Going from a 205 to. 225 tire

[Crambo]

I was fixing to order some new load range D tires the other day to replace the cheap load range C that came on the trailer. I just happened to stop by storage and I am glad I did before ordering tires. I was thinking I had 225 tires but they are 205. Now I am trying to decide if I should stay 205 or move up to 225. My wheels are lions head steel but I really don't know the width and it is a pain to take one to a dealer to pull a tire and check. It looks like I have the room to run a 225 but the rim width makes me wonder. is there even a need for me to go with a 225 on a 30 foot Coachmen Catalina that weighs in at around 6000 lbs dry?

[bobndot]

rbpru wrote:
My "C" rated OEM TT tires at 50 lbs. and my "P" rated TV tires at 40 lbs. work just fine.

My hope is the 65 lbs "D" rating will provide a bit more durability without jarring the TT interior.

TT axles are rated to 3500 lbs. nothing I do to the tires will change that.

That was my thought too. Having too hard a ride. We need to be careful adding too much rubber. These TT don't need any more help to rattle things loose. 🙂

.

My TT has two 3500# axles too and a 6500# GVWR .
my 205/75/15 C's (6 ply) have an 1820# x4 rating ....which is a little more than my axles.
In my case , now I see no point in upgrading the tires size or ply other than going to a more reliable brand .

I plan to weigh the TT to see how the weight is distributed over both axles, which I think is very important. There is no point in stressing one of the axles and 2 tires.
Im trying to get it as equal as possible, through loading it as well as hitching it. I will weigh each axle hitched up and NOT hitched up.

If anyone has handling issues or is having recurring tire issues (especially on one of the axles)and can't get an equal load over both axles by proper loading and correct hitch adjustments, it is possible for an RV shop to reposition an axle for you.

[gmw_photos]

rbpru wrote:
My concern was that the tire was going to require 80 psi for a "D" rating. But the tire spec said "C" @ 50 psi and "D" @ 65 psi.

As far as the rim is concerned, I as more concerned about the valve but they use the same valve for both applications. I suspect it is the same with the rim.

Correct, load range C is 50 psi, LR D is 65 psi, and LR E is 80psi. I went from LR C to LR D and changed the valve stems to the "snap in valves for high pressure". Also had the wheels/tires balanced.
Here is a little reading on valve stems:

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=208

[rbpru]

My "C" rated OEM TT tires at 50 lbs. and my "P" rated TV tires at 40 lbs. work just fine.

My hope is the 65 lbs "D" rating will provide a bit more durability without jarring the TT interior.

The TT axles are rated to 3500 lbs. nothing I do to the tires will change that.

[time2roll]

rbpru wrote:
My concern was that the tire was going to require 80 psi for a "D" rating. But the tire spec said "C" @ 50 psi and "D" @ 65 psi.

As far as the rim is concerned, I as more concerned about the valve but they use the same valve for both applications. I suspect it is the same with the rim.

Nothing wrong with getting 80psi snap in high pressure stems.

[wrenchbender]

I use 225 E rated tires on all trailers.

[Lynnmor]

All of the Dexstar brand 15" steel wheels are rated for 80 PSI. My guess is that would be the industry standard, but it would be best to verify if you have another brand.

[bobndot]

I really don't know about these ratings but etrailer has info regarding rim/wheel psi. Yes, as suggested ....watch the valve stems.

https://www.etrailer.com/question-48956.html

the following was copied from tirerack.



Special Trailer (ST) Tire Speed Ratings

Industry standards dictate tires with the ST designation are speed rated to 65 MPH (104 km/h) under normal inflation and load conditions.

However Goodyear Marathon and Power King Towmax STR tires featuring the ST size designation may be used at speeds between 66 and 75 mph (106 and 121 km/h) by increasing their cold inflation pressure by 10 psi (69 kPa) above the recommended pressure for the rated maximum load.

Do not exceed the wheel's maximum rated pressure. If the maximum pressure for the wheel prohibits the increase of air pressure, then maximum speed must be restricted to 65 mph (104 km/h).

