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!
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
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.
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.
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!
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.
I'm in Baraboo.
Quote from: Jsrcaptain on February 11, 2021, 09:48:54 AM
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).
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.
Quote from: HB of CJ on February 11, 2021, 11:13:14 AM
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.
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
Quote from: luvrbus on February 11, 2021, 12:13:07 PM
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.
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.
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
Hey Dave5Cs,
Any complaints about your highway speed with the smaller 11Rs?
I had 11 r 22.5s on my bus and could roll down the hiway at 70-75 easily.
I would go for a little more aggressive tread on the back. Not fun to get 'stuck' on wet grass.
Right now I'm running Goodyear endurance wha steer tires... just what the local tire man recommended
Right now I have 30 miles on them, we'll see how they work in there long run
It's almost impossible to compare top speed in one bus to another based on tire size alone. There are so many variable in the equation and it's difficult to get an apples to apples situation. The better question is how you thought your bus did with the 12R tires? I know that you only had a short ride with it, but you hopefully got some idea.
My GM 4106 had an 8V71 coupled to a V730 and had 11R tires. My current bus (GM 4108) has an 8V71 coupled to a Spicer 4-speed and rides on 12R tires. I don't notice any difference on the lower end at all between the two, but the 4108 can hit 80mph easily if I want it to. But, there are so many other variable (rear axle ratio, trans gear ratios, engine strength, etc.) that there is really no way to know specifically how much difference the tires make without doing lots of math. I hate math.
Quote from: richard5933 on February 11, 2021, 01:11:15 PM
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.
I bought 6- 295/80/22.5 from Les Schwab in the small town of Ontario Or so they must be to hard to find ,I had my choice of the 12Rx22.5 or the 295/80/22.55 fwiw the 12Rx22.5 is a bus tire and they can be tricky to find without ordering
Quote from: Jsrcaptain on February 11, 2021, 08:44:03 AM
I think stock was 12R-22.5.
There should be a builder's plaque somewhere on your coach, the stock location was above the driver's left shoulder riveted to the roof. If your bus was professionally converted, the converter may have moved it elsewhere (on my '78 5C, Angola riveted it to the inner door of the electrical compartment under the driver's window.) Not only will it have the month/year of the build, but also the Serial Number and the Unit Number. In between the date and the VIN, it will indicate the GVWR as well as the GAWR for the front and back axle when using the tire sizes recommended on the plaque. 99.99% chance it's going to say 12R22.5s. But look anyway.
Also, look at your outside dual. Chances are you'll find the wheel size (diameter & width) stamped into the wheel rim somewhere, often opposite the valve stem hole. If you've got stock steel wheels, again, chances are they're 22.5 x 8.25. (Side note: if a PO changed the wheels, and you've got 22.5 x 9 or 22.5 x 9.5, you're in luck, because you can now run 315/80R22.5s if you want. Just can't put those on the narrower 8.25" rims any longer.)
Finally, the fellow who now owns the MC-5C I used to have, changed all the wheels over to 24.5s and is running 11R24.5s. He's gone for the taller tires to reduce the rpm while running down the highway and hopefully increase the fuel mileage a little. He's been in the trucking industry for years, and I understand he's running Coopers on it now.
FWIW & HTH. . . ;)
Quote from: RJ on February 11, 2021, 07:48:02 PM
...Side note: if a PO changed the wheels, and you've got 22.5 x 9 or 22.5 x 9.5, you're in luck, because you can now run 315/80R22.5s if you want. Just can't put those on the narrower 8.25" rims any longer...
I've seen notes in at least two manufacturer's tire spec books (Firestone & Michelin) listing 315s tires on 8.25" rims, but at lower max. air pressure and a slightly de-rated max capacity. I wouldn't recommend going this route, but it does provide options if there is ample clearance and you should run across a great deal on some good used tires.
on my coach I put the tire size and vin.# to the left of the driver seat so it was easier to see and all tires are the 295/80 r22.5 and if you look in the pic. you can see it to the left of the thermo .
never had a problem getting this size of tire and my tire guy did say there are still used on a lot of trucks , rv's and bus
https://lh3.googleusercontent.com/pw/ACtC-3fRzB9TFTrMZDgf3aLXwTPNDkYVfwVuC73cFnms1RZLohddnH7-3ss28mumhny2laSC8sduDDGKL698ZqE8AyGWU8SPcRjYZKe7xvKnvdPUJ3j0tIc7XzKN-tqUOcdOXQb1fXuuwV0VQNb_35DS75Tw=w1157-h867-no?authuser=0
dave
I looked at my placards, all six, lots of information, weights etc., but no tire size. I'm sure everything is still stock.
The PO was the second owner. The first was the US Air Force. It spent it's early days in Colorado Springs, running back and forth from the airport to the Air Force Academy, so, not many miles and not much rust. Probably driven by inexperienced airmen as the sides are creased badly from tight turns. They took out a lot of stop signs I'm guessing.
Quote from: Jsrcaptain on February 12, 2021, 06:03:37 AM
I looked at my placards, all six, lots of information, weights etc., but no tire size. I'm sure everything is still stock.
The PO was the second owner. The first was the US Air Force. It spent it's early days in Colorado Springs, running back and forth from the airport to the Air Force Academy, so, not many miles and not much rust. Probably driven by inexperienced airmen as the sides are creased badly from tight turns. They took out a lot of stop signs I'm guessing.
The 12R x22.5 was standard issue for the MCI even up to the D models,bus people and tires lol you see up to 3 different size tires on the newer buses OEM my rv has 295/80/22.5 on the drive axle and tag axle and 315's on the front axle came from the factory set up like that according to the chart
The GMC 4905 service manual lists 12r, 12.5r and 13r x 22.5 tires. My spare coach has 12.75's on the front. Firestone lease tires, and didn't show any cracks in the sidewalls till about last or year before. They apparently use better rubber in their tires that they lease.
Price will help you decide. Generally 12r are noticeably more expensive compared to 11r, due to less demand. Also, consider Bandag or Michelin retreads for the rear. Remember that you'll never wear a set out unless someone else is footing the fuel bill. My dad wore out a set on the 4104 but fuel was less than $1.00 a gallon for a lot of those years. And he got 8 to 10 with the generator using from same tanks.
That's kinda what I was thinking. Not enough years left to wear out a set of tires. I won't be circling the globe, mileage-wise that is. Gotta have some money left at the other end to eat.