Trailer Tire Clearance

[tboltmike]

My trailer has a catwalk down one side and it acts as fender. I noticed that there are tire marks on underside of the catwalk.

Also, the trailer has P rated tires. Now that it is time to replace, I would like to go to trailer tires.

This is a single axle trailer with 14" five lug rims and leaf springs. The center of the axle to the catwalk measures 12.5 inches with the boat loaded on it. The 18' trihull boat is about 2000 lbs loaded out, but not sure about the trailer wt. It is galvanized steel.

It isn't practicle to raise the catwalk.

What would be a good method to get more clearance?

 

[Silvertip]

Re: Trailer Tire Clearance

You provided lots of data but not much of it useful in solving your problem.
1) What size tires are on the trailer now (Look at the sidewall).
2) Trailer tires have many available "load ratings" in the same tire size. You could probably go to the next size smaller trailer tire but with a higher load rating and still maintain the GVWR (gross vehicle weight rating) indicated on the capacity label on the trailer.
3) If the spring is mounted above the axle you can add a spacer block to increase the clearance. If the spring is mounted below the axle you cannot do that as it has the opposite effect.
4) Increase the length of the spring shackles.

 

[tboltmike]

Re: Trailer Tire Clearance

Thanks for the reply.

The tires are p185 r65 14's

 

[180shabah]

Re: Trailer Tire Clearance

Silvertip gave some great suggestions, perjaps you could provide a couple pics (with and without the tire) so we can see you exact setup.

Or, get another set of car tires AS LONG AS the load rating is sufficient for your total weight.

 

[dockwrecker]

Re: Trailer Tire Clearance

A 185/65-14 is the same as a 185/80 -13 height wise. Trailer tires don't come in 185/65-14, so if you want to use PROPER trailer tires you'll have to drop back to 13" wheels. But, the issue of the tires hitting up in the catwalk remains as the tires are the same rolling diameter. Are you sure that the marks aren't the result of pulling the trailer through a very uneven condition ie. deep gutter, over a curb etc that may have pushed the tire much higher than it normally runs? I can't see how the trailer could run anything smaller tire wise. Possibly the springs aren't adequate for the weight of your boat, adding a leaf may help or take them off to be re-arched at a spring shop or replace them. But as tempting as it may be to put passenger tires under there (yes I know the weight rating would indicate that you can) don't do it. Fix the height issue and get proper tires. If you want to stay with the 14" wheels, you're going to need an additional 2-3" to clear a trailer tire.

 

[Titanium48]

Re: Trailer Tire Clearance

A 185/65R14 is 11.7 inches in radius and you only have 12.5 inches between the axle and the fender. No wonder the tires are hitting the fender. The smallest 13 inch trailer tire (175/80-13) is actually taller (12.0 inch radius), so that won't fix the problem.

It might just be that the springs need replacing, but I'm wondering if the trailer was actually designed for 12 inch tires (10.6 inch radius), which a previous owner replaced with the 14 inch car tires that happened to be on rims with the right bolt pattern. If that is the case, your axle and suspension are likely rated for 2000 lbs and your trailer is slightly overloaded in addition to having tires that are too tall.

If you're not exceeding the spring and axle ratings, you could try load range D ST145R12 tires. These are rated for 1200 lb each and should solve the clearance problem.

 

[reelfishin]

Re: Trailer Tire Clearance

Had an older trailer that sounds similar to what the OP describes, it had expanded metal walkways down each side, over the wheels atop the fenders. It used 10" wheels with 20.5x8x10" tires which were about 21" or so in diameter. It would work with 12" tires but they looked lost in the wheel wells due to being much narrower than the original wheels. The tires were rated at over 1500lb each.

The proper amount of clearance between the tires and the tops of the fenders should be about 3/4" or so more than the distance of maximum spring travel. This allows for both tire expansion at highway speed and for the occasional unequal axle movement.

 

[wbc1957]

Re: Trailer Tire Clearance

An additional suggestion is to make sure the tires you are buying are freshly made. Many buyer's clubs or wholesale shops, and small time tire and service garages sell old stock. The DOT number will be on all tires made, like a branded animal. Just look along the mounting area of the tire until you see the letters DOT. The numbers after that represent the plant, the shift, and the date made. The last four numbers respresent the week and year the tire was made. An example would be 2210, meaning the twenty-second week of 2010. A rule held by most quality tire dealers, is to sell tires that are less than one year old from the date of manufacturing. This allows them to provide a decent dry rot warranty and sell at retail price. Buying at wholesale price somewhere, will be most likely buying a tire that was either discontinued, old stock (old DOT number), or not in popular demand. Food for thought...