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OK to replace 12R22.5 with 315/80R22.5 tires?

Yahoo Message Number: 94729
Has anyone replaced their 12R22.5 tires with 315/80R22.5 tires?
This week we will pick up our first diesel pusher -- a 2002 Country Coach Allure 36' with two slides on the drivers side. It has ancient 12R22.5 tires that must be replaced. I'm considering replacing the 12R22.5 tires with 315/80R22.5 Michelin XZA2-Energy tires. These tires are close in revolutions per mile (492 versus 488), have a higher load rating, and I've been told asre easier to locate if/when a replacement is needed on short notice.
My concern is minimum dual spacing. Generic specs for 12R22.5 tires seem to call for 13.5 minimum dual spacing whereas the Michelin 315/80R22.5 tire calls for a minimum dual spacing of 13.8. Does anyone know what the actual dual spacing is on the 2002 Country Coach 36' rear axle or have first hand knowledge regarding the use of 315/80R22.5 tires?

Ernie Payne

2002 Country Coach Allure 36' dual slide

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #1 –
Yahoo Message Number: 94730
Ernie,


I replaced my 12R22.5' with 295X80 22.5, higher load rating than the 12R's No problem with clearance and did not really change tach or speedometer readings.


Jock Vargo

2005 Inspire
51428

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #2 –
Yahoo Message Number: 94731
Hi Ernie, Good luck with your Allure. We replaced our Intrigue 40' (dual slide) tires in 2012 and have no issues. 30k miles later they are doing much better than a set of commercial Kumho's put on in '07. We are maxed out at 33,500lbs and run 115psi rear and 105psi front, good ride and performance. Dual spacing has not been a problem. I see no sidewall temperature problems or rock trapping between the tires(Smartire temp. and psi. sensors). We boondock all the time and are on gravel roads a lot, the Michelins are great......Skip, 2002 Intrigue #11329

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #3 –
Yahoo Message Number: 94732
I replaced my XZ2 12 R Michelin with 315's made by Continental. I went to Bob Dickman's Les Schwab in Junction City. Paul and Don looked at the coach after the deflated the air bags and measured the front wheel opening. They then said they would mount the tires at N/C on one side and after checking clearances proceeded to do the other side. Dave at OMC and Chris Snyder where hesitant but it worked out fine. Now if I had the C-12 instead of the ISL the 315's would not have fit because of the different drive and tag axle.
The Continentals aren't as smooth riding as the highway XZ2, but they are much better than the original Toyos. The steering response is much faster than the XZ2 as the Continentals have a stiffer side wall. The tread is similar to Michelins XZA2 315, which is an all weather tire. So I imagine the road noise would be about the same. The Continental's have wear pattern indicators on the tires. As my coach is lighter using the charts Paul and I figured about 110 lbs pressure. But after checking the wear marks I'm at 117 lbs for the front tires. 112 for Drive axles and 117 for the Tags. So don't believe the published inflation charts, just check Continentals wear pattern indicators and you'll get the best service life.
The reason I went with the Continentals this time is their warranty. I had 275R 80's on my 98 Allure, when all the Toyo 275 R 70's were failing and they were great. They do warrant side wall cracking and failure, Michelin doesn't. After 38 months the XZ2 failed. The XZE is a regional tire with thicker sidewalls than the XZ2. So they may have stood up to the air pollution and sun better than the XZ2. They have a thicker tread and suffer from more squirm, though. Where the 315's from Continental do not squirm. You will experience some overnight flat spotting on the 315 until you get about 25 hours on the tires. Les Schwab bought back the time remaining on the Michelin ZX2. So I didn't have to swallow the entire magilla.
TWI 2004 Intrigue 11731

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #4 –
Yahoo Message Number: 94733
Ernie,

Your concern about dual spacing is well placed. The Michelin 315s require a 9 inch wheel. Your wheels are probably 8.25 inch. So the Michelins are not a good choice. Continental offers Coach tires at 315R22.5 that are speced for 8.25 inch wheels.

Good luck.

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

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #5 –
Yahoo Message Number: 94734
I forgot to mention that the side wall being much flatter on the Continental tire than on the Michelin. Part of it maybe the shoulder is wider on the Continental, too. I have the HSLR 1 I believe, which is more of a highway tire, but with the All weather tread, where the 2 model is more of a regional tire as I remember.
TWI 2004 Intrigue 11731

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #6 –
Yahoo Message Number: 94737
You can put 315/80/r22.5's on 8.25" rims, depending on the rim. I went through this last year.

Refer to this post which has many of the details. You need to be able to identify your specific rim.
https://groups.yahoo.com/neo/groups/Country-Coach-Owners/conversations/messages/88392
Good Luck!



Dan 2006 Allure with tag #31344

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #7 –
Yahoo Message Number: 94741
Quote
Your concern about dual spacing is well placed. The Michelin 315s require a 9 inch wheel. Your wheels are probably 8.25 inch. So the Michelins are not a good choice. Continental offers Coach tires at 315R22.5 that are speced for 8.25 inch wheels.

The Michelin charts approve the XZA2 Energy 275/70R22.5, 295/80R22.5, and 315/80R22.5 tires for both the 9.00 and the 8.25 rims. There is a separate inflation chart for these tires when used on the 8.25 rims.

