Trailer rocks when towing over uneven road surface- time for new springs or?

[Bob Miller]

I have ST175/80R13, Load Range "C" tires on my Hunter.
Look at the max pressure indicated on the sidewall. 50 PSI will indicate that it is a load range "C" tire. The ST indicates that it is a trailer tire.

[Bob in Mb]

The fact that the tire has contacted the wheel well indicates a suspension problem . It is obvious that you need tires as well . The tires should be inflated to the recomended pressure as to tire size and weight of trailer .
There should be a label , usually inside a closet or cupboard door , that lists the tire size and proper inflation . There is also a chart on the net if you google 'tire pressure chart' . As an example my Surf-Side tire pressure is 20 lbs. both on the label and on the internet chart . I run at 25 lbs to account for contents of the trailer. The trailer rides great and tire wear is even . Inflating to the maximum pressure would cause all kinds of trouble.

[Civilguy]

Originally Posted by Cathie Sadler-Pare

The 3 digit code says it was made in a decade in the 1900's that ends in a 4. So 1994, or 1984 . They say there is a triangle with the code if it was the 90's. Arrrgh... I am afraid to pump the tires to the 55 psi.

I had to search for a familiar size, i'd never heard of B80-13.

Cathie,

It looks like you read the Edmunds article or similar on the dangers of old tires, investigated, and found something important, which is great news!

I grew up with "Alpha" tire sizes such as B78, G78 etc. in the 1970's. The higher the letter, the wider the tire. The current system uses P-metric and euro-metric tire designations such as the ST175/80R13 that Bob mentions. So, suffice to say you had some really old tires.

Opinions vary on the pressure to maintain in your tires as noted in this and likely many other threads:

http://www.fiberglassrv.com/forums/f55/surf-side-tire-pressure-70771.html

I am relatively new to towing and am on a learning curve. Personally, I am currently maintaining pressure at 10 lbs above the "load-rated" pressure Goodyear cites in the below-link. In my case this is 40 + 10 = 50 pounds, which also happens to be the maximum pressure for my ST205/75R15 Marathons.

http://www.goodyearrvtires.com/pdfs/tire-care-guide.pdf

One reason for the shift in my approach since the July thread is that my tires will likely "age out" before tread wear ever becomes an issue. I also reason that the additional pressure should increase stiffness, reduce sway, and allow for higher-than-expected loading.

In any event replacing all three tires with fresh, new ST (= Special Trailer = stiffer sidewall) tires will be a critical step here.

http://www.tirerack.com/tires/tirete...jsp?techid=219

Finally, while it's great to say 'Eureka, I have found it!', please consider that there may be multiple issues and have the frame, suspension and bearings thoroughly checked out too.

After you have resolved these critical safety issues, you can then apply some attention to the almost-equally-critical issue of how to arrive with proper coffee gear.

[Bob Miller]

Tire pressure/size recommendation labels inside any trailer more than 10 years old are reflective of the tires available when it was made, and often do not reflect current tire designs or pressure/load requirements.


The commonly used ST175/80R13 tire size found on many Scamps, Surfsides, Hunters etc didn't even exist when many of these trailers were new.


For example, if you mounted a new ST175/80R13, load range "C" tire, which is rated at 1360 lbs capacity (cold) @ 50 PSI, and used a trailer manufacturers chart value of 20 PSI, you would be reducing tire capacity to 795 lbs, perhaps under the capacity needed for many 13' FGRV's. In addition, as there would be more sidewall flex, you will also increase tire heat generated.


I set my ST175/80R13's on my Hunter at exactly 50 PSI cold (per tire label) and it tracks like it is on rails for at least the past 8000 miles I have put on these tires in the past 6 months.


Here is a tire pressure vs load chart for ST tires
http://www.goodyearrvtires.com/pdfs/rv_inflation.pdf


For Bob in Mb: And, while over-inflation can lead to additional tire wear, I don't know of any creditable source that suggests that running ST tires on trailers at the maximum indicated tire pressure (cold) will lead to additional tire wear or "cause all kinds of trouble". Please explain....


While checking for loose suspension components on a used trailer is always a good idea, tire/wheel well contact in a Hunter can also be caused by incorrect tire size or excessive load.

[Cathie Sadler-Pare]

Wow Tires are a hot topic! I was shocked at the age of the existing tires. I do think the under inflation was a huge contributor to my unusual rocking. While the wheels are off will be the perfect time to check and replace original bearings, shackles and springs. I am lucky to have a neighbor who is well skilled as a mechanic, he just doesn't know I'll be consulting and hiring him ... Yet😄
So only driveway camping for me right now. It's so cold I'm almost considering reinstalling the duo therm heater that's sitting on the garage. Ok cold for so cal- not real winter.
When's the next gathering I need a goal to finish and meet y'all!
Bummed I missed lake casitas- next year.
Bee Happy

[Civilguy]

Originally Posted by Cathie Sadler-Pare

Wow Tires are a hot topic!

