2006 Roadtrek 210 tire capacity and dually conversion options

[booster]

I was just digging for old discussions and came up with a posting from the guy who did the 210 dually and was mentioned above. He put it up for sale in 2023 so there might be chance that is the same one up above.

He also said in one post that he spent 3 months working lots of hours to get the conversion finished. That would be, mostly likely, many hundreds of hours.

 

[TWX]

I was just digging for old discussions and came up with a posting from the guy who did the 210 dually and was mentioned above. He put it up for sale in 2023 so there might be chance that is the same one up above.

He also said in one post that he spent 3 months working lots of hours to get the conversion finished. That would be, mostly likely, many hundreds of hours.

I'm left wondering if he had some difficulty finding all of the necessary information when he did his conversion. There are some tools now that might make it easier.

I looked up my VIN on a site that supposedly does GM vin decoding. This was what I got:

Vehicle Name​	Chevrolet Express Cargo Van​
Body Style​	3500 Cargo Van 155" WB​
Body Code​	ZW9​
Drivetrain​	Rear Wheel Drive​
Passenger Capacity​	1, 2 1.0 min 2.0 max​
Gross Axle Wt Rating - Front​	4300 lbs 4300.0 min 4300.0 max​
Gross Axle Wt Rating - Rear​	6084 lbs 6084.0 min 6084.0 max​
Curb Weight - Front​	3090 lbs 3090.0 min 3090.0 max​
Curb Weight - Rear​	2442 lbs 2442.0 min 2442.0 max​
Gross Vehicle Weight Rating Cap​	9600 lbs 9600.0 min 9600.0 max​
Gross Combined Wt Rating​	16000, 14000 lbs 14000.0 min 16000.0 max​
Dead Weight Hitch - Max Trailer Wt.​	4000 lbs 4000.0 min 4000.0 max​
Dead Weight Hitch - Max Tongue Wt.​	400 lbs 400.0 min 400.0 max​
Wt Distributing Hitch - Max Trailer Wt.​	10000, 8000 lbs 8000.0 min 10000.0 max​
Wt Distributing Hitch - Max Tongue Wt.​	1000, 800 lbs 800.0 min 1000.0 max​
Engine Order Code​	LQ4​
Engine Type​	Gas V8​
Displacement​	6.0L/364​
Fuel System​	SFI​
SAE Net Horsepower @ RPM​	300 @ 4400​
SAE Net Torque @ RPM​	360 @ 4000​
Trans Order Code​	MT1​
Trans Type​	4 4.0 min 4.0 max​
Trans Description Cont.​	HD Automatic w/OD​
First Gear Ratio​	2.48 2.48 min 2.48 max​
Second Gear Ratio​	1.48 1.48 min 1.48 max​
Third Gear Ratio​	1.00 1.0 min 1.0 max​
Fourth Gear Ratio​	0.75 0.75 min 0.75 max​
Reverse Ratio​	2.07 2.07 min 2.07 max​
Cold Cranking Amps @ 0° F (Primary)​	800 600.0 min 800.0 max​
Maximum Alternator Capacity (amps)​	145 105.0 min 145.0 max​
Total Cooling System Capacity​	14.4 qts 13.4 min 14.4 max​
Engine Oil Cooler​	Yes​
