Question about Tires and Rims/wheels for a boat

Discussion in 'Boat Tips' started by TOPS, Mar 27, 2006.

  1. TOPS

    TOPS New Member

    Messages:
    4,099
    State:
    Cabot,Arkansas
    My daughter just bought new tires for her car than she wrecked it.[totaled] my question is the tire size in the car is: P175/70R/13 and the tire size on the boat is: P175/80D/13 WILL the New car tires fit my boat rims/wheels? What exactly is the difference between the two tires?
     
  2. metalman

    metalman Well-Known Member

    Messages:
    3,457
    State:
    IN
    Name:
    Winston
    Verlon,
    That must be some strange boat to have wheels:p
    Seriously, it's not good to put car tires on trailers, they don't have the necessary sidewall stiffness and load bearing characteristics.
    Now, others will tell you different and I do know guys who have done what you are thinking about doing and have had no problem.
    Something else to think about is if her car was totalled there may be some internal damage to the tire carcass that you can't see but would cause the tire to fail on you.
    Be safe...W
     

  3. Mutt

    Mutt Administrator Staff Member Supporting Member

    Messages:
    18,950
    State:
    Ca
    Name:
    Mutt
    Verlon I dont see why they wouldnt work myself as long as you do not exceed thier load capacity. I went over to car tires on my tracker with great results. it tows better dont bounce as much. over all a trailer tire is a btter way to go though. but i see no problems if you dont tow it far and dont over load them.
     
  4. TOPS

    TOPS New Member

    Messages:
    4,099
    State:
    Cabot,Arkansas
    When on land boat and trailer is one and same in my opinion:) I Hope members understand what I was referring to. I just need the info:eek:
     
  5. Nobody Special

    Nobody Special New Member

    Messages:
    614
    State:
    TN
    The 80 would be slightly wider and not as tall as the 70, but I doubt there would be enough difference to even notice. I have used car tires on a boat trialer and it's my experence that they usually last longer than the tires specifically made for a trailer. As long as you don't exceed the load capacity, I don't think it would hurt.

    My wife recently brought home a bunch of old BASS magazines from a yard sale. They were from the 70's and the Ranger and other brands of boats in the ads had white letter passenger tires on the trailers.
     
  6. catwacker

    catwacker New Member

    Messages:
    202
    State:
    illinois
    the tires will fit the rims, just check fender clearance. if the boat is lighter than the car was, i don't see that you will have a problem.
     
  7. Crispy Critter

    Crispy Critter New Member

    Messages:
    431
    State:
    Missouri
    They should work fine.The tires on your trailer are already a passenger tire with the P at the beginning.The "Trailer Tires" start with ST for "special trailer".The only differences will be the width the 70 is a little wider than the 80 and your current trailer tire is a radial while your daughter's is a Diagonal Bias Ply,that's what the "D" stands for.The height should be the same they're both 175s.
     
  8. Crispy Critter

    Crispy Critter New Member

    Messages:
    431
    State:
    Missouri
    I read your post wrong you have the Bias on your trailer now and the other is the radial.
     
  9. ultima_cat_man

    ultima_cat_man New Member

    Messages:
    65
    State:
    granite city, ill
    what does the tires sizes mean on tires.

    p175 70 r13

    1. p stand for passenger tire
    2. 175 is the width of the tire in millimeters (mm)
    3. 70 is the percentage of the sidewall from the width of 175(70% of 175) a p175 80 r13 would be the same width with a 10% higher sidewall
    4. r stands for radial
    5. 13 size of rim

    ive worked in a tire shop for over 10 years, trailer tires have stiffer sidewall than passanger tires because on cars the suspension takes alot of the cars movement side to side but on a boat all the side to side movement is absorbed by the tires, is it possable to use car tires on a boat, yes , will you have a firey crash and die probably not but under the right conditions a accident could very well happen....
     
