Tires are confusing!

[Cladano]

Any info is appreciated!
I'm a new bus owner and I'm looking at replacing the front tires. I've looked at a ton of posts and It's only made me a little more confused I think.
What my spec plate says: 265/75R22.5 - 22.5x7.5
What my bus has on it:
Rear: 10R22.5 (Good Year with 3/4 tread on them I think made in '08 )
Front: 10R22.5 (Good Year with 1/2 tread on them made in '06)

I don't have enough money to replace all 6 tires so I'm just hoping to replace the front 2.

Eventually replacing the back ones but not sure when.

From what I've been reading the 10R is not very common and is recommended to go to 11R.

Also- Speed is important to me so going from 65 to 68 would be a plus.

I've seen about 5 different tires sizes people are using so no clue what to do here.

Thanks!

[Sehnsucht]

To sum it up: 265 is the width of the tire sidewall to sidewall and is in millimeters. 75 is the height of the sidewall as a ratio of the width so in this case 75% of the 265mm. R is the construction of the tire meaning it's a radial tire. 22.5 is the rim size however this is given in inches. There are usually also numbers following which indicate load and speed rating of the tire. It can be a little confusing.

Once you get into truck tires, some of the millimeter stuff gets converted to 'regular' measurements because gosh darn it this is Murica and we ain't gonna let no namby-pamby European socialists tell us how to measure stuff! LOL. Seriously though, most of it just boils down to matching what you have or should have. I say 'should have' because someone could have gone off the manufacturer recommended size for their own reason. I think some folks here will advocate for resizing tires for fuel economy, handling, clearance height, or whatever. Just be aware that changing the tire size also affects speedometer accuracy.

[Ronnie]

I would add to that check your rim width, it will be marked on the rim. Make sure any change in tire size will fit your rim. Each tire size has a specified rim size it will properly fit.

[ermracing]

Does your bus have a flat floor or wheel well humps in the back? The 265/75 tires are considered 'low profile'. I would also bet your have 8.25" wide rims, that seems to be the standard width although a lot are spec'ed out with 7.5" wide rims.

The 265/75x22.5 is 38.1" tall and the 10rx22.5 are about 2" taller so I would just make sure nothing is rubbing.

Since you bought it locally you might be able to check with the bus garage and see why they went with the larger tires.

(Our bus has flat floors and spec'ed to run 265/70x22.5, but is currently shod with 255/70x22.5, all on 8.25" wide rims.)

[Ronnie]

10r22.5 actually is pretty common. Another thing to think about is if you change size on just the front you no longer have matching sizes on your bus. Nice to have all matched so so you can move one to another position in case of a flat.

[Cladano]

Thanks for the info!

The rim size is 22.5 x 7.5.
The floor is not flat. It has wheel wells on it.
Not sure on clearance. It appears to have a decent amount of room but not sure.

If I keep the back ones, any benefit to a different size up front or best to stick with 10R22.5 for front too?

[Ronnie]

11r22.5 recommends a 8.25" wide rim. 10r22.5 can use either the 7.5 or 8.25. I would check with a local dealer and ask to verify.

I would stay the same size all around. whatever you choose.

[EastCoastCB]

Originally Posted by Ronnie

11r22.5 recommends a 8.25" wide rim. 10r22.5 can use either the 7.5 or 8.25. I would check with a local dealer and ask to verify.

I would stay the same size all around. whatever you choose.

https://www.doublecointires.com/wp-c...-InfoSheet.pdf

[Ronnie]

Nice chart, I saved it. So an 11 would fit just is not the recommended size by this chart. I had looked on Firestones site and they only listed 8.25 rim for the 11r22.5

[EastCoastCB]

Those charts vary slightly by manufacturer.
From what I've always been told its fine to put an 11R on a 7.5 rim but its better to avoid a 10R on a 8.25 rim.

[magnakansas]

I would tell you "stick with the 10r22.5"

wiliam

[kazetsukai]

Originally Posted by Cladano

What my bus has on it:
Rear: 10R22.5 (Good Year with 3/4 tread on them I think made in '08 )
Front: 10R22.5 (Good Year with 1/2 tread on them made in '06)

I'm pretty sure all of your tires are aged out. Mine were, I replaced all 6 for about $2200.


