Tire size

[Jsrcaptain]

My 72 MC5B tire cracks are so big, I can see the air inside the tire! I'm looking for suggestions on the best tire size. I think stock was 12R-22.5. Are 11R-22.5s more readily available? I know this is a perennial question, just wondering what the latest thinking is.
Also, any of my fellow Wisconsinites have a good source of tires they could recommend?

Thanks!

[richard5933]

If you have 12R22.5 and they are working for you there is no reason to switch. The 11R22.5 is more common, but the 12R22.5 is not difficult to find. The difference in the load capacity will likely make the 11R require a higher presser, plus the 11R22.5 is a smaller tire and will mess with your ratios.

Pomp's Tires is where I got my Firestone FS 561 in 12R22.5 size. Not sure where you are in Wisconsin, but they have locations all over. You're looking for one which sells/services commercial tires.

Scroll down this page till you see the commercial tire section, then find your nearest location:

https://commercial.pompstire.com/Service/Services-by-Location

[Ed Hackenbruch]

The 12 R22.5 is an inch wider than the 11R 22.5 and may need a wider wheel.  The height/diameter should be the same for both if the sidewall ratio is the same.

[chessie4905]

depends. weight of coach for one thing. If it is not that heavy vs. gvw, 11r22.5 would be much cheaper and easier to get, especially at any truck stop out on the road. ride may be rougher, but everyone runs their tires near the max anyway. One thing that may be important to you is a loss of about 3 to 4 mph top speed, due to smaller rolling diameter. If a manual transmission, will make starting out a little easier, and gain a small amount of power on the hills. Many truck stops sell takeoffs in that size, if you arent planning on travalling a lot of miles a year. Several here have gone with that smaller size with satisfactory results. If you arent sure of your weight, take it to a truck stop that has Cat scales. get axle weights.

[Jsrcaptain]

Thanks, I'm going to replace all 6 with new. Weight will not be a factor I think, being a conversion. would I want to get all 6 identical or should the steering be a better tire with more plies? For safety sake.
Do you guys carry a spare? With 24 hour road service, it might not be necessary, I'm thinking. Unless I get waaay off the path!

[neoneddy]

I'm from MN, hopefully we won't hold that against each other. I'd say keep the 12r22.5s.  Find the best one from the take offs and keep it as a spare.  If you've been running tires with cracks, I have two 12r 22.5s on the side of my house. I bought them from a guy on CL who scraps trucks and buses.  Turns out they are out of date, but look great still... If you're looking for a spare tire,  you can have one.

[Jsrcaptain]

I'm in Baraboo.

[richard5933]

Thanks, I'm going to replace all 6 with new. Weight will not be a factor I think, being a conversion. would I want to get all 6 identical or should the steering be a better tire with more plies? For safety sake.
Do you guys carry a spare? With 24 hour road service, it might not be necessary, I'm thinking. Unless I get waaay off the path!

Don't be so sure about the weight. Once you start adding things like 800 lbs of water and a 500 lbs generator, things start to add up fast. All that plywood and interior finishing gets heavy when you add it all up.

Pomp's has a commercial tire location in De Forest just north of Madison. That's not too far south of you, but it's obviously not something you'll do over your lunch break.

Here's the Firestone commercial dealer listing for your area: https://commercial.firestone.com/en-us/dealerLookup#address=baraboo%20wi&bu=AG

Yes to the spare. If you don't have a spare wheel they can be bought for under $100, less if you get used. Should fit nicely in your spare tire compartment up front.

I prefer all 6 tires to match. The front steer tires are the primary concern though, so if you get used tires put them on the rear only. New, proper sized tires up front only. Balanced as well to reduce vibration and handling problems. If you haven't had an alignment recently this would be the time. While you're doing that, have them confirm that the rear axle is properly aligned (centered and running square to the chassis).

[HB of CJ]

The original sized 12R x 22.5 do require a wider wheel.  Thus was such on my old Crown Supercoach.   Finding new wheels to support a 11R x 22,5 or even the taller 11R x 24.5 might be expensive.  If going to aluminimumium Alcoa wheels longer lug nut studs will be required.  Expensive again.

Weigh your coach.  You should know what is resting on each axle end plus a total for aft and front plus the grand total for the whole nine yards.  Also consider the local friendly knowledgeable heavy truck recycling yards.  Sometimes they have nice sets of wheels and tires from trucks that do not need them anymore.

[richard5933]

The original sized 12R x 22.5 do require a wider wheel.  Thus was such on my old Crown Supercoach.   Finding new wheels to support a 11R x 22,5 or even the taller 11R x 24.5 might be expensive.  If going to aluminimumium Alcoa wheels longer lug nut studs will be required.  Expensive again.

Weigh your coach.  You should know what is resting on each axle end plus a total for aft and front plus the grand total for the whole nine yards.  Also consider the local friendly knowledgeable heavy truck recycling yards.  Sometimes they have nice sets of wheels and tires from trucks that do not need them anymore.

Without knowing the existing size wheels on the coach it's hard to know if new wheels are needed. The 12R22.5 tires can easily be put on 8.25" rims which is exactly what I've got, and the Firestone data book shows this as an acceptable mounting.

What size wheels are on the bus right now?

If you need to replace the steel wheels, they can be had a reasonable price. Less if you get used.

[luvrbus]

The 295/80/22.5 tires are real close to a 12R/22.5 in size,load carrying and are usually cheaper than the 12R x22.5

[richard5933]

The 295/80/22.5 tires are real close to a 12R/22.5 in size,load carrying and are usually cheaper than the 12R x22.5

From what I've seen the 295/80R22.5 is no easier to find than the 12R22.5. Not any cheaper either last year when I went shopping. Might be different now.

Here's a chart I did when I was tire shopping to compare the options. I ended up going with the 12R22.5 as they were the closest to the OEM tires.

[Jsrcaptain]

Thanks again.
There's a good truck salvage just south of Verona. Plenty of rims available.
I only drove it home 30 miles with those cracked tires, although they were on the back and decent used steer tires. All the wheels are stock and I'll stick with the 12R22.5s.
I got home and discovered the spare and thought "How lucky!" until I pulled it out and it was a split rim! It took me all day to break it down, as waste management wouldn't take it with the tire on the rim.

[Dave5Cs]

12R x 22.5 Had  on my 5C MCI
11R x 22,5 Have now and for 5 years no problems same rim's, 8.25 original rims. Psi 90 all around. Toyo's very smooth riding tires

[Jsrcaptain]

Hey Dave5Cs,
Any complaints about your highway speed with the smaller 11Rs?