Frame Type​	Ladder​
Suspension Type - Front​	Independent Coil​
Suspension Type - Rear​	Hypoid Multi-Leaf​
Spring Capacity - Front​	4300 lbs 4300.0 min 4300.0 max​
Spring Capacity - Rear​	6084 lbs 6084.0 min 6084.0 max​
Axle Type - Front​	Independent​
Axle Type - Rear​	Full-Floating​
Axle Capacity - Front​	4300 lbs 4300.0 min 4300.0 max​
Axle Capacity - Rear​	6084 lbs 6084.0 min 6084.0 max​
Axle Ratio - Rear​	4.10, 3.73 3.73 min 4.1 max​
Stabilizer Bar Diameter - Front​	1.38 in 1.3 min 1.38 max​
Front Tire Order Code​	XHH​
Rear Tire Order Code​	YHH​
Spare Tire Order Code​	ZHH​
Front Tire Size​	LT245/75R16E​
Rear Tire Size​	LT245/75R16E​
Spare Tire Size​	LT245/75R16E​
Front Tire Capacity​	2205 lbs 2205.0 min 2205.0 max​
Rear Tire Capacity​	3042 lbs 3042.0 min 3042.0 max​
Spare Tire Capacity​	-TBD- lbs​
Front Wheel Material​	Steel​
Rear Wheel Material​	Steel​
Spare Wheel Material​	Steel​
Steering Type​	Pwr-Assisted​
Steering Ratio, On Center​	17.2 17.2 min 17.2 max​
Turning Diameter - Curb to Curb​	54.5 ft 54.5 min 54.5 max​
Brake Type​	Pwr​
Brake ABS System​	4-Wheel​
Disc - Front (Yes or )​	Yes​
Disc - Rear (Yes or )​	Yes​
Front Brake Rotor Diam x Thickness​	12.8 x 1.5 in​
Rear Brake Rotor Diam x Thickness​	13 x 1.1 in​
Fuel Tank Capacity, Approx​	31 gal 20.0 min 31.0 max​
Fuel Tank Location​	LH Midship Inboard​
Front Head Room​	40.2 in 40.2 min 40.2 max​
Front Leg Room​	41.3 in 41.3 min 41.3 max​
Front Shoulder Room​	68.8 in 68.8 min 68.8 max​
Front Hip Room​	65.5 in 65.5 min 65.5 max​
Wheelbase​	155 in 155.0 min 155.0 max​
Length, Overall w/rear bumper​	244.1 in 244.1 min 244.1 max​
Width, Max w/o mirrors​	79.4 in 79.4 min 79.4 max​
Height, Overall​	82.0 in 82.0 min 82.0 max​
Ground to Top of Load Floor​	27.3 in 27.3 min 27.3 max​
Ground Clearance, Front​	8.4 in 8.4 min 8.4 max​
Ground Clearance, Rear​	8.1 in 8.1 min 8.1 max​
Rear Door Type​	Dual Swing-out​
Rear Door Opening Height​	49.4 in 49.4 min 49.4 max​
Rear Door Opening Width​	57.0 in 57.0 min 57.0 max​
Side Door Type​	Sliding, Swing-out​
Side Door Opening Height​	47.9 in 47.9 min 47.9 max​
Side Door Opening Width​	44.1 in 44.1 min 44.1 max​
Step Up Height - Front​	19.6 in 19.6 min 19.6 max​
Step Up Height - Side​	20.5 in 20.5 min 20.5 max​
Cargo Area Length @ Floor to Console​	173.6 in 173.6 min 173.6 max​
Cargo Area Length @ Floor to Seat 1​	147.8 in 147.8 min 147.8 max​
Cargo Box Width @ Wheelhousings​	52.7 in 52.7 min 52.7 max​
Cargo Box (Area) Height​	51.9 in 51.9 min 51.9 max​
Cargo Volume​	261.6 ft³ 261.6 min 261.6 max​
Country of Origin​	United States Chevrolet Trucks​

