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Author Topic:   What size tire?
whalertim posted 11-20-2001 08:49 AM ET (US)   Profile for whalertim   Send Email to whalertim  
I have been reading Jim's reference section on tires and wondered, what size tire do most whaler owners run on their trailers and do you run Bias or Radial?
JBCornwell posted 11-20-2001 11:23 AM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
I have 1.75X13C on both trailers, WhalerTim (and one spare shared by both). One trailer carries a Montauk, the other an OR-18.

We will now hear why that is the wrong tire to use. Heh heh. :)) Fire away, Z.

Red sky at night. . .
JB :)

bigz posted 11-20-2001 01:59 PM ET (US)     Profile for bigz    
Seems a "tad" narrow jb! think my daughters roller skate wheels are about that wide ---

Tim use the largest size which fits your trailer configuration safely. We have one trailer with bias and two with radial both seem to work ok. Tom

whalertim posted 11-20-2001 02:15 PM ET (US)     Profile for whalertim  Send Email to whalertim     
I am thinking of replacing my tires this winter and moving up to a 14" in the place of a 13. I am also going to replace the springs, wheels, and axle. It all needs replacing, so I thought I would move up in size.
Dick posted 11-20-2001 02:26 PM ET (US)     Profile for Dick  Send Email to Dick     
The correct tire size and load rating will depend on the weight capacity of the trailer and if it is a single axel or a tandem.

My 1999 Montauk trailer is a 2400# capacity Shorelander running ST185/80R13C radial tires.
The trailer under my 1988 13' is a 1000# capacity E-Z Loader running 480x12B bias ply tires.
Both are the correct tire size for the trailers they are on. If I dropped down to an ST175/80R13B on the Montauk trailer the weight capacity would drop to 1750#s. Hence trailer capacity is goverened by the frame construction, spring capacity and tire size.

Tsuriki BW posted 11-20-2001 07:32 PM ET (US)     Profile for Tsuriki BW  Send Email to Tsuriki BW     
I'm running ST175/80D13B 13x4.5 tires on my Caulkins trailer for the Dauntless 14. Couldn't tell if they are radial or bias. Assuming bias. The trailer is longer than necessary for the 14 and I was told it would fit a 16. Max load is 1750lb on the label.

Dick, you have one heck of a trailer...2400# for a Montauk? WOW. You seem right on with the statement that moving down to the 13B would reduce the load to 1750 (as is mine).


Tsuriki BW posted 11-20-2001 07:36 PM ET (US)     Profile for Tsuriki BW  Send Email to Tsuriki BW     

Remember, JB Cronwell runs the minimum hp therefore his motor is soooo light, tiny tires are OK. LOL


Dick posted 11-20-2001 08:13 PM ET (US)     Profile for Dick  Send Email to Dick     

My trailer was part of a factory Sea Ray package. The customer didn't want a trailer with his boat so I grabbed it, at the right price. A perfect fit for the Montauk, allthough I don't need that much weight capacity I know I can't overload it and it tows like a dream.


JBCornwell posted 11-20-2001 08:53 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
OOOPS! Where did that decimal come from???

Does 175/80R13C sound better, Tsuriki? Let your girl-child try to skate on those, Z.:)

BTW, my "minimum hp" Suzi 70 on the Montauk weighs more than a OMC 100 V4.

Now if I can just figure out how to disguise a Yammy F225 as a 150 for my OR-18. . . OOPS!

Red sky at night. . .
JB :)

Dick posted 11-20-2001 09:06 PM ET (US)     Profile for Dick  Send Email to Dick     

Those 175/80R13Cs are fine for the Montauk, should give you a max capacity of 2000#s depending on the trailer. Unless you have a tandem under the Outrage you had better shop for a new trailer.

JBCornwell posted 11-20-2001 10:29 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Good point, Dick.
Actually, "C" loading is 1350#per tire. The rest of the trailer is a 3400# axle and 1500# (ea.) springs. I pulled rusted out 14" wheels off of it to bring it home.

