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A Tire Question

Yahoo Message Number: 85354
This question may have been answered in an earlier post---I so, I apologize for the repetition. I am about to replace the drive and tag axle tires on my '06 Magna. I plan to go with Michelins through the FMCA program. I am debating about going to 315 rather than the 12R that are standard. The 315's are XZA2 while the 12R are XZE. The dealer that I am working with in Eugene feels that the XZA2 is slightly preferable as a coach tire and it is about $45 less/tire.

I'd be interested in experiences from this group of people who have made the switch. Any problems? The 315 is about .30 inch taller. Does this impact the lift of the tag? Is there any rubbing? Is the ride height of the coach impacted? Does the speedo feel the change, and if so, in which direction (mine reads 1-2% over as it is).

I can live with quirkiness, but do not want to do any damage to the coach. Thanks in advance for any thoughts, including anyone who might be a professional in this area.

Dave Glen

'06 magna 36591

Re: A Tire Question

Reply #1 –
Yahoo Message Number: 85355
Dave, I'd check your information on the 315 being .30 inches taller. The Michelin Truck Website shows the 315 @ 42.3" diameter and the XZE 12R @ 42.6" diameter, I have the XZE 12R on my Allure which are 42.6" diameter.
The issue to go over with your tire supplier thoroughly is the minimum space requirement on the 315 is 13.8" and the XZE is 13.2".
If you go 315 I'd recommend your ECM Features & Parameters for Tire Revolution Per Mile be changed as the XZE is 486 whereas the 315 is 492, that will take care of your speedo and Silverleaf milage calculations.

Regards, Mike 03 Allure 1st Ave. #30898

Re: A Tire Question

Reply #2 –
Yahoo Message Number: 85358
I'm in the same position with tire replacement. My 2000 Magna has 12R22.5 tires and I'm coming due for new tires so this discussion is very interesting to me.
I'm not so much concerned with the slight diameter change between the 12R's and the 315's but do worry a bit about the spacing for the duals on the rear and width of the 315's. The 315's require a dual spacing of 13.8" while the 12R's require 13.2".
The table I found for Michelin tires shows the 315's with 0.3 inch smaller loaded radius but a 1.1 inch greater width.
There is also a slight load reduction for putting the 315's on an 8.25 inch rim but it is still above the load rating for the 12R's. To carry my front axle weight, the 12R's require 120psi while the 315's require only 110psi.

I too would like to hear from those who have made this change.

pete

2000 40' Magna #5892
Pete
 2000 40'  Magna #5892  CAT C-10

Re: A Tire Question

Reply #3 –
Yahoo Message Number: 85360
Like Intrigues of that period some Magnas can't support 315's on the duals or Tags due to clearance issues. Some 315's on 8.25 inch rims don't have enough spacing in the dual configuration allowing the side walls to touch and prematurely fail. Les Schwab in Junction City mounted my 315s on the duals and checked for spacing and clearance, agreeing if the 315's didn't fit the XZE would be installed. Fortunately for me I had a Cummins ISl engine which gave me the extra space. If I had a Cat C-12 or 13 the larger tag and longer dual axles would have prevented me from going with 315's all around. I went with Continentals, having seen quite a few Michelin 315 and 12R with cracking. Michelin 5 year warranty does cover cracking.
TWI 2004 Intrigue 11731

Re: A Tire Question

Reply #5 –
Yahoo Message Number: 85372
Pete,

I bought Michelins last summer for my 2000 Magna. I purchased them thru the FMCA program from TCI,a Michelin owned company. I wanted to switch to 315's all the way around but there were two questions regarding using them on the rear duals, the spacing between the duals and mounting them on the smaller rear wheels. They had the 12R XZE's in stock and agreed to get a set of the 315 XZA2's to see if they would work.
They mounted a set of the duals with the 315's and neither of us were convinced that there was sufficient spacing when the tires/wheels were paired up. I ended up going with the 12R XZE's on the rear and the 315 XZA2's on the front. So far I haven't seen any issues using the 315's on the steer axle.

Hope this is helpful to you.

