8 inch tires not highway legal right?

Acton

Petty Officer 3rd Class
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Jan 15, 2015
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I bought a new to me boat w/ accompanying trailer that came w/ 8 inch tires recently. From previous experience with a previous harbor freight trailer I knew 8 inch tires where not highway legal, so on that trailer I took off the fenders and replaced them with 12 inch rims w/ tires. Even the 12"ers where only rated at 55 mph max speed limit, but at the time I felt more comfortable taking those on the highway then I did with the 8"ers. When I took my previous trailer for inspection last year little did I know that NYS recently changed their laws and beginning this year all boat trailers need to have fenders or they wont pass inspection, and the guys who did the inspection on that trailer last year gave me a hard time about it before passing it. On my last trailer I just took off the fenders and threw on the new tires, obviously that's not going to be possible with this trailer.

I've been told there are fender lift kits online but I cant find them, can anyone link me to these kits? And if not can they at least tell me what google query to use? I've tried googling "boat trailer fender lift kit, and trailer fender lift kit" with no success.

Also my neighbor mentioned that if I get thicker 8 inch tires those might be highway legal and I wont have to screw with lifting the fenders, is that true? From what I understand 8 and 12 inch tires aren't highway legal because at 65 mph plus they spin around to fast and heat up the bearings in the wheel hubs which could cause them to seize up. The width of the tire shouldn't make a difference in that case, it's the diameter of the tire that would define how fast the tire is spinning around right?

So just to summarize my questions are:
Where can I find a fender lift kit for a boat trailer to allow for larger tires
Is it possible to get thicker 8 inch tires that are highway legal so I wont have to get a fender lifter, or does the width of the tire not make a difference?

Just to be clear my axle taxes five lug tires. Pictures to follow.

Thanks!
 

JimS123

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Boy, some of the stories you hear these days.....LOL.

8" tires certainly ARE legal in NYS. It is very common to see light weight utility trailers, small boat trailers, etc. with 8 inchers. Of course, we're talking about road legal equipment.

Now, you might find a small trailer used in the backyard for lawn use that have 8" tires, but these are not highway certified and the tires will be labeled "not for highway use".
 

GA_Boater

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Where do these stories come from? :eek:

8 inch trailer tires are DOT approved, so of course they are highway legal.

BTW - DOT approvals are not needed for off-road tires for towing a trailer behind your Kubota or JD in the back forty..
 

jbcurt00

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IIRC Gator trailers had split rims w tube tires back in the 50s 60s and were about 8in rims, and they ARE illegal as are all split rims. So that may have been what started the confusion...

Bead lock rims too, I think....
 

Acton

Petty Officer 3rd Class
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Jan 15, 2015
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77
I think you guys misread my post. Running a utility trailer without FENDERS is now illegal in NYS. This is what I was told by the shop who inspected my trailer last year.

8" tires are usually only rated at max 45mph, 12" tires are rated at max 55mph. Both sets of tires I got from harbor freight say as much on the decal stickers they put on the rims. The max mph rating has nothing to do with THE NYS law I mentioned. Edit: I noticed that the topic title would be misleading. I didn't mean to say that 8"ers are illegal, but that they're not rated for anything greater then 45mph+.

I'll post a link to show you guys what I mean about mph ratings and rim sizes. There's plenty of topics here on iboats that talk about the issue but don't mention how to do fender lift.

http://forums.iboats.com/forum/gene...ties/trailers-and-towing/301913-long-distance

Here's a quote from the topic referring to what I'm talking about. Sorry again about the misunderstanding, the topic title was misleading.

An 8 inch tire will travel approx 25 inches for one full rotation while a 12 inch tire will travel around 37 inches for a full rotation using the Pi formula of 3.14159 to one to convert diameter to circumference. So a smaller tire spins more over the same distance wearing everything out along the way quicker. Tires, bearings, seals, etc...
 

roscoe

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Oct 30, 2002
Messages
21,657
trailer tires on 8" and 12" wheels are perfectly legal, and yes they are available rated for 65 mph.
So, the point is that you don't need to raise your fenders and use larger tires.

Don't look for good tires are harbor freight or northern tool.
Go to a trailer shop, or farm supply/tire center.

Spinning a hub on a bearing doesn't wear it out.
Lack of grease and water intrusion tear them apart.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Harbor freight cheep china tires may only be rated that low of speed. They are the cheapest round things that sort of hold air on the face of the earth. You cant call them tires, much less trailer tires (ST). Trailer tires meet DOT requirements and hold air

Real tires from a real tire company would be rated at a higher speed of 65 or 75. Load range c tires with pressure of 90 psi will sit behind a truck doing 75 for more than 24 hours straight with over 700# each on them. Load range D will hold more

Fenders have been required for years
 

Bayou Dave

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So, you need to raise the height of the fenders to accomadate the 12" tires. Post a pic of your fenders with the bracket they now have and where they will go on the trailer. I am sure we can figure out how to raise them.
 

H20Rat

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Harbor freight cheep china tires may only be rated that low of speed. They are the cheapest round things that sort of hold air on the face of the earth. You cant call them tires, much less trailer tires (ST). Trailer tires meet DOT requirements and hold air

Not saying they aren't cheap, but I've had shockingly good luck with them. I've got one of those HF folding trailers, had it for 10 years, and only replaced one tire, with another HF tire. (sidewall puncture) I put on about a thousand miles each year on it, and it has been SEVERELY overloaded and generally abused. (so apparently you aren't supposed to put 2500 pounds of dirt on a trailer rated for 1100... The bowed axle did return back to normal though!)
 

km1125

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An 8 inch tire will travel approx 25 inches for one full rotation while a 12 inch tire will travel around 37 inches for a full rotation using the Pi formula of 3.14159 to one to convert diameter to circumference. So a smaller tire spins more over the same distance wearing everything out along the way quicker. Tires, bearings, seals, etc..
Just to correct this... We're talking about 8" or 12" rims, right... not the outside tire diameter. The calculations above would be if the outside diameter of the tires were 8 and 12". It is true that generally an 8" rimmed tire will rotate more than a 12" rimmed tire, but the difference may not be as significant as 50% if the tire sidewalls are different. In my case there was only about a 10% difference in actual wheel RPMs
 

bigdee

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Jul 27, 2006
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Not saying they aren't cheap, but I've had shockingly good luck with them. I've got one of those HF folding trailers, had it for 10 years, and only replaced one tire, with another HF tire. (sidewall puncture) I put on about a thousand miles each year on it, and it has been SEVERELY overloaded and generally abused. (so apparently you aren't supposed to put 2500 pounds of dirt on a trailer rated for 1100... The bowed axle did return back to normal though!)

I have built 3 of those HF 4x8 folding trailers the oldest (8 yrs) and most used one still has the original tires. Like you I have towed it thousands of miles, overloaded the trailer capacity and the tire capacity many times. I did away with the foldable feature along with the tilt bed and instead added slide out ramps that hang under the bed. Great trailer. It is light enough for an old man like me to un-hitch it and roll it out of the way. The tires say max speed =55 but have been 70+ on the interstates. I always make sure tires are inflated to 60psi.
 
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