Got a question about tires

[leesumm]

My boat is a 15 foot trihull with a 70 hp Johnson. Its an old boat , boat/motor/trailer are about a '77 model. Right now it has 5.30x12 tires on a 4x4 bolt/hole pattern. The boat sits high on the trailer and off the ground. With the low water we have now and the short distance (15 miles) I travel to the lake I am thinking of replacing the tires to a 4.80x12 same hole pattern. Its a single axle trailer. Most I would pull the trailer is maybe 85 miles once or twice a year but mostly the 15 miles to the local lake. Will I be in trouble with the smaller tires? It will lower the boat about 4 inches which will improve unloading and loading in shallow water.

 

[EddiePetty]

Re: Got a question about tires

In lieu of changing wheel assemblies, do you have sufficient clearance to place the axle on top of the springs?

The 12" wheels are so much easier on bearings and tires, especially at highway speeds. I just went the other way on our Stumpnocker...from 8" to 12"!

 

[matt167]

Re: Got a question about tires

You may be ok for short distances. Not that big of a difference What I would do for long distance is use the tires you have now, and buy a set of 4.80/8's on rims from TSC or Northern and then swap out the tires when you get to the ramp. Smaller wheel increases the bearing speed, but going a bit slower does cure that.. 15 miles at 50 MPH might be ok, but same speed going 85 miles is impractical.

 

[leesumm]

Re: Got a question about tires

I do have 12 tires now but they need replaced due to weather cracks. My thought is going to 4.8 x 12 from 5.3 x 12 same 12 inch rim but about 4 inches shorter in height. Just a smaller tire.

 

[leesumm]

Re: Got a question about tires

You may be ok for short distances. Not that big of a difference What I would do for long distance is use the tires you have now, and buy a set of 4.80/8's on rims from TSC or Northern and then swap out the tires when you get to the ramp. Smaller wheel increases the bearing speed, but going a bit slower does cure that.. 15 miles at 50 MPH might be ok, but same speed going 85 miles is impractical.

My thoughts the 4.8 tires are rated at 735 lbs and not sure what the 5.30 tires are for rating. The closes lake is 6 miles the furthest lake is roughly 25 miles Only once or twice would I travel the 80 plus to the other lake and that would be in the fall at trout stocking. I don't think my boat /motor and trailer has the weight to worry about only for 6 to 15 miles on smaller tires. I really didn't know for sure. At any rate both tires need replaced due to weather cracks and its just about the same cost as tire and rim as it is for tire alone.

 

[MH Hawker]

Re: Got a question about tires

As long as the load rating is the same it should be fine.

 

[Bondo]

Re: Got a question about tires

My boat is a 15 foot trihull with a 70 hp Johnson. Its an old boat , boat/motor/trailer are about a '77 model. Right now it has 5.30x12 tires on a 4x4 bolt/hole pattern. The boat sits high on the trailer and off the ground. With the low water we have now and the short distance (15 miles) I travel to the lake I am thinking of replacing the tires to a 4.80x12 same hole pattern. Its a single axle trailer. Most I would pull the trailer is maybe 85 miles once or twice a year but mostly the 15 miles to the local lake. Will I be in trouble with the smaller tires? It will lower the boat about 4 inches which will improve unloading and loading in shallow water.

Ayuh,.... The 5.30 is a heavier duty tire over the 4.80, 'n their diameters are nearly the same...
The 4.80s might not be rated at a high enough load limit too...

Goin' to an 8" wheel will lower the load, 2"s at best...

 

[NYBo]

Re: Got a question about tires

No way you'd lower the boat 4". That would mean a difference in diameter of 8". They are actually only around 1.5" different, for a lowering of 3/4".

 

[Frank Acampora]

Re: Got a question about tires



You did write 4.80 X 12 and they do make them, but did you mean 4.80 X 8?

Here is a 15 foot Glastron with a 105 Chrysler with power trim--about 275 pounds for engine. As you can see, it is sitting on a trailer with 4.80 X 8 tires. Total weight is probably pretty close to the 1580 pound capacity of the two tires.

