Forum Discussion

DesertTracker's avatar
Jul 23, 2016

Changing From 14" to 15" Tires and Rims

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.

15 Replies

  • 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?
  • 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.
  • 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.
  • 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.
  • 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.