replacing my 2015 ST 235/75R15 tires . . .

[gw1800]

I don't understand the reason for off road tires with a aggressive tread on a travel trailer.
The tires are not being driven, only following the tow vehicle. Sounds like advertising hype to make you think these tires will do better off road.

The difference in height between the 235 and 225 is only about a 1/2 inch total. The width is about the same.
As far a air pressure, you not have to inflate them to the max. The tire pressure depends on the load on the tire. You can inflate the load range E tires to the same pressure as the originals. The biggest thing to look for is the max pressure the wheel can handle. It's marked on the rim.

I put load range E tires on my pickup and never run them at 80lbs.

[Bogieboy]

Originally Posted by Airdale

Ask the manufacturer before purchase if they offer options. If not, you'll have to violate safety standards to use another designated size.

you may want to read into it a bit more, https://www.rvtiresafety.net/2018/08...n-your-rv.html

i know that is one persons opinion, but common sense would say that you don't have to use the exact same size tire as long as you meet the load capacity, which RVIA states should be roughly 110% of the axle rating... if it meets the load capacity, who cares what size the tire is? do you think everyone that puts aftermarket tires and rims on a vehicle is violating a safety standard? if so, that is absurd. if it meets the load capacities of the vehicle it will be fine.

[NavyLCDR]

Originally Posted by Airdale

Ask the manufacturer before purchase if they offer options. If not, you'll have to violate safety standards to use another designated size.

I must respectfully disagree. The substitute tire can still meet all safety standards even if not designated by the manufacturer. All that it means is that the manufacturer has not evaluated it, it does not mean the standards are not being met.

[gw1800]

Originally Posted by Bogieboy

you may want to read into it a bit more, https://www.rvtiresafety.net/2018/08...n-your-rv.html

i know that is one persons opinion, but common sense would say that you don't have to use the exact same size tire as long as you meet the load capacity, which RVIA states should be roughly 110% of the axle rating... if it meets the load capacity, who cares what size the tire is? do you think everyone that puts aftermarket tires and rims on a vehicle is violating a safety standard? if so, that is absurd. if it meets the load capacities of the vehicle it will be fine.

You say to choose a tire rated at 110% of the axle rating. I have 4400,b axles on my toy hauler. There is no such a thing as a tire with 4400lb load rating.

[AZ Pete]

a pair of tires do...

[gw1800]

Originally Posted by AZ Pete

a pair of tires do...

Not what the post says.



"same size tire as long as you meet the load capacity, which RVIA states should be roughly 110% of the axle rating."

[RedLdr1]

Originally Posted by VR51

My RPod also has 235/75/15 tires (mine are Westlake’s). I called a very reputable local tire shop and was told -

1. Westlake tires are a good brand (I was very concerned that they were ‘China bombs’, but was assured they are fine - not as good as Endurance but still good)
2. A 225 tire is 1 one inch less diameter than the stock 235’s.

Would a tire that’s just 1 inch shorter total make any meaningful difference? Personally I’d rather go to a best quality tire like the Goodyear’s than stick with a slightly taller tire that has a tread pattern that’s far more aggressive than necessary and is lesser quality.

The Eastern region version of your RP-171, the non-Hood River Edition, should have come with ST225/75R15D tires as standard equipment. Most of us upgrade to the Endurance ST225/75R15E tires to get rid of the China bombs the Eastern region installs.

You may lose an inch in height, and some ground clearance, but you'll pick up E load range tires in the process.

If you have any concerns contact R-Pod Service for their advice. I'd also ask what the recommended PSI is for the Eastern version tires so you have a starting point for the Endurance tires. You can reach them at:
Katlyn Mabie
(574) 642-3119
kmabie@forestriverinc.com

[Bogieboy]

Originally Posted by gw1800

You say to choose a tire rated at 110% of the axle rating. I have 4400,b axles on my toy hauler. There is no such a thing as a tire with 4400lb load rating.

Show me a trailer with a single tire on an axle and i might just humor your ignorance....

[Larry-NC]

Originally Posted by RedLdr1

The Eastern region version of your RP-171, the non-Hood River Edition, should have come with ST225/75R15D tires as standard equipment. Most of us upgrade to the Endurance ST225/75R15E tires to get rid of the China bombs the Eastern region installs.

You may lose an inch in height, and some ground clearance, but you'll pick up E load range tires in the process.

If you have any concerns contact R-Pod Service for their advice. I'd also ask what the recommended PSI is for the Eastern version tires so you have a starting point for the Endurance tires. You can reach them at:
Katlyn Mabie
(574) 642-3119
kmabie@forestriverinc.com

No, no. It's only 1/2".

One inch less in diameter corresponds to 1/2" less in radius--the distance the axle center is from the ground. The 1/2" greater clearance at the top is irrelevant.

[gw1800]

The st225 are 28.3 outer diameter, and 8.9 wide
The st235 is 28.9 outer diameter and 9.3 inches wide.

.6 inch difference in total diameter. which means .3 inch difference in ride height. 1/2 the total diameter of the tire.

[AZ Pete]

Originally Posted by gw1800

Not what the post says.



