Tires, Rims, Valve Stems and Comfort Zones - Montana Owners Club

MacDR50 · 11-12-2007, 09:16 AM

I have spent most of the day researching this subject as I plan on changing out the Mission Tires as soon as I get my new 3585 in May. I still have some questions but thanks to this forum, manufacturer's and retailer's sites I am way ahead of where I was only yesterday.

I assume my new trailer will be loaded to the maximum. (IMHO When it comes to safety it is bettter to over rather than under estimate.) According to the specs. that is 15,325 lbs. Allowing 20% for pin weight that leaves me with 12,260 lbs riding on the wheels or an average of 3065 per wheel. I understand that the 08 3585 has 7000 lb axles or 3500 per wheel. Now I know that the reality is that no trailer is perfectly balanced, side to side or back to front. There is also the issue of wind, road camber, cornering etc that can increase/decrease the load any individual wheel has to carry at any given time. My "Mission" (no pun intended) is to choose a replacement tire that has the maximum capacity, that fits the aluminum wheel, is is generally available and hopefully made in NA. I stuck with LT tires as that 65 MPH max on the ST's didn't sit very well with me. Here is what I learned. Please be patient as I may have missed some tires or information although I tried to be thorough.

1. The 3585 alum. rims are 6.5" wide. None of the tires I found that had a load rating above 3300 lbs had a recommended rim width of less than 7.0" except, of course, the Missions and they are ST's.
2. The tire that I found with highest rating was the Goodyear Wrangler SR-A 285-75-R16 at 80psi=3750 lbs. It has a minimum rim width of 7.5". Is that one inch too much out of spec? I need help here.
3. I couldn't find any other LT 16" tire with a load rating of more than 3415 lbs. These were all 265-75-R16. All the remaining 285's were 3305 lbs.
4. The maximum pressure for the alum. wheels on the 3585 is a key element that I still don't know. All the tires I have looked at had a max. inflation pressure of 80 psi.
5. A good tire with a cheap valve stem is trouble looking for a place to happen. I will replace any all rubber stem with a steel or brass tube type.

Unless I have missed a tire that is better or I can get away with the GY 285-75-R16 on the narrow rim, I will go with the 265-75-R16. It is a popular tire and made by at least 7 companies. At 3415 lbs at 80psi it gives a comfort margin of 11.5% = 350 lbs per wheel or 700 lbs side to side or back to front. I would prefer more (the GY 285 Wrangler would have been 22.5%) but unless I can go to a higher pressure tire this is the best alternative I can find. I could change wheels but that is getting expensive to fix a problem that Keystone should already have fixed.

BTW the 235-80-R16E Mission tire is rated by them at 3520 lbs. I couldn't find any tire in the same size listed by any of the other companies.

MacDR50 · 11-12-2007, 04:09 PM

In another post I was told the aluminum wheels are rated to 110 lbs. That makes a Goodyear G614 RST 235-85R16G tire a posibility. At 3750 lbs @ 110psi they are designed for a 6.5" rim. Running them at 100 still gives 3550 lbs load. The max speed is 75 mph. I don't expect to drive above 65 so that is okay. I now just need to find out availabilty and price.

RMccord · 11-12-2007, 04:16 PM

I would be interested if they will work on the 6.5 rims. Also what kind of price the Goodyears are running. I suspect a set of four probably about 650 plus mounting and balancing?
If you would not posting your findings I would appreciate it very much.
Bob

stiles watson · 11-12-2007, 04:32 PM

That G-rated Goodyear runs about $300+ per tire. After a lot of research similar to yours, I have about decided it may be the best tire.

neighborman · 11-13-2007, 08:20 AM

Our 3670RL is a 2002 model, and I looked at the Goodyear G rated tire too. My problem is that the earlier Montanas all had six lug, 80# rated wheels, and I could not find any replacements that would accommodate 110# of air.

I went with the best Michelins I could find, LT235/85R/16, XPS RIB. I had the steel valve stems installed, and run the Pressurepro system.

We live in TN, and towed to AZ and back for the winter, and took a trip to VA, PA, MA, ME, NY, OH and then back to TN. I put 80# in each tire, and during the hottest weather, the pressure crept up to 88 and 89#s.

