Tire Pressure

[BobK]

I've done a search on tire pressure on the site, have read various online info about proper tire inflation and it seems that all conventional wisdom and advice is to inflate the tires to the max cold pressure rating on the side wall of the tire.
I will be trailering my 150SC to Canada leaving next weekend and want to make sure all is in order with the trailer, tires etc.
Here's the scary (at least for me) part. The recommend tire pressure on the side walls of my 4.80 - 12 load range C tires is 90PSI - I made sure I was not standing on my head and reading the pressure upside down, it's 90PSI for sure. I checked the pressure in the tires and I was at 45 lbs, so pulled the boat to my neighbors and used his compressor and took the tires up to 85 PSI - I just couldn't bring myself to go that 5 extra pounds - seems like a whole lot of pressure inside a little tire. Much to my surprise, neither tire blew apart, and after taking the boat for a 5 mile test ride all seems to be in order, the boat seemed to bounce a little more than in the past, but with double the pressure in the tire I expected as much.
Is anyone out there running this much pressure? I have only had the boat since this May, so this is a new chapter in my learning about boating etc.
Any advice or reassurance I did the right thing would be most appreciated

Bob K
2001 Logic 150SC

[fridaysoff]

Bob,
I run 50 PSI on my trailer tires. Thats what the max PSI on the tire states. 90 sounds high. I would reccomend one or 2 spare tires/wheels for your trip.They are probably cheaper where you live than trying to buy them in the Canadian outback. If you do not use them you will have 2 new tires when you return if your old ones are worn.Good luck and enjoy your trip.
John D.

[BobK]

Thanks for getting back to me John. I am nervous about having that much pressure in the tires, but that's what the side wall is calling for. It's only a 12 inch tire, but I am also worried about towing a long distance at highway speeds (55MPH in PA when towing - 65 in NY) with an under inflated tire, so its's damned if I do, damned if I don't kind of feeling.
You said you are running 50psi, but then I see you are also going by what is recommended on the side wall, and I imagine with your larger boat you are running a larger tire than I am.

[Davekfl]

I have ST 185/80R13 radials on my trailer for my 170 Bass and the max cold PSI is 50. 90 PSI sounds much too high. Are you sure it doesnt say 50. Its very hard to read. I use a magnifying glass and a strong light.
Davekfl ( Sarasota, Florida)

[HighTechRedneck]

My suggestion is to call the trailer manufacture and the tire manufacture and talk to there customer service. If your side walls flex to much they heat up, get weak and will blow out. here is what i went off of for my goodyear tires http://www.goodyear.com/rv/pdf/rv_inflation.pdf.

Good luck and make sure you have a spare tire. If you dont it will blow out for sure. thats what happen to me.

HTR

[JimW]

BobK,
Does your tires have the "ST" rating (that is for "Special Trailer")? Read some of the sites from web search.
ST tire rating - Google Search
Hope this is helpful, and as the others have said be sure to carry a spare or two. Good luck on your trip.

[Putershark]

Be careful and remember, tire pressure ratings is for X amount of weight (also stated on the sidewall) on that tire and some BMT combo's, just do not weigh that much more than one tire is designed to carry.

If not careful one punch the tires up overly tight, and will wear out the center treads and have a boat that is bouncing like a basketball from the lack of sidewall flex

[BobK]

Thanks for all the feedback guys. Here's where I stand with this. I went to Pep Boys at lunch time and spoke to one of the tire guys there. He checked the inventory and had a 4.80-12 ST tire and it had the same cold rating as mine, 90PSI. He explained that was max per tire and was based on the load rating of the tire, in this case 880lbs X 2 for a total max load of 1760lbs with the tires set at 90PSI. Since my boat. 2/C motor and trailer weigh in the neighborhood of 1200lbs he said that I would want to decrease the tire pressure to 70 - 75 lbs to come us with a minimal tire wear ratio vrs the actual load weight on the tire. If at this reduced pressure I notice the trailer bouncing more than usual, I should drop each tire another 5 PSI.
I also bought a new tire gauge and an on the road flat repair kit that included a small portable 300psi 12V compressor for $19.99 which I thought to be very reasonable. So with a good spare, my repair kit, and a reduced tire pressure, I feel somewhat more comfortable with the 8 1/2 hour trip facing me next week.
Thanks again for the input.
Bob.

[BarryB]

I run 50 psi as stated on the tire.