So it looks like if this decoder is right, it was not a commercial cutaway chassis, it was an actual cargo van. That was a lot of sheet metal that Roadtrek bought and discarded in order to build these. But that also explains the rear doors, they didn't make their own rear doors that would have better fit the extra width because they bought doors from GM.

I should be able to look up some collision repair information on the van now that it's likely it has a standard van frame rather than a commercial cutaway frame, that would get me dimensional information helpful in weighing just how the design sat when stock and might point at a direction better.

 

[TWX]

Some photos.

I pulled a hubcap to look at the type of rear axle, and it is not, despite the VIN decoder, a true full-floater:

It also looks hubcentric, annoyingly.

 

[TWX]

When I was checking some things I noticed that there's still a door handle for the passenger's side aft rear-swing door in the door jamb, and that handle is not immobilized, it pulls. Doesn't seem to do anything but I suspect that at least a significant portion of that door is still there, under the widening-out fiberglass, perhaps even the whole thing back to the frame. I would need to do a lot more checking to see. from a crashworthiness perspective it makes sense, it's probably safer with that, but it feels a little silly that there's part of the original door hidden inside. Also lends further credence to them having just bought regular cargo vans and not commercial cutaways.

 

[youngnretired]

My wife and I are new to this RV world and especially new to a Class B and Roadtrek. After purchasing our first 210 just about a year ago and learning that some RV's are, or could have been, built on cutaway chassis, the more time I spent with our 210 the less likely I thought it started from a cutaway. When you think about it, an RV company could purchase a cutaway, but then have to purchase an entire rear door assembly area, taillights, door panels, glass, door handle and operation mechanisms, electric locks, latches, wiring for all those systems, along with the same components for a complete side door area, along with any partial sheet metal areas to support those door systems, then assemble those, paint them inside and out, connect that to the frame/chassis, then likely have to go thru another round of paint in the end? My guess is unlikely. Also, the cost to purchase a cutaway then add side and rear door assemblies probably comes pretty close to what a complete van would cost, when you could essentially cut the middle of the van out which leave all of what you had to buy, assemble and mount to the frame/chassis and be further ahead. I just think a cutaway would be much more time and work than to start with a complete van first, IMO.

 

[TWX]

The wheelbase was part of what was giving me the initial hangup. The cutaway models don't have 155" wheelbases. If they were buying enough they might well be able to get more from GM than a normal cutaway, but I would not expect the wheelbase to be altered.

 

[booster]

The 210s have always been built that way, by taking full bodied van and cutting off the roof like the other raised top vans, then removing the sides down to the floor, then slicing off the rear end complete with the doors and frame and moving it back by 16 inches. They are floor to fill the sides and rear where there is none. Then they put the fiberglass sides and top on. We saw them being built at the Roadtrek factory, including the metal arches to better support the body in a rollover.

The only Roadtrek built on a cutaway was the 200.

That is positively not a full floater so would be the Dana Super 60.

Why would you be worried about hubcentric? IMO it is a very good thing, especially on heavy vans and if you use spacers it is very good idea to have them be hubcentric if at all possible.

One thing I like about using the pickup truck wheels, both the aluminum and steel, is that they used the same hub diameter so the wheels are also hubcentric on out vans.

I haven't found the VIN decoders all that great either, and certainly not using the same databases as the dealers have where they know every part number that went into the vehicle. The VIN itself gives some information, but not all. Most of the stuff on the printout is stock stuff on all the vans. Don't know where they got the full floating though unless it looked at previous or other models.

The only way I have found without actually looking at the axle, to identify which axle is in a van is to look at the RPO sticker on the door. If it has a G80, which is the locking rear axle option it will be the Dana Super 70 full floater. If it doesn't have the G80 it will be a Dana 60 semi floater. There never was a Govlock produced for a Super 60 so it can't be confused and the Super 70 came with the trailer tow package and that package including a locker.

The guy who did the conversion is in Michigan and had some kind of connection the automotive business as he said he got the axle through some kind of deal where he could get "take off" parts directly from some related affiliation that wasn't made clear. My guess is he would have access to much more information than the rest of us do.

 

[TWX]

Why would you be worried about hubcentric? IMO it is a very good thing, especially on heavy vans and if you use spacers it is very good idea to have them be hubcentric if at all possible.

I'm annoyed because it limits wheel choice. Dodge/Ram apparently still uses 8 on 6.5 (as 8 on 165.1mm) to this day on the heavier single rear wheel, "light trucks," even if their dually trucks have changed to a larger bolt-circle, but the SRW center bore is larger so wouldn't be hubcentric on an Express. Nissan also uses 8 on 6.5 on the NV1500/2500/3500 and has slightly wider 17" wheels with similar but ever so slightly more positive offsets, but again the center bore is slightly larger.

It looks like GM has used 8 on 6.5 on their modern crop of electric trucks and vans, so possibly a new development for a weight class that might well be higher than typical on account of the battery weight.

 

[booster]

You can get hubcentric rings to space a larger wheel hole diameter to a smaller hub. I have them on my 96 Buick Roadmaster.

