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Old 10-16-2007, 07:36 PM   #1
RMccord
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Tires and trailer tires

I have a 2005HD and the current tires are rated at 3042 lbs. I have read here that some have gone up to 265 size tires and they are rated at 3400 lbs capacity.
Will these fit on the same wheels my current tires are on and what pressure would they most likely need. My current tires are at 85 psi.

Also If I wanted to replace the stock Mission tires that will be coming in with my Big Sky in about 6 weeks what size LT tire should I get. I know I would want a G rated tire. What are the preferred ones that most are going to. Goodyear?? Etc. I will use the Missions for a year or so perhaps as for that length of time we wont be going out for more than a couple of weeks at a time. Probably also a weekend a month in between and I hate to toss them right out of the hopper. Maybe replace them up front and store them as replacements.

Thanks
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Old 10-17-2007, 02:36 AM   #2
Bill and Ann
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We have changed the 245's on our truck to 265's Michelin LTX M&S and keep the front at 65 and the rear at 80. They will fit the same rims. Many of us have made the change to 265's and there are many posts in the past regarding the pros and cons.
The only tire G rated that I know of that SOBs use are Goodyear GB14 RST (I think) and to keep the rating of 3042 lbs keep them inflated at 80lbs. You can go up to 3750 lbs but need to use 110 lbs. inflation which your rims can't handle.
I am in the process of putting on Cooper SRM radial Lt LT235/85 R16 rated at 3042 lbs @ 80 PSI.
Others will probably also reply with their comments. We have a couple of tire people on the forum.
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Old 10-17-2007, 04:16 AM   #3
kerry
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http://www.goodyear.com/rv/pdf/rvbrochure.pdf

Check out Pg 7 Kerry
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Old 10-17-2007, 04:55 AM   #4
RMccord
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Thanks for the Goodyear information. Sounds like a perfect replacement.

If I am correct these will need new rims as well or are the current tires the Missions inflated to 110PSI?

THanks Bob
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Old 10-17-2007, 09:53 AM   #5
snfexpress
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The current Mission Tires should be inflated to 80 PSI. Your stock aluminum rims on the Montana are rated at 3,042 pounds. The steel spare is rated at 3,750 pounds.

Your choices for going to a G rated tire and increasing the PSI are few, but I got some from Les Schwab Tires. I inflated them to 90 PSI to increase the weight capacity of the tire. I don't run them at 110 PSI because it's a waste, in my opinion, because my axles are only rated at 6,000 pounds. I went with the G rated tires mainly for the belief that I would lessen my chances of a blow-out. Other, more knowledgeable members like Lonnie and Glenn can comment.

If you choose to increase the PSI in your tires, and you buy new tires that can handle the increase in PSI, you have a few choices. If you want white steel rims, they can be used up to 110 PSI for a weight rating of 3,750 pounds. If you want Aluminum wheels, I would go with the ALCOA rims. They are pricey, but I feel much more confident with them than the stock rims from Tredit that have, in the past, had issues with cracks. Also, I couldn't get steel valve stems on the stock rims, but can on the ALCOAs.

I derived this formula for PSI and would really like someone who is knowledgeable to let me know if it is accurate:

Weight on axles. Let's say it is 12,000 pounds. Number of wheels: 4. Each tire is rated at 3,750 pounds at maximum inflation of 110 PSI. The formula, then, is: Weight (12,0000) divided by Number of Wheels (4) divided by 3,750 times 110 PSI which equals 88 PSI. I run mine at 90 PSI.

Hope this all makes sense.
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Old 10-17-2007, 11:22 AM   #6
kerry
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You should inflate your tires to max cold as stamped on the tire you have. On the back side of the rim should be stamped to indicate max tire pressure the rim supports. The alum rims Montana uses are good to 110psi. Hope this helps. Kerry
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Old 10-17-2007, 11:44 AM   #7
RMccord
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What is the current load rating for the Monatana Mission tires 3042 or 3400 at 80 psi. I know they are E rated tires?

If 3042 then I have a question. Montana puts 6750 lb axles on the BS. two tires per axle and if they are rated at 3042 then they are way short of the axles load rating. I am assuming the Missions are rated at 3400 lbs at 80 psi just that they are E rated rather than a better G rated tire.

