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About TireHobby

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  • Birthday 01/21/1939

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  1. TireHobby

    Axle spacing on Heartland 4100 King.

    A lot of 5th wheel trailers with OE tire size ST235/80R16, regardless of brand, have a standard 32" spacing between axles. Get a tape measure and check from center to center on both sides. If actually 32" the ST235/85R16 tires are probably to tall. https://tiresize.com/calculator/
  2. Here are the specs for the steel cased Sailuns.....http://www.sailuntires.ca/PLT/S637st.html Note: The GY G614 (LT235/85R16G IS a trailer tire. That's what the RST on it's sidewall is telling you, Regional Service Trailer.
  3. That's probably because they have quit building them. They now have two steel cased ST tires that have replaced the LT (RSTs). They are in sizes ST235/80R16 LRG rated at 4080# @ 110 PSI and, ST235/85R16 LRG rated at 4400# @ 110 PSI.
  4. TireHobby


    In RV trailer model years 2005 - 2007 a great many of their manufacturers selected the LT235/85R16E tires for Original Equipment fitments on 6000# GAWR axles. Their load capacities - 3042# @ 80 PSI - needed very close monitoring to insure they were always inflated to the 80 PSI. Many owners found that the heavy duty steel cased tires were much more durable for replacements. Those brands were Michelin & Bridgestone. It’s the trailer manufacturer’s prerogative to select whatever tires they deem appropriate for OE fitments. Once certified to the vehicle they become the benchmark. Many ST tire manufacturer's are building like sized tires sized ST235/85R16E. Their physical dimensions are very similar to the LT tires. However, their load capacity is much higher at 3640# @ 80 PSI. Almost all ST name brands provide them.
  5. TireHobby

    Tire Question

    Continental builds a 225/75R16 European designed tire with a Vanco brand in load range E rated at 3195# @ 83 PSI (121/120R E). It’s a highway all-season radial and very popular on class B and smaller class C RVs. General also builds the same tire with those specs.
  6. Are the tires the same size as what is recommended on the tire placard or certification label? How old are they? Here is a picture of what can happen to a tire that has a tread separation but not yet lost the tread. Both of the tires in the picture have the same size designation and are from the same manufacturer. It's amazing how much larger a tire can get before it throws the tread. http://www.irv2.com/photopost/showfull.php?photo=27625 On Edit: The distance between tires is normally a question the axle manufacturer can answer. Dexter says for their axles the minimum is 1".
  7. TireHobby

    Tire Pressures

    Motor Home owners seem to always give information on this subject that is intended for vehicles governed by different regulations. If your MHs federal certification label has recommended cold inflation pressures on it, the standards for maintaining them will come from FMVSS standards. Under FMVSS standards tire manufacturers do not set vehicle tire inflation pressures, vehicle manufacturers do. It's a standards requirement. In chapter 4 provided below you will find the correct procedures. Read the whole thing. Reading til you find what you're looking for may be out of context and you'll be right back where you started from. http://www.mcgeecompany.com/wp-content/uploads/2010/12/complete-manual.pdf For those that won't take the time to read the document I'll add this. It's an industry wide standard to NEVER use less tire inflation pressure than what has been recommended on the vehicle's certification label, tire placard or in the vehicle owner's manual.
  8. TireHobby

    New 5er - New Hitch - New Tires?

    Your trailer's axles probably have a GAWR on the certification label/tire placard of 6000# per axle. The OEM tires, when serviced to 80 PSI will provide nearly 18 percent of load capacity above the maximum load for that trailer. That's a far better reserve load capacity than many other models are equipped with. Depending on usage - your call - they are good for 3-5 years. Trailer tires are not mileage tires. OEM Westlake tires are provided to the vehicle manufacturers serviced with 100% nitrogen (green valve cap). That's good for new trailers because it pretty much assures there is no water vapor in the tires.
  9. TireHobby

    Tire Choices

    Were the OEM tires 17.5"?
  10. TireHobby

    trailer tires and tow speeds

    Tire industry standards are very consistent. Here is something about them by Michelin. http://www.michelinman.com/US/en/help/how-to-choose-tires.html#tab-4
  11. TireHobby

    trailer tires and tow speeds

    There are a lot of different brand name manufacturers building 16" trailer tires with load capacities from 3420# to 4080# In load ranges E, F & G. Some are ST235/80 R16 and others are ST235/85R16. The ST235/80R16E has three load capacities, 3420#, 3500# & 3520#, all at 80 PSI. Read the specs or sidewall info before you by them. The ST235/85R16E has a load capacity of 3640# at 80 PSI. The ST235/85R16F has a load capacity of 3960# at 95 PSI. The ST235/80 R16G has a load capacity of 4080# at 110 PSI. There are some - what I call hybrid LT trailer tires - 16" LT trailer tires size LT235/85R16G rated at 3750# at 110 PSI. They are called RST (regional service trailer) and will have that information on their sidewalls. Happy hunting.
  12. TireHobby

    trailer tires and tow speeds

    Special Trailer tires (ST) without any speed markings on their sidewalls have a maximum speed rating of 65 MPH. Manufacturers of ST tires are in the process of identifying their tires with an official speed letter or actually molding the speed restriction into the tire’s sidewall. There is no speed letter for 65 MPH. Speed letter K is for 68 MPH but seldom used. The speed letters follow a tire service description displayed on the tire‘s sidewall. A typical service description may look like this, 117/112N, the N is the speed rating and it is 87 MPH. Replacement tires for RV trailers are a complicated proposition. The only official recommendations an owner can get is from the trailer manufacturer. Hardly anyone likes that idea so the internet forums are loaded with misinformation. The best thing an owner can do is find a tire manufacturer like Bridgestone/Firestone that publishes their tire industry standards for replacement tires in a PDF on the internet. I used that name because (IMO) their’s is the easiest to figure out for trailer tires (any design).
  13. TireHobby

    Tire size

    The difference in the overall width of the 85 tires are not normally going to present a fitment problem. However, most large RV trailers will have triple axle spacing very close to one another and the larger diameter of the 85 tires could cause them to be to close to each other. You could ask the specific axle manufacturer what the minimum clearance requirements are. Dexter says 1”.
  14. TireHobby

    RV Tire Issues

    Your truck was manufactured to accommodate the specifications found in the vehicle owner’s manual and on the federal certification label. Upgrading specs to that of another truck is not authorized without certification. So, you’re overloaded and worrying about tire overloading. You can’t have it both ways. Sooner or later those overloaded tires are going to fail. If you’re not willing to conform to the specs of your current truck than bite the bullet and get some tire & wheel assemblies that will support your overloaded conditions and try to stay under your truck‘s GAWR limits.
  15. TireHobby

    RV Tire Issues

    Which manufacturer's load rating? The vehicle manufacturer's load rating is on the tire label, it's called recommended cold inflation pressure. It's always the correct inflation pressure unless otherwise stated in the vehicle owner's manual. The tire manufacturer's load rating is the amount of inflation pressure needed for the tire to provide it's maximum load capacity. That inflation pressure is depicted on the tire's sidewall and when used is not considered to be over inflating the tire. If you're asking about going over safe limits you're probably not going to get much advice about beating the odds.