I notice that people change the tire diameter on cars frequently and in fact we increased the diameter of our tires by 1 inch on our Smart Car and some folks increased by 2 inches. That is all the wheel wells will tolerate. For me the tires were also wider. Made for better ride and stability. I understand that coaches with the 22 inch tires ride better. I seem to have plenty of wheel well room on my Vista 30T. Why shouldn't I consider increasing the diameter when time to change tires. I understand that width might be a problem if I increased because of distance between duals. Any thoughts?

On Michelin Tires website they have a chart on what tire that you can move up or down to.

Surely you know that you can't simply change the diameter of the tire without changing wheels as well, and that is going to be a really expensive change with very little payback.As for the larger tires riding better, that is debatable. It may be true on a chassis designed for the larger and heavier wheel and tire, but adding them to your light and short chassis could just turn it from a "Bread Truck" ride to that of a "Log Wagon".I have an older 16" wheel coach and I hear folks with the 19.5s and the 22.5s with the same complaints that I have. Weigh your coach and set the right tire pressures.

Not sure what trans you have, but changing tire size can really mess up the shift points. I do know someone who went up in diameter with the Allison 6 speed and his shifting was really messed up. Of course transmissions can be reprogrammed.Goldencrazy wrote:I notice that people change the tire diameter on cars frequently and in fact we increased the diameter of our tires by 1 inch on our Smart Car and some folks increased by 2 inches. That is all the wheel wells will tolerate. For me the tires were also wider. Made for better ride and stability. I understand that coaches with the 22 inch tires ride better. I seem to have plenty of wheel well room on my Vista 30T. Why shouldn't I consider increasing the diameter when time to change tires. I understand that width might be a problem if I increased because of distance between duals. Any thoughts?

There's going to be more involved than just changing tires and wheels. The lug nut torque on our 2001 F53 chassis with the 19.5" wheels was 165 ft. lbs. The torque for the lug nuts on our 2013 F53 chassis with 22.5" wheels is 450 ft. lbs. The wheel studs on the new one are almost twice the diameter of the old ones.I think you'd be hard pressed to find 22.5" wheels to fit the old style studs. Even if you did I doubt they could be torqued tight enough to keep them in place. There's no way you could torque the lug nuts on the smaller studs anywhere near 450 ft. lbs. I doubt they could take 250 ft. lbs. before they twisted off.

If you have the clearance changing out the rear axle should solve your problem with ratio and lug bolts, etc..

change tires from 19 to 22 | Good Sam Community

MCDDY
Explorer
Jan 06, 2014
Beside the inherent problems already stated there's also the matter of your speedometer and odometer since the outer diameter/circumference of the tire will be different. Went thru that when Monaco decided to retro-fit the 99&00 Windsors from 275/70/22.5 tires to 295/80/22.5 tires. Do the math either way, O.D. or Revs/Mi. Had to make the adjustments on the back of the speedo.

Dave
timmac
Explorer
Jan 06, 2014
Pirate wrote:
My 2006 chassis could come with 19.5 or 22 wheels. I wonder what exactly Ford did to the chassis to make that difference?

Motorhome factories could order the chassis with 22 wheels for upgrade if wanted, 19.5 is fine for motorhomes under 20,000 lbs.

Cheaper to replace and us 19.5 tire RV's can carry a spare..
OnaQuest
Explorer
Jan 05, 2014
Pirate wrote:
My 2006 chassis could come with 19.5 or 22 wheels. I wonder what exactly Ford did to the chassis to make that difference?

Different axles and different hubs, to start.
Pirate1
Explorer
Jan 04, 2014
My 2006 chassis could come with 19.5 or 22 wheels. I wonder what exactly Ford did to the chassis to make that difference?
timmac
Explorer
Jan 04, 2014
Goldencrazy wrote:
OK. Thanks folks. Scratch that idea. Always looking for ways to modify to improve. This is obviously not one. Buy another lamp.

Do you have a Ford F-53 chassis, if so those Bilstein shocks are to harsh of shocks for a small RV like yours, install Monroe's they help with a softer ride, also air bags can help also.

Also to help with the sway you need to adjust the sway bars under your F-53 if that's your chassis.
Goldencrazy
Explorer
Jan 04, 2014
OK. Thanks folks. Scratch that idea. Always looking for ways to modify to improve. This is obviously not one. Buy another lamp.
bluwtr49
Explorer II
Jan 04, 2014
bluwtr49 wrote:
Nice thing about modifications, virtually anything can be done with appropriate input of cubic dollars.

You would have to find a front and rear axles from a class A with 22.5 hubs. Not a big problem. Modifying the new axles to accept your springs, linkages, and etc....again not a problem. You also may have to cut the axle tubes a bit, not a big deal, done all the time by a good shop. They can also change your gear ratio and build the new drive-shaft. You may need fab new springs if you need to lift the coach for clearance.

Alternatively you can just buy a MH with 22.5" tires and same a few $$$
bluwtr49
Explorer II
Jan 04, 2014
Nice thing about modifications, virtually anything can be done with appropriate input of cubic dollars.

You would have to find a front and rear axles from a class A with 22.5 hubs. Not a big problem. Modifying the rear axles to accept your springs, linkages, and etc....again not a problem. You also may have to cut the axle tubes a bit, not a big deal, done all the time by a good shop. They can also change your gear ratio and build the new drive-shaft. You may need fab new springs if you need to lift the coach for clearance.

Alternatively you can just buy a MH with 22.5" tires and same a few $$$
PastorCharlie
Explorer
Jan 04, 2014
If you have the clearance changing out the rear axle should solve your problem with ratio and lug bolts, etc..
Hikerdogs
Explorer
Jan 04, 2014
There's going to be more involved than just changing tires and wheels. The lug nut torque on our 2001 F53 chassis with the 19.5" wheels was 165 ft. lbs. The torque for the lug nuts on our 2013 F53 chassis with 22.5" wheels is 450 ft. lbs. The wheel studs on the new one are almost twice the diameter of the old ones.

I think you'd be hard pressed to find 22.5" wheels to fit the old style studs. Even if you did I doubt they could be torqued tight enough to keep them in place. There's no way you could torque the lug nuts on the smaller studs anywhere near 450 ft. lbs. I doubt they could take 250 ft. lbs. before they twisted off.

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