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tires 12R to 315R80

Yahoo Message Number: 82125
hello charles here we have a 2000 MAGNA, IN NEED OF NEW TIRES, HAVE 12R22.5 NOW WANT TO GO TO 31580R22.5 THEY ARE A BIT WIDER.Has anybody used the 315 instead of 12r thanks 5886

Re: tires 12R to 315R80

Reply #1 –
Yahoo Message Number: 82127
I recently did on my Intrigue. But because I have an ISL 400 instead of a C-12 I have a shorter drive and

narrow tag axles and there fore my 315's fit perfectly. I also have an IFS front end. I saw my Friends

2006 Magna and anothers 04 Intrigue with the heaver axles and the 315's won't fit. All I can say is if

you have an one inch clearance when you drop your suspension down to the stops, you will probably be

OK. I know Jon and Paul at Dickmans Les Schwab in Junction City offered to mount the 315's at no extra

charge if they didn't fit and had to go back to 12R's. I learned one Thing. A 295 is the same width as a 315 under load at recommended tire pressure as it has a different profile.
By the way according to my

GPS the difference in speedometer reedings at 60 mph is to close evaluate.
TWI 2004 Intrigue 11731

Original Message:
-----------------

From: Charles Ervin driveit55@... Date: Tue, 04 Sep 2012 15:56:49 -0000 To: Country-Coach-Owners@yahoogroups.com Subject: [Country-Coach-Owners] tires 12R to 315R80

hello charles here we have a 2000 MAGNA, IN NEED OF NEW TIRES, HAVE 12R22.5 NOW WANT TO GO

TO 31580R22.5 THEY ARE A BIT WIDER.Has anybody used the 315 instead of 12r thanks 5886

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Re: tires 12R to 315R80

Reply #2 –
Yahoo Message Number: 82134
My coach was standard with 31580R22.5 on steer axle and 12R22.5 on drive and tag. I put the 31580s all the way around in May. You need to be certain of the dual spacing requirement for your dual wheels and the tire specification.

Good luck.

George in Birmingham
'03 Magna 6298
George in Birmingham
2003 Magna 6298

Re: tires 12R to 315R80

Reply #3 –
Yahoo Message Number: 82135
It is quite easy to determine the rolling distance of a tire. The circumference formula is Pi X D D for diameter. The diameter is made up of the rim which is 22 inches plus 2 sidewall heights to come up with the total diameter. The tires are in millimeters the first number is the width of the tread the next number is the ratio of height to width, so a 315/80 has a a sidewall of 0.8 X 315 which equals 252 MM of height. There are 25.4 mm to the inch , so the height is 252/ 25.4 equals 9.92 inches. So the total diameter is 9.92 + 9.91 + 22 equals 41,84 inches times 3.14 etc equals 131.38 inches. I think the 295 has ratio of 75 . If not you can correct. Doing the formula for the 295/75 equals 123.78 inches. For the same revolutions per mile your speed will be approximately 6% higher. When doing service , the ECM has an entry for revolutions per mile and you can do the calculation and correct your speedometer. Hope this helps

Ron Baran 09 Magna 7025

Re: tires 12R to 315R80

Reply #4 –
Yahoo Message Number: 82139
Charles

I recently investigated this and the consensus opinion was there was not enough width difference to cause me a problem. I replaced all six of my Toyo 12R22.5 with Michelin 315R22.5 on my 2000 Allure. I went with the XZA2 Energy and after approximately 5,000 miles, I'm extrmely pleased with them.

Charles

2000 Allure 30555
Hoover, AL

Re: tires 12R to 315R80

Reply #5 –
Yahoo Message Number: 82140
Charles,

I recently put new Michelins on my 2000 Magna. I intended to go with 315's all the way around but after we mounted a pair of 315's and didn't have spacing between the duals I ended up with 12R22.5 on the duals and 315's on the front. While I have lost the ability to rotate front to back, I haven't seen uneven wear and wanted the extra weight capability in the front. I went with XZE* on the back and XZA2 Energy up front. I'm happy so far - but then I've only driven it the 20 miles home from the tire dealer.

Dan

2000 Magna 5788

Re: tires 12R to 315R80

Reply #6 –
Yahoo Message Number: 82186
George,

You are right: 318's were put on my 2002 Magna drive and tag by accident some years ago. CC freaked and said the dual spacing was too narrow. Had to switch them out for 12R 22.5's. How did you deal with the dual spacing? I would assume your '03 is the same setup as my 02.

