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Tire Sizes

Yahoo Message Number: 3118
I've occasionally read in the forums about changing from the stock Kodiak 225 tire size and going up to a 245. What would be the benefit(s) of this? Bill

Re: Tire Sizes

Reply #1 –
Yahoo Message Number: 3119
A 245/70R19.5 Load Range F tire will carry about 400 lbs per tire more than a 225 tire. Because of the 1" large diameter of the 245 it rotates 23 RPMs per mile less than the 225.
I have found the 245's cost less at many tire dealers. Must be a more common tire than the 225.

Re: Tire Sizes

Reply #2 –
Yahoo Message Number: 3120
Quote
A 245/70R19.5 Load Range F tire will carry about 400 lbs per tire more than a 225 tire.

Thanks Ron. I thought I remembered that you had the larger tires. I was
interested in this info because I've noted multiple hairline cracks in
my sidewalls so a new set of tires looks likely in the not too distant
future. I didn't know about the additional +400lbs/tire so that's good
news.

Using one of the numerous tire size calculators (here's one:
Tire Size Calculator - Compare Tire Sizes | Tacoma World ), I also noted the slight
difference in diameter and resultant actual MPH increase per given
RPM's. So (without a change in gearing somewhere) when your speedo says
you are going 60mph you are actually going a couple mph higher than
that. Did you make any gearing or speedo sender changes on your rig? If
not, how does your Scanguage handle the differences?

Thanks, Bill

Re: Tire Sizes

Reply #3 –
Yahoo Message Number: 3122
I must admit that the speedo error wouldn't concern me as I don't use it. I much prefer the digital speedo on the GPS.

If or when I need new tires I will up the size as well. I like to have a good cushion over the GVWR. The Winnie Journey we had was terrible in that regard. The maximum capacity of the tires (those terrible Michelin XRV's) on the front equalled exactly the GAWR for the front. So, was the limit based on the tires or did they simply match the tires to the front axle? Our next MH - the Ambassador had a very good cushion up front (GY's) and we had no problems at all compared with constant problems with the XRV's.

Rear axle seems to always get a good cushion.

Another alternative would be to stay with the same size and go to the G rating (cost? ? ? ? ). It would mean inflating to 110 from 95. I think the wider tire is a better route since you get a bit more capacity than the 225G and stay at 95 psi. I assume 265's would be too wide?

Don

Re: Tire Sizes

Reply #4 –
Yahoo Message Number: 3123
My 35GS came with the 245s. The speedo is dead on with GPS.
Denny

Re: Tire Sizes

Reply #5 –
Yahoo Message Number: 3124
I've put the Goodyear Brochure on ties that has the recommended pressures and the Michelin Load and Inflation pressure tables in the files section.

Don

Re: Tire Sizes

Reply #6 –
Yahoo Message Number: 3129
I put the Michelin Data files up here. It shows that the Michelin tires are just a little larger than the Goodyear.

Re: Tire Sizes

Reply #7 –
Yahoo Message Number: 3131
I have not changed tires yet. Still have the 225's. Took MH to local Michelin tire dealer and had them inspected. Some tiny cracks near rim. Nothing to worry about.
New tires are in the budget for next year. Probably will go with the Michelins.

Re: Tire Sizes

Reply #8 –
Yahoo Message Number: 3132
My 2005 Jayco Seneca 35GS on the Kodiak chassis (6.6 Duramax) came with Goodyear 245/70R19.5 LRG tires. I have just put new 245/70R19.5 LRH Michelins, with liquid balancing on. Cost out the door was 2430. Best upgrade ever!!! Great ride. Less sway. No pushing when trucks pass.

However, you need to have someone that knows what they are doing take a look at your rims and make sure you will have proper spacing on the dual wheels. Any place that does truck tires should be able to tell you with a look.

Re: Tire Sizes

Reply #9 –
Yahoo Message Number: 3133
Do you have XRV's? I'd be inclined to go to the XRE's. After my experience (and many many others) with XRV's on Class A's, I wouldn't touch them.

In 2005 we took our Winnie to Freightliner in Gaffney for annual service. They were great. While they did their work we had a tour of the plant. They do MH chassis and assemble Sprinters (or at least in 2005 that is what they did at Gaffney). The Sprinters are built in Germany, knocked down and boxed, and then assembled in the US. That somehow makes them US built. Canada won't buy that and says "they are German" and get taxed as such.

Anyway, during the tour of the MH chassis line I noticed GY tires going on a lot of them. Until 2004 FTL provided ONLY Michelins on its chassis. So, I asked. Clearly I probed a ticklish situation. Seems that the MH manufacturers made it clear their buyers wanted a choice and many did not want Michelin XRV's (my view to a tee). What surprised me is that they didn't consider using XRE's instead since no problems were being reported with them.

What really irked me was that whenever a MH owner reported a problem to Michelin and tried to get it fixed under warranty he was told he was running under inflated or overloaded - and case closed. Many of those owners were like me - checked pressures daily when travelling and carried a air compressor with them. It was interesting to note that in the middle of the XRV kerfuffle, Michelin changed its inflation table and added 10lbs for the XRV's. I think that told the story but Michelin was clearly petrified of the risk of getting into a Firestone/Explorer situation and simply denied denied denied.

