Need help with new trailer tires

[txarmydude]

My boat project is going to need new tires. I have a 1978 Cobalt 18' Ski boat. It sits on a single axle trailer that has one cheap-o radial tire on one side, and a dry-rotted bias-ply tire on the other. The rims are size 14.5" (I had never even heard of such a size before I got this thing).

I had given some thought to just buying new rims altogether. I don't like the color of these rims, and I think maybe new rims might dress the trailer up a bit. Many websites sell the tires pre-mounted on new rims.

My problem is this: I don't know what the boat weighs and I would like to avoid trailering the thing all the way to the truck stop to use the scales on these crappy tires. I need opinions on what size tire is going to be appropriate for this trailer, and what load rating it needs to be.

Thanks for the help....

 

[Silvertip]

Re: Need help with new trailer tires

Look at the existing tire sidewall for the actual tire size. Also look for the load capacity of those tires at maximum inflation pressure. Buy new tires with the same or higher capacity.

 

[Bondo]

Re: Need help with new trailer tires

The rims are size 14.5" (I had never even heard of such a size before I got this thing).

Ayuh,... That's the size used on Housetrailers....

What is the bolt pattern of these wheels,..??

 

[mfgniagara]

Re: Need help with new trailer tires

14.5" is a valid tire size but not on boat trailers. If you do indeed have 14.5" tires, chances are someone replaced the axle using one from an old camper or commercial trailer.
What does the tire size read on the sidewall?
Got any pics? Do the rims have a normal lug pattern?

 

[txarmydude]

Re: Need help with new trailer tires

Here are some pics of the rim and bolt pattern.

 

[txarmydude]

Re: Need help with new trailer tires

Bolt pattern measures 4 1/2" so I assume that a standard size wheel will fit.

 

[Bondo]

Re: Need help with new trailer tires

Bolt pattern measures 4 1/2" so I assume that a standard size wheel will fit.

Ayuh,... So go buy a set of either 14", or 15" tires, 'n wheels...
As 14.5" is a Non-standard, single-use size that Don't belong on a boat trailer...

 

[dockwrecker]

Re: Need help with new trailer tires

^Roger that. If you've accurately measured skipping one lug center to center and have 4 1/2 ", that's a common 5-4 1/2 axle pattern and given what I've found about the weight for your #2700 boat, well within standard capabilities of aftermarket products. From looking at your photos, those appear to be stock Ford 15" rims that someone mounted 14.5" Dayton style trailer tires on. (with considerable effort to do so!) Best to lose them and pretty things up with some 15" tires and wheels. 14" will also fit but you'll have better load rating options in 15". I'd recommend going ST (means trailer rated) tires, with radials if you tow any distance. You can knock yourself out researching prior threads about tire quality and the benefits of radials vs. bias ply. 99% of the tires out there are Chinese/Taiwanese in manufacture, most of them of questionable quaility in bias ply applications. There are good quality radials built by Maxxis, Kumho, maybe Cooper available to you depending what's in your area. Bias ply tires are a crapshoot given that there hasn't been a reason for manufacturers to invest in new technology in such a limited market. Most are re-branded copies of 40 yr old tech. Expect to change a bias ply tire regularly. Given your single axle trailer, it's wise to invest in better quality radials rather than risk a blowout with an unknown quality bias ply. Single axle blowouts are always bad, and my advice is driven towards getting quality radials as a margin of safety. I'm sure there will be several to follow about the great deal they got at Wally World or how long they've limped around on Brand X or Y. Regardless of what you buy brand wise, err to the higher load capacity, and use the stated max pressure on the sidewall. Nothing ruins a boat trip short of sinking faster than a bad tire.

 

[txarmydude]

Re: Need help with new trailer tires

Thanks for the write up. What type of weight rating should the tires have? I have seen some tires rated at 1850 lbs; would that be sufficient?

 

[txarmydude]

Re: Need help with new trailer tires

Would this work?

http://www.easternmarine.com/ST225/75R-15-RADIAL-Tire/Rim-Ptd/

 

[dockwrecker]

Re: Need help with new trailer tires

Should be OK but it's close if you have a boatload so to speak. 1850 X 2= 3700lbs. NADA weight given dry for your boat is 2700, trailer and fuel, onboard crap is probably another 1000. Thus, you'll be right at capacity with no magin of error. Again, err to the safe side. If you can find tires with a bit more capacity, it can only help.

P.S. I've never seen a 14.5" radial tire.

 

[txarmydude]

Re: Need help with new trailer tires

Thanks a lot for your help!

 

[skyking897]

Re: Need help with new trailer tires

Looks like an old Ford rim. They used that 14.5" on early 1980's Thunderbird. Wasn't too popular and most people bought 14" or 15" wheels and tires as a replacement. Was only used for a couple of years, that should tell you something.

 

[wbc1957]

Re: Need help with new trailer tires

Wrong, sorry. The '80's Thunderchickens and Muscrats were using metric sized rims, not inched (or in this case half inched tires). Getting a tire on a rim with a half inch smaller diameter is possible, foolish, and just plain dangerous. My guess is the previous owner went to a local yokel and they just didn't have his size handy, but wanted to rid themselves of these two oddballs. The risk was on the road all these years, which makes me continue to wonder just what else is on the roads these days to deal with and watch out for....

 

[gozierdt]

Re: Need help with new trailer tires

I bought Kumho 857 D range tires from Tire Rack last summer, and I'm very happy with them
so far. Around 2000 lbs load rating in a 195R14 size. About $100/tire. I also got Galvanized
wheels from Trailer-Wheels.com for $40/each. Tire rack has a list of installers in your area that
will mount the tires for you.

 

[DJ]

Re: Need help with new trailer tires

Some "lively" discussion here:

http://forums.iboats.com/showthread.php?t=454668

 

[wbc1957]

Re: Need help with new trailer tires

If you go to Cobaltboats.com you will see their library of brochures and owners manuals. It will tell you your boat is 2800 lbs. dry. Therefore, you can expect to add an extra 1000lbs for fuel, accessories, and the trailer itself. This leads you to plan on at least a 6 ply rated trailer tire in the larger 14 inch sized tire that fits under your fenders, if you have them. Most likely a 205/75x14 either in a radial or bias design, your choice. BUT, you will need to check your rims and most likely, you will wish to replace them due to their questionable previous use with fitment problems. I have a Cobalt with the same weight also, and run a single axle also. Brand, level of price, and planned maintenance is all up to you. Tires are bashed here as much as Bayliners, but you'll catch onto that fast enough....

 

[txarmydude]

Re: Need help with new trailer tires

I got my wheels and tires in this week. I went with these from recstuff.com .

http://recstuff.com/ST225-75R15-Load-Range-D-Radial-Trailer-Tire.aspx

I chose to use radials as opposed to bias ply tires. The tires look great on the boat, and it is obvious that they are going to be plenty strong for my application.

Only one issue..... Now the fenders don't fit!!! No big deal, I will just go to the metal fabricator and have him cut me some 1/4"x2"x3" steel extensions for the bolts to allow the fender to ride higher.

 

[jayhanig]

Re: Need help with new trailer tires

I know this is a little late to throw this in but I hope you're not going into salt water with those rims. You'll want galvanized rims if you are. If those are for fresh water use you're good to go.

 

[txarmydude]

Re: Need help with new trailer tires

Nope, just freshwater!