12R 22.5 or 11R 24.5

[Ednj]

Here's what the tag says

[NJT 5573]

 Eagle always used 11R24.5 because of its superior suspension. The others all needed help so they used a taller sidewall. The 11R24.5/11R22.5 tire width is the same on like tire models. This is an ideal footprint for a bus. Wider is not a good thing. Dump trucks, garbage trucks, fire trucks etc. are very difficult to drive in rain and snow. To much tire just skids. I bet you can't find a dump truck driver that won't laugh at you if you put "wide" tires on your coach.

[RJ]

The 12R's are the original tire that buses were made with in the 50's and 60's. 

TomC -

Minor correction here, Tom.  The 4104s and 4106s, built from 1953 > 1965, all came with 11.00x20 bias ply tube tires, not 12s.  The 12R22.5s didn't start showing up until the late '60's, early '70's, starting with the 4903 Buffalo and the MC-7.  Even the mighty Scenicruiser came with 11.00x20 tires.

According to a friend of mine who's in the commercial tire industry, it won't be much longer until ALL the tires will be metric-sized.  (Just like auto tires - remember the "F78-14"?)  He also says that the 22.5s are by far and away the most popular rim size today, as more and more truckers are going to the smaller/lighter 22.5 and making up the difference in fuel mileage loss by using overdrive transmissions.  The smaller/lighter tire allows heavier loads which equals more $$ for them, as you're well aware, since you sell the things.


Ednj -

Good point, posting the data plate for your MCI.  Everyone can see specifically what MCI intended for the coach, the weight ratings per axle, and the recommended air pressure.

So, when it comes time to shop for tires, if the only thing available is metric sizing, all you have to do is sit down with your dealer and find a tire that matches the old sizing, load rating, etc.  Definitely NOT brain surgery, and most commercial tire dealers will be more than happy to work with you.


Doug -

I suspect MCI is still delivering 12Rs simply because that's what the customers are ordering.  Remember, most coaches leave the plant with tires supplied by the buyer, often thru a leasing program.


All -

Whatever tire size you finally choose, pay attention to the speed rating of the tire.  For example, on one of the major brand's sites, there are two 315/80R22.5 listed - one has a 55 mph maximum speed rating, the other has a 75 mph rating.  The lower speed-rated tire is for TRANSIT BUS operations on city streets.  These tires are built differently to withstand the constant abuse they're given in this application.  (Transit drivers think that curbs are part of the braking system, especially on the front.)  Running a transit tire at freeway speeds for hours on end, especially in the summertime, is a recipe for potential disaster. 

Do your homework, and choose wisely!!

FWIW & HTH. . .

[JackConrad]

I suspect MCI is still delivering 12Rs simply because that's what the customers are ordering.  Remember, most coaches leave the plant with tires supplied by the buyer, often thru a leasing program.


A friend just bought a new 45' MCI shell from MCI. It came with 22.5 wheels  Jack

[tekebird]

Eagle superior Suspension??

Although I will give you the Eagle does have a nice Ride......as did the Flxibles with Torsilastic Suspensions, if it was truely superior in all aspects why did it not cross over into other brands?

[jjrbus]

Jack, those tires were 315  22.5. The gross front axle weigth on that bus was a whopping 16,000 pounds!!

[TomC]

Just to give you a small idea of the difference between 22.5's and 24.5's, some of the sizes 22.5's come in are: 8, 9, 10, 11, 12 (inches), 235, 245, 255, 265, 275, 295, 305, 315, 365, 425, 445, 445 (metric) with 50, 55, 65, 70, 75, 85 aspect ratios mixed in.  24.5's come in 11, 12, 275, 285, that I know of-big difference.  The 11x20 is the tube tire equivalent to 12R22.5.  19.5's are getting to be more popular with the low profile set (car haulers) and the light weight groups (liquid and bulk haulers) since they are even lighter than the 22.5's and can carry the weights.  Michelin will be bringing out a 19.5 equivalent to the big X-one 22.5's to be sized the same as the 255/70R-22.5 for use on low profile trailers and car haulers.  Michelin is the creator of most all tire advances.  Then the other tire companies lay back and watch to see if it works then bring out their versions of the tire a couple of years later.  Just like what happened with the X-one super single.  Bridgestone and I believe Yokohama both have these tires now.

One comment (actually I've said it before, but can't say it enough)-tires are more than big black round things that support the load.  If you go to the Michelin or any other tire manufacturer that carries commercial tires, you'll see the numerous models of tires that are very specific in the job they are supposed to perform.  I hope all of you put the tires performance and load capability above the price of the tire.  Always-safety first-if you can't afford the best of tires, maybe a little less expensive hobby would be a good choice.  Good Luck, TomC

[gus]

On a lighter bus there is no point in getting heavy duty tires, waste of money and ride quality.

Metric sizing makes no difference, the tire doesn't know or care what is written on the sidewall.