Planocat

Tire Thing Has Me Totally Confused

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Planocat   

I need 6 new tires for '04 Dutch Star 38' on a Spartan chassis. Michelin tire models and sizing has me totally confused. Current Michelin size is 275/80R 22.5. Dealers claim this Michelin size is interchangeable to 295/75R 22.5 from brands that don't offer the original size. They tell me there will be no ill effects on the drive line or instrumentation.

Valid point from one of the Michelin dealers is the premium prices commanded by the Michelins give you the longest mileage and that is a moot point since I don't drive enough to wear out the tires...... they will be removed due to old age, not lack of tread.

So, I think I have decided on the Continental HSR2 SA at a $1000+ savings. They come in the 275/80R22.5 size and are an H rated tire that has the same load ratings as the Michelin. My other considerations were Toyo, Sumitomo, and Kuhmo. The Continentals appear to have a very extensive dealer network for National travel and that played a part in my decision. And they come in the original Michelin size.

I'm thinking of taking the tire savings and buying the Centramatic on-board balancing system. Does anyone have experience with that product? I have one close friend who has had them on his last 3 coaches and swears by them. I priced all tires with spin balancing as I don't want to mess with any beads in the tires. After spin balancing and adding the Centramatics, I should have a smooth tire ride as the H rated tires would allow me to run lower tire pressures while handling the load.

I'm far from being a tire expert, so I welcome any comments on my flawed thinking before I pull the trigger.

****

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Guest BillAdams   
Guest BillAdams

I believe that you have it all right! That's the same course that I would take.

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DeWat   

While the amount is negligible, the difference will be .25% - .30% less on the speedo and odo. IIRC, anything below 1.6% is acceptable on cars, but I might be off. I got the % numbers from 1010 Tires Calculator (http://www.1010tires...p?action=submit) and Miata.net's Tire Calculator (http://www.miata.net/garage/tirecalc.html). I used 22 for 1010 Tires because it wouldn't take 22.5.

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I have had Centramatics I my coach for 10 years and they work. I have a computer balancer which I bought the adapters for 22.5 wheels, When I change tires I spin them on the balancer and check how far they are off. If they are off a great deal I rotate the tire on the wheel until I get the minimum off balance. This makes the Centramatic work better as there is a maximum unbalance that they can compensate for. As for speedo calibration some have switches on the back for calibration, also the ecm can be reset for tire size and revs per mile. This is necessary if using a monitor such a Road Relay or Scan Gauge.

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When I change tires I spin them on the balancer and check how far they are off. If they are off a great deal I rotate the tire on the wheel until I get the minimum off balance.

What is considered too far off, 4oz, 10oz? On a passenger car or truck 4oz would be considered way off. But on a 22.5 tire thay may be OK.

Just wondering.

Herman

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rorr1821   

I need 6 new tires for '04 Dutch Star 38' on a Spartan chassis. Michelin tire models and sizing has me totally confused. Current Michelin size is 275/80R 22.5. Dealers claim this Michelin size is interchangeable to 295/75R 22.5 from brands that don't offer the original size. They tell me there will be no ill effects on the drive line or instrumentation.

Valid point from one of the Michelin dealers is the premium prices commanded by the Michelins give you the longest mileage and that is a moot point since I don't drive enough to wear out the tires...... they will be removed due to old age, not lack of tread.

So, I think I have decided on the Continental HSR2 SA at a $1000+ savings. They come in the 275/80R22.5 size and are an H rated tire that has the same load ratings as the Michelin. My other considerations were Toyo, Sumitomo, and Kuhmo. The Continentals appear to have a very extensive dealer network for National travel and that played a part in my decision. And they come in the original Michelin size.

I'm thinking of taking the tire savings and buying the Centramatic on-board balancing system. Does anyone have experience with that product? I have one close friend who has had them on his last 3 coaches and swears by them. I priced all tires with spin balancing as I don't want to mess with any beads in the tires. After spin balancing and adding the Centramatics, I should have a smooth tire ride as the H rated tires would allow me to run lower tire pressures while handling the load.

