range D tires and a diameter over 2" larger.

"

That's pretty much the same conclusion I've come up with too. I think I'll stick with the stiffer sidewalls, higher weight ratings, and only 1" bump. LT's are certainly less expensive, but I think I'll ride out some 8-ply's and see how they hold up.

 

Thanks for the input, folks. Much appreciated!!

Link to comment
Share on other sites

If you ever get a chance in a tire shop, lift up an. ST tire and get anidea of their weight. Then lift up an L t tire of the same load carrying capacity. The L T tire will be much heavier. Ther is no rubber in the STTires. Did Imention they are junk?

 

I know... lol But the only LT tires in 15" I can find have a lower load capacity than the 14" marathons I have on there now. 1609 vs 1760.. and the 8-ply ST's I'm looking at (in 15") are rated at 2150. The 14" LT's I'm running across are only 1520 (10% BELOW max gross trailer weight).

 

I am VERY open to suggestions though. If I could find a 14" or 15" LT in the 1850+ range (10% above max gross), I would certainly consider them. I'm really trying to maintain 15-20% capacity above absolute max gross though.

Link to comment
Share on other sites

From what I have heard at my brothers tire shop, finding 14 and 15 inch tires is very difficult. Companies can order the OEM from the tire companies because they buy thousands at a time. Finding the replacements get's very hard and we all know the bean counters at the manufactures want the lowest price for every part of the trailer. Even the really important ones. Before you purchase any replacement wheels and tires. Question your supplier on the availability of those same tires in the near and distant future.

 

Just my opinion.

 

Rod

Link to comment
Share on other sites

 

...I am VERY open to suggestions though. If I could find a 14" or 15" LT in the 1850+ range (10% above max gross), I would certainly consider them. I'm really trying to maintain 15-20% capacity above absolute max gross though...

Did you look at the link I provided for the Kumho metric tires? All have a Maximum load of above 1850#. I do not believe that they are really considered ST tires, Kumho says they are: "For commercial light truck, transporter, van and trailer." As I said in my earlier post they are speed rated for much more than the 65MPH of most ST tires. As far as I know, they are not made in China. At least they weren't when I had them.

 

185R14C 1874 @ 65

195R14C 2094 @ 65

205R14C 2271 @ 65

Link to comment
Share on other sites

Did you look at the link I provided for the Kumho metric tires? All have a Maximum load of above 1850#. I do not believe that they are really considered ST tires, Kumho says they are: "For commercial light truck, transporter, van and trailer." As I said in my earlier post they are speed rated for much more than the 65MPH of most ST tires. As far as I know, they are not made in China. At least they weren't when I had them.

 

185R14C 1874 @ 65

195R14C 2094 @ 65

205R14C 2271 @ 65

 

I did actually. Kumho's are made in South Korea, and from their construction, are ST tires. I appreciate the link, but I was thinking of going Maxxis over the Kumho. They are less expensive, but more difficult to come across on the road if a tire needs replacing.

Link to comment
Share on other sites

 

I did actually. Kumho's are made in South Korea, and from their construction, are ST tires. I appreciate the link, but I was thinking of going Maxxis over the Kumho. They are less expensive, but more difficult to come across on the road if a tire needs replacing.

I have 15" Maxxis 8008 ST tires on our current trailer, mainly because the Kumhos do not come in a 15" size that I could use. The Maxxis seem to be holding up well after two years and over 12,000 miles. I am not crazy about the 65MPH speed rating even though I normally drive 60-62 even if on the interstates.

 

From what I have heard/read, Carlisle Radial Trail RH are made in the USA and Carlisle is the only tire company currently producing ST tires in the USA. This information about speed ratings that is supposed to be from Carlisle was posted on another forum:

 

Carlisle%20Radial%20RH%20tire%20speed%20

I think you will be happy with the Maxxis. They have a pretty good reputation, I believe they are made in Thailand, at least that's what mine say,

Link to comment
Share on other sites

u will be happy with the Maxxis. They have a pretty good reputation, I believe they are made in Thailand, at least that's what mine say,

 

 

I appreciate the follow-up, Tony! That is my understanding too with the Maxxis, but so many folks seem to get really good wear out of them (12k so far is reallyyyyy decent) that I am willing to try it. That's what I am looking at as well... the 8008's in the 8pr. I certainly haven't found anything else that can compare to their load ratings.

 

Much appreciated!

Link to comment
Share on other sites

Sometimes a tire's overall diameter can be a major problem when going from 14" to 15" tires. The link below has a couple of 15" tires very close in diameter with OE 14" tires.