Usually I tow about 17 miles to the ramp at speeds varying from 45-55. Occasionally I tow 1 1/2 hours to the Chesapeake and I have even towed it 135 miles up the Jersey turnpike at speeds of 60.

SO: Do you think you will be Ok with 4.80s? On a 12 inch wheel, certainly. On an 8 inch wheel most likely. Just be certain to carry a spare.

I have had them (4.80) for years. I always did want to upgrade to 12 inchers but there is no room under the fenders so I stay with the small tires..

 

[leesumm]

Re: Got a question about tires

Thanks Frank, yes I did write 4.80x12, I have 5.30x12 on the trailer now and both are weather checked and one is leaking. I was in a local farm store the other day and noticed they had the 4.80x12 on the same rim. I put the two sizes side beside and compared, the 4.80x12 is about 2 inches shorter than the 5.30 ( I did also write that the smaller one would make 4 inches difference in height but meant about 2 inches). It just made me think about launching in shallow water and gaining lower ground clearance with the 4.80's to the 5.30's . The 5.30's on rims are 75 $ and the 4.80's are 59$ on rims. So I was just wondering if the size would make that much difference.
But if yours is running on 8 inch I should be fine then. Thanks.

 

[NYBo]

Re: Got a question about tires

Remember that the trailer will only be lowered by 1/2 the difference in total tire "height".

 

[Bamaman1]

Re: Got a question about tires

Go for the heaviest rated tire you can get. Disregard price. There's nothing worse than a surprise--50 miles from home--with a blown tire. Your tires are already marginal at best. If you were buying a boat trailer today, it'd probably be 13" tires.

 

[JimS123]

Re: Got a question about tires

The OP is talking about 12" tires and 12" tires. Where did the responses for 8" tires come from?

 

[EddiePetty]

Re: Got a question about tires

The OP is talking about 12" tires and 12" tires. Where did the responses for 8" tires come from?

They followed my lead! :redface:

In my haste, while watching Jimmy Johnson splatter the wall at Phoenix, as I read the OP's initial "480" comment may feeble mind made the jump to 8" as this is that tires normal wheel diameter for that tread width.

Whew, looks like the blind leading the blind!

 

[bigdee]

Re: Got a question about tires

4 inches???? I have 4.80x12 on my utility trailer and use a 5.30x12 for the spare it is 5/8”taller.

 

[roscoe]

Re: Got a question about tires

Might I suggest 5.70x8 load range C 910# capacity each.

If you have room to mount them, you can get them with rims for about $50 a piece.


Don't worry about 8" wheel speed vs 12" wheel speed.

If your bearings are good, and greased, they will be fine.

People have been running 8" wheels for decades with no problems.

H188 & LOADSTAR 8 and 10 inch Tire/Rim at Trailer Parts Superstore

 

[lrak]

Re: Got a question about tires

You may be ok for short distances. Not that big of a difference What I would do for long distance is use the tires you have now, and buy a set of 4.80/8's on rims from TSC or Northern and then swap out the tires when you get to the ramp. Smaller wheel increases the bearing speed, but going a bit slower does cure that.. 15 miles at 50 MPH might be ok, but same speed going 85 miles is impractical.

Changing wheels at the ramp is crazy. I've towed from New England to the FL Keys four times on 8" tires. I've also put tens of thousands of miles on utility trailers with 8" tires over the years. I just keep it under 75 except for very short bursts to pass and check the bearings every few hours when I need gas/food/bathroom break. If the tires aren't rotten and the bearings are well lubricated 1200rpm is NOT an issue.

 

[ajgraz]

Re: Got a question about tires

Have you considered a drop axle?

 

[leesumm]

Re: Got a question about tires

After all the reading and thinking I went with a set of 5.70x8 I found. Good looking tire and its a 6 ply with a load rating C of about 915 lbs I think. After putting them on the trailer they look like they belong on there instead of the 5.30x12 that was on it. Its suppose to get up to 65 here today so think I might have to go to the lake today and see if it makes any difference . They did lower it about 1 1/2 to 2 inches.