I will replace it, however, because it is a roller that I bought just to get the OR-18 back to Texas. I want a 3000-3500# keel roller and bunk trailer for the Outrage.

triblet posted 11-20-2001 10:58 PM ET (US)     Profile for triblet  Send Email to triblet     
I've got Goodyear ST175/80R13s, load range C,
1350 pounds each at 50 PSI max, under my
Montauk. Trailer is a Shorland'r with about
2400 pounds capacity (gross). It came with
some bias ply tires (never heard of the
brand), and I put the radials on when they
wore out. It seemed to tow a little
straighter and easier with the radials, but
that's subjective.

Dick, the old OR-18 is only a touch heavier
than the Montauk. JB may be OK with those
tires, but I'd put the rig on a scale.


Dr T posted 11-21-2001 12:03 PM ET (US)     Profile for Dr T  Send Email to Dr T     
My 13 rides on the little 4.80 x 12. Right now I have a couple of wheels that I could use for a different tire. Has anyone tried the 12 in. passenger car radials?


jimh posted 11-21-2001 07:27 PM ET (US)     Profile for jimh  Send Email to jimh     
I have Goodyear Marathon ST Radials on both my trailers. On the 15-Sport's trailer they're 13-inch tires; on the 20-Revenge they're tandem 14-inch tires.

I just replaced the tires on the tandem trailer (all five) late this summer. While towing to Missouri we were in rain most of the day. Just as it got dark we had very heavy rain, and the wind switched from a 30-knot southerly crosswind to a 30-knot northerly crosswind as we drove through the storm front.

The trailer behaved beautifully; I was very glad to have the new tires on it.

swede5 posted 11-21-2001 11:18 PM ET (US)     Profile for swede5  Send Email to swede5     
I have 13 inch tires on the original holsclaw trailer under my 22 revenge. Does any body else have a holsclaw trailer?
RSKC posted 11-25-2001 01:35 AM ET (US)     Profile for RSKC  Send Email to RSKC     
I replaced the 480/12 trailer tires with 155R12 passenger tires. Max load is 925 lbs. at 44 PSI. I believe this tire is a better performer than the 480 or the 530/12 at lower air pressure. I run less than max air pressure because I run less than max load. I have used these tires for years with no problems and my boat gets a better ride. Do not lower the air pressure in regular boat trailer tires.
lhg posted 11-28-2001 06:09 PM ET (US)     Profile for lhg    
Sizing your trailer tires is really no big deal, since the max load carrying capacity is always shown on the tire. You just have to know the correct weights of your boat rig and trailer. It is always good to have a few hundred pounds leeway.

Here are my basic rules on tires for a trailer:

1. Use trailer rated tires, since they carry more weight for a given size. Your trailer usualy has a plate which specifies the tires it was designed for.

2. Spend the few extra dollars for radials.
They are MUCH safer and less like to blow, with better traction in wet weather and a wider footprint. They also have a slighly higher load carrying capacity & wear 50% longer. There are three major brands, Goodyear, Carlisle and Titan. I have had the best luck with Carlisle, which are very similar in appearance to Goodyear Marathons. The Titans have a narrower profile. But have never had a blow out with any of these.

3. Keep them inflated to the full allowable pressure.

4. Unless you have a 15' or smaller Whaler, use at least 13" wheels, always load range "C" or higher. (All passenger car tires are load range "B".)

What do I use?

For my 18 Outrage, a 2800# capacity single axle trailer with Goodyear P205/75/R14 Marathon radials, 1760# capacity each tire.

For my 25 Outrage, a 6000# capacity tandem axle trailer, with same tires as above, except Carlisle brand.

gunnelgrabber posted 12-01-2001 09:37 PM ET (US)     Profile for gunnelgrabber  Send Email to gunnelgrabber     
tire/wheel question before the cat dies: my trailer came from the bw dealer with the boat best i can tell.. it has those doughnut,high floatation looking 20.5 x80 on 10 " wheels.they do fine.i have a 4.80x12 as a,all of you seem to say you need 13" wheels?...that seems like it'd mess up your height by putting you higher up...added hassle launching? the tire-wheel setup i have unsatisfactory or risky? i've gone 170 miles one way several trips ,haven't pulled to the keys yet...have i missed something here? a 16 katama....lm
triblet posted 12-02-2001 10:09 AM ET (US)     Profile for triblet  Send Email to triblet     
The problem with 10" wheels is that that the
wheel RPM is higher. 65 MPH with a 10" is
about the same RPM as 85 MPH with a 13".
That means the bearings have to work harder,
and I suspect there's a square law (or worse)
relationship between RPM and bearing wear.