 

[TWX]

You can get hubcentric rings to space a larger wheel hole diameter to a smaller hub. I have them on my 96 Buick Roadmaster.

A cursory look didn't find much in the way for this application, but admittedly I wasn't trying real hard.

I have a '95 Impala SS, so a platform-mate to your Roadmaster. Fun car, but it could use some heavier swaybars. I thought about the Spohn kit back in the day but never got to doing it.

 

[booster]

A cursory look didn't find much in the way for this application, but admittedly I wasn't trying real hard.

I have a '95 Impala SS, so a platform-mate to your Roadmaster. Fun car, but it could use some heavier swaybars. I thought about the Spohn kit back in the day but never got to doing it.

I put a set Hellwig bars in the wagon, plus I modified the upper control arms for 6* of caster. With the Lee built steering gear with more effort it feels more like a Camaro, a very heavy one, do drive. SS are really nice cars, and the civilian version of the Caprice 9C1 that all the law enforcement absolutely loved.

 

[TWX]

Well, over the last couple of days since buying the Roadtrek 210 we've spend a considerable amount of time cleaning, mending, repairing, etc. We've found no less than four different kinds of tape and two different kinds of bailing wire, and for what amounts to being incredibly simple stuff to have fixed properly.

The biggest issue was the bathroom door. The door was pulling itself apart, the top rail was pulling away from the stile at the hinge-side. Since the top half is mirrors on both sides this seemed particularly problematic, so we took the mirror-panel out and then dismounted the door and took it out to fix.

Of course the prior attempt at a repair had involved duct tape:

View media item 447005
I cleaned it up and used proper wood glue to affix the rail back to the stile and then clamped it:

View media item 447004
After that I took to cleaning up the rest of the door. They apparently had problems with the door rattling in place, and the solution had been to duct-tape random stuff to the door in order to pad it out a bit:

View media item 447003
In the process of pulling all of this off I found what specifically they had used to pad it:

View media item 447002
Cheese. To stop the bathroom door from rattling, they padded it with cheese.


The detector (propane? CO?) mounted near the back bed was held with tape too. This is an electrical component so naturally it was secured with black electrical tape. Peeled all that off, used Goo Gone to clean it up, and then reassembled it properly.


When I got back to the TV I found that it had cardboard washers holding it:

View media item 447006
Obviously nothing EVER will top the cheese, but really, cardboard washers?


We put the bathroom door back on, I'm going to install some magnets and plates to help hold it at the top and bottom, and I might put something on it to press against the door frame when closed to keep it from trying to pull itself apart.

 

[youngnretired]

As you found out, people do all sorts of weird stuff when trying to fix things. Some of it comical and some of it really serious.

The previous owner of our 210 got tired of replacing the bathroom door latch over the years, so they used a bungee cord to hold it closed. The door used to rattle. One look at it showed that there was too much space between the latch and catch, so i bent the catch a bit, replaced the latch and so far no problems. Some people don't have many skills and have to pay someone to fix a simple broken latch on an RV bathroom door like the PO of ours. We're all different.

 

[TWX]

Bending the catch was how I got rid of the rattle on this door too, but I still want to reinforce so it doesn't try to pull itself apart again.

The starboard aft large cabinet behind the bathroom cannot latch, the catch plate is not tall enough from the cabinet to engage the bolt on the latch. I need to put some spacers behind it. After the silliness here I think I'll start some proper threads on my RV rather than perpetuating this one. But I wanted to share the silliness somewhere.

 

[TX-Trek]

Based on info here, especially from Booster, here's what I did suspension-wise on our 2010 210P. Still works well after a few years. As mentioned, nothing to do with load capacity, but better comfort and control. For reference I've attached a CAT scale weight of our full travel mode while on a trip. As you can see, rear axle close to 6k capacity.

I also replace the rear tires more frequently, 10 ply spec size. 60/80psi front/rear.