XZA2® ENERGY HIGHWAY APPLICATIONS Fuel-efficient(†), all-position radial designed for long life in highway steer axle service

Unique intermediate rib design helps combat the onset of irregular wear in highway service
Exceptional handling and responsiveness through optimized shoulder design
Traction and lateral control offered by miniature sipes and variable groove angles

Size
Load Range
Catalog Number
Tread Depth
Max. Speed (*)
Loaded Radius
Overall Diameter
Overall Width (‡)
Approved Rims (Measuring rim listed first.)
Min. Dual Spacing (‡)
Revs Per Mile
Max. Load and Pressure Single
Max. Load and Pressure Dual
page40image7784832nds
page40image78576mph
page40image79304in.
page40image80032mm
page40image80760in.
page40image81488mm
page40image82216in.
page40image82944mm
page40image83672in
page40image84400mm
page40image85128lbs.
page40image85856psi
page40image86584kg.
page40image87312kPa
page40image88040lbs.
page40image88768psi
page40image89496kg.
page40image90224kPa
275/70R22.5 (1)
J
90059
18
75
17.6
448
38.0
966
10.9
277
7.50, 8.25
11.9
303
545
6940
130
3150
900
6395
120
2900
830
295/60R22.5 (2)
J
33215
16
65
16.7
424
36.1
918
11.4
290
9.00 (4)
13.0
329
575
7390
130
3350
900
6780
130
3075
900
295/80R22.5 (1)
H
76807
16
75
19.1
486
41.3
1048
11.8
299
9.00, 8.25
13.2
335
503
7830
120
3550
830
6940
120
3150
830
315/80R22.5 (1)
L
76184
17
75
19.5
496
42.3
1074
12.5
318
9.00, 8.25 (3)
13.8
351
492
9090
130
4125
900
8270
130
3750
900
Ernie Payne
2002 Country Coach Allure 36' with dual slides

Re: Cracks on all four (4) corners of my 2007 Magna

Reply #8 –
Yahoo Message Number: 94747

I hope someone can help me on what causes these cracks on the roof of my 2007 Magna.
I had only one crack on the passenger side above the door when I was at Country Coach. When I returned home I had three more. what causes these cracks. My insurance indicated it was due to fair ware and tear. I don't think so.

Willie

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #9 –
Yahoo Message Number: 94752
Tom,

Why would the 315's not fit if you had a C-12?

Rich 2002 Magna

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #10 –
Yahoo Message Number: 94754
The tag axle on ISL equipped coach is set up with the wheels being mounted in a concave fashion, with the tag for the C-12/13 the the heavier tag is set up with the wheels inverted( convex). For some reason like the Magna from the period the width of the track of the tires is about a inch to and inch and half wider placing the 12 R right up against the fibre glass, so when you mount the 315 tire there is no room. The drive axle is different, too. The ISL uses a 20,000 lb. rear axle with a 4.88 ratio. The C-12/13 drive axle has a 3.92 ratio and I think its the same axle from the Magna/Affinity which is rated at 24,000 lbs and has again a wider track. I have a recollection that Mr Churchill, Director of the Chassis Plant, and Dave Remington of the chassis department told me CC only rated the axle at 20,000 lbs because of Oregon and Federal weight limit regulations. Its reminds me of CC rating the rear axle on my 98 Allure at 19,000 lbs, when in this case it was actually 20,000 lbs. I guess I should have kept a log of all this hear say information from the Home Coming rallys and visits to the factory for repairs. I always took a factory tour when in the area. I think Pat Mason's were the most fun and Carolyn Gzell's the most informative. That reminds me she still owes me one, I guess I'll have to wait for the next life.
TWI 2004 Intrigue 11731

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #11 –
Yahoo Message Number: 94758
Ernie, Have you made a decision on installing the 315/80R22.5s? I'm considering the same change on my 2002 Intrigue and not sure of what I will do.

Don Intrigue #11430

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #12 –
Yahoo Message Number: 94760
Hi Skip, I have a 02 40ft Intrigue with 12Rs I would like to replace with Michelin XZA2 315/80s. I understand you installed 315/80, were they Michelin XZA2s? and how are they working out>

Thanks Don Intrigue #11430

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #13 –
Yahoo Message Number: 94761
Rich,

I know that Tom will answer your question but I don't think it relates to your coach which is, rear suspension wise, the same as my 2003 Magna. I have the Same tires as Tom(Conti HSR1 Coach 31580R22.5) in stalled on my C12 powered coach. I think he is talking about a C12 in an Intrigue and the axle that was installed in that application. I think your application is different.

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

Re: Cracks on all four (4) corners of my 2007 Magna

Reply #14 –
Yahoo Message Number: 94763
Kaz, nice to hear from you! Unfortunately we are not dealers for Detroit so can supply none of what you requested. We buy from the manufacturers-not Detroit, so we have access to heat exchangers, oil and fuel coolers, etc. I'll look forward to your next visit.

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #15 –
Yahoo Message Number: 94764
Hi Don, Yes they were. They are doing great, over 30k miles and over 2 years, no problems. 2002 Intrigue #11329 Skip

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #16 –
Yahoo Message Number: 94773
George,

Are the Contis narrower? When I purchased my coach, the dealer accidentally installed 315 Michelins all around. CC almost had a heart attack on the dual spacing in the rear with the 315's (said they were not safe) and they were replaced with 12R's. I do remember the clearance to the fender at the top was very tight. The only reason I ask is that I would like to put XZA2 Energy's on the rear since that is what I have on the front now. Six 12 R's in the rear are plenty of tire for this coach. I guess you might get a bit more ground clearance with 315's

Rich 2002 Magna

Re: OK to replace 12R22.5 with 315/80R22.5 tires?

Reply #17 –
Yahoo Message Number: 94788
Rich,

I don't know the difference, if any, in width between the Mich and Conti. I do see that one of the other commenters is correct in that the XZA2s are now speced for 8.25 inch wheels. You are right that there is no excess clearance between the fiberglass and the rear tires but I have not yet had any touch. My tires were installed by Bob Dickman in Junction City. Paul seems to be the accepted expert and he is the one who recommended and sold them to me. I just don't know anything more about the Michelins.

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