Gas class A weight limits

[gfmucci]

I notice that the great majority of gas class As older than 2021 use the F53 Ford chassis with the 10 cylinder, 320 HP, 460 FP of torque engines. The same engine/chassis is used whether the rig is 28' or 38' long. Yikes!

I would think that for decent performance it is best to keep length below ~32 feet and gross weight below ~23,000-ish pounds? Is this a reasonable rule of thumb?

Do coaches longer and heavier than this have performance issues and struggles? Or is this just something you accept, go with the flow and don't sweat it?

 

[GypsyR]

Power-to-weight ratio is somewhat lacking on our 38' 7.5 gasser. So what? I pretty well knew what I was buying and wasn't surprised by its capabilities. Or lack of them.

"Saluda grade" is the local killer steep hill. I about have to go up it if we are going to the Blue Ridge area. So I've been up several times now. Slow and plodding, but so far every time when I got to the top I was able to exclaim: "I wasn't the slowest!" Even when it had a running issue once I still managed to pass at least one truck. No big deal, I have two and four wheeled vehicles that can pass about everything on that hill. That the big lumbering motorhome can't doesn't bother me at all. I didn't pay for 500 horses of turbo diesel power.

 

[Joe Hogan]

The 2018 Canyon Star on the F53 chassis we owned never struggled noticeably on any interstate or state road. We traveled Coast to Coast, both N-S and E-W. The CanyonStar was 40' and we traveled maxed out at 30K lbs.

 

[gfmucci]

Good to know. But I am surprised that there are no larger gas engines than the V-10 or newish 7.3 V-8 for larger motor homes.

 

[Rich W.]

Good to know. But I am surprised that there are no larger gas engines than the V-10 or newish 7.3 V-8 for larger motor homes.

There is no market for performance versions of delivery truck chassis (which is essentially what an F53 is) so they don’t exist. And there’s also keeping the EPA happy to consider. One helpful thing you’ll find is that gear ratios change as GVWR goes up with small gas Class A coaches having a 4.88 or 5.38 rear end and larger ones having 5.86 gears or even 6.14 these days.

 

[BGMAC]

I have a 38ft Georgetown gasser V10 and travel back and forth across the smokies with a toad. I’m happy with the performance. It’s not a diesel pusher which a usually much heavier. So in some ways they equal out.

 

[Bigblockyeti]

Good to know. But I am surprised that there are no larger gas engines than the V-10 or newish 7.3 V-8 for larger motor homes.

The problem is, they can't really make them any bigger while producing more power and still passing emissions. A gas engine as a V8 or V10 between 8L & 9L would likely make less power but more torque, it would cost more to produce and it would weigh more. Turbocharging is an option and that's exactly what Jeep has done with the grand wagoneer. The engine has too little displacement to be a serious contender but does acceptability well making more hp than torque for a bloated, overpriced station wagon. A turbocharged 7.3L gas Ford V8 could be tuned to reliably make 500hp and ~690lbft of torque but it would be expensive and tedious to handle all of the heat generated around the engine.