Maximum Single-Rear-Wheel GVWR

[Chance]

Was watching a video where a Heavy Duty 3/4-ton Chevy Diesel pickup had a surprisingly high 11,350 pound GVWR. Front axle GAWR was 5,600 pounds and rear axle GAWR was 6,600 pounds. That’s in 1-ton SRW pickup territory, which raises the question of how high will new 1-ton SRW trucks and chassis go? Can 12,500 pounds (E-350 range) be that far off? Perhaps even higher?

In your opinion, is there a practical weight limit where drivers/buyers no longer feel secure with single rear wheels? Other than a concern of a possible rear blowout, what’s not to like about having 4 identical wheels and tires as long as they can handle the load?



P.S. — Wondering how this upward trend will affect motorhome designs, not just pickup-truck tow ratings.

[Oneilkeys]

Both my Vegas and Axis have weighed in right around 5000# front and 7500# rear. That maxed out the 350 Vegas, but gives me 2000# extra rear for my 450 Axis. What size tires are on the Chevy truck? If there are tires that will carry 7500#, I don’t see the necessity of 6 vs 4 tires. Most RVs have to have their tires replaced because they are old or heat cracked, not because they are worn out.

[Chance]

I’m not that familiar with Chevy trucks, so I had to look it up. It appears the 2WD and or gas have 5,200-pound front suspensions, with 4WD and or diesel 5,600 pounds. I’m not clear on combinations.

The 3/4-Ton have 6,600 pound rated rear axles and 1-Ton 7,250 pounds. These ratings may be limited by tires rather than axles themselves. I’m not sure what drives the limits.

3/4-Ton show LT245/75R17E, LT265/70R17E, LT275/70R18E, or LT275/65R20E tires.

1-Ton show LT275/70R18E and LT275/65R20E tires.

I saw specs for 2020 SRW diesel Chevy with 4WD rated at 12,250 pounds, which is highest I recall seeing. I suppose Ford could try to beat that with 2020 SRW 4WD F-350.

In any case, that’s much higher than the 11,500-pounds my Class C was built on, and is practically the same as E-350. It also beats Sprinter and Transit maximum GVWR.

[Chance]

Originally Posted by Oneilkeys

.....cut..... If there are tires that will carry 7500#, I don’t see the necessity of 6 vs 4 tires. Most RVs have to have their tires replaced because they are old or heat cracked, not because they are worn out.

What got me thinking about this subject again was a vehicle I saw on the road yesterday that looked “different” from a distance. As I got closer it became obvious that not only did it have rear singles, but was also a bit larger than the common Ford SRW E-350 step van, so I spoke briefly with the driver and he said it was a Freightliner diesel, which I later researched. It turns out the Freightliner stripped chassis was available with SRWs, and 14,140-pound GVWR. If not too expensive, that chassis could have made a nice compact Class A the size of an Axis/Vegas.

To get that weight rating with only four tires, Freightliner used Michelin 225/70R19.5, 12-ply commercial tires. That’s a very common truck and motorhome size. As can be seen in pictures, it used rear wheel drive with beefy 8-lug wheels.

[Oneilkeys]

The only problem is when you go to 19.5” tires rather than the 16” on the Axis, I bet four 19.5” cost about the same as six 16”. In addition, the F53 chassis is a whole step up from the Axis which increases your overall height and affects stability, unless like the F53, the Freightliner is wider than the Axis. One thing I really like about the Axis is it’s smaller size. Everything is a trade off.

[Chance]

Not sure when these ratings became effective, but they look promising regarding how SRW GVWR is increasing:

Mercedes Sprinter specs now show single rear wheel options up to 11,030 pound GVWR on vans and Cutaways. These are based on wider 16-inch rear wheels and tires they call Super Single. However, having different size tires makes carrying a spare a problem and also limits tire rotation; so not a great solution in my opinion. Super Single have been around for years, but initially with lower GVWR if I recall correctly.

Ford’s new 2020 F-350 Super Duty pickup with single rear wheels are available up to 11,500 pounds GVWR with rear wheel drive (4X2), and up to 12,400 pounds with four wheel drive (4X4). And these high ratings are accomplished with four common pickup tires of equal size. That’s much more practical.


Given these higher SRW GVWRs are viable, it’d be great to see Ford upgrade 2021 E-Series SRW Cutaway to at least 11,000 pounds so that motorhomes the same size as those built on Transit and Sprinter could also be built on E-Series. For same or lower price point, RV manufacturers could offer V8 power and towing in a simpler package. All that’s missing are higher capacity wheels and tires; and how difficult can that be to upgrade? I hope Ford is working on it.