Dan

2000 40' Magna #5788

Re: A Tire Question

Reply #6 –
Yahoo Message Number: 85489
Has anyone on the list replaced their 12R' on the drive and tag axles with the 315's on an '05-'05 Magna with the C-13? Any problems?

Figured I'd ask specifically about my coach.

Thanks,
Dave Glen

'06 Magna 6591

Re: A Tire Question

Reply #7 –
Yahoo Message Number: 85583
I'm close to having to make the order, so I'll ask the group one more time: Has anyone ACTUALLY MOUNTED 315's on the drive and tag axles of an '05 or '06 Magna with the C-13 Cat? If so, were there any problems? The dealer that I plan to use would have to special order the 12R's, so I doubt that I'll be able to try each while there.

Many thanks for the help.

Dave Glen

'06 Magna 6591

Re: A Tire Question

Reply #8 –
Yahoo Message Number: 85595
Dave, I'm parked next to my friend who just bought an 06 Magna, C-13 thats has new Hankook 315/80R's on it. He's put about 3k miles on it and hasn't had any issues. When he levels the coach, there isn't much clearance on the rear duals, but they don't hit. Hope that hjelps.

Dan 06 Intrigue 11936

Re: A Tire Question

Reply #9 –
Yahoo Message Number: 85621
HI Dave. I just made a purchase of a 06 Affinity that has 315/80R22.5 tires. They had about 3,000 on them when i picked them up and I put 1060 miles bringing it home.
There seems to be plenty room all around.
OJ in OK

06 Affinity #6614

Re: A Tire Question

Reply #10 –
Yahoo Message Number: 85623
I would make a suggestion to OJ. Each ALCOA wheel has a number on it. This indicates all the pertinent data about the wheel, including such item as Offset. This would indicate to Dave , that if his wheel identification is the same , then he would no problem fitting the 315's. If it is different , Dave could contact Alcoa to see what the differences are. Just an idea

Ron Baran 09 Magna 7025with 315's driven wheel

Re: A Tire Question

Reply #11 –
Yahoo Message Number: 85624
Ok Ron, that i will do. The Coach is in storage right now, should be back there in a day or so.
OJ in OK

Re: A Tire Question

Reply #12 –
Yahoo Message Number: 85638
Hi OJ... as has been suggested in various other posts, I think, the number of miles on RV tires is not the determining factor... it is the age as indicated by the DOT stamp. This would be a four digit number on the sidewalls like 1107, or 4409 for example. Those would indicate the date of manufacture as 11th week of 2007, or 44th week of 2009. The latter would still indicate you have a reasonable lifespan left; the former would indicate you are near the end of your safe-use lifespan... 6 years. All the experts agree that a visual inspection by the owner of the outside of the tire is useful to discover obvious defects, but it cannot detect internal ones which can lead to a blowout. And after 6 years you are on borrowed time with most brands of RV tires. Currently Michelin is the only manufacturer who suggests their tires may last 10 years if cared for properly (see their online tire owners guide)
Bear in mind also that many other factors affect the useful life of a tire and may shorten it to much less than the 6 years... Running a tire at 20% below recommended pressures is a big one... likewise leaving a tire sit too long in one spot with no driving to "exercise" the tire (allowing the tire to 'lubricate itself which keeps them pliable and extends their life). Hard blows on bad roads is another. When you buy a used rig you just don't know what abuse the tires may have suffered, regardless of their mileage. Personally I think the best bet is to buy a rig whose price is discounted because of old tires and then start out your ownership with new ones where you can take care of them properly and know the history.
Your life may be riding on those tires... we had a forum member not long ago who was killed driving his Class A on a Florida Interstate, when he suffered a front end blowout and ran off the road. Even if you survive, the damage from 100+ pounds of pressure blowing up those steel belts and dispersing them like shrapnel is tantamount to an IED going off in your wheel well, and you will be lucky if you only have $10-15K in damage to repair and are without your coach for just 2-3 months. Is it worth the risk? For me it was not. I bought my 08 coach with 5.5 years of age on the Goodyear 670 tires, according to the DOT numbers. I knew it had only been on the road 16K miles and 2.25 years though and the original owner had had health issues, so it was pretty clear the coach has probably sat around a lot on those tires. We got a good price and decided we would start out our travels on 8 new Michelin XZA2 Energies, expensive at around $850 each, but cheap insurance for our lives and travel safety and longevity. I have not regretted that decision a single moment. And they are probably the best steering tires on the road, further enhancing your driving safety.
So check the age of your tires... the DOT numbers are supposed to be on the outside of the tires when mounted, if installed properly, but you may not be so lucky and may have to crawl under and look on the inside to find it. And if they fall within the 6 years, consider the prior use as best you can. Many have suggested it is worth having them inspected by a professional to determine their actual condition. It is probably a wise idea.
Oh... and for anyone reading this thread who is interested... I was at the Quartzsite RV show a week or so ago and picked up a couple bottles of JustOnce tire dressing... www.justonce.com. I was told it contains no silicone or petroleum distillates and they REALLY enhance the look of your tires, protect against UV and do not leave the tire sticky or "wet" looking and so they don't attract and hold dirt. I really like to keep my tires and wheels looking sharp and this is the best stuff I have ever used. We give it 4 thumbs and 8 paws up!

