Community Forums

Sunraydoc · 02-21-2017, 11:22 PM

When I looked at the spec sheet for the 2017 Storm 36D I see it is listed as coming with 22.5 tires, yet I have 19.5s on ours. My favorite service advisor tells me that happens for whatever reason (mainly expense) and wasn't unusual. The rig has a 22K chassis, and I was wondering if I could upgrade with bigger rims and tires when tire change time comes around---seems reasonable since Fleetwood lists the Storm as coming with the larger tires, so it seems they should clear the fender wells and steering linkage. I understand the speedometer programming will have to change.
Thanks, Bob

ualdriver · 02-22-2017, 12:03 AM

I have a Storm with little wheels too. What's the advantage of big wheels and tires vs. the smaller ones we have?

vsheetz · 02-22-2017, 12:18 AM

Our previous coach was available with two differing chassis, one with 22" tires, the other with 19.5" tires. I had the one with 19.5" tires. As it drove and road OK, and the tires met the weight requirements, I never had the urge to change to the larger tire. When it was time for a new set of tires I liked spending less $$ than I would have with 22.5" tires. Also enabled to carry a spare tire - more difficult to do with the larger tires.

twinboat · 02-22-2017, 06:05 AM

The differential gear ratio is also different on the heavier chassis.

If you install larger tires, you drop the engine cruising RPMs down. You may find it hunting between gears in some situations.

tderonne · 02-22-2017, 07:01 AM

Same axle ratio whether it has 19.5" or 22.5" tires, 5.38.

http://www.fleet.ford.com/resources/...2014_LoRes.pdf

(The 20,500 and the 22,000 chassis have been this way over the years. 24,000 and 26,000 chassis only have 22.5" tires.)

Wheels can't be easily swapped. Two different bolt patterns. 8x275 and 10x225 if I recall correctly.

Gary RVRoamer · 02-22-2017, 07:25 AM

As tderonne says, the tire & wheel size is a chassis option on several of the Ford F53's. Was on the Workhorse W20 chassis too, back in the day.

The drive train (tranny gearing and axle ratio) is configured to allow for the overall tire circumference, but a 19.5" wheel vs 22.5" doesn't necessarily mean the tire circumference is a lot different. Have to compare the rest of the tire spec to determine that.

Quote:

I was wondering if I could upgrade with bigger rims and tires when tire change time comes around

For what reason? What benefit are you expecting from spending a substantial amount of extra money?

tderonne · 02-22-2017, 08:41 AM

Quote:

Originally Posted by Gary RVRoamer

The drive train (tranny gearing and axle ratio) is configured to allow for the overall tire circumference, but a 19.5" wheel vs 22.5" doesn't necessarily mean the tire circumference is a lot different. Have to compare the rest of the tire spec to determine that.

Tires are:
245/70R19.5 - 33" diameter
235/80R22.5 - 37.30" diameter
So even a bit more than the 3" wheel diameter difference.

Ends up being about 250 RPM difference in engine speed at 60 MPH (2021 vs 2273 RPM in 6th gear.)

ualdriver · 02-22-2017, 10:12 AM

Is there any discernible change in ride quality with the 22.5" vs. 19.5" wheels on a given RV? One would think the bigger wheel would "ride" over some imperfections in the road that the smaller wheel might "sink" deeper into and therefore make for a bumpier ride.

Sunraydoc · 02-25-2017, 10:59 AM

Thanks for all the info, guys. Looking further I think the Storm comes stock with the smaller tires; though the rvusa website says 22.5s, that doesn't appear to be the case from pictures I see on the Fleetwood website...looks the the bigger tires start with the Southwind.

I'm fine with the coach as is. We put Sumosprings and a Roadmaster steering compensator on her, and I think they civilize the ride and handling quite a bit. We hit some woop-de-doo bridges on the way to Florida, and I think without the Sumos the back wheels would have left the pavement LOL.

In a perfect world I'd like the 22.5s, but from what I'm hearing here it's not worth the outlay to change out the 19.5s, assuming it could even be done.

Bob