What if any differences are there between a 3500 dually with no bed and a 3500 Chassis Cab?

I know that the Chassis cab reg. cab has a 137" wheelbase (4" longer) and comes with a smaller 27 gal. fuel tank (but also has a 23 gal. rear tank where the spare tire normally is).

Are there any differences in the frame?

What about the width of the rear axle measured to the wheel mounting flanges? Is the chassis cab axle the same width as the dually (and the SRW)?

What about the optional RPO "GTY Rear axle, wide-track" (Increases axle width 8" to 74")? Is that just what it sounds like?

I have an 03 Cab and Chassis. I believe the rear axle is a couple inches narrower.

OK.

Since the standard rear axle width on a chassis cab is listed at 66,"
if anyone with a regular 3500 dually can verify what their rear axle width is, it would definitively answer the question.

Chassis cab rear dually axle is 8" narrower. Frame is 34" wide verses the "standard" 42" wide (pu). Narrower frame allows the narrower axle to fit without rubbing springs. Distance from rear of cab to center of rear axle is 4" longer. Chassis also gets a rear 2nd 15 gal fuel tank.

Chassis cab rear dually axle is 8" narrower. Frame is 34" wide verses the "standard" 42" wide (pu). Narrower frame allows the narrower axle to fit without rubbing springs. Distance from rear of cab to center of rear axle is 4" longer. Chassis also gets a rear 2nd 15 gal fuel tank.

So in that case, what you're saying is that the optional "GTY Rear axle, wide-track" (Increases axle width 8" to 74") is the same as a standard dually axle.

I didn't realize the axle on a standard dually was that wide, because I thought the SRW and dually had the same width rear axle.

another main difference, I think the 3500 chassis cabs come with a rear sway bar :cool:

If the Chassis Cab's rear leaf springs are 8" closer together, it would definitely need a rear sway bar.

The narrower space between the frame rails also explains why the front fuel tank is 27 gal., compared to 34 gal. for a regular long bed 3500.

That narrower space inside does allow more room outboard of the frame for toolboxes, etc., though.

UPDATE: The 3500 chassis cab DRW is not as wide as the 3500DRW.
The "GTY Rear axle, wide-track" (increases axle width 8" to 74") evidently changes that, providing the same rear axle as the regular dually.
Here are the overall widths (which in the case of the chassis cab is the rear tires):

*K35903 3500 long bed 4WD Regular Cab
Body width, with Single rear wheels: 79.70"
Body width, with Dual rear wheels: 96.10"

*K36003 3500 DRW chassis cab 4WD Regular Cab
Body width 86.00"
Body width, with (GTY) Rear axle: 93.90"

I'm assuming that the bed on a dually adds the extra 2.2" of width compared to the chassis cab with GTY axle.

So compared to a 3500 dually (11,400 GVWR), the chassis cab is a way of getting a higher 12,000 GVWR in a narrower width (or the same width with the GTY option).

UPDATE: The 3500 chassis cab DRW is not as wide as the 3500DRW.
The "GTY Rear axle, wide-track" (increases axle width 8" to 74") evidently changes that, providing the same rear axle as the regular dually.
Here are the overall widths (which in the case of the chassis cab is the rear tires):

*K35903 3500 long bed 4WD Regular Cab
Body width, with Single rear wheels: 79.70"
Body width, with Dual rear wheels: 96.10"

*K36003 3500 DRW chassis cab 4WD Regular Cab
Body width 86.00"
Body width, with (GTY) Rear axle: 93.90"

I'm assuming that the bed on a dually adds the extra 2.2" of width compared to the chassis cab with GTY axle.

So compared to a 3500 dually (11,400 GVWR), the chassis cab is a way of getting a higher 12,000 GVWR in a narrower width (or the same width with the GTY option).



Yep.

Side note. Chassis cabs are limited on packages (LS, LT), options, cab configs, and colors. They are also harder to find and usually don't get any price incentives.:rant:

I found the specs and all the dimensions from the upfitter guides here:
http://www.gmupfitter.com/publicat/ld_2006.htm

Chassis cabs are limited on packages (LS, LT), options, cab configs, and colors. They are also harder to find and usually don't get any price incentives.
True. But the regular cab version has a 137" wheelbase, allowing a slightly longer bed with only a slight increase in length and turing radius. In fact, it is shorter and turns tighter than a 2500HD standard bed extended cab, which has much lower GVWR & payload.

2006 3500 chassis cab and 1999 2500 or 3500 SRW (previous generation) with no bed:

Here's a 3500 chassis cab with the rear fuel tank:

Chassis diagram of 3500CC with standard 66" width rear axle,
compared to 2500HD/3500SRW/3500DRW (74" wide rear axle),
and an illustration of a 1999 6.5' bed rear chassis:

Rear frame section detail of 2500HD/3500SRW:

Elvis,

Those are really nice diagrams.

Now I have to try to find the part numbers to install that 23 gal. rear fuel tank. I suspect it will be cheaper to go with aftermarket tanks and mounting. A 30 to 40 gallon tank would be a lot nicer. :)

Thanks.