Joseph Burkle

2008 Country Coach Inspire 360 Founders Edition 43' quad slide tag axle 425 HP C9 pusher http://www. Wind-seeker.com/

Re: A Tire Question

Reply #13 –
Yahoo Message Number: 85642
Hello Joseph. The Michelins were mounted 1111. Thanks for your concern.
OJ in OK

06 Affinity #6614

Re: A Tire Question

Reply #14 –
Yahoo Message Number: 85646
The drive wheel is the only one that has numbers showing on outside of rim. (061 0 2 J) max load 7250 PSA COLD 28615 22.5X8.25 DOT-T.
HOPE THIS WILL HELP VERIFY, DAVE.
OJ in OK

2006 Affinity #6614

Re: A Tire Question

Reply #15 –
Yahoo Message Number: 85648
OJ There should be a part number about 10 or 12 digits, That is the important one. As a point , my 09 Magna has 9 inch rims. My part number is on the outside along with the other data. I have the Alcoa wheels with their patented coating- which- incidentally was not worth spending the extra for, and the part number would be different due to the coating .

Ron Baran 09 Magna 7025

Re: A Tire Question

Reply #16 –
Yahoo Message Number: 85706
You might want to run this question by Bob Dickman tire in Junction City. I have found them super helpful on a number of tire-related questions.

Re: A Tire Question

Reply #17 –
Yahoo Message Number: 85708
Your 06 Acfinity may or may not have 315's on all eight slots. A later build Affinity may. While at OMCC I asked the question of the techs that did the build. The answer was for 2007 the axle was SHORTENED two inches. I have forgot now if that was a side or in entire witdth.
My 06 45' MAGNA was as most built with 315 steering and 295 drives and tag. Paul at Les Shwabb in JC did a entire 315 Michelin conversion. Five miles down the road they returned only to Chang back to original sizing. The drives rubbed the coach on the outside. This is why in later builds the a le was shortened.
On my early build 2006 I replaced the tag with 315 Michelin and kept the 295 sizing on the drives. This combination improved sway and handling. Releasing air on the tag assembly actually seemed to improve. CC was constantly improving upon design as the build year went on. You never know when a change may have been made in chassis design improvements. Personally I only recamend the tag upgrade.
Give OMCC a call or Paul at Les Shwabb in Juntion City for full info. It has been two years now since our former yearly visit to JC. It's over a seven thousand mile round trip to visit Lane County.
James/Angela & Milo 06 MAGNA #5668

Re: A Tire Question

Reply #18 –
Yahoo Message Number: 87345
I am also now in the position of changing tires on a 2006 Allure and contemplating going to 315/80/r22.5 on all tires (it has a tag axle).
This thread has some great info, but I don't think I saw actual confirmation that the Michelin XZA2 Energy tire has adequate spacing when used on the duals.
My rims are Accuride model 28615AIP Accuride Specs here More Accuride Specs Michelin Specs here From these charts it seems my rims have a 6.59" offset which would equate to 13.18" when used in a dual configuration.
The Michelin chart indicates that the 315/80's minimum spacing when used in a dual configuration is 13.8".
So just going by the raw specs and numbers I would be .62" too narrow. That isn't much (5/8"), but if they touch it obviously wont work.