  10. Cattracker16

    Cattracker16 New Member

    Messages:
    356
    State:
    Wilton Iowa
    I use car tires on my car trailer, i don't seem to have a problem with them, i use a 185/65/15 they seem to have a higher load cap. i've had them on there since it was new. so Top i say go for it i'm sure that the car weight is prolly more than the boat loaded.. JMO
     
  11. Crispy Critter

    Crispy Critter New Member

    Messages:
    431
    State:
    Missouri
    Ultima_cat_man has got it right on on the specs for the tires.In your case though it would be a small difference in your height.your trailer tire should be about 1 1/3 inch taller than than the car tire. Since your already running passenger tires the only major difference would be the Radial vs the Bias ply.
     
  12. triggerhappy

    triggerhappy New Member

    Messages:
    70
    State:
    IL
    Everything about the two tire's differences has already been said except that the tire with a higher sidewall will naturally have more flex in it.

    I say save 'em until you need 'em. When you do, try them out and just watch the tires in your mirror and the "feel" in the truck. If they're gonna be a problem you'll know.

    Oh, and according to Dee, you'll have to sit the trailer a whole 2/3" deeper to unload the boat.:p
     
  13. Crispy Critter

    Crispy Critter New Member

    Messages:
    431
    State:
    Missouri
    Just in case anyone is interested it's easy to figure the height on any tire like that.

    You take the first number which is your tread width in millimeters and convert it to inches by dividing by 25.4. Say your car tire is 175 divided by 25.4=6.889*** inches.Then multiply that by your profile which is 70%=4.822****inches.that is how tall your sidewall is on one side.Since you have that on both sides multiply by two=9.645***inches plus your rim which is 13 inches your 175/70/13 tire is 22.645*** inches tall.

    your trailer tire is 175 divided by 25.4=6.889*** x 80% profile=5.511*** inches X 2 = 11.023***inches plus 13" rim =24.023***inches.

    the 175/70/13=22.6" tall
    the 175/80/13=24.02" tall

    Wheww.that sounds complicated when you write it out but it's a pretty easy formula.

    1st # divided by 25.4
    then X that by 2nd# %
    X 2
    + rim inches
    = height

    I never was good at writing out formulas in school but I could come up with the answer.
     
  14. Crispy Critter

    Crispy Critter New Member

    Messages:
    431
    State:
    Missouri
    No the new tires will be that much lower ;)
     
  15. jtrew

    jtrew New Member

    Messages:
    4,404
    State:
    Little Rock, AR
    Check the load limits on the old tires on your trailer, then check the load limits on the car tires. If they are pretty similar, I wouldn't worry about any difference in sidewall flex or anything like that, because that's simply the way the tire is designed to operate. Another way would be to look up the loaded weight of the car, then weigh your boat and trailer and calculate what the loaded (trailered) weight for the boat and trailer would be. If it's over half the weight of the car, I wouldn't use those tires, assuming it's a 2 wheel trailer. If it's a tandem (4 wheel) trailer, as long as the loaded weight of the boat and trailer didn't exceed the loaded weight of the car, the tires should work fine.
     
  16. Hootowlc3

    Hootowlc3 New Member

    Messages:
    409
    State:
    Florida
    If your boat isn't a fiberglass boat they should work. A true trailer tire calls for 50lbs of air. Helps make it stiffer when the boat is bouncing or you run the tire off the road. I have had 2 tires blow out until I started putting the recomended 50 lbs of air in them.
     
  17. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    I've always been told not to run a radial tire on a boat trailer but to run a high bias ply tire like a 7 ply tire.
     
  18. flatheadhunterx

    flatheadhunterx Active Member

    Messages:
    1,374
    State:
    South Carolina
    i dont know but i have been thinking of putting car tires on my pontoon.i have already went to to a 1350 weight tire and i still blow them. dont know if i pull it to fast or what but they just explode going down the rd.not as bad since i went to a higher load capacity but it still happens.
     
  19. triggerhappy

    triggerhappy New Member

    Messages:
    70
    State:
    IL
    Woops:eek: got turned around...
     
  20. jtrew

    jtrew New Member

    Messages:
    4,404
    State:
    Little Rock, AR
    Ronald, I had that trouble with my 2 wheeled trailer carrying a big 20' center console deep-V that I used for the Pacific and the Gulf of Mexico. I stopped the problem by getting some extra high load rated tires. That boat really should have been on a tandem axle trailer, but I foolishly depended on the dealer to provide the right trailer for the boat.