Dumb trailer tire question

[Elkins45]

Technically I think this question is more about the axle, hub and weight distribution but it’s caused by a tire, so…

My 16.5’ aluminum boat (around 1300 pounds including the trailer) came with 13” wheels, but since all 13” trailer tires seem to be garbage I bought a set of 14” wheels and mounted Goodyear trailer tires on them. My spare, however is still a 13” and I wonder how much of a problem it would be driving with it mounted for several hundred miles to get home. The boat would obviously be tilted toward the smaller wheel and my understanding of vectors makes me think that would make the tire, hub and axle on that side carry over 50% of the weight since the boat would be tilting “downhill” into the smaller tire.

Should I spend more money for a third 14” wheel and tire or am I overthinking this? Or should I just carry all three of the old 13” tires with me as a backup LOL?

[Tennessee Boy]

Personally I would replace the spare.  I spend a lot of money on fishing stuff that is not necessary.  Safety is a necessity in my opinion and I don’t skimp on it.

[A-Jay]

Having different size tires on your trailer can cause a couple of different issues.

The longer you do it, the more of a concern they become. 

The first one being that they have different weight capacities. 

 

An important point of consideration is when using two different size tires,

the load has to be no more than the capacity of the lowest rated tire.

With a substantial difference with both weight capacities and inflation levels,

the chances of inadvertently overloading on the smaller side tire is quite possible.

 

The other issues are the uneven wearing of the tires which can lead to greater wear of suspension components and the load being carried un-level.

With these different possibilities, the end result could be a blown tire

(at usually the most inopportune time) which can cause damage to your trailer and/or your load.

 

None for me, thank you.

A-Jay

 

 

[gim]

Put me in the camp of having a spare the same size as the two on the trailer.

[volzfan59]

1 minute ago, gimruis said:

Put me in the camp of having a spare the same size as the two on the trailer.

Me too.

[Elkins45]

11 minutes ago, A-Jay said:

Having different size tires on your trailer can cause a couple of different issues.

The longer you do it, the more of a concern they become. 

The first one being that they have different weight capacities. 

 

An important point of consideration is when using two different size tires,

the load has to be no more than the capacity of the lowest rated tire.

With a substantial difference with both weight capacities and inflation levels,

the chances of inadvertently overloading on the smaller side tire is quite possible.

 

The other issues are the uneven wearing of the tires which can lead to greater wear of suspension components and the load being carried un-level.

With these different possibilities, the end result could be a blown tire

(at usually the most inopportune time) which can cause damage to your trailer and/or your load.

 

None for me, thank you.

A-Jay

 

 

The spare is identical to the ones that were on the axles so presumably the weight capacity wouldn’t be an issue. I totally get your point about uneven wear, but do you think this would be a problem for just a few hundred miles?

[A-Jay]

8 minutes ago, Elkins45 said:

The spare is identical to the ones that were on the axles so presumably the weight capacity wouldn’t be an issue. I totally get your point about uneven wear, but do you think this would be a problem for just a few hundred miles?

No Clue as I'd never even consider it.

I prefer to eliminate risk best I can rather than manufacture it. 

Good Luck though.

A-Jay

[padlin]

I’ve seen a good number of folks driving on the spare donut on their car so I obviously can be done. There is a 50 mph speed limit when doing such, and I believe a 70 mile range. If one were to use a car as an example you could not drive a couple hundred miles on the baby tire. 
 That said, after many miles towing a small RV, 3 sets on my last one, not once did I scrimp on tires, bad things can happen when a trailer tire goes, although I don’t suppose an 16’ aluminum boat can wag the dog. Spend the $ and get another 14.

[Glenn]

I cannot think of a single sane reason to use 2 different-size tires on a single-axle trailer.

 

Not one.

 

For any reason. 

 

Not even for 1 mile.

 

Trailers should be equipped with tires on the same axle that are matched in construction and tire size designation and should be matched for overall diameter within one-half inch. The Laws of Physics will force their will on anything outside of those parameters.  

 

The outcome is never good.

 

[Catt]

Would I do it to get my behonkus home?

 

Why certainly 

 

I would however try to avoid that situation with the right tire-n-rim in the first place.

[GaryH]

For the cost of the proper wheel and tire it’s not worth the danger you could encounter to both properties and lives. 

[Chris Catignani]

11 hours ago, Elkins45 said:

... Or should I just carry all three of the old 13” tires with me as a backup LOL?

If money is your main concern...then just carry two of the 13" tires.
When you get a flat....replace both.

[Catt]

5 minutes ago, Chris Catignani said:

If money is your main concern...then just carry two of the 13" tires.
When you get a flat....replace both.

