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1990 Chevy Silverado 1t 4x4

Discussion in 'Chevy Trucks' started by kingriver, Nov 20, 2005.

  1. kingriver

    kingriver Senior Member
    from alaska
    Messages: 217

    TIRES ????
    Guys !!!! The local tire dealer here sold me P235/75R16's for this truck, when he installed the tires on the rear (dually) and front it cost me around 1200.00, that was 2 years ago, anyway, never noticed until this winter that the damn things rub when I load my v-box sander with around 1.-2 yrds of sand, Said that was norm, then went on to say that I should have 225's, at additional cost to me. (Should I switch to the 225's ??) Is it just me or does this have lawsuit written all over it ?:cool: [/SIZE]
     
  2. Joe D

    Joe D Senior Member
    Messages: 605

    I want to say it should have 215/85/16's on it. Look at the door jamb it may be listed. If the tires rub it's a bad thing.
     
  3. kingriver

    kingriver Senior Member
    from alaska
    Messages: 217

    Hey Joe, the dealer said that the 225's would give it an additional 1" clearance, and the 215's he didnt mention !!! the sticker on the door jamb has been removed, he looked in his book, supposedly.....:cool:
     
  4. echovalley

    echovalley Senior Member
    from CT
    Messages: 456

    Dually should have 85s not 75s.The height is fine it is the width that is the problem
     
  5. lawnmedic

    lawnmedic Senior Member
    Messages: 703

    You state that the tires are P235/75R16....That P at the begining stands for passenger. They should be LT,,,light truck.... If they are P series tires they will rub because the tires are being grossly overloaded.

    As far as size, go by your door sticker, both size and weight rating are listed there. If you have a tire failure and accident the cops can sight you if tires do not match the specs on the door....
     
  6. Oshkosh

    Oshkosh PlowSite.com Addict
    Messages: 1,655

    My 1989 runs...

    The sticker on my 1989 says 7.5x16 and I have 235 85 16s on the rear and haul 4,000 pounds on a regular basis with no issues.
     
  7. kingriver

    kingriver Senior Member
    from alaska
    Messages: 217

    So then if I get 235's 85 16's I shouldn't have any isue???
    Is the 235-75-16 that much wider ? 225-75-16 I was told would be around 1" narrower so I should have around 2" between the tires in the rear when I'm empty and around 1" + when loaded with sand ???:
     
  8. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    235/85's are even bigger than what you have.

    Lets decode the number a bit. We'll use the example of an LT235/85R16 since it is pretty much the standard tire for most older heavy trucks.

    LT stands for Light Truck. If there was a P here its for a Passenger car and is of lighter construction.

    235 is the nominal width of the tire (not the tread, but across the body of the tire) in millimeters when mounted on the recommended rim size. In this case, it is 235mm. You can divide this by 25.4 to get it in inches... approx. 9.25 inches.

    85 is a percentage... it means the tire's sectional height (from rim to road) is 85% as tall as it is wide. In this case, 85% of 235 is 200mm/7.86" tall (which can be doubled and added to the rim size to get total height, in this case it is almost 32")

    R stands for radial construction.

    16 is the rim size in inches. Funny that they mix the numbers like that, huh?

    So now you can decode them yourself and compare them. Note that these are the nominal figures, real life numbers may be different due to manufacturing tolerances etc.

    The 235's I took off my truck last year showed evidence of touching together (in the form of logo's being transferred from one tire to the other) under load plus bouncing. It was never a problem on my truck. I replaced the tires with 255's but added a 1.5" thick bolt-on style spacer on the truck for clearance, which also eliminated my problem with worn-out rim holes getting longer and breaking studs while plowing (back and forth and back and forth seems to keep doing that).
     
  9. Oshkosh

    Oshkosh PlowSite.com Addict
    Messages: 1,655

    Forgot to mention,Load Range E

    This may be stating the obvious but load range E and I run the recommended psi for the truck.
     
  10. kingriver

    kingriver Senior Member
    from alaska
    Messages: 217

    Thanks this is actually what I was looking for,, so let me get this straight.. if I have 235's @ (9.1/4") and hes selling me 225's at 8.85 or (8 7/8") I would only gain 3/8" per tire a total of 3/4" total between tires.. is this correct
     
  11. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    That is correct, but remember those are 'idealistic' nominal numbers which may not translate into reality as well as one would hope. Always best to measure after they are mounted just to be sure.

