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airagone

Class A Tire Size

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Shopping for drive tires, 38 ft Newmar, originals are 275/70R22.5 - very few to choose from at this size.

So has anyone upped the size to a 275/80 with good results?

Southern travel only so no snow.

Thanks all

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If you are fair weather only ignore this I just installed last spring 

conti hybrid hd3 tires in that size  as a drive tire  80mph and traction tire 

one day I will get to use in snow  

 

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 I have Sailun 275/70R22.5 LR H truck tires on our MH. They are all position tires that are very quiet-running, track well,  and although I never drive in snow or muddy conditions they have good traction when parking on wet grass.

Sailun has some open tread designs that you may like better.

I bought from a local tire shop instead of online, the total bill was $1,380 for 6 tires mounted, balanced and installed in Aug 2018.

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Have you checked with Newmar to be certain that the larger tire size isn't going to cause a problem? Sometime a larger tire looks good standing still, but it still creates a problem as the suspension moves to full travel. Wouldn't hurt to make a phone call.

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Have you checked the 

On 3/21/2019 at 8:27 PM, airagone said:

Shopping for drive tires, 38 ft Newmar, originals are 275/70R22.5 - very few to choose from at this size.

So has anyone upped the size to a 275/80 with good results?

Southern travel only so no snow.

Thanks all

If both tires are load range "G" are you sure there is an increase in load capacity?  Have you look online for the diameter of the tires?  If the 275/80 is much larger it could rub on something.  Especially the steer tires.  

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12 hours ago, manholt said:

I would give Newmar Tech a call before changing from 70 to 80!

Same here.  I'm very hesitant to change anything the factory has installed.  They used that particular size for a reason.

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Like I mentioned earlier, often it's not possible to see the problem with the coach standing still. Hit a pothole or large bump with the wheels turned all the way to one side and suddenly you might find the problem. This is not a cheap vehicle, and I'd hate to have to pay a repair bill because the tire hit something mechanical unexpectedly. Or worse, have the tire blow and cause an accident. Sounds extreme, I know, but the engineers design clearance for wheel travel for the size they intend to be mounted on the coach.

I've got a similar situation on our coach - it came to us with 315/80R22.5 tires. Really nice tires. They are often chosen as the metric equivalent to the 12R22.5 tires that came on the coach when the coach was manufactured. Problem is that the 315s are about 1/2" wider than the 12R22.5 and at full turn it's possible for the tire inside the turn to make slight contact with the air bag. If I should hit a bump during this time the tire could possibly do damage to the airbag. I'm going to switch back to the proper size 12R22.5 to avoid this from happening.

I wouldn't switch tire size until it was confirmed from the manufacturer that it will be safe.

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24 minutes ago, richard5933 said:

Like I mentioned earlier, often it's not possible to see the problem with the coach standing still. Hit a pothole or large bump with the wheels turned all the way to one side and suddenly you might find the problem. This is not a cheap vehicle, and I'd hate to have to pay a repair bill because the tire hit something mechanical unexpectedly. Or worse, have the tire blow and cause an accident. Sounds extreme, I know, but the engineers design clearance for wheel travel for the size they intend to be mounted on the coach.

I've got a similar situation on our coach - it came to us with 315/80R22.5 tires. Really nice tires. They are often chosen as the metric equivalent to the 12R22.5 tires that came on the coach when the coach was manufactured. Problem is that the 315s are about 1/2" wider than the 12R22.5 and at full turn it's possible for the tire inside the turn to make slight contact with the air bag. If I should hit a bump during this time the tire could possibly do damage to the airbag. I'm going to switch back to the proper size 12R22.5 to avoid this from happening.

I wouldn't switch tire size until it was confirmed from the manufacturer that it will be safe.

That is amazing. I would bet if you measure the difference between the major manufactuers for this tire the differences in diameter will be more than 1.1inch. 

Why don't you adjust the stop in your steering so it can't hit the airbag? 

Bill

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Bill, could be that he only has a 50 degree turn radius to begin with.  My 1973 coach had a 50 and I had to back up a lot to make turns, especially in campgrounds!  Wow, what a difference, when we got a 55 degree!

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8 hours ago, WILDEBILL308 said:

That is amazing. I would bet if you measure the difference between the major manufactuers for this tire the differences in diameter will be more than 1.1inch. 

Why don't you adjust the stop in your steering so it can't hit the airbag? 

Bill

We've had this conversation in another thread and I don't want to take focus from the original topic. Bottom line for me is that sometimes the best tire for a coach is the one the engineers and designers built it for. I investigated your suggestion, and it quickly became similar to that little old lady who swallowed a fly.

I only brought this up as an example of what can go wrong when tire sizes are changed. Someone put these tires on my coach without doing a thorough investigation into the situation, and the result is tires that make contact with the airbags. Lesson? Important to do thorough research and not just assume they'll fit.

Also, the fact that not all manufacturers stick with the 'standard' dimensions for tire sizes is another reason why a consumer needs to do thorough research. I set up a spreadsheet for all the possible replacement tires for my coach, and you are correct about the variances in sizing. Setting up a spreadsheet allowed me to look at all the dimensions side-by-side and eliminate a couple of tire options since their sizing was different enough to not work for me.

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