Sorry this is a long post.

I currently have an older 33' 5er made by Cardinal, the older Cobra one. It currently has 225/75 R15 tires load range D tires on it with 2 axles. Need to replace the tires. Got the trailer weighed and it is 9820# mostly empty. The tires currently on the trailer are rated 2520 each. If my numbers are correct that means that the tire capacity is almost equal to the trailer weight.

First question, do you subtract the tounge weight from the trailer load?


If so I have some breathing room as the tounge weight is 1960 leaving trailer weight at 7860 which gives more breathing room.

I have not been able to find a name brand 15" tire load range E (10 ply other than Carsile and I have not heard much good about them.

Looking to upsize tires & wheels to 225/75 R16 load range E and I have found a pretty good price from a supplier in Elkhart Indiana for the tires & wheels. I now would have a 1/2 inch higher trailer height which is good, and a load range of 2680 lbs which would give me a better margian.

Final question, would this be a good thing, bigger tires & wheels, or go with the 15" Carsile. We are planing a 5000 mile + trip next spring and do not want any problems if we can help it.
Does anyone have any other thoughts/suggestions. Plan on keeping 1 of the 15's as a spare (only 1/2 inch smaller in height) if we go with the 16" and if we have a problem will get it fixed at the first place we can.

Additional Information:

Had unit weighed 2 months ago and the weights were as follows:

Holding tanks empty/water less that 1/4 tank, some food and clothes but not all.

Front Axle truck 4440#
Rear Axle truck 5020#
Trailer 7860#
Total hooked up 17320#

Empty truck only:
Front Axle 4380#
Rear Axle 3060#
Total 7440#

My figures from this are as follows (minor weight differance from fuel load).

Trailer weighs aprox 9820#
Truck = 7440#
Tounge weight should be 1960#

Per door sticker:

GAWR Front 5200#
GAWR Rear 6000#

I do not believe that that the above numbers exceed my trucks limits anywhere. Truck is rated to pull 13000+ pounds per owner manual and I am substantually under that also.

 

Empty weight is fine, if you pull it empty - but most folks don't. Wet weight depends on many factors and personalities of the owner(s) and how much stuff from home they bring with them. Next time you go out with it loaded for bear, it might be worth your while to stop at the CAT scales for a weight slip.

You've got the right idea about axle weights and pin weight. Axle weight + pin weight = total trailer weight.

When you weighed the trailer, what was the weight on the axles? 9820 or 7860? Did you weigh truck and trailer, then unhook the trailer and weigh the truck by itself?

Being that you've got a 2500, the weight ****'s may want to have a field day with you because that almost 2000 pin weight will put you over your trucks GVWR - or very very close until you and the little lady get in with the normal junk we all keep in the truck.

Can't help you if you should upgrade tires/wheels. I too have heard many unhappy stories about Carlisle tires; and load range E 16's may give you a peace of mind.

 

Another thing to worry about or atleast look at is the axles. They are rated for a certian weight so just because you put bigger better tires on the trailer won't make a difference if the axles aren't designed to handle the weight anyway.
Take a look at your owners manual for the trailer and see what it stataes for the trailers axles, you might be surprised at whats under there.

 

Unfortunatly I bought this unit used, manufacturer no longer in business, Cobra, no info came in trailer so kinda out-a-luck so to speak. That was the reason for the question, not trying to increase axle load but I don't know how to figure load on axle for sure. As above if it is trailer on truck I have lots of room per scale, if it is empty trailer off truck I am almost at tire limit. Trailer weighs 9820 off truck, tire rating is 2520x4=10080 which is only 260 lbs left for loading of trailer. Thats kinda close for me. If it is axle weight on truck it is now 7860 on 2 axles and tires are as above I now have 2220 lbs for loading. Just not sure how it is figured so help would be greatly appreciated. The reason for the 16" tire change is more options on brand of tires other than Carsile which is the major player in the 15" load range E HD market. The cost for the Carsile is about $80 per tire only plus mounting etc. The other offer I had was for 4 new 16" white spoke wheels with tires already mounted for $98 each. Would make more sense to buy the package for $5 more that just the tires to me as the existing wheels are in rough shape aperance wise anyways.

Thanks so far....Don

 

Don, using your trailer weight of 9820 lbs; and assuming 20% pin weight of 1964 lbs, that translates into about 7860 lbs on the axles. Divide that number by 4 (tires) and thats less than 2000 lbs per tire.

Your 15'ers will be fine. And I'm sure that was taken into account by the OEM when they built the trailer.

Using the same math, do the same thing with your trailers GVWR (or estimated fully loaded wet weight - using the heavier of the two weights).

I would bet that the 15's will be ok; but if the 16's fit without any interference issues, and they give you a warm and fuzzy feeling - go for it.

 

From what your first post read, your one trailer axle was at 5000 lbs., so those tires are at the maximum. I would go with the 16's. If you decide later to upgrade the axles, you can still do so.