Tire Size?

[rcb]

Ladies and Gentleman,

I have a keystone Passport with a tire size of 205/75R 14C with factory wheels and tires (currently). I am like everyone else on earth and getting rid of the "bombs".

I am keeping the factory wheels and upgrading the tires. Should I stick to this factory tire size or do I have room to get a larger tire. And If I can get a bigger tire what is the advantage of doing so?

Thanks

[JRTJH]

Here is what you have and what you can get if you stay with your current wheels:

205/75R14 LRC @ 50 PSI max 1760 pounds x 4 = 7040 max tire capacity
205/75R14 LRD @ 65 PSI max 2040 pounds x 4 = 8160 max tire capacity

So you can install load range D tires in the same size and increase your capacity by 1120 pounds.

WalMart has Carlisle Radial Trail HD tires in that size for $50 each. They are currently out of stock on the WalMart website, so when they are back in stock, they should be a relatively current manufacture date.
https://www.walmart.com/ip/Carlisle-Radial-Trail-HD-Trailer-Tire-ST205-75R14-D-8/189531797

[sourdough]

You don't give the size of your trailer but running 14s I'm assuming it's not a big trailer. Given that, I would go with the LRD upgrade in the same size. Much less expense than new wheels etc., less problematic (actually easy) and accomplishes what you're after.

Note: and I do recommend the Carlisle Radial HDs. That's what I put on in 2016 and have been very pleased.

[Tbos]

I kept my stock wheels and upgraded the load range on original size Carlisle tires.


2016 Passport GT 2810BHS, 2016 F350 CC DRW

[rcb]

Thanks for the advise. It is a 29ft TT that weights around 5500lbs dry.

[CWtheMan]

When increasing load capacity with the same designated tire size (ST205/75R14) from LRC - LRD there isn’t a warranty problem, they both use the same load inflation chart and provide the same load capacity at 50 PSI. However, there are a couple of safety checks you should confirm. One is the load capacity and PSI limits of the current wheels. The PSI is the primary concern because you’ll have to use inflation pressures above the 50 PSI limit of the LRC tires if you want to gain some desirable load capacity reserves from the LRD tires. . Sometimes the wheel/tire assembly provider will put the assembly together using the trailer manufacturer’s recommendations. That means a minimum PSI (50) valve stem may have been used and will have to be upgraded. Steel bolt-in valve stems are recommended for trailer wheels and they are very desirable if you want to add a Tire Pressure Monitoring system.

[kinggartk]

When increasing load capacity with the same designated tire size (ST205/75R14) from LRC - LRD there isn’t a warranty problem, they both use the same load inflation chart and provide the same load capacity at 50 PSI. However, there are a couple of safety checks you should confirm. One is the load capacity and PSI limits of the current wheels. The PSI is the primary concern because you’ll have to use inflation pressures above the 50 PSI limit of the LRC tires if you want to gain some desirable load capacity reserves from the LRD tires. . Sometimes the wheel/tire assembly provider will put the assembly together using the trailer manufacturer’s recommendations. That means a minimum PSI (50) valve stem may have been used and will have to be upgraded. Steel bolt-in valve stems are recommended for trailer wheels and they are very desirable if you want to add a Tire Pressure Monitoring system.

How do you determine the "load capacity and PSI limits of the current wheels"?

[JRTJH]

How do you determine the "load capacity and PSI limits of the current wheels"?

It's stamped on the reverse side of the wheel (typically on the spoke) or is stamped inside the wheel, in which case you'd need to remove the tire to see the rating stamp. Here's one example

[sourdough]

My wheels did not have the psi rating, just the weight rating which you can correlate back to the psi rating. They had the E rated weight stamped (28??) at 80 psi vs the 2540/65psi of the OEM tires.

[CWtheMan]

It's stamped on the reverse side of the wheel (typically on the spoke) or is stamped inside the wheel, in which case you'd need to remove the tire to see the rating stamp. Here's one example

IMO, those pictures confirm that the wheel is manufactured in two configurations. One is for four lug mounting and provides 2540# of load capacity with a maximum recommended PSI pressure of 65 PSI. The other configuration is for 5 lug mounting and provides 2830# of load capacity with a recommended maximum PSI pressure of 80 PSI.

NOTE: When increasing a tire's load capacity by increasing its PSI, one must insure the valve stem is certified for the higher PSI.

[JRTJH]

IMO, those pictures confirm that the wheel is manufactured in two configurations. One is for four lug mounting and provides 2540# of load capacity with a maximum recommended PSI pressure of 65 PSI. The other configuration is for 5 lug mounting and provides 2830# of load capacity with a recommended maximum PSI pressure of 80 PSI.

NOTE: When increasing a tire's load capacity by increasing its PSI, one must insure the valve stem is certified for the higher PSI.

No, actually, one is for 5 lug and one is for 6 lug (not 4/5 lug configurations). The weight rating is based on the number of lug holes drilled in the casting. Six lugs will "hold more weight when attached to the hub" on the casting than 5 lugs, hence the higher rating. As for pressure, it's my understanding that there is no difference in PSI rating on either assembly, the higher pressure rating applies to all variations of the wheel when placed in production.

ADDED: You are correct, many valve stems used in passenger tire applications are only rated to 60 or 65 PSI and typically are not suitable for any D/E trailer tire applications. Heavy duty valve stems should always be used on all travel trailer applications. Metal valve stems are preferable to rubber or rubber coated stems for anything rated heavier than load range C. And, I'd suggest using HD valve stems even on them.

[CWtheMan]

No, actually, one is for 5 lug and one is for 6 lug (not 4/5 lug configurations). The weight rating is based on the number of lug holes drilled in the casting. Six lugs will "hold more weight when attached to the hub" on the casting than 5 lugs, hence the higher rating. As for pressure, it's my understanding that there is no difference in PSI rating on either assembly, the higher pressure rating applies to all variations of the wheel when placed in production.

ADDED: You are correct, many valve stems used in passenger tire applications are only rated to 60 or 65 PSI and typically are not suitable for any D/E trailer tire applications. Heavy duty valve stems should always be used on all travel trailer applications. Metal valve stems are preferable to rubber or rubber coated stems for anything rated heavier than load range C. And, I'd suggest using HD valve stems even on them.

Yup, I got the lug numbers wrong, sorry.

The PSI rating being displayed on the actual wheel, IMO, is a limiting factor for the fitment. Wheel specifications are certified by the Society of Automotive Engineers (SAE), so whatever is on the wheel would be part of their specs for that wheel configuration.

The U.S. Tire Manufacturer's association standards say, "do not exceed" a wheel's recommended maximum inflation pressure or its load capacity.

Referenced here on page #37 under NOTE.

https://www.ustires.org/sites/default/files/CareAndService_PassengerAndLightTruckTires.pdf