The tires now have about 8K on them and look great tread wise. I'm really pleased with them and think that they were worth the extra money I spent on them.

MacDR50 · 11-13-2007, 09:48 AM

I'll post information on price here as soon as I get to my local tire store. My experience is that it can vary widely. For those who want more info on tire here is the link.

http://www.goodyear.com/truck/products/G614RST.html

Old GI · 11-16-2007, 11:16 AM

I have the 3400RL and am also going to get rid of the missions, question....the rims that came with the Montana, are they from China? are they any good? do I need to change the tires and rims? any advice would be appreciated.

dsprik · 11-16-2007, 11:28 AM

Quote:

quote:Originally posted by neighborman

Our 3670RL is a 2002 model, and I looked at the Goodyear G rated tire too. My problem is that the earlier Montanas all had six lug, 80# rated wheels, and I could not find any replacements that would accommodate 110# of air.

This may the biggest problem with G rated tires... I don't think the aluminum 6.5" wheels are rated to handle the 110# pressure.

I would go with the Michelins, too, when it comes time to replace my Missions. So far they are going great after 7,245 miles.

kerry · 11-16-2007, 12:21 PM

The alum rims on the newer Montana's are rated @ 110psi. It should be stamped on the rim (under trailer). Kerry

dsprik · 11-16-2007, 01:38 PM

I'm glad to see that they upgrade that rating. Just curious... what happens when on the road and heat builds that press up over the 110# cold press that the tire started out with?

MacDR50 · 11-17-2007, 09:20 AM

dsprik:

I tried to find an definitive answer to this question. The tire data sheet says the rims must be approved for 3750 lbs load and 110 psi. It gives two approved wheels ALCOA’s 16x7J and DEXTER AXLE 16X6K. Does anyone know the who manufactures the aluminum Montana wheels? I would cold inflate to 100 lbs and still have 3550 lbs of load carrying capacity, making the 7000 lb axle rating the critical rating. These tires are specifically designed for trailers and are limited to 75 mph. In the old parlance they are 16 ply although I am not sure what this means.

Added on edit.

I checked several aluminum wheel specs and they all give the maximum as a "Cold" inflation pressure. The 16X7J Alcoa wheel is under recall and has been replaced by the 7" wide wheel (16041). The DexStar rims are steel. http://www.dexstarwheel.com/products.html#changer

Delaine and Lindy · 11-17-2007, 11:15 AM

Don't know what the Montana's are running but the Cambridge had Tredit Aluminum wheels and were stamped 3750 at 110 lbs air. I had two of the Tredit Aluminum wheels crack. I replaced them with Alcoa Aluminum 16/7's and rated at 3750 and I run all tires at 110 lbs or air. I wouldn't run Tredit Aluminum wheels.... Good Luck with your tires... I also run Goodyear tires and the longest pull at one time was 1,675 and only stopped for about 6 hrs and was running 68 mph. GBY....

timandsusan · 11-17-2007, 11:23 AM

I have the original Missions on my 3475 (2006 model) with about 20,000 miles on them since March 2006 2ith no problems. I realize some Montana owners have had problems but I will run mine until I need to replace them. I also use Pressure Pro tire monitors, run the Missions at 80 PSI and while towing the pressure goes up to about 88 PSI. After our Alaska trip this summer, I had the Monty in for a few dealer fixes and was asked how the tires did--I said Great!

RLVoumard · 11-22-2007, 07:02 AM

In the area of TRUCK TIRES vs TRAILER TIRES are most folks sticking with a TRAILER TIRE type tire or is it OK to use a LT tire ?

bsmeaton · 11-22-2007, 06:42 PM

Quote:

quote:Originally posted by RLVoumard

In the area of TRUCK TIRES vs TRAILER TIRES are most folks sticking with a TRAILER TIRE type tire or is it OK to use a LT tire ?

Our Montanas have come from the factory with both LT and ST. Our 2003 had LTs, and this one has ST. I dont think it makes any difference at all as long as its within specs. ST tires give you a higher weight to pressure ratio, but lower speed limit.

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