Thanks
Bob
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Old 10-17-2007, 03:39 PM   #8
CmdrDewey
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You should NOT inflate to the maximum shown on the sidewall. You SHOULD inflate to what the manufacturer recommends and you SHOULD go to the Michelin manufacturers site and watch some of the video and review all the recommendations. (I suspect other manufactures have such sites as well but I haven't checked.
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Old 10-17-2007, 04:37 PM   #9
bncinwv
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Now I am as usual approaching a confused state of mind. Regardless, I believe I will keep mine inflated to 80 psi cold simply because that is the pressure for the maximum load rating on the now infamous Missions. Any less or any more seems to me like flirting with disaster knowing the sporadic history of these tires????? LonnieB, time to chime in please, I am definitely not a tire guru and I forgot to stay at a Holiday Inn Express last night!!!!
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Bingo and Cathy - Our adventures begin in the hills of WV. We are blessed by our 2014 3850FL Big Sky (previous 2011 3750FL and 2007 3400RL) that we pull with a 2007 Chevy Silverado Classic DRW CC dually.
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Old 10-17-2007, 05:40 PM   #10
LonnieB
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OK Bingo, I'm fixin ta chime...........DING...DING...DING .

Bob, just because the Goodyear G614 tire is rated for a maximum air pressure of 110 psi, doesn't mean it requires 110 psi. You need to weigh the trailer axles while it is hooked to the truck. Each axle individually would be ideal. Use that weight to calculate the air pressure for each axle. Michael's formula looks like it should work just fine.

Another thing Bob. Your axles may be rated for 6750 lbs each, but that doesn't mean your tires have to be rated for 3375 lbs to be safe and legal. Again, the ONLY way you are going to know, is to weigh the trailer.

As far as the Mission ST235/80R16E goes, I set them at 80 psi and constantly worry about them flying into little pieces. Because of what they are, not because of air pressure. Sometime this week, or this weekend I am going to replace them with LT235/85R16E Bridgestone Duravis R500 commercial light truck tires. They also will be set at 80 psi, and I won't worry one bit about them.
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Old 10-17-2007, 06:03 PM   #11
RMccord
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Lonnie

What do you expect these new tires will cost and will they function on the same wheels.

Thanks
Bob
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Old 10-17-2007, 07:31 PM   #12
LonnieB
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Yes they will work just fine on the wheels that come with the trailer. They are nothing special or out of the ordinary, I just feel they are better for me.
Because my business is selling tires, in order to be in compliance with the rules and regulations of this forum, I don't think I am at liberty to discuss cost. Sorry Bob
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Old 10-18-2007, 05:03 AM   #13
kerry
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Didn't mean to stir up a hornets mess. Being in the RV industry for almost 30 years, most tire failures I see are from under inflation or ozone damage. Under inflation is worse on tires than over inflation because it generates heat. The max psi cold on a tire is for max load. If the max load is less, lower max psi may be OK. I am not a tire expert, however if one reads the Goodyear RV Tire link I posted, it has a lot of good info in it that pertains to all brand tires. I'm not pushing GY Tires, but I haven't a trailer tire in another brand with a 75MPH speed rating. JMHO, Kerry
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Old 10-18-2007, 10:11 AM   #14
steves
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I had my rims replaced last year because of leaks. I crawled under the rig today to check what the ratings were. While there was no air pressure ratings, there was a weight rating stamped in the rim of 3,750#. This is the same rating my friend has on his SOB that runs Goodyear GB14 RST at 110#. I believe if you have the 3,750# weight rating then your rims will handle the "G" tires. It would make sense to me to use the higher rated tires. My friends experience of pulling a 2,000# heavier trailer than my Montana and he has about 30,000 miles on the tires with "NO PROBLEM" should be an indicator of a good set-up and good tire.
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Old 10-18-2007, 10:36 AM   #15
snfexpress
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One more comment on the stock aluminum rims. The person at Keystone whom I spoke with about running more than 80 PSI on the Tredit rims said, in no uncertain terms, that the rims are not designed for 110 PSI and I would risk a failure. I guess it is all in who you speak with...
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