Our Tubby Roadtrek 210 – A Long Post on Suspension Upgrades

This is about the suspension changes to our 2010 210P on the Express 3500 chassis. Current mileage 76k. Stock AR wheels and stock LT245/75R16 tires. It’s no secret that this era of vans are overloaded. I decided to improve the suspension on ours based on the excellent information in this forum...

www.classbforum.com

 

[TWX]

Based on info here, especially from Booster, here's what I did suspension-wise on our 2010 210P. Still works well after a few years. As mentioned, nothing to do with load capacity, but better comfort and control. For reference I've attached a CAT scale weight of our full travel mode while on a trip. As you can see, rear axle close to 6k capacity.

I also replace the rear tires more frequently, 10 ply spec size. 60/80psi front/rear.

Our Tubby Roadtrek 210 – A Long Post on Suspension Upgrades

This is about the suspension changes to our 2010 210P on the Express 3500 chassis. Current mileage 76k. Stock AR wheels and stock LT245/75R16 tires. It’s no secret that this era of vans are overloaded. I decided to improve the suspension on ours based on the excellent information in this forum...

www.classbforum.com

Thanks, skimmed your thread and looks helpful. Will need to reread when I have some time.

In the meantime I have been taking measurements of my unit for just what sorts of clearances would be required in a hypothetical dually configuration and then pulling the GM upfitter guides for the various heavier light-truck platforms to see what factory axle dimensions exist. Downside, looks like the GMT600/610 uses the widest SRW axle of any of GM's conventional light truck offerings and even the commercial cutaway version is still the widest in the 8 on 6.5 era. The pickup truck dually axle has less width between interior sidewalls than the widest commercial cutaway axle has, and none clear the spring-to-spring total clearance needed with duals installed. That's why other dually conversions required spacers, and why it would be prudent to find a real full floating axle that self-supports with the axle shafts pulled if going dually. But one nice thing, 245/75/16 is an acceptable dually tire so if I do decide to perform the change then the money I just spent for tires isn't wasted.

Wife is getting some experience driving it too, it's still a lot of vehicle compared to what she's used to but she's not white-knuckling it in normal urban conditions either.

 

[TWX]

The guy that did the one here used and Amecrican Axle full floating rear from a later year Express 3500 single wheel per him selling another of the same axle he had. It was a single wheel axle so he must have used spacers in the rear.

I ran some numbers from GM's "G/H Van (GMT 610) 2005 – Revised 08/2005", which is available as a PDF from the GM Upfitter's website. Best I can tell they've never revised it, the 2005 edition was considered current in 2021.

In short, the normal cargo van 3500 is a "G33705" or "G337(05)", and a passenger van 3500 is a "G33706" or "G337(06)". I suspect that there's a misprint in the publication, because for the LT245/75R16 tire they list a tire width of 225mm for the cargo version, but list 245mm for the passenger version. Track width is listed as 69.96" or 1777.2mm. Factoring the 28mm or 1.10" wheel offset, that yields around 72.16" for hub face to hub face.

The dually 3500 cutaways/cab-chassis models also seem to have something of a misprint. The track width is listed as 84.79" / 2153.8mm, but this does not work as far as I can tell when I compare the "dimension A" widest outside-sidewall to outside-sidewall of 94.44" / 2398.8mm and the "dimension B" inside-sidewall to inside-sidewall of 54.99" / 1396.8mm. The dually wheels are 19.72" / 501.0mm wide for the pair on each side, which would mean that the hub face and thus the track width would be approximately 74.72". The published "84.79" seems like it's the track-width of just the outer dually tires.

I mention all of this because the one dimension that I have not been able to find is the axle perch spacing. This would be rather important since if the cab and chassis / commercial cutaways have the same spacing for the leafsprings as the vans, it would be very easy to swap a dually axle with presumably much wider-spaced full floater bearings into a vehicle that started out as a regular cargo van, but if the spring perch width on the axle is different then it would need to be cut off and welded on again in the right spot.

It looks like the dually ~74.72" hub to hub width is not quite sufficient for clearing the body due to the 54.99" inner clearance inner-sidewall to inner-sidewall, but since a true dually axle will have the outer bearing positioned out from the center of the vehicle further than a SRW application, running a small spacer of something like an inch to an inch and a half wouldn't be stressing the bearing as much as either a SRW fullfloater whose outer bearing is closer to the hub face or a SRW semi-floater whose bearing might be inboard even more. That spacer would no longer center the hub-face right between the bearings, but for a vehicle whose GVW is only 9600#, an axle for an 11,000# or heavier GVW should shrug-off this difference from ideal offset.

