Tire Sizing confusion

Discussion in 'Tires / Brakes / Bearings / Axles' started by grandebob, Aug 5, 2009.

  1. grandebob

    grandebob New Member

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    So I blew out a tire over the weekend, and was looking to get 2, maybe 3 new ones so they all match.

    I find my running tires are labeled ST175/80 D13
    My Spare is labeled B78-13ST
    Shopping around I find that
    Discount tire offers ST175/80R-13/C1 BLK for just the Rubber for $69 + mounting etc.
    JCWhitney has C78-13ST Load Rating D With rims for $115
    Etrailer has ST175/80-R13 Looks like Load rating C with Rims for $99

    My camper says it's GVWR is 2900 lbs. Two 1350lb rated tires doesn't seem like it would support the weight.

    Help me make sence of my tire debacle. What should I get? Should I get all new rims or just get new rubber mounted? Seems to be about the same price either way.
     
  2. Twisty

    Twisty New Member

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    My Loadstar ST185/80 D13's (C78-13) are rated at 1660 max load. I haven't found a tire with a higher max load rating in 13" which is a drag because my gross trailer weight is about 3600#. I'll have to go to a 14" rim to have the gross covered.
    IMO, get tires mounted on rims. It will give you a storage set and the new rims will be all SHINY!
     
  3. grandebob

    grandebob New Member

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    I think I'm going to try a set of ST185/80 D13 (load rated D) and see if they fit. They have about about .7" larger diamater, and about .6" wider then the ST175/80 D13 (load rated C)

    At about 1700 lbs of load capacity per, that should cover me from a weight point of view. Now, lets just hope they fit...
     
  4. grandebob

    grandebob New Member

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    So now the question at hand...

    Do I just get the rubber, pay for some one to mount it to my rims, and have no hope of a refund or...

    Do I buy with rims and be able to at least return 2/3 of them if they don't fit...
     
  5. Twisty

    Twisty New Member

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    If you get the rubber only, you can have HP stems installed and get them balanced. While they're spinning to get balanced, make sure that they are round.
    I noticed on one site that some of the tires are shipped "flat" and it was mentioned that it makes mounting difficult.
    On the other hand,
    "get tires mounted on rims. It will give you a storage set and the new rims will be all SHINY!" [;)]
     
  6. my3kids

    my3kids New Member

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    If you're going to also order the rim make sure it also has the same or higher load rating. I just ordered a 2nd spare tire/rim and I specifically ordered the rim with the 1660lbs rating otherwise you'll get the 1350lb version. I could not find any kind of rim in a 13 inch size with a higher rating than 1660lbs. A rim failure will be ugly compared to a tire blowout so make sure you order the correct rim.

    BTW, the tire I ordered (ST185/80-D13) now has a max load rating of 1730lbs. It use to be 1660lbs. They're LoadStars K550. My 07 Fleetwood Saratoga came with LoadStars and they seem fine so I stayed with the same brand. Only difference now is that it has a higher load rating.

    The tire/rim came mounted but I forgot to ask them to also balance it. My local tire guy balanced it for me for free. Because these D-range tires have a max psi of 65 they went ahead and did the right thing and installed a high pressure valve.

    Hope this helps™,
    Ray + lovely wife + our 3 kids
    07 Fleetwood Saratoga
    08 Nissan Armada
     
  7. grandebob

    grandebob New Member

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    Rim load ratings too! Wow, haven't even seen any loads listed for any rims before.

    My current quandary is that if I buy just rubber of a size that i'm not sure will fit, I won't be able to return them since I'll have to mount them to see if they fit (and now i don't know if my rims support more then a C rating).
    If I get tires and rims from JC Whitney, they charge $60 per tire/rim combo if I return them. I'm having a hard time finding a local tire shop that carries 185/80D13 class D's (but at least i know they exist). Most only carrie 175/80D13's in a class C. Class D's seem to be like bigfoot, people have heard of them, but no one has a picture or no where I can find them

    I can imagine how spectacular a rim failure is at 70 mph.
     
  8. my3kids

    my3kids New Member

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    I found this out after I ordered my tire/rim and paid $35 to ship it via UPS. Turns out you can order this particular size and load rating of tire from your local America's Tire Co. They don't list it on their website but if you drop by they can order it for you.

    They're the guys that balanced the tire/rim for me for free. As I was talking to one of the guys I mentioned that I would've bought it from them but they didn't list on their website.

    Turns out they can get just about any odd sized tire out there. The guy simply entered the size and load rating and up came two different brands. They can get the tire to me in about 2 days. This is good to know when it comes time to cycle out the old tires.

    What I'd do is talk your local America's Tire Co store to order one for you. Mount it then see if it fits on your PUP. If not then bring it back. Its worth trying ...

    You're right about the ST185/80-D13 tires. Most places don't carry them and they're somewhat difficult to locate. That is until I discovered America's Tire Co.

    Ray + lovely wife + our 3 kids
    07 Fleetwood Saratoa
    08 Nissan Armada
     
  9. silvermickey2002

    silvermickey2002 Morris County, NJ Gold Supporting Member

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    I just looked at www.tirerack.com and they sell trailer tires. I looked at the tire I would need for our trailer. It is a Goodyear Marathon 175/80R13. It is rated for 1360 lbs. They do show a 185/80r13 rated for 1480 lbs. the 175 tire is $67.00 +tax and mounting.

    But I guess the nice thing is that it is a radial and they are suppossed to run cooler.
     
  10. grandebob

    grandebob New Member

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    I called my local Discount Tire. They don't have any 185/80D13 class D's in stock, but they can order them. He said they will install them on our rims, and if they don't fit right, they will put the old ones back on and not charge me a dime. With installation on my existing rims, it's going to be about $100 a tire. Not a bad price from what I've seen.

    I have to say, Discount Tire has treated my wife very well in the past when she needed 4 new rims/tires for her car, and so far are treating me well with the camper. I will let you guys know how it pans out in the end.
     
  11. grandebob

    grandebob New Member

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    So we did it. We went to Discount Tire, and got 185/80 D13's Class D's installed. Their isn't much room around the front/back of the tires (between the tire and front/back of wheel well) but above their appears to be ample room for the suspension to compress. The ride is fairly smooth, and haven't run into any problems yet. It's definatly a tight fit, but I don't think i need to worry about a blow out now.
     

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