Has anyone switched 22.5 rims and tires to 24.5?

[crazycal]

I was wondering if anyone has made the switch. Were there any problems. I need all new rubber and was thinking about the larger wheels and tires. My bus is a 1989 Blue Bird RE 84 pax.

[frank-id]

All 10 hole wheels are interchangeable. Larger diameter wheels usually get better milage than all the small diameter wheels. In some cases, changing a wheels size can alter the final gear ratio. One time I decided that my old GMC 4905 needed a little better top speed. I bought a new set of tires and wheels. After a few short test rides, a long trip was planned. I drove from a high elevation to a lower elevation. Boy the speed and fuel milage was really great. But the ride home was terrible. My transmission really got a workout. Going up Baker grade on hiway 15 going to Las Vegas was about 300 shifts between 2nd and 3rd. Anything with wheels passed me. I think a kid on a skateboard wizzed past. Just about any size can be used in the front, but the rears must be carefully selected, and must begrouped accordingly to tire's outside diameter. If a couple of tires are placed side by side in a dual arrangement, the larger tire will become the size of the smaller tire. Load sharing is important. When installing rear wheels, measuring the outside diameter is very important. An easy method of measurement is done by wraping a string around tire and measuring the string. Write the number on the wheel/tire side wall. After the numbers are gathered, selecting pairs is easy. Frank

[crazycal]

What about clearance? Was there any rubbing? I am not sure what you mean about matching. If I do this, I will replace all wheels and tires with new and same size. I was kind of worried about lugging the motor on the freeway. Right now, I am turning about 1800-1900 at 60mph. Going up grades is another issue. I was doing 25-30 on the Grapevine. That was no fun. I am looking to see what I can do to get more power.

[frank-id]

To what are ya refering? Most buses have lots of tire clearance at top, sides and all around tire. The suspension is heavy duty, not as a car.If ya can go at least 60-65 mph at 1800 rpm, that is the best range for power and economy. The grapevine is not the usual test road for determining power requirements. But is ya wanna go 1800 rpm at 65 mph, up da hill, get more muscle as in 425HP with a really big turbo. Just add money, time and labor and you may gto about any speed ya want at any time. Frank

[crazycal]

I don't think clearance on the rears will be a problem. I have a 23k axle with springs to match. There is no way I will ever come close to bottoming out in back. It's the front that I am worried about. This bus slants down in the front and a little to the right. Not knowing exactly how I will be raising the front, I wouldn't want to be making a turn going into a dip and have the tire hit the body. This is my first bus (I hope I will be saying that for a long time), so I am trying to learn from other peoples mi$takes, I mean experience. As to the power issue, I have owned several Powerstrokes and a couple of Cummins in some pickemup trucks. I am aware of what kind of power you can acheive with a diesel.

[the_experience03]

You need to maintain proper clearance BETWEEN the duals. swapping from a 10.00-20 tube style to the 11x22.5 tubeless style without too much issue since they are the same overall size, but make sure you have those clearances correct.

[sportyrick]

WRONG Wrong wrong, all 10 hole wheels are not the same. I found this out in buying the alloy wheels for my bus. There are 2 kinds of wheels, HUB centered and LUG centered and they WILL NOT INTERCHANGE! Take a tape measure and find out for yourself. The older ones (sometime pre 90's) are lug centered and later ones are hub centered. You can look at the lug nuts and figure out which is which. If you see a lug nut that has a flange that is holding the wheel on then it's hub centered. If you see no flange on the nut and a tapered lug nut like on a car then it's lug centered. Also you don't need to change the inner rears out unless you want to, steels work fine, the only difference is weight savings. Buyer beware, don't buy the wrong wheels because you probably won't get to sell them back to the same person and will be stuck with them, work out something beforehand. Also I believe a 24.5 is a taller tire than SOME of the 22.5's, the metric numbered ones being the taller ones. Be forwarned that taller tires will give you more top end speed at the expense of power IE: you will have less power to climb hills and fight headwinds. If you can barely handle hills now then a lower final ratio will make it worse on hills but you will go faster down the other side, all other things being equal. The opposite is if you want to climb hills easier you need a higher final ratio/RPM at the sacrifice of speed. If you are topped out in RPM and don't even slow down on hills you need a lower final drive ratio which will make the engine work more, pull the RPMs down and gain some top end speed. For every 10 MPH gained in speed the wind resistance is @ squared, you can't just put a rearend in that makes you go 200 MPH, it doesn't work that way. Change one thing for the better and you lose something somewhere else, the old ying/yang. Think about a 21 speed bicycle, first gear will let you climb a wall with mechanical reduction but you top out at 2 MPH and RPMs (higher drive ratio); top gear you can do 40 MPH but can't climb a small hill because you are using all your power and no RPMs or mechanical reduction (lower drive ratio). sportyrick