The 23 gal. tank used with the chassis cab is probably too tall. Also, it's not as wide as it could be. There are better alternatives in the 25 gal. range.

The problem is that the 2500HD/3500SRW spare tire mount crossmember prevents the tank from being mounted up as high as it otherwise could be. If the tank is as wide as it can be, then it needs beveled corners to clear the shock absorber on the left, and for clearance with the exhaust pipe on the right (like the 20 gal. S10 Blazer tank, which is 10.5" high & also conveniently has the fill pipe at the rear & pointed outboard; 1st photo).

The 33 gal. tank used in GM vans (2nd photo) is 12.3" tall, and the 40 gal. version of this style tank is over 13" tall. Unfortunately, there's only about 10.5" from the bottom of the frame rails in the rear section to the lowest part of the frame rails (under the cab).

A tank designed to use all the available space while still allowing clearance to the shock & the exhaust could hold nearly 50 gal. (or even more on a long bed).

chassis cab does better burnouts :D):h J/K

It's already been said, but the cab/chassis rear axles are narrower. Also, there is not a crew cab in cab/chassis. Only reg. and ext. cabs

It's already been said, but the cab/chassis rear axles are narrower.
The 3500 chassis-cab standard rear axle is about 66" wide (same as a 3500SRW)
The 3500 chassis-cab optional GTY rear axle is about 74" wide (same as a regular 3500 dually)

This phrase, "...compared to 2500HD/3500SRW/3500DRW" in post #14 above mistakenly lumps the SRWs in with the DRW.

But the first image shows it correctly: the top half of the drawing shows the SRW rear wheel centerline lined up with the 3500 chassis cab, while the bottom half shows the 3500 dually axle is wider than the chassis cab.

The 77.8" dimension in that drawing is the width of the main part of the body (not including fender flares).

just wondering how long is the shortest bed you could fit on a chassis cab? 8 ft or does it have to be longer?

just wondering how long is the shortest bed you could fit on a chassis cab? 8 ft or does it have to be longer?
It could be a little less than 8 ft. if the frame rails are shortened and if the rear bumper is mounted as far forward as possible. Probably about 7.5 ft. is the practical minimum.

The "short" wheelbase chassis cab (.....003) has a 137" wheelbase, and is 60.4" from the back of the cab to rear axle centerline, both of which are only about 4" longer than the standard regular cab long bed. This chassis cab is about 51" from the rear axle centerline to the rear of the frame rails, for a total of 111.4" from the back of the cab to the rear of the framerails.

The regular cab longbed is 55.9" from the back of the cab to rear axle centerline, and about 42.7" from the rear axle centerline to the rear of the frame rails, for a total of 98.6" from the back of the cab to the rear of the framerails. The rear bumper extends back roughly another 10" (52.0" from rear axle centerline to the back of the hitch receiver).

At face value it would seem that the shortest chassis cab is 12.8" longer than a regular long bed, but the rear bumper on a chassis cab does not have to stick back nearly as far as on a regular long bed, and the rear of the chassis cab frame is designed to be shortened by up to 12" if needed, as this dimensional drawing from the upfitter's guide shows:

Since the 3500/2500HD SRW have the narrower rear axle, would it be possible to convert them to duallys without the need for a dually bed, just maybe extra large wheel well flares?

Since the 3500/2500HD SRW have the narrower rear axle, would it be possible to convert them to duallys without the need for a dually bed, just maybe extra large wheel well flares?

I don't think so. The inner dual would hit the spring or the wheel well. That is why the chassis cabs have a narrower frame to go along with the narrower axle.

I don't think so. The inner dual would hit the spring or the wheel well. That is why the chassis cabs have a narrower frame to go along with the narrower axle.
Correct. You can see the difference here, even thou it doesn't show the dimensions:
http://dieselplace.com/forum/showpost.php?p=1237892&postcount=14
http://dieselplace.com/forum/attachment.php?attachmentid=23503&d=1155484249

A 3500 chassis cab with the standard "66 inch" wide axle (same width as the 3500SRW) has about 47.6" between the inner tires. A 3500 chassis cab with the GTY "74 inch" wide axle (same width as the 3500 dually) has about 55.5" between the inner tires.

The widest part of the regular HD rear rear spring mounts (not incl. the bolt) is about 52.5" wide, and the front rear spring mount is about 53.3" wide. The max width of the rear spring leafs is a bit less, but still more than 47.6"

The only way around it would be the very bad idea of using a large spacer, which would put a lot of extra stress on the wheel bearings. While technically you'd need to gain 4" of extra width on each side, in practice you could probably get by with a bit less, reducing the clearance between the inner tires and the rear leaf springs.

However it is possible to run either single rear wheels or dual rear wheels on a chassis cab. That's one of the advantages it has. Running dual rear wheels on a chassis cab with the standard 66" wide axle provides more stability than a SRW with less width than a regular dually.