Preferred Size of Boat Trailer Wheel - 13" or 15"

[Noelm]

Just adding to the diameter thing, there can be way more that 2" difference between the overall diameter of 13-15" wheels, the tyre profile determines that, not the rim size, the 13" I am changing out, are nearly 2" smaller than the old 13" tyres, and still "light truck" rated, and capable of carrying the weight. Measure the overall diameter of a big 4X4 15" then measure a 13" trailer tyre! Do not get cheap Chinese tyres in any size, look for a known brand. When they build the trailer, they use offset springs, meaning the axle doesn't sit in the very centre of the spring (but you can buy centred springs) for 13" wheels, they will have them reversed to 15" wheels to keep the spacing between the tyres the same. If I think of it later, I will take a picture with a tape to show the difference between the two 13" setups.

[tunaticer]

I would opt for 13" wheels. Lowering the trailer a little can make a big difference in loading and unloading your boat on relatively flat angle ramps.

If you are overheating your bearings the most likely cause is your brakes not releasing fully causing friction heat being transferred into the grease breaking it down.

Good quality bearings and fitted and adjusted correctly will definitely not overheat at 110kph.

Look at the little Mini cars that used to drive around on 12" wheels that did not have bearing issues... in fact it was uncommon to do a bearing on these cars.

[Lovey80]

The heat build up isn’t an issue unless there is a brake issue or heavy braking before launching. By the time the boat is ready at the ramp, the hubs are always cool. Though I do run durahub oil instead of grease which also helps. Attached is my single axle off road build. Absolutely love them.

[Noelm]

That's a damn fine setup, beats my pile of rust........

[Splash]

Thanks Gents. Fantastic input!

Noelm - What is the issue with high profile 13" tires for boat trailers? Can you advise the make/model/spec of the lower tires you will instead be using?

Lovey80 - Nice setup. Where and how do you insert the durahub oil? How does this oil get retained in it's place?

FYI - Here is the link for the trailer I have ordered (SA6.5-2300T) - Scroll down to see the specs:

ALLOY TRAILERS – Easytow Boat Trailers


Splash

[Noelm]

I just wanted to get the boat as low as possible on the trailer for launching/retrieving, I will have a look at the tyres, I got them complete off a wrecked excavator trailer, rims, tyres and any parts I wanted for a case of beer! Nothing wrong with higher profile tyres at all, or 15" either, it's just because of my trailer design (for a cat) the boat sits very high, and when I rebuilt it, I changed as much as I could to lower it, every bit counts.

[Dignity]

All good info, my 15" aren't higher than the 13" I had on previously. The reason for the change was I uprated my trailer to 3T as 2T would have left me liable as the tyres and rims were under rated. Check the rims, on the inside they should have a rating, also the tyres needed an increase in rating and tyres also have a life, generally 5 years.
Have and accident and all 3 items can void your insurance. As this unit is already over 1700 kg dry weight it will definitely go over 2T by the time it is loaded to go fishing,therefore work for at least a 2.5T rating.

[Splash]

Thanks NoelM and Dignity.

So, all 4 x wheels on the tandem trailer should each have a load rating of at least 2.5T?

Splash

[Lovey80]

Thanks Gents. Fantastic input!

Noelm - What is the issue with high profile 13" tires for boat trailers? Can you advise the make/model/spec of the lower tires you will instead be using?

Lovey80 - Nice setup. Where and how do you insert the durahub oil? How does this oil get retained in it's place?

FYI - Here is the link for the trailer I have ordered (SA6.5-2300T) - Scroll down to see the specs:

ALLOY TRAILERS – Easytow Boat Trailers


Splash

a double lip oil seal like the one below. I use speedy sleeves over the axles so there is a super smooth surface for it to spin on. Just for that extra little bit of insurance. If you look closely on the curved side of the durahub there is a little ally hex nut for filling and draining them. Oh and a tip if you are going that route with dual axles. When backing down the ramp, if there is a bit of a turn where the axles can get a bit of sideways torque on each other and it doesn’t fully come out before you hit the water. Just drive forward a few meters and back back down so there’s no sideways torque on the tyres. Sometimes a little bit of water gets in that way. Even then, the beauty is you know it’s there and can come home and drain/refill without damage. The ones in the picture above lasted 5 years and when I replaced them, just because, they were like new.

[Splash]

excellent - thanks Lovey80

[billfisher]

If you winch on it saves a lot of maintenance if you can keep your hubs/ bearings out of the water (also more of the trailer and axles and springs). Larger wheels can enable this.

[Noelm]

As long as your trailer is OK to have all that weight on the end before it gets to the point of balance!

[Dignity]

Thanks NoelM and Dignity.

So, all 4 x wheels on the tandem trailer should each have a load rating of at least 2.5T?

Splash

Combined, surprising how many rims will be below the necessary rating.

[tunaticer]

I just wanted to get the boat as low as possible on the trailer for launching/retrieving, I will have a look at the tyres, I got them complete off a wrecked excavator trailer, rims, tyres and any parts I wanted for a case of beer! Nothing wrong with higher profile tyres at all, or 15" either, it's just because of my trailer design (for a cat) the boat sits very high, and when I rebuilt it, I changed as much as I could to lower it, every bit counts.

I set my boats as low as possible at the back of the trailer then up about 40mm towards the front.
This nose up attitude helps with both launch and retrieve even with drive on setups.
It also is better for draining the hull if you leave it hitched to the tow vehicle

[DATCOL]

Available 13" tyres 195/50x13 C L/T (light truck) 900KG load rating per tyre 520Mm high ( 165x13 C LT 670KG load 596 Mm high) (175x13 C LT 730KG load 611Mm high ) ( 185x13 C LT 800KG load 627 Mm high )
Cheers COL