    Someone should make a sticky of the tire number decoding posting or something... it has come up before.
     
  12. lawnmedic

    lawnmedic Senior Member
    Messages: 703

    Kingriver,
    What is the "Load Rating" on your tires? It should be in the line with the recomended pressure.
     
  13. kingriver

    kingriver Senior Member
    from alaska
    Messages: 217

    Lawnmedic, I havn't checked this thread in afew days. I will take a look tomorrow and give you the "load rating"
    thanks for your response
    kingriver:cool:
     
  14. Jpocket

    Jpocket Senior Member
    Messages: 302

    The tires on a dual wheel truck should never rub, unless they are low on air.
     
  15. Detroitdan

    Detroitdan PlowSite.com Addict
    Messages: 1,937

    my 97 dually came with 225/75/16s, tons of room between them. Some same era duallies (2wds for sure) came with 235/85/16s, still enough room between them. Newer duallies come with 215/85/16s. If you paid 1200 for "P" 225s, you got boned hard. Get those tires off there. Also, newer duallies (around 2001, I think) went to a 16x6.5 rim, older like mine are 16x6. I almost put 255/85s on, but the tire guy talked me out of it due to rim width. I know many guys have done it and gotten away with it though. I am seriously considering changing my 225s for 235/85s, just gain some height and not look like a 2wd, and with 235/85s i wont need the spacer. Keep in mind your final tire diameter will affect your speedometer reading, as well as odometer, which can result in both speeding tickets and miscalculated fuel economy. Oh, yeah by the way, I have seen a few DRWs pop because they were rubbing. Even a little rubbing creates an intense amount of heat.
     
  16. kingriver

    kingriver Senior Member
    from alaska
    Messages: 217

    [ i wont need the spacer.
    What spacer are you talking about, also the tires are LT235/85/R16 and unloaded with just the v-box sander I only have maybe 3/4". The tires are suppose to be rated @ #2500 each tire so I should be able to haul 10,000 lbs according to the tire manufacturer without an issue. When I load the sander (level) with sand @ lets say 2yrds wet sand (6600) lbs the tires rub just barely, but they do rub. Oh yea, the tire pressure is at max 80#. Any thoughts !!:cool:
     
    Last edited: Nov 24, 2005
  17. Detroitdan

    Detroitdan PlowSite.com Addict
    Messages: 1,937

    DOT says you have to have one inch between duals. I think 3/4 inch should be fine, but I'm not sure if we are figuring the load ratings right. I suspect that 6600# is too much for a one ton. Your GVWR is probably being exceeded. I'll have to check my door sticker tomorrow. I thought the recommended (factory) payload was somewhere around 3300#, I'm really not sure. I know their numbers are always on the low side (except for new Fords), so you can safely go beyond the GVWR, but I don't know if you can double it. The new Fords are advertising 5900# for a 2wd dually, but I'd have to see it to believe it, considering that everytime I see one with an atv in the back or towing a camper off the bumper, it's squatting way down in back. I'll check my truck and get back to you. Whatever you do, even if it means getting spacers, you can't let the tires rub.
     
  18. Detroitdan

    Detroitdan PlowSite.com Addict
    Messages: 1,937

    The spacer I was referring to is the one to go between the dual wheels, bolts over the first wheel and has another set of studs for the outer wheel. I said I dont need them because I decided not to get the 255/85/16s that are real wide. I know the 235/85s will fit without rubbing, that's what a lot of duallies came with. I just picked up a set today, I'm going up from 225/75 to 235/85. They are only a little wider but a good bit taller.
     
  19. KentuckyPlow

    KentuckyPlow Member
    Messages: 64

    I have a 1987 4X4 Dually and I am looking to put a little wider tire on. Where can I get the spacers that you are talking about?
    Thanks.
     
  20. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    I purchased mine from wheelspacer.com, but since then people have started selling them on ebay a lot cheaper. Look up 'wheel spacer*' on ebay and several should appear. On a working truck, its probably better to stick with steel spacers rather than aluminum.