It would be far more effective for launching
to have a trailer with 13" wheels where the
the boat sits between the trailer wheels
rather than above them. This is a point
often missed, and something I was fortunate
to stumble into by getting the right sort
of trailer with the boat. I rarely get even
the truck tires wet, and then only if things
are sloshing pretty good on the ramp.


AZdave posted 12-03-2001 02:45 AM ET (US)     Profile for AZdave  Send Email to AZdave     
I've been using 155R12 passenger car tires on the trailer for my 13 ft. I don't run the boat trailer really long distances, but my utility trailer has been around the country the long way. I found that the bias ply trailer tires wore rapidly, and I had trouble with pinholes in three different tires. I eventually put tubes in them. The radials track well, show very little tread wear, and are agressively marketed by the tire chains down here. The price is a lot less than trailer tires. Note that in this application I have some overkill on load capacity. I'm not sure I would push generic radials to their maximum rated capacity. Smooth rolling. Dave
whalerron posted 12-04-2001 05:51 PM ET (US)     Profile for whalerron  Send Email to whalerron     
I have read that radial tires should not be used on trailers because of the tendency for the tire tread to "roll" away from the rim during turns. This has the potential to cause the trailer to swerve. Until now, that was the only school of thought I had read concerning radials on trailers. The SEMA article below contradicts this.

Here is some interesting reading concerning trailer tires:

From Champion Trailers:

From Field & Stream (see the section Buying the right rubber):

From SEMA. (See Bias vs. Radial) This article clearly states that radials are ok on a trailer:


skookum point posted 12-14-2001 12:49 AM ET (US)     Profile for skookum point  Send Email to skookum point     
The 12" tires on my 15' whaler trailer feel much warmer than the tow vehicle tires after a few hours of 75mph freeway driving. so, I plan to change to 13" next season to reduce the rpm's and hopefully solve the oveheating and possibly avert a very inconvenient tire failure.
Whalerdan posted 12-14-2001 09:23 AM ET (US)     Profile for Whalerdan  Send Email to Whalerdan     
I've heard the same thing, not to use radials. Also had a friend who had that problem with the trailer swerving using them. He went to bias ply and cured it.
lhg posted 12-14-2001 03:58 PM ET (US)     Profile for lhg    
If trailering a 25 Outrage close to 100,000 miles over the last 12 years means anything in trailering experience, and using 14" trailer rated radials for the entire time, I can say that all this talk about bias tires being better, or safer, is untrue. Why don't we still use them on our cars? They are basically out of date tire technology, and the only reason they are still being made is for "price points" in the bottom line trailer industry.

The reason given to buy bias tires, trailer swerve, is strictly a function of tongue weight and a properly loaded and secured trailer. It could be, with the slightly lower profile of the radial, that tongue weight is effected on some rigs, so maybe the trailer wheel carriage has to be re-adjusted for radials. One should have almost 10% of total loaded trailer weight on the tongue. If you do, will not get swerve with radials.

My experience is that they are superior in all respects. Great wear, slightly higher load capacity (at least in the 14" size - 1710 vs 1768 lbs), better traction, cooler running which means less likely to fail and shread on you, etc. The traction of radials, particularly on a wet road, is a major reason to buy them. This prevents fishtailing and loss of control more than anything.

Once you have them, you will agree they're worth the extra $15 a tire. Be sure to have them balanced. Remember, I am talking about trailer rated load range "C" or "D" radials, not automotive load range "B" radials. The trailer tires have stiffer & stronger sidewalls and require 50psi inflation. Most of this also refers to the 13"-15" size tires.

To me, the most important issue in trailering a big Whaler around, is knowing that I have it on a safe and well equipped trailer, and the radial tires underneath it re-inforce this feeling. Roadside tire failures are the last thing you want to spoil your recreation time with the boat, or even worse, cause injury to yourself and damage to your boat.

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