Rich 2002 Magna

Re: tires 12R to 315R80

Reply #7 –
Yahoo Message Number: 82230
Rich,

It was Paul at Bob Dickman in Junction city that recommended the the tire for my application. He assured me that dual spacing was not a problem for the tire.
I have already driven 7,500 miles on the tires and there is no indication of spacing problems. For example, I would expect them to heat up more than my experience would see as normal if they are touching, or even close.
Sorry I can't give a more technical explanation than that "Paul says so".

George in Birmingham
'03 Magna 6298
George in Birmingham
2003 Magna 6298

Re: tires 12R to 315R80

Reply #8 –
Yahoo Message Number: 82245
Some additional data in answer to questions regarding chang from 12R22.5 to 315 80R 22.5 tires.
I found that the tire mounting requirement for Toyo 12R calls for either 8.25 or 9 inch rim and 13.5 inch dual spacing.
Toyo 315 80 rim size requires 9 inch. That is probably why CC was concerned with your installation of 315s. Your rims are too small. Dual spacing requirement for Toyo 315s is 13.95 inches.
The Continental HSL1 Coach tires require either 8.25 or 9 inch rims for the 315 tire and dual spacing is 13.9 inches. Thus there is no problem with rim size and the rim offset supports 13.9 inch dual spacing.
Sorry if I have not explained it clearly. I'll try again if questions.

George in Birmingham
'03 Magna 6298
George in Birmingham
2003 Magna 6298

Re: tires 12R to 315R80

Reply #9 –
Yahoo Message Number: 82257
Thanks George,

My 315's on the rear were Michelins. CC was insistent. I think Michelin became involved as well. That is all I remember.

Rich 2002 Magna

Re: tires 12R to 315R80/ What's the overall difference?

Reply #10 –
Yahoo Message Number: 82258
So why change from a 12r22.5 to a 315 22.5 tire? Are you changing out just the rear tires? John 03 Allure 30951

Re: tires 12R to 315R80/ What's the overall difference?

Reply #11 –
Yahoo Message Number: 82260
Older Magnas came with 315's on the front and 12R's on the rears, so you couldn't roatate tires, which

needs to be done at various times depending on the Model of the coach, the Tire Manufacturer, and

driving habits. As the coaches were getting longer, front ends heavier and fuel tanks larger 12R's

weren't adequate up front, so the 315's up front and 295's on the rear.
With heavier engines C-15 and

16, 12R's/295's weren't really adequate for the tags either when it came to wear patterns. Then when

you figure having to raise the tag all that weight on just four tires and some times very hot. In 06 CC

started moving fuel tanks from the front to the rear on some coaches. When you figure they went from

two to three and then four slides with full tile floors, the tires needed to up graded. In my case 12's up front weren't adequate as I was within 100 lbs up front even with the tires filled to 120 lbs. So now I

can fill my 315's to the wheel rating with 106 lbs of presssure, but as I drive over 61 mph I add another

5 lbs of pressure. This safety factor wasn't possible with my 12R's.
Michelin recommended 10 lbs

additional pressure a few years ago if driving at 70 mph for their Long Haul tire, which is no longer

available in the 12 R size. Its this issue which may have contributed to premature cracking on my

Michelin 12R. So That;s why I went with 315's, and as I wanted to be able to rotate my tires and the

Continentals would fit on the duals and tags, I bought a full set.
Unfortunately for us each coach is different, Allure, Intrigue Magna, etc and what would apply to one won't apply to all. I think I remember

the Veranda coaches had 365's on the heavier coaches with 315's on the Allure and Inspire. I know I

winced when I used to see the 4 slide 45' Magnas with the 295's on the rear enter and exit the CC

Service camping sites on 6th ST. The tires were totally over taxed.
TWI 2004 Intrigue 11731 42 ft 3
slides.

Original Message:
-----------------

From: grandmajackiem quietstorm366@... Date: Tue, 11 Sep 2012 03:36:50 -0000 To: Country-Coach-Owners@yahoogroups.com Subject: [Country-Coach-Owners] Re: tires 12R to 315R80/ What's the overall difference?

