Fifth wheel tires

Been looking to replace tires on my 3 axle fifth wheel. total load is 19,000 lbs. Have Michelin LT tires on now. 235/85r16 Load E 3046 lbs. Problem is this is the third set of tires and they all have weather cracked on side wall. Been looking for new tires, thought I could figure this out with a little research, well now I know nothing, LT tires, ST tires, E F G load. Rim widths, Brands that I have never heard off. Read all about the China bomb tires, well come to find out that most tires are made over seas. Need help to chose a new set of tires.

What axle? If you have 6K axles then the Michelins should be fine.  Michelin has had weather check issues in the past.  Firestone Transforce steel belted should be good .

OK, some basic points:

1. "China Bomb" is not the same as "made in a Chinese factory". China has some brands or factories with low quality standards, but they have quality production too. When an internationally known brand has tires made in a Chinese factory, they still meet the company's quality standards. There are many quality tires still made in the USA, and also in Korea, Japan, Europe, etc.

2. LT tires can carry less weight than an ST of the same size, but if you replace your LT tires with any brand of LT of the same size, the load rating will be about the same. The key question is whether the original tires had enough load capacity (max load rating) to carry your trailer safely and with some extra margin of safety.

3. Michelin tires are notorious for weather checking, tiny surface cracks. Disconcerting, but not necessarily dangerous. Other brands use different rubber compounds and not as likely to show surface cracks, but not necessarily ant better tire. I say this, even though I'm NOT a Micheline fan!


The trailer tires have to carry the max weight on the axles, which generally is 80% of the trailer GVWR on a 5W.  If 19,000 lbs is the trailer GVWR, than 80% =  15,200 lbs. Spread on 2 axles (4 tires) that is 3800 lbs/tires, WAY over the load rating for those 235/85R16's you have. If its a triple axle trailer (6 tires), than  it's OK. So first you need to determine what load the tires carry and what size or load range is adequate for the task.


Assuming the size an LT type is OK, there are plenty of quality brands in that size. Firestone and Goodrich (a Micheline subsidiary) make it, also Cooper (USA), Hankook (a top Korean mfgr). Yokohoma (Japan), and General (USA).

We have the Goodyear G614 RST, load range G tires on our fiver. I personally have never seen a better constructed tire. They probably have 30,000 miles on them and tread looks like new. They are expensive, but they are awesome.
Michelin tires are actually very good, but they don?t seem to tolerate exposure to ozone and UV rays very well though. It?s disappointing they haven?t addressed the problem after years of complaints about it. To be fair though, our camper stays in a climate controlled pole barn and the tires are not exposed to the elements.
I retired from the Michelin plant that makes most of the rubber for the tire plants in the US. They take quality very seriously, so I?m surprised they don?t seem to be addressing this tire cracking issue. Even if it isn?t a safety issue, nobody wants to pay for a premium tire with cracks in it and lesser priced tires don?t seem to have the problem. Can?t stay in business long without responding to consumer concerns. Way too much competition out there.

Good answers above.

How old are the tires?  Anything over 5 or 6 years need to be replaced regardless of mileage or remaining tread depth.

A 19,000 lb FW will carry about 20%, or 3800 lbs on the pin.  The remaining 15,200 lbs are spread over the 6 tires, or about 2530 lbs per tire.  The load is NEVER equal, so you want tires that will carry at least 3000 lb each.  Your current tires do this.

Load Range is a gross estimate of the tire load carrying capability, and correlate to  Ply Rating (how many layers of rubber are between the air and the tread) G rated will carry heavier loads than F rated, and will need higher tire pressure.  While you need to compare actual load capacity for any tire you are considering, since the current tires are LR E, the replacements will need to be LR E or higher.

ST tires are Special Tires for use on trailers.  They are not intended for use on cars or trucks.  LT tires are designed for use on Light Trucks.  P are designed for Passenger cars.

You could move to LT tires for the FW if you wish, but you will need to move up at least 1 or 2 letter levels to get the required load range, as Gary said.

Your current tires are 235/85R 16 E.  This means:  the TREAD is 235mm wide.    The PROFILE is 85, which means the distance from the rim to the tread is 85% of the tread width, or 200 mm high.  It is a R adial tire.  The rim diameter is 16 inches.  The Load Range is  E .  The rim is also a specific width, not shown, but is important for proper tire fit if you are changing size.  Rims also have a pressure rating, so a rim with LR E tires may not hold the extra pressure (95 psi) for a LR  F tire.