Our GYs on our first, third and fourth MHs have been far better than the XRV's. Having said that, I wouldn't hesitate to go with the XRE's or XRA's.

Don

Re: Tire Sizes

Reply #10 –
Yahoo Message Number: 3134
Have been reading with interest about the tires. I have a 35GS Seneca 2006. Factory tires were Michelins 245 70/R19.5 XZE. Motorhome rides like a dream and I have been very pleased with these tires so far. We have about 20K miles and we travel at about 55-60 mph. Compared to our Greyhawk the ride is much superior. No one has mentioned these particular tires.

Regards

John

Re: Tire Sizes

Reply #11 –
Yahoo Message Number: 3136
John - Let me support you - my experience with the XZE is great. I was considering shocks - springs - airbags... anything to get rid of the rock and roll! I upgraded from GY Level G to the XZE at level H, and my oh my. The ride was so improved I have not pursued any other chassis changes. Lots of tread as well.
I run the air pressure a bit high 100 - 110 lbs. But if you think about what happens when the center of gravity shifts on breaking and hill climbing, and the effect on mileage... I think high is good.
Here is my post from 9/2008 - since then we have another year of experience, and all is good. We did have one front tire loosing air - Les Schwab in Port Angeles fixed a tire side valve stem problem and sent us on our way.

Kevin
Jayco Seneca HD 34 SS Diesel (2006)
30.67742N, 97.58730W

Re: Tire Sizes

Reply #12 –
Yahoo Message Number: 3138

I also have XZE's on my coach, and the ride and load range are great. I am wondering though about the 245's.... I wanted the larger tires on my coach, but was told the extra width did not allow enough clearance between the rear duals, so I bought the 225's instead.... did this issue come up for anyone else, or was my tire dealer simply blowing smoke? I have the 19,500 lb Dutchmen.

Denny

Re: Tire Sizes

Reply #13 –
Yahoo Message Number: 3139
I have them on our Funmover, it came with them on it ( 245's) but ours is a 22,000 lb don't know if that difference in the
wieght would cause a difference in rear tire space.

Re: Tire Sizes

Reply #14 –
Yahoo Message Number: 3140
I understand that the minimum dual separation increases by one inch between 225 & 245s. The actual number varies between manufacturers but is about 10 for 225 and around 11 inches for 245s.

Kevin

Re: Tire Sizes

Reply #16 –
Yahoo Message Number: 3142
GM offered only 2 sets of 19.5 wheels for the Kodiak MH Chassis. Aluminum and Steel. It did not matter which size tires you got. The same set off wheels was used for both 225 and 245 tires. There is a small difference in the Steel to Aluminum wheels on front. Offset is 5.551" for Aluminum wheels on front.
You can check out wheel sizes in this 2009 build sheet.
http://eogld.ecomm.gm.com/NASApp/mediumduty/proddesc.jsp?year=2009&brandID=1&line=206&modelID=1473&package=1593&series=1§ion=1&page=0#cat15

Re: Tire Sizes

Reply #18 –
Yahoo Message Number: 3144
Not sure it is recommended to not rotate out tires. In my case. Front tires are Goodyear. Rear tires are Michelin. Outer are on aluminum wheels. Inners are on steel wheels. Other than rotating from side to side I see no need to rotate tires. I have even wear all the way around.
Michelin has a paper on truck tire maintenance. Shows all the things to consider when rotating tires. See page 45 of Truck Tire Service Manual.
http://www.michelintruck.com/michelintruck/toolbox/reference-material.jsp

Re: Tire Sizes

Reply #19 –
Yahoo Message Number: 3145
Unless you see an unusual wear pattern it is felt that the tire will "age out" before it wears out. As long as you keep them properly inflated, balanced and the alingment in check you should never need to. I know Michelin says that in their paperwork. I managed a dump truck fleet for 15 years and we never roatated those. I also found the same on our E-450 class "C" tires never showed any unusual wear once the alignment was fixed (40,000+ miles).

Re: Tire Sizes

Reply #20 –
Yahoo Message Number: 3146
Actually I think it is recommended if needed. I recall reading that changing the direction of rotation is recommended if you see unbalanced tire wear. Here is the sections from the Michelin RV tire guide.
All tires mounted on RV's should wear in a smooth, even wear pattern when the tires are maintained with the correct air pressure for the load on the tire. If tires begin to show an irregular wear pattern, and the vehicle alignment is correct, sometimes just rotating the tires by changing direction of rotation and wheel position will allow the tires to wear evenly.
And in another section:
TIRE ROTATION
If correct air pressure and proper alignment are both continually maintained, tire rotation may never be needed. However, in other cases, tire rotation may be needed to help even out alignment, underinflation, or free rolling wear problems. Follow your motor home manufacturer's rotation service recommendations. There are no restrictions as to the method of rotation with your Michelin RV tires, however, Michelin recommends including the spare tire in the rotation pattern and changing the direction of rotation. Tires can be rotated front to rear and side to side.
K