There's a distinct possibility that my rear axle isn't original. It's definitely of the 'semifloater' variety even though a supposed VIN decoder says I should have a full floater. It looks like the SRW full floater might have become less common in 2006 and thereafter and technically my van body started out as a 2005. If the original rear end had a problem then it might have been just swapped. I may have to see if I can find any build info on it, but that may be difficult.

Either way plenty of checking and other research into the tedious minutia.

 

[TWX]

Something that I neglected to mention before, the generator exhaust bracket gave way basically the day we got it. I had to run the van through emissions and I suspect that the emissions tech stuck the sampler mechanism into the generator tailpipe before realizing his mistake, which took an already aged hanger rubber strap and compromised it. When I got home with it, backing into the driveway I ran it over. I don't know for how long it was dragging, but it was enough to flatten it and to far overbend the flexible joint that was installed on it. Suffering a fairly severe case of buyer's remorse I'd gotten under it that day and wired it up where it wouldn't drag, but I knew that it needed repair before I could use it. I called a few exhaust shops but no one stocked 1-1/4" OD tube, so I wasn't able to just take it somewhere for a quick repair, and when I looked up parts, even the local Cummins store that does generators and stuff don't have that size in stock.

Today I had time to put the van up on ramps to have a good look underneath and to pull the damaged exhaust. My objectives were firstly to see if I'd damaged the integrated muffler in the generator, secondly to see if there's anything I can personally do about it, and thirdly, to determine if I'm going to order one of those Onan resonators and other parts to upgrade it in addition to repairing it.

This was the sight I was greeted by:
View media item 447022View media item 447021Basically the exhaust tip is a bit mangled at the turndown at the side of the van, and the pipe is flattened nearly all of the way.

Pulled off:
View media item 447023Measured it's around 54" long from the initial LB out of the generator to the tip at the side of the van. The pipe is not stock pipe. I suspect there was an on-the-road repair performed at a regular exhaust shop, where larger pipe (at least 1-1/2") was installed, along with an even larger flex-joint that was not in the original design. I suppose on the plus side, I can just take this piece to an exhaust shop and have the end and the flex-joint replaced if I want. Downside, since it's not a stock diameter I cannot use an Onan resonator. I'll have to look at the available tubing, particular flared tubing that will slip over stock size, to see if I can do what I want myself or not.

While I was under there I looked at the axle and other stuff too.

View media item 447026So the tag indicates a Dana 60S, I presume that's a Dana Super 60, in 3.73:1 ratio with an open differential. This conflicts with the RPO code on the Express Van which says this should have a full-floater in 4.10:1. I don't have a build date on the original '05 Chevrolet Express but the axle date code makes me think that this is a replacement axle. Haven't confirmed if the tag's gear ratio is correct either. Regardless it moves down the road well enough that I'm noting what I'm seeing rather than specifically looking to make changes just yet. If I do a dually swap then I'll need to consider, and possibly after towing something with the van to see just how it performs.

I had a devil of a time finding good information on axle dimensions, so I took my own measurements. The leafsprings outside-to-outside are 53", inside-to-inside 48", meaning that the 2005 Chevrolet Express GMT-610 platform as built into a Roadtrek 210 Popular has rear axle spring perches on 50.5" centers. The axle lower shock absorber mounts are 34.25" outside, 30.5" inside, approximate:

View media item 447032
More to come...

 

[youngnretired]

That is definitely not an OEM exhaust. Ours looks much different, plus that is missing any surface rust from 10+ years of being under the van.

 

[TWX]

I do know that the prior owners, who took it from ~15k to ~90k, did suspension changes because they took it on corrugated roads. It certainly wasn't merely a pavement-princess. It seems to have been worked fairly hard but was mechanically maintained.

For what it's worth my attitude on modifying things has been, "if it ain't broke, take it apart and find out why," so that sort of thing doesn't bother me particularly. I'm going to modify it further anyway.