Bottom line.  Go to a TRUSTED  tire dealer and ask them for advise.  Stay with the same size of 235/85R 16 E or step up to 235/85R 16 F.
There are several good quality brands available.  Do not go with the cheapest, but you do not need the highest price ones, either.

Thanks for the information. One of my main concerns is should I stay with LT Tires Or switch to ST tires. The axles are 6000 lb. Have had LT Tires on fw wheel since it came from Newmar. Have never had a tire issue since new, have over 100,000 miles on trailer. Only problem has been the cracking of the side walls on of the tires. My tire dealers are telling me to switch to ST tires now. Not for sure if I need to or stay with LT tires. Michelin tires on fw are 3 years old.

ST tires as a general rule have a much lower speed rating, thus a higher load rating.  Like has been mentioned already Michelins are notorious for weather checking.  Also like has been mentioned ita no big deal.  I assume the axles have been checked, alignment checked, and weights are within the tire load rating.  So, your choices are going to a questionable ST tire thus lowering your max speed limit, or go to Firestone Transforce.  Which is a steel belt tire like the Michelin XPS Rib but at a lower cost.

At 3042 each, the LT 235's are barely adequate for a 6000 lb axle. However, you indicated no problems with yours so I'm guessing that are sufficient. You really should get the rig weighed to determine actual pin and combined axle loading, but your real life experience says it's fine. Therefore I see no reason to switch to ST tires. You would gain in weight capacity but lose highway speed capability cause the ST tires will be limited to 65 mph whereas the LT's are at least 77 mph. If I were you, I would stick with a top quality LT235/85R16.  Some candidates are the Goodyear G614, Hankook Dynapro, General Grabber, Goodrich T/A, Yokohoma Geolander, Cooper Discoverer HT3, etc.  I'd focus on a nationally known and available brands with a strong dealer network (just in case!).

Go with a load range G tire.  It's only a little more, and gives you peace of mind.

I have Sailuns.  A ST tire, speed rating 75 MPH.

Having always found Michelins to give me the best combination of ride, handling, and the only tires that ever approached their claimed useful miles, I'm a completely biased fan, based on my own experiences. That said, here's an interesting article from someone who knows a lot more than me.

https://www.quora.com/Why-are-Michelin-tires-considered-better-than-others-And-are-the-Michelin-tires-at-Costco-the-same-as-the-ones-at-a-regular-tire-shop

As Senator notes, there are a few ST tires that have a higher than 65 mph speed rating, though sometimes with caveats.  Maxxis is another brand that claims higher speeds in their STs.

The alphabet soup can be confusing, but there are simple numbers that make it easy. every tire has an actual weight carrying capacity stated on the sidewall, i.e. Max load xxxx lbs at yyy psi. If that number exceeds the weight that your trailer can put on the tire, it is sufficient.  You have 6000 lbs axles, so each tire could carry 3000 lbs assuming the weight is evenly distributed. It often is not, so batter to plan for 10% overage one one side or the other.  But if your actual loaded axle weights are under 6000 lbs, then the 3000 lbs/tire is sufficient. Given that you have a triple axle trailer, I'm confident your actual axle weights are substantially under 6000 each, so you have enough safety margin in the load capacity. I'd get it weighed to be sure, though.

The rest is about speed. 65 mph is simply too limiting  for most uses, so you want a tire rated for at least 75, even if you rarely drive that fast with the trailer. All LT tires will be at least that, but you can get a few ST models that are in that range as well.


You started out with the premise that weather-cracking has given you problems with the Michelins. If that's the reason you are changing tires that have otherwise served well, I suggest that you may be worrying over nothing but a cosmetic problem.  Tiny surface cracks are insignificant. Read what Michelin says about weather cracking in their RV Tire Guide. read or download at https://www.michelinrvtires.com/reference-materials/

Senator said:

Go with a load range G tire.  It's only a little more, and gives you peace of mind.

I have Sailuns.  A ST tire, speed rating 75 MPH.

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Make sure you understand the difference between steel-belted and all-steel radial.  From what I understand, the steel belted tires have a nylon (or similar) sidewall.  An All-steel radial has steel belts in the sidewall. 

The Sailuns, being a G rated tire, are a 14-ply tire.  Since tires seem to be the most problematic issue with RVs, and can lead to your death, over-kill on tires is a small expense.

