Substituting car wheels for trailer wheels? Offset issue?

   / Substituting car wheels for trailer wheels? Offset issue? #1  

KYErik

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Dec 2, 2005
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893
Location
South central IL
Tractor
1977 AC 7000, 1980 JD 2840, 1963 Case 930, 1963 Ford 4000, 1943 Case SC, Case 530CK backhoe
I have a small tilt boat trailer (single axle, 1 inch spindles, about 14 feet long) that originally had typical 12 inch (narrow) trailer tires on it. I am going to put a wood deck on it and use it for light hauling (less than 1000 pounds). I am replacing the wheel bearings now, but noticed that the rims and tires are in pretty bad shape.

I found two 14" car rims/tires that will bolt on, however the offset is different from the offset on the trailer wheels. The trailer rims have the bolting point in the center of the wheel, but the auto rims have the attachment point almost on one edge of the rim.

Will the different offset matter to the bearings/axles? Or should I stick with trailer rims?
 
   / Substituting car wheels for trailer wheels? Offset issue? #2  
I would think for a 1,000 pounds it should be fine as long as your bearings are adjusted right and lug nuts tight
Jim
:)
 
   / Substituting car wheels for trailer wheels? Offset issue? #3  
IMO you are correct in being concerned. I don't know anything about your trailer or the wheel bearings so I can't say yes or no on potential problems.

If the stk rims have no offset they will distribute the load they carry equally on inner and outer bearings. The auto rims you describe will place a higher percentage of the load in the inner bearings. It's beyond the scope of my answer to tell you what percentage of the load each of the bearings will see.

The best suggestion I can offer is to find out what the bearing capacity is for the inner bearing at the intended speed you intend to drive and see how close the intended load is to the rated capacity. Bearing capacity is based on rotational speed and increased speed reduces the load capacity.
 
   / Substituting car wheels for trailer wheels? Offset issue? #4  
I have no idea about the rims, but I do know that you should not replace trailer tires with care tires.

The construction is different. Trailer tires are made to minimize side-to-side sway, and car tires are made for a soft ride. The trailer will misbehave badly with car tires.
 
   / Substituting car wheels for trailer wheels? Offset issue? #5  
i would always err on the side of safety if you're not sure.

that being said, i would also think with the kind of loads you are planning, you would most likely be ok. it is true that bias ply tires are primarily made for trailer use and radials are primarily used on cars. i would argue that the previous poster's point may be backwards, though. radial tires are designed to corner better (hence the auto application) AND to provide a smooth ride. bias ply trailer tires are designed for straight line use and are usually able to carry more weight in the commonly found trailer rim sizes as the number of plys goes up.

the point is, for short runs with less than 1,000 lbs (500 per tire plus the trailer weight) you should be fine with car tires and decent rims and axles.

i don't think the offset loading is going to hurt you either at this weight. you didn't say if the offset was to the inside or outside (positive or negative) but assuming the rim is at most 6 inches wide, you are talking about three inches either way on a spindle that is probably sticking out at least 4 inches past the bearing races. just make sure your fenders clear and be careful to see how she handles with a full load.

probably the most important aspect of what you are doing will involve getting the tongue loading correct (about 10% - 12% of total weight) for the axle location you have.

also, don't forget, all this goes out the window as you start inching up on your load weight. your temptation will always be to haul just a little bit more to see what you can get away with. 1,000 pounds of sand or rock doesn't look like much so you can easily overshoot your planned weight with one half bucket load of material.
 
   / Substituting car wheels for trailer wheels? Offset issue? #6  
ampsucker said:
it is true that bias ply tires are primarily made for trailer use and radials are primarily used on cars. i would argue that the previous poster's point may be backwards, though. radial tires are designed to corner better (hence the auto application) AND to provide a smooth ride. bias ply trailer tires are designed for straight line use and are usually able to carry more weight in the commonly found trailer rim sizes as the number of plys goes up.

Used to be that way but it is no longer true about radials vs bias ply for trailers. Their construction is different for trailers but radials are now very common in trailer specific tires. In fact almost all the "better" trailer tires are radial.
 
   / Substituting car wheels for trailer wheels? Offset issue? #7  
Trailer hubs that are 5 lug design most of the time are either Ford or Chevy bolt pattern. I would look for rims that are neutral centers there are tons of them out there.
If it's 4 bolt that's a different issue. I took a hub to the junkyard looking for some spare rims for some construction equipment. I found the same 4 bolt circle but all of the rims had smaller center and wouldn't fit the hubs.
 
   / Substituting car wheels for trailer wheels? Offset issue?
  • Thread Starter
#8  
The auto rims have the bolts toward the outside edge.

Thanks to everyone for the advice. The inner/outer bearings are the same size so maybe they were designed for a symmetrical load.

That said- I think I'll play it safe and just use the car tires/rims around the farm (they are wider so they are less likely to sink into soft ground) and around town at low speeds (30 mph or less) with really light loads (500 lbs or less), but switch in some good 8 inch trailer rims/rims off my small trailer (4 x 6- not long enough to safely haul drywall or plywood) for carrying any high speed loads since they have the correct offset.

The 8 inch trailer tires aren't rated for as much weight as the 12 inch (and they will spin alot faster), but I'd hate to cause a wreck due to using improper wheels (the car rims). I'll just have to keep the load down when using the little trailer rims/tires on this boat trailer.
 
   / Substituting car wheels for trailer wheels? Offset issue? #9  
The most popular brands of trailer axles up to 1800 kg in Europe all have the same 5 bolt wheels as used on Mercedes automobiles. The rims come from the same factory, though the tires are usually cheaper Chinese tires which Mercedes doesnt fit to their cars ;)
 
 
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