Prioritize the fronts but get the rears done when you can. Depending on where you live, your mechanic, the condition of the tire, etc, it could be hard/impossible to get a vehicle inspection with tires that old.

[PNW_Steve]

I saved a bit on my last set of tires by running retreads on my drive tires. IIRC: They were 285/75R22.5's. The stores were $215 each and the Toyo steers were $430 each.

[Phil Saran]

Not mentioned is the age of your tires 2006 and 2008.
14 and 12 years old. They should be considered rolling time bombs.
On Motorhomes/travel trailers the recommended span is 5 to 6 years.

For you family and your safety consider replacing all your tires with
more current manufacturing dates.

[Ranchorossa]

10r22 is a common tire. They have them at walmart.com. I'd keep the same size tires, just make sure you get drive tires if you're replacing the front ones.

[Dirtdoctor]

I put 11r-22.5 load range H (slight overkill) but they handle potholes really well and well wear nice too. The 22.5’s are a wee bit taller so I get better road speeds. Ya loose a wee bit on the starting off but I’m not racing.

[WSallai]

You have received several good suggestions on what to check for regarding sizing:

• Rim/Wheel Width?
• Rim/Wheel Size Diameter?
• What size is currently utilised in all locations?

There were several omissions:

1. What is the recommended Tire Size at all locations from the Manufacturer Owner Manual?
2. What is the actual weight of your rig per axle as determined by a weight scale?
3. What is the additional weight that you plan on adding to the Rig, including cargo/luggage, people?

Once you find out what Wheel Sizes you have and what the recommended sizes for your Rig is, and the actual weight per axle, then you will be able to determine what Tire Size and Load Range will meet or exceed your needs.

Over-loaded and under-inflated tire pressure are the same thing. Suggest you purchase a Tire Pressure Monitor System that will capture the pressures of each of the tires on your Rig PLUS the tires on your Toad. This will prevent a catastrophic failure of a tire due to over-loading/under-inflation, which may be 2-psi too low! If you suffer a blow-out at speed, tire fragments will cause extensive damage to the body and undercarriage as well as loss of control.

One additional thing: tires on RVs rarely wear out from mileage, but rather must be replaced due to age. They suffer from dry-rot as evidenced by minute cracks in the side-walls and tread. Tires should be replaced at 5-years from date of manufacture. So, ensure that the tires that you purchase have a manufacture date that is within 3-months of your purchase date so that you will have 5-years of usage. The tires that you have on your Rig now are way too old and are quite dangerous!

If you are a Family Motor Coach Association (FMCA) member, you can get a tire discount from Michelin which includes Continental and BF Goodrich. The BF Goodrich ST230 is a solid Bus Tire with good sidewall protection for those curbs that jump out at you on turns.

Remember, Tires, Suspension Parts, and Brakes are the most important safety features of your Rig and a failure of any one item can be catastrophic! So, buy the best quality.

Good luck!

[BarnYardCamp]

I'm no where near the new tire point in my build...but am thinking about going to a slightly smaller tire as a way to change my final drive ratio. My bus really struggles to climb steep grades, got down to 35 on some of the grades in western Maryland when I drove the bus home last summer. I still had plenty of rpm capacity when driving 65mph...
I'm assuming that the speedo could be recalibrated through the computer???
Thoughts anyone?

[Oscar1]

Originally Posted by Ranchorossa

10r22 is a common tire. They have them at walmart.com. I'd keep the same size tires, just make sure you get drive tires if you're replacing the front ones.

Not sure if I'm reading this right? Are you saying you should put drive tires on the front? You will want to use steer or all position tires on the front, drive tires on the drive axle.
Cheers

[s2mikon]

I would stick with the 10r22.5 tires. They are about 2 inches taller than the 265's so you get a little more gearing. The rim width of 7.5" is border line for 11r 22.5 depending on the manufacture of tire. Of course your mileage may vary.