The cold inflation pressure must not exceed 10 psi (69 kPa) beyond the inflation specified for the maximum load of the tire.

Increasing the inflation pressure by 10 psi (69 kPa) does not provide any additional load carrying capacity.


Related Links
Trailer Tires >

[Crambo]

I had contacted Lionshead a few weeks ago and asked about the pressure rating of the rim and the lady acted like I was crazy. She said the rim did not have a pressure rating, only the tires. I would keep my weight the same, it just feels like the Load range D tires would firm up the ride some. The C rated tires are like rolling on balloons and are squirmy with 50 psi. I can tell that they are very marginal for the trailer.

[rbpru]

My concern was that the tire was going to require 80 psi for a "D" rating. But the tire spec said "C" @ 50 psi and "D" @ 65 psi.

As far as the rim is concerned, I as more concerned about the valve but they use the same valve for both applications. I suspect it is the same with the rim.

[bobndot]

JIMNLIN wrote:

bobndot wrote:
If the OEM 205's C's are on stock rim, it might be rated for 50# tire.
205 D = 65# .

Can a 65# tire be used on a 50# rated rim ? Just asking .

NO.
Tire and wheel mfg don't recommend it if your using 65 psi.

Having split trailer wheels on my flat decks in my younger dumber days when I ignored my tire dealer and mounted a 80 psi rated tire on steel wheels with a 60 psi rating...they split around the bead seat flange after airing to 80 psi and loading the trailer.
What happens is after the tires heat at highway speeds the 80 psi in the tire can go to 90 + psi.



Now you can use a 65 at 50 psi on a 50 psi rated wheel but you lost the benefit oif the D tire. The D tire needs to match the wheels width properly for best long term performance.
The benefit of a D tire comes only at those higher pressures.

Maybe I missed it but are you using 14" or 15" tire diameter ??

Thank you ,
I am running 205x15" . I Plan to get on a scale in the spring and weigh it all properly. As of now I don't have any issue running my OEM tires, im just looking down the road to upgrade a little for piece of mind. My TT is light, no slide, alum skin and not loaded up with stuff we never use. It only took us 40 yrs. to learn that. 🙂

[bobndot]

smkettner wrote:

bobndot wrote:
If the OEM 205's C's are on stock rim, it might be rated for 50# tire.
205 D = 65# .

Can a 65# tire be used on a 50# rated rim ? Just asking .

Is the wheel actually stamped with 50 psi max?
If not I would have no worry about going to 65 on a steel wheel.

Tnx . I will pull the tires before I order anything.

[time2roll]

bobndot wrote:
If the OEM 205's C's are on stock rim, it might be rated for 50# tire.
205 D = 65# .

Can a 65# tire be used on a 50# rated rim ? Just asking .

Is the wheel actually stamped with 50 psi max?
If not I would have no worry about going to 65 on a steel wheel.

[rbpru]

Keep in mind you cannot increase the payload of the TT buy increasing the tire rating, the axles, bearing and brakes have a finite design limit.

Tires are a consumable product, so it is assumed that operating below their rated load will extend their usable life. However, punctures, sidewall cuts and manufacturing errors play no favorites when it comes to tire cost or brand.

[JIMNLIN]

bobndot wrote:
If the OEM 205's C's are on stock rim, it might be rated for 50# tire.
205 D = 65# .

Can a 65# tire be used on a 50# rated rim ? Just asking .

NO.
Tire and wheel mfg don't recommend it if your using 65 psi.

Having split trailer wheels on my flat decks in my younger dumber days when I ignored my tire dealer and mounted a 80 psi rated tire on steel wheels with a 60 psi rating...they split around the bead seat flange after airing to 80 psi and loading the trailer.
What happens is after the tires heat at highway speeds the 80 psi in the tire can go to 90 + psi.

Now you can use a 65 at 50 psi on a 50 psi rated wheel but you lost the benefit oif the D tire. The D tire needs to match the wheels width properly for best long term performance.
The benefit of a D tire comes only at those higher pressures.

Maybe I missed it but are you using 14" or 15" tire diameter ??