 

http://www.tirerack.com/tires/tires.jsp?tireMake=Goodyear&code=yes&partnum=27R5G26&KEYWORD=tires.jsp_Goodyear_Cargo_G26_Tire&tireModel=Cargo+G26&GCID=C13674x012-tire

 

FastEagle

Link to comment
Share on other sites

Sometimes a tire's overall diameter can be a major problem when going from 14" to 15" tires. The link below has a couple of 15" tires very close in diameter with OE 14" tires.

http://www.tirerack.com/tires/tires.jsp?tireMake=Goodyear&code=yes&partnum=27R5G26&KEYWORD=tires.jsp_Goodyear_Cargo_G26_Tire&tireModel=Cargo+G26&GCID=C13674x012-tire

FastEagle

Thanks for the link! Looking at the specifications, the Goodyear G26 225/70R/15C needs a 6-7" rim, so is likely wider and at 27.4" taller than the OEM 14" tire and a liitle taller than the 27.1" ST205/75R/15. They probably would hit the plastic wheel well trim on my current trailer because of the extra width and would have slightly less weight capacity than the factory supplied ST225/75R/15 load range D rated at 2540# Max. The 195/70R/15C uses a 5-6" rim with a diameter of 25.8" which is a little less than the 26.1" of the ST205/75R/14. The 1985# Max Load is OK, but not quite as high as the 2150# of the Maxxis ST205/75R/15 Load Range D or the Kumho 195R14C or 205R14C. If it is a matter that is considered important to you, the Country of Origin Codes of FR, DE, & TR all represent factories located in China although not the same one where the Goodyear Marathons are made.

Link to comment
Share on other sites

Thanks for the link! Looking at the specifications, the Goodyear G26 225/70R/15C needs a 6-7" rim, so is likely wider and at 27.4" taller than the OEM 14" tire and a liitle taller than the 27.1" ST205/75R/15. They probably would hit the plastic wheel well trim on my current trailer because of the extra width and would have slightly less weight capacity than the factory supplied ST225/75R/15 load range D rated at 2540# Max. The 195/70R/15C uses a 5-6" rim with a diameter of 25.8" which is a little less than the 26.1" of the ST205/75R/14. The 1985# Max Load is OK, but not quite as high as the 2150# of the Maxxis ST205/75R/15 Load Range D or the Kumho 195R14C or 205R14C. If it is a matter that is considered important to you, the Country of Origin Codes of FR, DE, & TR all represent factories located in China although not the same one where the Goodyear Marathons are made.

I think you will find that this is the type of list the Tire Rack uses for country of origin codes.

 

http://www.capso.org/pdfs/SNORDirectory2005.pdf

 

FastEagle

Link to comment
Share on other sites

I think you will find that this is the type of list the Tire Rack uses for country of origin codes.

 

http://www.capso.org/pdfs/SNORDirectory2005.pdf

 

FastEagle

Maybe, but why would they use a code from the "Directory of National Origin Names & Country Codes" that "is to be used as a reference by Local Educational Agencies (LEAs) and private schools when conducting counts of eligible immigrant students as required by Title III of the No Child Left Behind Act and reporting these data to the California Department of Education (CDE) via the Student National Origin Report (SNOR)." when there is a specific list for tires maintained by the US DOT? If you look at the list that you linked to there is no DE, yet that is one of the abbreviations used by Tire Rack?

Link to comment
Share on other sites

Switching to 15" tires offers the choice of load range D,E, F, or G trailer tires. http://tiresunlimited.com/ALL%20TIRES/TBC%20sigma%20nankang/trailer/tbc_sigmas_trailer_tires.htm

The D & E tires at the link you provided are STs and are the same sizes often supplied by travel trailer manufacturers and tire manufacturers like Maxxis, etc.. There may be F & G and even H rated tires for 15" rims, but are the rims & tires too wide and or too tall to fit on a trailer designed for 14 or 15" ST tires? Can you get rims in the right size, pressure and weight rating for the the F & G tires with the correct bolt pattern for travel trailer hubs? Did you replace your 14" OEM tires with 15" F or G rated tires? Just curious because this has been mentioned before and F or G tires would seem to be really overkill for trailers originally equipped with 14" tires and for many equipped with 15" tires.

Link to comment
Share on other sites

Rims rated for these tires are available or they would never sell these tires. No, I've never owned a trailer with 14" or 15" tires. I' much rather have "overkill" tires than tires loaded to maximum continually. I posted the link for informational purposes only. 15" rims are available with bolt patterns for 14" hubs too.

Link to comment
Share on other sites

Maybe, but why would they use a code from the "Directory of National Origin Names & Country Codes" that "is to be used as a reference by Local Educational Agencies (LEAs) and private schools when conducting counts of eligible immigrant students as required by Title III of the No Child Left Behind Act and reporting these data to the California Department of Education (CDE) via the Student National Origin Report (SNOR)." when there is a specific list for tires maintained by the US DOT? If you look at the list that you linked to there is no DE, yet that is one of the abbreviations used by Tire Rack?

OK, Try this one. Germany is still DE.

 

http://www.1728.org/countries.htm

 

FastEagle

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Guest
This topic is now closed to further replies.
RVers Online University

campgroundviews.com

Our program provides accurate individual wheel weights for your RV, toad, and tow vehicle, and will help you trim the pounds if you need to.

Dish For My RV.

RV Cable Grip

RV Cable Grip

All the water you need...No matter where you go

Country Thunder Iowa

Nomad Internet

Rv Share

RV Air.

Find out more or sign up for Escapees RV'ers Bootcamp.

Advertise your product or service here.

The Rvers- Now Streaming

RVTravel.com Logo



×
×
  • Create New...