Tire Load Range

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17,914
Location
NH
Needed to buy a spare for my camper, as the 17 year old one was kinda sketchy. Looks like it came with LRC's, and if I'm reading it correctly, LRC's are good for 1,360lb per tire (this is a 175/80 13). Trailer GVWR is 2,500lb. Which means... probably not too much, unless if I go and weigh it and make sure it's never past that weight. Since I won't pack much into it (no water, no ac, etc) I ordered an LRC just now, as I "need" that spare for this weekend. I can see why a maker would use tires that just meet the rating. But when do you jump up a range? I realize that in an ideal setting I'd have at least 250lb of tongue weight, so it'd be 1,125lb per tire, which is below 1,360lb. But is that conservative, or are the ratings such that one can go to 100% of rating, as they derated them for you?
 
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9,735
Location
Ontario, Canada
I think the 100% load rating may only apply for 65mph? Anyways, IME trailer tires don't seem to have alot safety margin, especially with age. On a couple trailers, I have run near 100% load at 55mph for 10-20 miles, and the tires do heat up more than the car tires do. Running the same load, faster in higher ambiant temperatures isn't something I would do personally.
 

supton

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17,914
Location
NH
I'm not crazy about it, really would like to swap out to D's--but, if I keep my speed to 60-65, weight below max, and ambient temps below 100F, is it really pushing anything? This weekend is what I'd think is a short trip, 3 hour drive (albeit through Boston, so average speed of 5, lol). Some fall trips but those will be in much cooler temps. I had hopes to buy one D this year, and then next summer a second D, and keep the C's for spares; but kinda fell by the wayside. Truth is, we just won't be doing that much camping in really hot weather. They are 65mph tires. Err, now that I think about it I didn't verify that on the rubber. I do know the HF tires on my utility trailer and my other camper say 55 on them! That said, hour plus at 70mph didn't phase the HF tires last fall; but again, not near max rating and in cool weather. I do plan to check on things about once/hour, since it's a new setup (to me) and all.
 

supton

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17,914
Location
NH
Aired them up on Saturday, will see how they are after sitting for a few days. Not expecting too much, but will be curious if they stayed at 50psi or not. Not worried about the tires, other than hoping that Amazon Prime does their thing and gets me my tire on Thursday!
 
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6,388
Location
Washington St.
Supton, the easy thing to do is to go up to an ST185/75R13 trailer tire, 1480# @ 50 psi. A better move would be to go to 14" wheels and Kumho Radial 857 highway rib tire. These are designed for the narrow, heavy vans from Europe and Asia, and Kumho markets them in the U.S. for trailers. These would be a much more reliable tire than the usual ST junk. 185R14C = 1874# @ 65 psi. (Note here the "C" means Commercial, not Load Range C.) http://www.kumhousa.com/tire/category/truck-suv/7EAB87AD-62DC-4D82-897E-E59335DE416C I always balance trailer tires. Vibration from imbalance causes increased wear on the tire, bearings, suspension components, and stuff in the trailer. Many trailer wheels are so cheaply made that the center pilot hole is not in the true center. Have the tire shop use a lug-centric attachment on the balance machine to center the wheel by the lug holes.
 

supton

Thread starter
Messages
17,914
Location
NH
I already bought one tire; if I change sizes I'll need to buy three. Which I could do I guess, and CL the tires. Not sure if 14" wheels will fit. Good point on tire balancing, maybe I'll get a chance to do that before my trip. Just a static balance. But I can't do lug centric balancing. Am guessing though a simple static balance would go a ways though.
 
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