Yes, that's all well and fine, but the coffee Cathie, what about the coffee?

[alan H]

There is one in april /may near king city @ san lorenzo reg park
Email marianne dinsmore
Marianne.dinsmore@gmail.com
For details
We just made our 3 night resv for apr28 thru 30th
I m sure it is listed in forum under rallys
Hope to see you there


Sent from my iPhone using Fiberglass RV

[Cathie Sadler-Pare]

Originally Posted by Civilguy

Yes, that's all well and fine, but the coffee Cathie, what about the coffee?

That was the first problem that needed immediate! attention. Bought an old school percolater coffee pot. Not electric - If you take out the coffee insert it also works as a pot to boil water and to make hard boiled eggs. Nothing comes onboard that doesn't have more than one duty. Coffee being the beginning of All Things!

[Cathie Sadler-Pare]

The surf side tire pressure is 20 psi? The rating on the tires on my Hunter call for 50psi ! I am not going to even try to "blow them up" to the max pressure.

[Civilguy]

I have really got to get off this thread. The following link is from the Discount Tire web site.

http://www.discounttire.com/dtcs/inf...erTireFacts.do

I have found them to be a professional and well-informed outfit over the years. They sell well-known and high-end trailer tires including Goodyear Marathons, Carlisle, and Maxxis.

No. 1 in big red text on the left edge of the linked page is "Always inflate trailer tires to the maximum inflation indicated on the sidewall."

Additional to that, they have what I consider to be a pretty comprehensive list of recommendations including:


Trailer Tire Applications

• Trailer tires are designed for use on trailer axle positions only. They are not built to handle the loads applied to, or the traction required by, drive or steering axles.

Inflation

• Always inflate trailer tires to the maximum inflation indicated on the sidewall.
• Check inflation when the tires are cool and have not been exposed to the sun.
• If the tires are hot to the touch from operation, add three psi to the max inflation.
• Underinflation is the number one cause of trailer tire failure.

Load Carrying Capacity

• All tires must be identical in size for the tires to properly manage the weight of the trailer.
• The combined capacity of the tires must equal or exceed the Gross Vehicle Weight (GVW) of the axle.
• The combined capacity of all of the tires should exceed the loaded trailer weight by 20 percent.
• If the actual weight is not available, use the trailer GVW. If a tire fails on a tandem axle trailer, you should replace both tires on that side. The remaining tire is likely to have been subjected to excessive loading.
• If the tires are replaced with tires of larger diameter, the tongue height may need to be adjusted to maintain proper weight distribution.

Speed

• All "ST" tires have a maximum speed rating of 65 mph.
• As heat builds up, the tire's structure starts to disintegrate and weaken.
• The load carrying capacity gradually decreases as the heat and stresses generated by higher speed increases.

Time

• Time and the elements weaken a trailer tire.
• In approximately three years, roughly one-third of the tire's strength is gone.
• Three to five years is the projected life of a normal trailer tire.
• It is suggested that trailer tires be replaced after three to four years of service regardless of tread depth or tire appearance.

Mileage

• Trailer tires are not designed to wear out.
• The life of a trailer tire is limited by time and duty cycles.
• The mileage expectation of a trailer tire is 5,000 to 12,000 miles.

Why Use An "ST" Tire

• "ST" tires feature materials and construction to meet the higher load requirements and demands of trailering.
• The polyester cords are bigger than they would be for a comparable "P" or "LT" tire.
• The steel cords have a larger diameter and greater tensile strength to meet the additional load requirements.
• "ST" tire rubber compounds contain more chemicals to resist weather and ozone cracking.

Storage

• The ideal storage for trailer tires is in a cool, dark garage at maximum inflation.
• Use tire covers to protect the tires from direct sunlight.
• Use thin plywood sections between the tire and the pavement.
• For long term storage, put the trailer on blocks to take the weight off the tires. Then lower the air pressure and cover the tires to protect them from direct sunlight.

Maintenance

• Clean the tires using mild soap and water.
• Do not use tire-care products containing alcohol or petroleum distillates.
• Inspect the tires for any cuts, snags, bulges or punctures.
• Check the inflation before towing and again before the return trip.

Keys to Avoiding Trouble

• Make sure your rig is equipped with the proper tires.
• Maintain the tires meticulously.
• Replace trailer tires every three to five years, whether they look like they're worn out or not.