The 295/80's show a dual spacing of 13.2" which is exactly what my rims have when used as duals, so I know they will work.
So my question is if anyone firsthand has put the 315/80/22.5 XZA2 Energy tire on a 8.25" Accuride 28615 wheel? I would love to see a picture of how much clearance this configuration leaves.
If it wont work, I'll put 296's on the duals and 315's on the tag and steer tires. I like the idea of using the same tire on the tag and the fronts since you could use the tag as a spare tire in a pinch.
Thanks for any info!
Dan

2006 CC Allure Tag
#31344

Re: A Tire Question

Reply #19 –
Yahoo Message Number: 87346
You need to use the same diameter tire on the tag as the duals to distribute the weight properly. Having the larger 315 on the tag would shift a lot more weight to the tag. On Magnas from that period they put 315's on the front and 12R's on the duals and Tags, Michelin XZE. I have 315 Continentals all around on my 04 Intrigue with 8.25 wheels. But the Continental is a couple of tenths narrower. If I keep the duals at 110 to 115 lbs I have over an inch separation between the walls. If I deflate them to 100 lbs, which all I need for my weight I have only a 1/2 inch of separation, so Ive settled on 110 lbs. But each coach is different, if your in Junction City go to Les Schwab and talk to Don or Paul they'll mount what ever they recommend for you to try out and let you personally verify the mounting and spacing before continuing on with your selection of tires. Some where in the back of my mind I remember that at certain pressures a 295 is a couple of hundreds wide than a 315. Maybe that was Goodyear, Half-simers strikes again.
TWI 2004 Intrigue 11731

Re: A Tire Question

Reply #20 –
Yahoo Message Number: 87347
Also which engine do you have? If you have the 525 Cat the rear tag axle will have a different configuration and the 315's may not fit in the wheel well with out scraping the fiber glass wheel covering. I know that's the case with 04 and 05 Intrigues and o6 Magnas. TWI 2004 intrigue 11731

Re: A Tire Question

Reply #21 –
Yahoo Message Number: 87349
My engine is a Cummins 400 ISL, so I don't have to worry about the rear axle being different like it was on the CAT engine.
I am questioning your statement that the tag axle needs to have the same tire size. I would agree that all tires on the SAME axle need to be the same size, but I don't see any reason why the tags would take more weight with a different size tire. The weight they support is going to be a function of the amount of air applied to the airbags when the tag is lowered, correct? I would need to do a detailed weigh in and some adjusting, but I was planning on doing that with a loaded configuration.
If I am not mistaken, Country Coach has shipped some coaches with tag tires of a different size. Also I have talked to 2 or 3 shops as well and no one had any concerns over putting the different size on the tag. I would love to go to Junction City, but the coach is in Florida and I would prefer to not travel across the country on 7 year old Goodyears!

Thoughts?

Re: A Tire Question

Reply #22 –
Yahoo Message Number: 87350
I did talk to Bob Dickman about the issue. They confirmed that Country Coach did ship some coaches with different sizes on the tag axles as well as the fronts.
He did bring up one issue I hadn't considered. The 315's would have a larger diameter and thus circumference. He said this could cause a potential issue with the computer control of the braking. It may sense one wheel turning slower. He is checking with CC to see is that minor difference is within spec, or if there is a value that can be adjusted in the system.

Re: A Tire Question

Reply #23 –
Yahoo Message Number: 87352
If you need more space between the duals, perhaps Centramatics between the duals would provide balance and spacing.

Bob Wexler
SOB

Re: A Tire Question

Reply #24 –
Yahoo Message Number: 87358
A spacer is a great idea. I wouldn't need much, maybe ½" This looks like the correct Centramatic, but they don't specifythe thickness and it is hard to tell from the pictures.
Centramatic If it isn't thick enough, I would assume someone would sell an aluminum spacing ring.
Dan

2006 Allure Tag
#31344