24.5 wheels on a 4104?

[scotty_vince]

Will 24.5 wheels and tires fit on a 4104. If they will what are the advantages or disadvantages.

[4104GA]

 Yes they will fit and run ok.  My son had an 04 and used the 24.5 so he could rotate tires from his big rig to the bus and the bus tires to his trailer.

[gus]

24.5 is the size of the wheel, not the tire, so thr tire diameters could be the same as the 22.5.

It depends on the tire size and brand.

[NewbeeMC9]

what  I have been seeing and it varies from brand to brand



11R 24.5 are the tallest and the lowest revs-per-mile(rpm) at around 470-475 range


the 11r 22.5s and the lower profile 24.5s were about 20 - 30 more rpm.


YMMV    (pun intended)

[RJ]

Scotty -

I just posted this a couple days ago on the Yahoo GMC BusNuts Group.  Someone asked about metric-sized tires instead of 12R22.5s.  Here are my comments, which you should find useful:


Yes, the truck tire side of the industry is finally going to metric sizing.  Not a big deal, really - no worse than we went thru with our cars almost 20 years ago.

For GMC owners, the size is not what you should be concentrating on.  You need to look at the "revolutions per mile" figure for the various tires you're contemplating.

I've beat this into the ground countless times on this and other bus bulletin boards over the last ten years, but I guess it's time for a refresher:

GMC Coach Tire Sizing:

GMC designed the powertrains of their highway coaches around tires that turned 495 revs per mile, starting way back with the Yellow Coach 719 models (in the late 1930s) and continuing right thru until the end of 4905 production in 1980.  That was one thing about their drive line components that remained constant.

The closer you come to that number with replacement tires, the closer your coach will perform to OEM specs.

Choosing tires that turn MORE than 495 rpm will decrease your top speed, increase your fuel consumption, and give a slight improvement to initial startability from rest.

Tires that turn LESS than 495 will have the opposite effect - slightly greater top speed, slightly better fuel economy, but a little bit harder to get rolling.

You have to choose what you feel is right for YOUR coach, based on what YOU do with it!

Doesn't matter if it's a 12R22.5, an 11R22.5, an 11R24.5, a 315/80R22.5 or an old 10.00X20, look at the revs per mile as one of your guidelines for selecting new tires.

Two other things to consider:  Load Range and Speed Rating

You want tires capable of carrying the normal loading of your bus, plus a fudge factor for extra "stuff" that accumulates.  Load Range G & H seem to be the most common.

Be careful of Speed Ratings.  Your local dealer might have a smoking hot deal on some properly-sized "bus tires", but they're only speed rated for 50 or 55 mph.  These are transit bus tires, designed for running around town bumping curbs all day.  They're not really designed to run down the interstate at 65 - 70 for hours on end.  Pay attention!

And finally, for those of you who have a V-730 automatic in your GM, be aware that the bevel gear ratio ratio is different than the stick shift bus.  Not taking into consideration the fuel mileage issue (typically lower in ANY automatic-equipped bus), you also loose some top speed, which may or may not be an issue for you.

If it is, my research has been that Bridgestone makes a highway drive axle tire in 11R24.5 that turns 470 rpm.  Installing this tire on your V730-equipped GM will bring it's performance levels almost back to OEM with the stick.

Your coach, your decisions.  Do your homework!

FWIW & HTH. . .

RJ Long
PD4106-2784 No More
Fresno CA

[TomC]

My 11R-24.5 Michelin XZE have 476rpm.  If you had the biggest V drive gears of 4.1, then at 2300rpm you'd have a top speed of 80mph.  I have 4.56 and cruise at 1850rpm which is 58mph.  Good Luck, TomC