# 8" vs. 12" trailer tires



## tincansailor

I have a 15' Alumacraft jon boat and the trailer has 8" wheels. I notice that the back end of the trailer will bounce more than I like it to when I hit a bump in the road. I only have a 5 hp motor on the boat so I realize that it is not very heavy and lead to bouncing but I was wondering if I went to 12" wheels if that would reduce any of the bouncing. Walmart has the wheels so they would be readily available. Just wondering if there is anything other than adding weight to the back of the boat that would help. Thanks!


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## russ010

I stepped up to 12" wheels on my 1546 just because I got more life on the tread of my tires. It sits a little higher so I have to back in farther to launch, but it made a big difference in the ride of the boat behind my truck. I don't feel all of the bumps like I did with the smaller wheel/tire...

It's still going to jump on some bumps, but there's not much you can do about it... but stepping up in wheel/tire size does help.


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## basstender10.6

I have 12" tires on my trailer. They ride nicer on the highways but they are a pain to launch a boat. The trailer is now much higher off the ground so unless you have a long tongue on your trailer, your truck tires will be in the water at shallow ramps. Just something to keep in mind. You might want to consider the 10" tires as a median.


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## Catarafter

I would think that the 12 inch rims would be a better option than the 8 inchers, but you will have to back down the launch more as mentioned previously.


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## poolie

I've always heard people refer to 8" wheels are bearing burners. On short trips it's probably not an issue, but it you have a long drive to the lake it's something it think about. Other than the launching issue mentioned by others there's no reason not to go to the 12" wheels.


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## screwballl

poolie said:


> I've always heard people refer to 8" wheels are bearing burners. On short trips it's probably not an issue, but it you have a long drive to the lake it's something it think about. Other than the launching issue mentioned by others there's no reason not to go to the 12" wheels.




That is the same as I have heard. They are fine for trips up to 2-3 hours, but any longer and you want the larger diameter tires for fewer revs on the bearings.


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## Ringo Steele

Keep in mind that there is more than one size for each wheel diameter. My trailer came with 12" wheels and 4.30? tires that were about 20 inches in diameter, but I replaced them with 8" rims with 5.70 tires at 18.5 inches diameter. 8" rims also come with 4.80 tires that are only 16.5 inches in diameter, so the 5.70 x 8 are between the two, and have worked well for me the last 13 years. I just replaced them with more of the same (I don't do interstate travel with my rig, so my speeds are usually under 60 mph. The 8 inchers I used are also about $20 cheaper per tire/wheel that the 12" units too.


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## PSG-1

screwballl said:


> poolie said:
> 
> 
> 
> I've always heard people refer to 8" wheels are bearing burners. On short trips it's probably not an issue, but it you have a long drive to the lake it's something it think about. Other than the launching issue mentioned by others there's no reason not to go to the 12" wheels.
> 
> 
> 
> 
> 
> That is the same as I have heard. They are fine for trips up to 2-3 hours, but any longer and you want the larger diameter tires for fewer revs on the bearings.
Click to expand...



This is what I've always heard, too, and it does make sense. The advantage of 8 inch rims is that it lets the trailer sit lower, which means you can launch in shallower water. However, you can 'gain a little draft' so to speak, by mounting the axle on top of the springs, rather than underneath them. This will allow for a shallower launch. 

The only disadvantage of the axle on top of the springs, is that the U-bolts point toward the ground, and if a tire goes flat and you hit a bump, it will likely gouge the pavement, and eat up the exposed threads of the U-bolts, requiring a torch or a cut wheel on a grinder to remove them.

I use 12 inch rims on all my trailers, except for my jet ski trailers, and I have all my axles mounted on top of the springs.


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## bcbouy

i let the air down on my 12" tires,especially if i'm travelling forest service roads.they bounce around like crazy when they're rock hard.


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## Butthead

My trailer came with 5.30 x 12" rims but I switched to the 4.80 x 8" tires because my usual launch ramp is very shallow and thankfully I'm only about 10 miles away. I'd definitely move up to the 12"s, but like bcbouy talked about, I wouldn't run around with the full 60psi in them if you can help it.


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## richg99

Big tires are better than small tires...as everyone above has already posted. Can't add anything to that.

You may ( probably do ) have too stiff of springs for your little lightweight boat. Perhaps you can remove one leaf on each side?? That will give you a softer ride. Check Harbor Freight for replacement springs.

Or...how about adding a five gallon bucket or two, filled with water, capped, and tied down to add some temporarily weight on your trips? Two buckets would put 80 lbs or so back there. If you find the buckets with a side opening, you can just drain the water into the boat and let it drain out the bilge opening. No lifting at the launch...assuming you can re-fill with a hose on both ends of your trip. Pull the stopper a block or two away from the launch and let her flow, let her flow. 

New, larger, tires and rims are the ultimate solution...but not the only solution.

regards, R


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## F239141

I do not understand the problems people have with the 8" I got some 5.70 x 8 Load Range D (8 ply 1040Lb per tire) on a utility trailer, and it has 1000's of miles on it, never one bearing problem and most of the mile are doing 75MPH behind the truck or motorhome on the Interstate. Granted I take care of my bearings. I also had 5.30 x 12 tires on it for awhile, but it sat to high with them, and did not tow as well. 

I got some light duty 4.80 x 8 Load Range B (4ply 560LB per tire) on my jon boat trailer ....... but its pretty light and never on the interstate.

The main thing with the trailer tires is not getting light duty ones if you are doing alot of heavy or high speed towing. Personaly I'm going to ditch the 4.80's for some 5.70's soon, but stay with the 8's to keep me form having to put the truck in the water at the ramp.

Point is 8 or 12 get a good quality tire, and if you are going 8's up it to the 5.70 give you almost 1" more footprint


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## PaThwacker

My trailer is an 86 and has 8" rims. I tried to find 12" combos but the inner hub diameter is 2.8". Thus stuck in 8" rim purgatory.


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## flatboat

I put snowmobile trailer tires on mine worked great ,I think they were 8" . They were wide and low , made it VERY easy to launch . I never made cross country trips with them , put the axels s on top to get it lower ,man you could launch that thing in a teaspoon ......your results may vary


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## PaThwacker

I found 5.30 x 12 galv on ebay as a kenda tire and rim combo. Allegedly advertised as 2.81 inner diameter. I ordered 2 w/free shipping. Hopefully they line up. I had ordered 2 through etrailer but they had to be custom manufactured w/3 week backorder. Fail.


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## PaThwacker

I tried the 12" ebay deal out. fenders were too small, and had to send them back (at $40 shipping). costly beta test


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