In order to add a weight capacity reserve on my tires I am thinking of going from ST205/75r14C to ST205/75r15D. Lots of capacity reserve gained with this change. It seems simple enough; all size specs are the same except diameter is +1" so I will lose 1" between the tandems and 1/2" clearance from top of tires to fender wells. I have the needed clearance. Before I spend all those dollars at Discount Tire Direct for the wheel and tire upgrade I thought I had better check: is there anything else I need to consider? Thanks for any advice and help.

I have done excactly as you are proposing..My only suggetion is to not stop at 15s. Go all the way to 16s. That is where I eventually ended up. 6s gives you the best possible selection of QUALITY tires.You will of course need 16" rims. They are normally 6 lugs, so 6 lug drums will be needed. They are suprisingly affordable. they come with new bearings, so if you do it at bearing repaking time, it makes it much easier labor wise... No need to clean all the old parts, just lube up the new stuff and install.So in a nutshell... going from 14s to 15s is good.. but the tire selection isn't a ton better.16s is nirvana. That size is used on millons of pickups, so the market is huge. The tire manufacturers have responded with MANY choices.

Many Trailmanor owners went from 14's to 15's but it required a 2 and 1/2 inch lift kit which was available from the factory. These are mostly single axle trailers.

Every trailer(rv and non rv trailer) I've ever bought that came with 13"/14" tires I sold them and went with a 15" wheel and LT tires. That move put me away from ST tire issues and a much longer tire life at any speed. A LT215/75-15 D at 65 psi and a 2095 lb load rating will give you around 20 percent reserve above your OEM tires. Good upgrade if you have the room. Those taller 15" tires will ride easier over RR tracks/potholes/etc than a smaller 14" diameter tire.

JIMNLIN wrote:Every trailer(rv and non rv trailer) I've ever bought that came with 13"/14" tires I sold them and went with a 15" wheel and LT tires. That move put me away from ST tire issues and a much longer tire life at any speed. A LT215/75-15 D at 65 psi and a 2095 lb load rating will give you around 20 percent reserve above your OEM tires. Good upgrade if you have the room. Those taller 15" tires will ride easier over RR tracks/potholes/etc than a smaller 14" diameter tire.Did the same thing. When you decide on tires, check the recommended rim width before buying wheels. For example, the LT215/75-15 size mentioned above, should have 6" wide wheels.Love my made in USA Goodyear Wrangler HT's.

There would be no room in my wheel well for a bigger tire. You can see where the tire rubs the wheel well when the suspension bottoms out with the factory tires.Double check your clearance. More tire capacity does nothing for your axle rating or the gross TT capacity.How much over axle capacity is enough?

Changing From 14" to 15" Tires and Rims | Good Sam Community

15 Replies

coolbreeze01
Explorer
Jul 24, 2016
In 14", I would also look at this new Carlisle HD
MitchF150
Explorer III
Jul 24, 2016
Check out etrailer.com. They have wheel/tire combos in your size, but load range D.. That's #2040 max load per tire.

I have 13" tires on my trailer and the OEM tires were only LR B tires... I moved up to D tires in the same size and love the extra capacity, so no real worries..

Yes, they are "Made in China" tires... But, the only flat I've had in 14 years was with the original B rated Goodyear Marathon tires when it was brand new..

Anyway, upping the load range does not raise your sticker ratings, but it does raise the reliability of the tires IMO..

Good luck!

Mitch
Tom_Trostel
Explorer
Jul 24, 2016
Per Tire Rack specs, a Goodyear Marathon 215/75R 14 has a load rating of 1870 lbs. and a diameter of 26.7" A Kumho 857 205R14C has a load rating of 2271 lbs. and a diameter of 27". That is a 401 lb. difference.
braindead0
Explorer
Jul 24, 2016
Another option if you have a little space, you can get 215/75 R14. In a Goodyear Marathon it gives you 90# more load carrying per tire. Not much, but a bit more.
DesertTracker
Explorer
Jul 24, 2016
Thanks for the replies and advice. As I started looking at tire sizes and clearance, I ran across an article on etrailer that mentions 3" is minimum clearance at the wheel well and I am at 2.8" with the 14" tires so without a lift, bigger tires are out. I thought the extra half inch was no big deal, but it would just cut too close. I've seen the axle flip method of lift, and while cheap and well within my capabilities, 4 or 5 inches is WAY more lift than I need or want. I did find an affordable alignment kit that raises the trailer two inches (link at bottom)which is the amount of lift I want, but my tires wear evenly now and I hate to mess with an alignment kit. Not sure what to do at this point, but I need tires soon, so I need to make a decision.

http://www.pplmotorhomes.com/parts/rv-wheel-covers/axle-alignment-kits.htm
patperry2766
Explorer II
Jul 23, 2016
Kuhmo Radial 857

I have a set of the 205's for the last three years and I have been more than happy. Trailer tracks better and less sway from crosswinds.

I didn't have an option to switch to a larger size.
Lynnmor
Explorer
Jul 23, 2016
Coffee Grinder wrote:
What is difference between ST & LT

Google: "China bomb tires" and read. Come back next month with a report.
Coffee_Grinder
Explorer
Jul 23, 2016
What is difference between ST & LT
JIMNLIN
Explorer III
Jul 23, 2016
Not much left in a 15" LT tires anymore. When all 1/2 ton truck used 15" size wheels we had all size and load ranges of P and LT tires up to a D to choose from. Now 1/2 ton trucks come OEM with 17"/18" and 20" wheels.

Depending on room in the wheel well and proper wheel pressure/wheel width requirements the Goodyear Wrangler HT in a LT235/75-15 C (50 psi) at 1980 lb capacity. Most LT tire makers carry this size.

And a Wrangler HT in a LT215/75-15 D (65 psi) at 2090 lbs capacity.

Maxxis LT U-168 are a commercial grade tire with several 15" sizes and have became popular with all types of trailer owners.

Vanco 2 from Continental another popular tire for trailer users has several 15" sizes and load capacities.

I see the Yokohama RY215 in a 700R 15 D at 2040 lbs capacity is popular on some of the other RV websites.

Goodyear Cargo G26 2249 lb capacity in a 225/70R 15 C 65 psi load range D for trucks/vans and trailers.

Do your home work on the numbers.

rbpru brings up a very good point about a trailer unlike the tow vehicle can have too much tire capacity.
Murphsmom
Explorer
Jul 23, 2016
JIMNLIN wrote:
Every trailer(rv and non rv trailer) I've ever bought that came with 13"/14" tires I sold them and went with a 15" wheel and LT tires. .

What brand(s) of tires come in 15" LT? We were looking to upgrade ours, but only seem to be able to find 16" LT tires.