...must get off thread and on with life....

[Bob Miller]

Originally Posted by Cathie Sadler-Pare

The surf side tire pressure is 20 psi? The rating on the tires on my Hunter call for 50psi ! I am not going to even try to "blow them up" to the max pressure.

As I mentioned, I run the tires on my Hunter at 50 PSI

[Cathie Sadler-Pare]

Oh CivilGuy- where would I be without all the good info. I now know more about tires than any of my friends!


So last question for you and Bob. Now that the tires are off what do I look for to replace, repair and inspect before I put the new tires back on? And would you recommend taking the trailer to the tire store. I was planning on removing them at home.

[Civilguy]

Originally Posted by Cathie Sadler-Pare

Oh CivilGuy- where would I be without all the good info. I now know more about tires than any of my friends!

Be sure to note that the Goodyear and Discount Tire data don't always agree!

It's tough to say who is going to be a good resource for you here. Eventually someone needs to examine the whole assembled setup so they can evaluate why the tires might have been rubbing, etc. Tire folks are tire folks, and different ones may or may not fully appreciate or understand issues that are somewhat unique to trailers.

I don't know where you are located and what issues there might be in traveling with the trailer at present on those degraded skins. Maybe you could have the tires changed out, then tow it in for the suspension check.

Your neighbor might have some local perspective here.

Bob may have other ideas to suggest too. What with all this pesky search for the truth, I'm plumb tuckered out. Maybe it's time for some of that coffee!

[Bob Miller]

As far as the tire store, whatever is easiest for you. I Use Discount/America's Tire both in CA and in WA and they always take excellent care of us.


New valve stems are a must and, because the original rims are 40 y.o., I would opt for a new set of white spoke rims at the same time. Fairly cheep at D/A Tire. Of course, be sure that they are balanced.


On the trailer, pull both wheel hubs and take then to any garage to have the bearings cleaned, inspected and repacked w/new seals installed. If the shop indicates that there is any wear or discoloration from overheating, new bearings and new bearing races are the order of the day. Also check the axle spindle for any signs of damage or burn marks.


Other than that, not much

[Civilguy]

Originally Posted by Bob Miller

Other than that, not much

A hearty second to “what he said”.

Also, there was a problem with some of the rubber valve stems in recent history. They would degrade and crack. There was a potential for the tire to lose all its air in a rush, which could result in the trailer trying to take over and do all the steering for you. That and previous experiences lead some folks to only use metal valve stems. The PO or Casita put stainless steel ones on our wheels. Can't cost much more.

http://www.dillaircontrols.com/files...r%20Cracks.pdf

[WaltP]

Whew. No wonder we keep having discussions on tire pressure on all the forums. The sticker on my Bigfoot says 32psi, Goodyear says 40 psi, and Discount Tire says 50psi.
So that's three different recommendations from three "authoritative" sources. What's a poor trailer owner to do?
I have always run at 40psi, on the gut feeling that 32 will cause too much tread wear and 50 a too rough ride for the trailer and contents.

Perhaps more problematic with the Discount Tire recommendations is to limit tires to between 5,000 and 12,000 miles use. For many of us, even the upper figure would mean buying new tires more than once a year. Whew. Raise your hand if you do that. Or if you are willing to accept that. Not I.

Walt

[Bob Miller]

All three could be correct


The more important question is what tires did BigFoot have on the trailer when it was new. Passenger car tires have a standard pressure of 36 PSI, so 32 could be right for those tires, but very low for 6 ply rated "C" range tires.


. I run 50 psi on my 43 year old Hunter and have never seen anything fall apart.

[Civilguy]

Originally Posted by WaltP

Whew. No wonder we keep having discussions on tire pressure on all the forums. The sticker on my Bigfoot says 32psi, Goodyear says 40 psi, and Discount Tire says 50psi.

Walt,

The 40 psi I noted was based on the specific load and tire size for our Casita. In my case this is ST205/75R15 Marathons. The load is (2,600 + 600) / 2 = 1,550 lbs per tire. The nearest match on the table is 1,530 lbs at 40 psi. Your Bigfoot will probably calculate differently.

[Bob in Mb]

The max. pressure on my truck tires is 44 lb.
Ford recomended pressure is 30 lb.
I run at 30 lb.
I do not know why I would do differently on my trailer.

[tractors1]

Originally Posted by Bob in Mb

The max. pressure on my truck tires is 44 lb.
Ford recomended pressure is 30 lb.
I run at 30 lb.
I do not know why I would do differently on my trailer.

Trailers usually have a different suspension setup and ST tires have stiffer sidewalls for reducing sway effects.