 

Would it not be more cost effective to buy 1 tire the correct size?

[Bankc]

If you've got two tires of different sizes mounted to a fixed axle, the trailer will want to turn in the direction of the smaller tire.  For every revolution the axle makes, the larger tire will cover more ground than the smaller tire.  This will want to turn the trailer and cause you to pull the trailer at a slight angle and put a lot of wear on your tires.  The increased heat from the friction of the sliding tire (to make up for the lost ground) increases the chances of a blow out, and decreases gas mileage. 

 

Also, how old is the spare?  They only last about ten years, even if not being used.  The rubber breaks down over time.  So it's probably a good time and reason to replace the spare anyway.  

[gim]

1 hour ago, Catt said:

 

Would it not be more cost effective to buy 1 tire the correct size?

 

Yes, but he already has the original set of smaller ones and the extra spare of that size too.

 

I am still on record of of replacing the spare so that it matches the larger set on the trailer, but @Chris Catignani advice to replace both with smaller versions could work in a pinch.  The most important item here is that you don't have one big tire and one small one for hundreds of miles on the trailer.  That's a recipe for disaster.

[Catt]

6 minutes ago, gimruis said:

Yes, but he already has the original set of smaller ones and the extra spare of that size too

 

The smaller tire-n-rims would easily sell on Facebook for enough to buy 1 the correct size. 

[TnRiver46]

The correct size would be ideal but if you have the wrong one, don’t go “hundreds of miles “ to get home, go directly to tire store 

[Dwight Hottle]

26 minutes ago, Catt said:

 

The smaller tire-n-rims would easily sell on Facebook for enough to buy 1 the correct size. 

This is the correct answer. 

[gim]

1 hour ago, Catt said:

 

The smaller tire-n-rims would easily sell on Facebook for enough to buy 1 the correct size. 

Not to mention who wants to change out TWO tires on a trailer instead of one?

[Darth-Baiter]

i think as a last resort, go for it.  i would go slow and go short.   total emergency.  like if i pulled up to my buddies busted tire and we had no resort but to loan him my 13".  

 

but if it could be avoided, i would get the correct one from the get go.  

 

the above car "donut" analogy was a good one.  put those on the back axle and your car doenst want to pull to one side.  i cant imagine a trailer doing it either.  the tire is spinning to match the speed the asphalt is going by.  it isnt isnt under power. 

[airshot]

On 9/18/2023 at 9:20 AM, Bankc said:

If you've got two tires of different sizes mounted to a fixed axle, the trailer will want to turn in the direction of the smaller tire.  For every revolution the axle makes, the larger tire will cover more ground than the smaller tire.  This will want to turn the trailer and cause you to pull the trailer at a slight angle and put a lot of wear on your tires.  The increased heat from the friction of the sliding tire (to make up for the lost ground) increases the chances of a blow out, and decreases gas mileage. 

 

Also, how old is the spare?  They only last about ten years, even if not being used.  The rubber breaks down over time.  So it's probably a good time and reason to replace the spare anyway.  

True on a solid axle but trailer tires/ wheels are independent so, no pulling but will ride at an angle for sure.

[airshot]

In all honesty, the rim size means little...tires come in different balloon sizes for the same rim diameter.  It is very possible to have a 13" wheel with a large balloon size tire that could be the same circumference as the tire with a 14" wheel size.  While all the afore posts were correct for safety reasons, the real issue here is getting tires with the same circumference no matter what the rim size might be.  Just look at all the different size tires in 14 & 15" wheel sizes !!  13" & 14"  tires can be the same.  If you don't want to spend what is needed to be correct at least match the circumference of the tires.  Most good tire dealers have a tire circumference chart for all the different tire sizes.

[Bankc]

56 minutes ago, airshot said:

True on a solid axle but trailer tires/ wheels are independent so, no pulling but will ride at an angle for sure.

Yeah, it's been about 20 years since I owned a trailer, and I never did mess with the trailer too much, so I my mind was a bit hazy on that.  Thanks for the clarification!  

[rboat]

I would get the 14" spare. If not that angle would wear the tires and put abnormal stress and possibly extra heat on that bearing. It could make steering a bit awkward and unsafe. If you were only going a few miles, maybe, but a long higher speed drive like you referred to, I would not risk it.

[WRB]

The OP has already made the change so the bolt hole must have been 5 hole pattern.

Know one is going to suggest you use different size / diameter tires on the same trailer. The question about is it possible and it is if the bolt pattern is the same. In an emergency the smaller spare drive at under 35 mph a short distance should be OK. The 13” tire will spin faster then the 14” and over heat if the speed is too fast.

Tom