Sailun in particular is hyping their all-steel construction, with steel radial cords as well as steel tread belt.  However, I haven't cone across any data to show that is inherently stronger or better than a well-constructed tire using other belt materials (polyester, kevlar, nylon, etc.), or that cord failures are a significant cause of tire damage.  Regardless of individual cord strength, tires can still get punctured, overheated or over-flexed.  Insufficient pressure is still going to cause failure.

It may well be the all-steel tires can be made in higher strengths or that such tires have greater resistance to sidewall damage (like hitting a curb). However, tire strength is directly indicated by the load capacity  stated in lbs or kg on the sidewall.  3000 lbs is 3000 lbs regardless of the cord material, and it is tested and verified.

Also be aware that no modern tire actually has 12 or 14 or 16 plies. Today the ply number is merely a rating index, not an actual ply count. Load Range G and 14-ply rating are equivalent. Load Index is another scale you may see - a tire with a Load Index of 120 can carry up to 3086 lbs.  It is a more precise measure than Load range or Ply Rating.

A higher Load Range, Ply Rating, or Load Index means the tire can be safely inflated to a higher psi and thus can carry more load (weight). If it is not actually inflated to a higher psi than a lower rated sibling, there is very little benefit. The sidewalls may be somewhat more resistant to direct external damage and may be a little stiffer, but that's about it.

Been looking at a lot of tires, has come down to either the Gladiator G rated or the Sailumns G rated.

If you do jump up to a G rated tire from a E rated tire make sure your rims are designed for the additional air pressure. Some 16" rims are only designed to handle 85 psi and the G rated will take 110 psi. It should be stamped on the inside of the rim.

falconhunter said:

If you do jump up to a G rated tire from a E rated tire make sure your rims are designed for the additional air pressure. Some 16" rims are only designed to handle 85 psi and the G rated will take 110 psi. It should be stamped on the inside of the rim.

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Just a random question. When you say your axles are 6000# are you quoting that from the tag on the axle or the certification label on the trailer?


With a trailer your size you must have a maximum hitch weight in the 4000# range. That would only require 5200# - 5400# vehicle certified axles. Back when that trailer was built, it was very common for the manufacturer to use 6000# axles and derate them to comply with vehicle certification minimums.


Michelin tires are notorious for sidewall cracking. They will not cover them with the warranty if the cracking is weather related. I'd look for something in your size with Kevlar sidewalls. 

Just an FYI. There is a reason that neither steel or kevlar is commonly used as sidewall reinforcement. That reason is shrinkage when heated during the cure. Nylon, polyester, and rayon, common tire fabrics, have the characteristic that they shrink up to eight to twelve percent when heated to temperatures on the close order of 300 F. Neither steel or kevlar has this characteristic. Since there is inevitably some slack in the fabric when a tire is built, the shrinkage effectively removes the slack during the cure (tight containment in the mold prevents excess shrinkage). A second consideration with kevlar is that it doesn't perform well when bent to a tight radius such as the tire bead.

Neither of the above problems has a substantive effect when used as the belts in a radial tire.

Ernie

Still have not bought new tires yet. Considering here in Illinois its -20 degrees out. This hole tire thing is like the black hole , lots of should work. Would like to thank ever body for their input.

Pawtna said:

Thanks for the information. One of my main concerns is should I stay with LT Tires Or switch to ST tires. The axles are 6000 lb. Have had LT Tires on fw wheel since it came from Newmar. Have never had a tire issue since new, have over 100,000 miles on trailer. Only problem has been the cracking of the side walls on of the tires. My tire dealers are telling me to switch to ST tires now. Not for sure if I need to or stay with LT tires. Michelin tires on fw are 3 years old.

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No tire problems for 100k miles  with a commercial grade all steel carcass Michelin XPS Rib tires is the norm. You sure won't get that from a 16" ST E load tire.

We also use the same size all steel carcass commercial grade 16" LT E Bridgestone R-250 and their R-238 on our commercial trailers. These tires aren't as pricey as the XPS tires but are just as good. Check them out

You sure don't need a ST load g tire at 110 psi/4080-4400 lbs capacity for 6k axles with maybe 2600-2800 lbs load per tire. Thats a bum recommendation unless the trailers has 7k/8k axles.

  We?re running 17.5? on our 3 axle, 20 K pound unit. Real, feel good insurance. We?re running Continental trailer tires!