I'm far from being a tire expert, so I welcome any comments on my flawed thinking before I pull the trigger.

****

I also am in the process of replacing my 6 Goodyear tires (very disappointed in the performance of these tires and I was a Goodyear believer) but have decided to go with Michelin brand. I need the 275/80x22.5 load range H. The model I am going with is the XZA3+ which is a fuel efficient directional tire. The approximate cost complete will be just under $4000 purchasing under the FMCA Advantage program. If you can buy in a tax free state you could save the tax which for me is around $300. The key to using this program is that you must find a dealer who participates in national accounts. I have heard good reviews for this tire and it is used on more than just RV's so if you needed a replacement it should be available.

I have the Centramatic balance system and am very happy with the results. I live in Texas and as you may know this is a Texas company. You can go to their location which is near Dallas and they will install the units. Also another point on tires. I would pay close attention to the date code on the side walls. Personally, if I am going to spend $4000, I do not want tires with year old date codes. If I were running an 18 wheeler it would not matter because I would wear the tread out before they aged out. A MH is another story because you will most likely age out first. Also I would be sure they mount the tires with the date code on the outside and be sure they replace all valve stems. They need to use weights and not powder to balance the tires. In my oppinion there are several reasons not to use powder weigh but most importantly Centramatic told me is does not work well with their system.

On the point of changing tire size. I would check with your coach manufacture and get a Tech's oppinion. A larger tire could give unforseen problems and the tire manufacture will most likely not take the tires back. Bigger is not necessarily better. I would strongly caution against changing tire size unless you know someone who you can trust with the exact same year and model who has changed tire size. You can get into clearance issues, handling issues and the list goes on.

Just some thoughts!

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Planocat   

"have decided to go with Michelin brand. I need the 275/80x22.5 load range H. The model I am going with is the XZA3+ which is a fuel efficient directional tire. The approximate cost complete will be just under $4000 purchasing under the FMCA Advantage program."

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rorr1821:

I'm out the door with the 6 Continentals at $2992. A $1000 savings that I can use other places. We have a couple of dealers in the area that are familiar with the Michelin FMCA program and while a nice savings (dealer can only guess at the final cost) it's probably not that far off from Costco's price of $563.99 each on the XZA3. Both FMCA and Costco would be a substantial savings over the $4845 price I received as a walk-up customer!

The Continentals out-the-door for under $3,000 bell rings the loudest with me.

I just noticed you were referencing XZA3+ and Costco quoted me XZA3........ so there is that confusion over Michelin's tire designation rearing its ugly head again.

When Tireman9 listed all the Michelin tire designations I about fell out as who can keep track?

D ick

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rorr1821   

"have decided to go with Michelin brand. I need the 275/80x22.5 load range H. The model I am going with is the XZA3+ which is a fuel efficient directional tire. The approximate cost complete will be just under $4000 purchasing under the FMCA Advantage program."

------------------------------------------------------------------------------------------------------------------------------

rorr1821:

I'm out the door with the 6 Continentals at $2992. A $1000 savings that I can use other places. We have a couple of dealers in the area that are familiar with the Michelin FMCA program and while a nice savings (dealer can only guess at the final cost) it's probably not that far off from Costco's price of $563.99 each on the XZA3. Both FMCA and Costco would be a substantial savings over the $4845 price I received as a walk-up customer!

The Continentals out-the-door for under $3,000 bell rings the loudest with me.

I just noticed you were referencing XZA3+ and Costco quoted me XZA3........ so there is that confusion over Michelin's tire designation rearing its ugly head again.

When Tireman9 listed all the Michelin tire designations I about fell out as who can keep track?

D ick

Not sure about just about XZA3. However , if you go to the Michelin website it provides all information on XZA3+ Evertread tire which is the one I am talking about. The FMCA price as I said before was quoted to me as being about $3800 including tax, mounting, valve stems, and balancing. This was from TCI which specialize in large commercial tires. I find it remarkable Continental can sell 6 tires, mounted, balances and new valve stems of this size for $500 ea.

