Community Forums

Bussinit · 05-30-2023, 01:36 PM

I'm a little confused here. My coach currently has 11R22.5 size tires. This matches the white placard inside the coach (see attached). However, the blue placard shows a tire size of 295/75R22.5. I've researched this in the forums and I realize that they are relatively comparable tires in size but that the preference is 11R22.5 (maybe?). My questions are why would these two placards have different size tires, and which ones should I be running?

Gary RVRoamer · 05-30-2023, 02:12 PM

Roadmaster, a subsidiary of Monaco at the time, is the chassis builder and made the white placard. Apparently Monaco changed the tire configuration when they built the coach and issued a new tire placard (the blue one), superceding the original. Usually when that is done it means they have determined the original tire is inadequate is some way and the new designation is an upgrade. I think you will find the 295/75 has a bit more load (weight) capacity, around 500 lbs/tire if I remember correctly.

The 11R22.5 size is commonly used on commercial trucks & trailers and thus widely stocked in local tire warehouses. The 295/75 is mostly used on motorhomes and thus more of a specialty tire. If you need a new tire while out on the highway somewhere, the 11R is more likely to be available. If you don't need the extra load capacity of the 295/75, the 11R might be preferred.

My own coach used 295/80's, but when replacement time came I installed 11R's on rear axle where I didn't need the extra capacity of the 295/80. The 11R was somewhat less expensive ans well as being more easily replaced in an emergency.

Bussinit · 05-30-2023, 04:05 PM

Thanks for the information. That’s exactly what I needed to know. I’m mainly concerned with the steer position. I am running very close to the 13000 lb rating (6375/6525 lbs) on the front axle with H rated11Rs so I probably don’t need the extra capacity correct?

I think what I need to do is get some weight to the rear. I have a tag axle and from what I understand, if I lower the pressure in the tag airbags, it should shift the weight to the rear. Does that sound right?

The 10000lb tag is carrying very little weight (3425/3500 lbs) and the drive duals are well under the rated capacity (10050/8750).

Crasher · 05-31-2023, 08:32 AM

Quote:

Originally Posted by Bussinit

Thanks for the information. That’s exactly what I needed to know. I’m mainly concerned with the steer position. I am running very close to the 13000 lb rating (6375/6525 lbs) on the front axle with H rated11Rs so I probably don’t need the extra capacity correct?

I think what I need to do is get some weight to the rear. I have a tag axle and from what I understand, if I lower the pressure in the tag airbags, it should shift the weight to the rear. Does that sound right?

The 10000lb tag is carrying very little weight (3425/3500 lbs) and the drive duals are well under the rated capacity (10050/8750).

If you lower the tag suspension bag pressures, you will add weight to the drive axle and take some off of the steer. On my 43' Bus, for every 7# taken off of the tag, reduced the steer by 1# and all 8#s went onto the drive. What is the capacity of your drive axle,,,,,20,000#? If you took 1050# off of the tag, it would only take 150# off of the steer and add 1200# to the drive axle which would put it up to it's rating.

Bussinit · 05-31-2023, 11:25 AM

The drive axle is rated at 23000 lbs

Crasher · 05-31-2023, 11:40 AM

Quote:

Originally Posted by Bussinit

The drive axle is rated at 23000 lbs

Then you could transfer more weight from the tag to the drive, however, I wouldn't go much below 5,000# on the tag. Transferring 2000# from the tag to the drive would take about 300# off of the steer. In my case the tag was carrying 9,000#, but the drive was only at 14,500#. I transferred 4,000# from the tag to the drive and took about 600# off of the steer. I also had a 23,000# drive rating. There are a lot of tag coaches on the road with the steer axle at or very near its rating. Most owners don't bother with it.

Bussinit · 05-31-2023, 08:15 PM

Thank you. So there’s no concern running at or near max capacity in front? Going back to my original post, I’m running H-rated 11R 22.5 up front which according to the inflation charts and my current weight distribution must be aired up to the max pressure of 120 psi. I just feel like I’d be safer running less weight up front and a little less air pressure.

The other reason I’m asking is these tires are 7 years old and I will be replacing them. Im wondering also if I should go to a 295/75R 22.5 as is shown on the Monaco placard in my original post. Those have a bit more capacity and seem to be what I should be running anyway according to Monaco.

Another question I have is if I decide to go with the 295/75R 22.5 up front can I leave the tag and drive axles with 11R 22.5?

153stars · 06-01-2023, 05:23 AM

It is fine to just run 295 in front... many MH have bigger fronts than rears. Owners have increased front size tires within reason. Issue only comes if moving fronts to a rear position.
Not a tag owner but I think you could the move 295s to tags and just adjust weights tag pressure but not in put on dual position.

Crasher · 06-01-2023, 07:27 AM

I would replace with the 295 tires which gives a bit more margin of safety on the steer. You could also decrease the tag suspension pressure for some more space. The drive can remain 11R 22.5 as can the tag. In the future, you could also move the 295's to the tag with no adjustment needed. The tag suspension doesn't care what the tire size is. It only controls how much weight it needs to support. The important thing is to keep all tires on any one axle the same size.

Bussinit · 06-01-2023, 07:45 AM

I'm leaning toward a set of Toyos. However, their inflation charts do not show an H-rating for their 295/75R22.5. The H-rating comes in at the 295/80R22.5. There is a note for the 295/75R that says it is equivalent to Michelin 275/80R. Not sure what this means. But my question is, would it be ok to go with the 295/80R if needed to get to the H-rating? Size comparison shows me that the 295/80R is closer in diameter to the 11R (not as low profile). As you have mentioned, as long as the tires are the same size on the same axle, this shouldn't make a difference, correct?

RichardE · 06-01-2023, 09:36 AM

Not to throw a wrench into your thinking, but you might look at 315 tires for the front if you want more margin, and lower inflation pressures. You may or may not be able to fit them.

Gary RVRoamer · 06-01-2023, 09:48 AM

Changing to a wider or taller tire on the front axle depends on the amount of clearance in the wheel well. A 295/80 is slightly taller than a 295/75 but the same width.

A tire size calculator like this one makes it easy to figure the difference, but determining if it fits in the RV is mostly trail & error.

Since you are running near axle max, I'd put the more capable (higher load capacity) tire on the front axle. You don't have to use the same size front & rear.

vito.a · 06-01-2023, 10:18 AM

The Signature was Monaco's higher end coach and got heavier each year. The front axle is at or above capacity on most Signatures. Monaco specified 295/80-R22.5 tires on all the slightly newer models and towards the 2008 model increased to 315/80-R22.5 front tires.

On your coach I would install 295/80-R22.5 front tires and use 11R22.5 tires on the rear. This combination will allow lower air pressure in the front to maintain the weight capacity and result in s slightly better ride.

On a side note, Monaco was not the only manufacturer with heavy front axle weights. A friend with a 2004 Newmar Essex upgraded his front tires to 315/80-R22.5 because his front axle was overweight.

moisheh · 06-01-2023, 05:57 PM

Most Monacos run 295/80. Some can take the 315/80 but you have to do a trial fit. One nice thing about 11r is that everyone makes them. The choice is amazing. The prices are much less than 295/80.