"same size tire as long as you meet the load capacity, which RVIA states should be roughly 110% of the axle rating."

no trailer axle rides on a single tire...

[NavyLCDR]

Originally Posted by AZ Pete

no trailer axle rides on a single tire...

I must respectfully disagree.....

Again, though, as I stated early - the disappearance of common sense from today's society is truly frightening.

[AZ Pete]

as you hav just demonstrated with the photo.....we were talking travel trailers.

[NavyLCDR]

Originally Posted by AZ Pete

as you hav just demonstrated with the photo.....we were talking travel trailers.

I should have clarified. My common sense remark was in regards to trailer tires needing to be rated for 110% of the axle. Note: tires plural. Of course if the axle has two tires - one on each side, the combined rating of the two tires should not be less than 110% of the axle because we are talking about the weight the axle and both the tires attached to it can handle. Saying that a single tire must be rated for 110% of the axle capacity limit does not pass the common sense check.

[Airdale]

Originally Posted by NavyLCDR

I must respectfully disagree. The substitute tire can still meet all safety standards even if not designated by the manufacturer. All that it means is that the manufacturer has not evaluated it, it does not mean the standards are not being met.

Highway safety decisions are set by established regulations and tire industry standards. Consumers responsibilities are to follow safety standards. If everyone went out and set their own standards, traffic safety of all kinds would wane.

Dissemination of federal rules and regulations requires linking all that pertain to a subject into a final decision. Vehicle certification holds the answer to tire selections for your RV or RV trailer. Vehicle manufacturers were told by regulations to install Original Equipment tires and set a recommended cold inflation pressure for them that is appropriate for that vehicle.

Consumers are supposed to or are expected to abide vehicle certification standards. Part of the tire selection process includes a selection of the proper designated tire size to be used. Designated tire sizes include the prefix. It can be ST, LT or P. If a deviation is not offered by the vehicle manufacturer, the OE tire size is the minimum standard.

Industry wide replacement tire standards can be very similar to the following statement: Replacement tires should be the same size as the OE tire size. Never use smaller tires or tires that cannot provide a load capacity equal to or greater than what is provided by the OE tires at their recommended inflation pressures. Deviation sizes/optional sizes must be recommended by the vehicle manufacturer to become acceptable.

Federal regulations that are in effect at the time of vehicle certification may provide tire information not commonly acted upon but because the regulation is senior is statute it must be included/considered.

All of that information is in my words. I've been studying tire regulations and tire industry standards for more than 15 years. The vast majority in this message comes from FMVSS standards, CFR 49 part 567 vehicle certification, CFR 570 and USTMA industry standards manuals.

[Bogieboy]

Originally Posted by Airdale

...
Industry wide replacement tire standards can be very similar to the following statement: Replacement tires should be the same size as the OE tire size. Never use smaller tires or tires that cannot provide a load capacity equal to or greater than what is provided by the OE tires at their recommended inflation pressures. Deviation sizes/optional sizes must be recommended by the vehicle manufacturer to become acceptable.

...

the way a person correctly trained in english would extrapolate this phrase about the tire size would be that if you cannot (or would not like to) use the original size tire, one that is smaller, but meets or exceeds the load capacity may be used in it's place. we have also already established that the same trailer has used smaller tires from the manufacturer in 2 separate posts, yet you continue to argue? common sense must truly be dead.

[NJKris]

Originally Posted by gw1800

I don't understand the reason for off road tires with a aggressive tread on a travel trailer.
The tires are not being driven, only following the tow vehicle. Sounds like advertising hype to make you think these tires will do better off road.

The difference in height between the 235 and 225 is only about a 1/2 inch total. The width is about the same.
As far a air pressure, you not have to inflate them to the max. The tire pressure depends on the load on the tire. You can inflate the load range E tires to the same pressure as the originals. The biggest thing to look for is the max pressure the wheel can handle. It's marked on the rim.

I put load range E tires on my pickup and never run them at 80lbs.

I never pulled 'off road', but due to a knocked down sign warning 'no trailers', I drove up and down a mountain road that turned to mostly dirt with some gravel. It was harrowing, and I had to go really slow. Truck had to be switched into 4x4 as rear wheels kept slipping. I believe the aggressive tread helped with side slip and slowing the trailer's wheels while braking going down the steep road with sharps curves.

[D W]

Gosh, if only our tires got as much mileage as these "tire threads"...

[NJKris]

Or if our batteries lasted as long as THOSE threads!

[Airdale]

Originally Posted by Bogieboy

the way a person correctly trained in english would extrapolate this phrase about the tire size would be that if you cannot (or would not like to) use the original size tire, one that is smaller, but meets or exceeds the load capacity may be used in it's place. we have also already established that the same trailer has used smaller tires from the manufacturer in 2 separate posts, yet you continue to argue? common sense must truly be dead.

Okay, here is a verbatim quote from USTMA: "Replacement tires should be the same as the OE size designation, or approved options, as recommended by the vehicle or tire manufacturer. Never choose a replacement tire of a smaller size or with less load-carrying capacity than the OE tire size at the specified vehicle tire placard pressure."

Government regulations and tire industry standards are specific and to the point. They give direction, not maybe directions.