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Herman,

Somewhere above 12 oz. Rotate tire 180 degrees on the wheel and re-spin. I have seen 20 oz out. The larger the tire the higher weight may be.

The Centramatics balance the tire, wheel and the hub and drum, I just balanced a pair of front drums that were between a 1/2 and 3/4 lb off.

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wolfe10   
14 hours ago, Travelin2 said:

upsizing the tire from 275x70rx22.5 to the bigger size will reduce your turning radius.  The tire will rub on the inside as you turn

Travelin2,

Welcome to the FMCA Forum.

I would slightly rephrase that.  A larger size MAY cause interference issues. 

Unless you reduce cut angles to avoid contact with body, suspension or chassis elements (easily done with some steering boxes such as Sheppard M100) I can't picture how it would change turning radius.  And, if it did, it would INCREASE the turning radius.

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14 hours ago, Travelin2 said:

upsizing the tire from 275x70rx22.5 to the bigger size will reduce your turning radius.  The tire will rub on the inside as you turn

Using a tirecomparitor like this one will let you know how much the size changes. 

https://tiresize.com/comparison/

I just went from 255/80R22.5 to 275/80R22.5 with no problem.

Bill

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FIVE   

If the tires being replaced, assuming they are OEM, can carry the load and do the job, I fail to see why folks want to change the size from what the factory put on.  As noted, a change in width/height can cause the tires to rub...each other and/or the frame, change transmission shift points, change speedometer readings, etc.

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wolfe10   

Five,

Counter point:  To save money,  many coaches are on marginally sized tires.  Said another way, there is little safety reserve with the OE size/load range tire.

Were my tires loaded to over 85% or so of their carrying capacity, I would sure consider upgrading.

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tireman9   
On 9/2/2017 at 8:22 AM, WILDEBILL308 said:

Using a tirecomparitor like this one will let you know how much the size changes. 

https://tiresize.com/comparison/

I just went from 255/80R22.5 to 275/80R22.5 with no problem.

Bill

Glad you have confirmed your new tires meet the "Minimum Dual Spacing" requirement. The simple tire comparison web site is reasonable for cars and Light trucks but they only offer an approximation and do not tell you the Minimum Dual Spacing. A failure to consider this dimension can lead to tire "kissing" and potentially two failures.

 

255/80R22.5 have a MDS of  11.30"  and 275/80R22.5 have MDS of 12.24

Since the spacing is controlled by the wheel offset it is sometimes possible to make such a change if the wheels were designed for the wider tire but used by the RV company for the narrower tire.

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FIVE   
On 9/2/2017 at 6:15 PM, manholt said:

Five.  295's are like finding chicken teeth !:P

I know.  When we had a RF blow out the previous coach on I55 southwest of Chicago, it took them five and a half hours to find a 295.  Tech said if it had been a 315, it would have taken much less time.

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manholt   

Currently run 315 in front, rest 295's all are 7/2014...thinking of getting 305's for drive and tag next time (2020 or 21).  Really like the 315's!  

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On 9/3/2017 at 2:31 PM, tireman9 said:

Glad you have confirmed your new tires meet the "Minimum Dual Spacing" requirement. The simple tire comparison web site is reasonable for cars and Light trucks but they only offer an approximation and do not tell you the Minimum Dual Spacing. A failure to consider this dimension can lead to tire "kissing" and potentially two failures.

 

255/80R22.5 have a MDS of  11.30"  and 275/80R22.5 have MDS of 12.24

Since the spacing is controlled by the wheel offset it is sometimes possible to make such a change if the wheels were designed for the wider tire but used by the RV company for the narrower tire.

Yes I fully understand the problems associated with dual spacing. I am having a hard time believing a difference of 0.94 inches in a 11.0inch separation can cause kissing. I can't see or detect any deflection that could possibly cause kissing. I have seen tires that were extremely close that under load might kiss but not 11.0 inches apart.

Bill

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manholt   

WBill.  See what happens to your brain, when you stay up too late on the East Coast, after being half baked in Texas? :lol: Radiation does strange things to your "Mental file cabinet"!

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