So why change from a 12r22.5 to a 315 22.5 tire? Are you changing out just the rear tires? John 03
Allure 30951

Quote from: George

> Some additional data in answer to questions regarding chang from 12R22.5
to 315 80R 22.5 tires.

Quote
>

I found that the tire mounting requirement for Toyo 12R calls for either

8.25 or 9 inch rim and 13.5

inch dual spacing.

Quote
>

Toyo 315 80 rim size requires 9 inch. That is probably why CC was
concerned with your installation

of 315s. Your rims are too small. Dual spacing requirement for Toyo 315s is 13.95 inches.

Quote
>

The Continental HSL1 Coach tires require either 8.25 or 9 inch rims for
the 315 tire and dual spacing

is 13.9 inches. Thus there is no problem with rim size and the rim offset supports 13.9 inch dual
spacing.

Quote
>

Sorry if I have not explained it clearly. I'll try again if questions.

George in Birmingham
'03 Magna 6298

Quote from: George" \[br\
\[/quote\]\[br\]wrote\:\[br\]\[br\]\[quote\] \> \>\[br\] \> \> Rich,\[br\] \> \>\[br\] \> \> It was Paul at Bob Dickman in Junction city that recommended the the\[br\]\[/quote\]\[br\]tire for my application\. He\[br\] assured me that dual spacing was not a problem for the tire\.\[br\]\[br\]\[quote\] \> \>\[br\] \> \> I have already driven 7,500 miles on the tires and there is no\[br\]\[/quote\]\[br\]indication of spacing problems\. For\[br\] example, I would expect them to heat up more than my experience would see\[br\] as normal if they are\[br\] touching, or even close\. \[br\]\[br\]\[quote\] \> \>\[br\] \> \> Sorry I can't give a more technical explanation than that "Paul says\[br\]\[/quote\]\[br\]so"\.\[br\]\[br\]\[quote\] \> \>\[br\] \> \> George in Birmingham\[br\] \> \> '03 Magna 6298\[br\] \> \>\[br\] \> \> \-\-\- In \[email\=Country\-Coach\-Owners@yahoogroups\.com\]Country\-Coach\-Owners@yahoogroups\.com\[/email\], "Rich" \[br\]\[/quote\]\[br\]wrote\:\[br\]\[br\]\[quote\] \> \> \>\[br\] \> \> \> George,\[br\] \> \> \>\[br\] \> \> \> You are right\: 318's were put on my 2002 Magna drive and tag by\[br\]\[/quote\]\[br\]accident some years ago\. CC\[br\] freaked and said the dual spacing was too narrow\. Had to switch them out\[br\] for 12R 22\.5's\. How did you\[br\] deal with the dual spacing\? I would assume your '03 is the same setup as my\[br\] 02\.\[br\]\[br\]\[quote\] \> \> \>\[br\] \> \> \> Rich 2002 Magna\[br\] \> \> \>\[br\] \> \> \> \-\-\- In \[email\=Country\-Coach\-Owners@yahoogroups\.com\]Country\-Coach\-Owners@yahoogroups\.com\[/email\], "George"\[br\]\[/quote\]\[br\]] > > > >

> > > My coach was standard with 31580R22.5 on steer axle and 12R22.5 on
drive and tag. I put the

31580s all the way around in May. You need to be certain of the dual spacing requirement for your dual
wheels and the tire specification.

Quote
> >
> > > Good luck.
> > >

> > > George in Birmingham
> > > '03 Magna 6298
> > >
> > >

Quote from: Charles Ervin"\[br\
\[/quote\]\[br\]] > > > > >

> > > > hello charles here we have a 2000 MAGNA, IN NEED OF NEW
TIRES, HAVE 12R22.5 NOW

WANT TO GO TO 31580R22.5 THEY ARE A BIT WIDER.Has anybody used the 315 instead of 12r thanks
5886

Quote
> > >
> > >
> >
>
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Re: tires 12R to 315R80/ What's the overall difference?

Reply #12 –
Yahoo Message Number: 82288
John,

My steers are specified as 315s so there wasnot change there.

I changed the rears for a variety of reason.

1. Now I can rotate the tires if needed. I did that once on my allure and added a lot of miles and years to my tires.

2. These continentals a are coach specific design rather than a general truck tire.

3. Not a huge fan of Michelins

4. Retailer had too long a wait for Toyos

George in Birmingham
'03 Magna 6298
George in Birmingham
2003 Magna 6298