Roadtrek Chevrolet Popular 190 Max Tire Size?

[booster]

My van has the 70S with an open differential (GT4) and as you can see the rating is the same at 6084 which matches the tires. In theory, the tires are rated for it so they should be able to do the job as long as you put your vehicle across a scale to confirm you are within limits from time to time. I don't know what the safety margin is for tires or how much it varies by manufacturer.
I would be surprised if any of the 170s or 190s came without the trailer hitch because there is a shroud attached to it that protects parts of the propane system on the passenger side.
My van also has the KD1 transmission cooler but it is nothing more than the cooler built into the radiator. I added the Dorman 918-290 as mentioned. https://www.dormanproducts.com/p-97695-918-290.aspx
The transmission cooler hose selection on these vans is a bit nutty, you may want to buy all types of hoses available and then return the ones you don't use. The beauty of this cooler and the factory lines associated with it is that you can get nice steel hoses all of the way to the front of your vehicle without a bunch of loose rubber hose. They do make plug-in hose barb adapters that you can use to tie in an additional external cooler using this setup.

The towing package term is a carryover from the base GM vehicle that Roadtrek buys, so it has nothing to do with the hitch even though called towing package. It includes the 70s axle with Govloc locking mechanism and the small GM trans cooler. All Roadtreks got hitches, I think, but most were not tow package vehicles.



GT4 is the RPO code for a 3.73 gear ratio, so that would be the first one I have heard of without the 4.10 gears. (I just looked at the Roadtrek brochures and 2004 190 was 3.73 like the 170, by 2005 they moved to the 4.10 for the 190) This would be odd on a towing package, normally, as they usually come with the deeper gears. The GT4 does not determine if it is an open differential or not AFAIK. That would be controlled by the RPO code G80. If it has a G80 RPO code it has a locker in it and if it doesn't have that code, it would be open. It might also carry a Z82 code which is listed as trailering HD but it may be different or not there.



It is always a good idea to take a pic of the RPO code sticker and look them all up. Sometimes you get some surprises on how the vehicle is equipped.

 

[solidsnake]

What type of modification did you do to the tire carrier so that the bigger tire clears the bumper?

I have a 2005 210, not a 190. However the OE tires for both are 245/75x16. I upgraded to 265/75x16, they will not fit under the bed in the rear. I had to modify the carrier to accept the larger tire and the stainless ring cover does not fit either. I used a grey vinyl cover in the larger size and bolted the fiberglass to the mount upright.

 

[booster]

You need to add about 1" of height to square vertical support of the carrier or add an adapter plate to tire mount area so the holes can be moved up. To get the tire only lightly touching the upright to prevent bouncing you need to add about 1/2" of spacers to move the away from the support.

I also have a vinyl cover on with the stock fiberglass dish modified to tight up the cover and it is also bolted to the upright like Deano's. I have a thread on the forum of the modification and some pix.

 

[solidsnake]

An adapter plate seems more feasible for my skillset . I did find some gmc 17x7 aluminum rims on Facebook marketplace which I plan to buy. With stock suspension on 2008 210 the 265-70-17 wheels fit without rubbing correct?

 

[booster]

An adapter plate seems more feasible for my skillset . I did find some gmc 17x7 aluminum rims on Facebook marketplace which I plan to buy. With stock suspension on 2008 210 the 265-70-17 wheels fit without rubbing correct?

Almost all the larger tire swaps are also lifted, plus 210s ride really low to the ground, but you should be OK with perhaps for minor trimming on the corners of the ground effects around the front wheels. You will have stock offset wheels and that helps a lot because they won't move as far front to rear as they turn compared to the -6 or zero offset wheels. Every van is also a bit different, especially ours on our 190 because the right front wheel sat 5/8" of an inch to the rear when compared to the left side. It was visually very easy to see it was way off center of the wheel. Even lifted we came very close to touching the rear of the wheelwell and ground effects because of it. Now that I fixed the location of the lower control arm on that side we have plenty of room with a just under 2" lift.

On the carrier modification, you might be time and money ahead to go to a custom trailer hitch place and ask them. They probably have short pieces of the tubing lying around because it a used in lots of heavy duty hitch work. They would have no problem, cutting the upright and adding an inch or two by welding in a small piece. You also would have it welded by somebody that would make sure it looked OK and was safe. Once that is done all you need are a bunch of big washers to space out the wheel a bit at the lug nut studs in the carrier.

Be sure to check the wheels over closely, as it is Facebook where some bad stuff can happen. They will have GM logo, no weight limit marked, GM part numbers and probably "made in Hungary" on them. Take them to you tire place before putting on the tires and have them spin them to look for damage or runout.

If they have the center cover, a big bonus especially if they are chrome ones, not painted silver, and are in good shape. They sell for almost as much as the wheels a lot of the time for the GMC version.

 

[solidsnake]

Almost all the larger tire swaps are also lifted, plus 210s ride really low to the ground, but you should be OK with perhaps for minor trimming on the corners of the ground effects around the front wheels. You will have stock offset wheels and that helps a lot because they won't move as far front to rear as they turn compared to the -6 or zero offset wheels. Every van is also a bit different, especially ours on our 190 because the right front wheel sat 5/8" of an inch to the rear when compared to the left side. It was visually very easy to see it was way off center of the wheel. Even lifted we came very close to touching the rear of the wheelwell and ground effects because of it. Now that I fixed the location of the lower control arm on that side we have plenty of room with a just under 2" lift.

On the carrier modification, you might be time and money ahead to go to a custom trailer hitch place and ask them. They probably have short pieces of the tubing lying around because it a used in lots of heavy duty hitch work. They would have no problem, cutting the upright and adding an inch or two by welding in a small piece. You also would have it welded by somebody that would make sure it looked OK and was safe. Once that is done all you need are a bunch of big washers to space out the wheel a bit at the lug nut studs in the carrier.

Be sure to check the wheels over closely, as it is Facebook where some bad stuff can happen. They will have GM logo, no weight limit marked, GM part numbers and probably "made in Hungary" on them. Take them to you tire place before putting on the tires and have them spin them to look for damage or runout.

If they have the center cover, a big bonus especially if they are chrome ones, not painted silver, and are in good shape. They sell for almost as much as the wheels a lot of the time for the GMC version.

Thanks for the heads up on checking the wheels closely, I’ll ask the seller to send pics. They’re about 2hrs away so I’d hate to drive out there only to find out they are knockoffs.

I do eventually plan on getting the 3inch spindle lift from Weldtech and installing rear airbags but for now hoping the bigger tires fit on current suspension.

 

[booster]

Thanks for the heads up on checking the wheels closely, I’ll ask the seller to send pics. They’re about 2hrs away so I’d hate to drive out there only to find out they are knockoffs.

I do eventually plan on getting the 3inch spindle lift from Weldtech and installing rear airbags but for now hoping the bigger tires fit on current suspension.

Smart move to do that check if they are that far away.

Be aware that the 3" lift from Weldtec is a knuckly lift so you will have the front wheels pushed outboard and the steering geometry altered. The +28 wheels may or may not be best for that geometry. Please note that the wheels that Weldtec recommends are not +28mm offset, the last time I looked.

We have had a lot discussions here on the benefit vs detriment of knuckle lifts, and I am plainly on the side of not using them for anything but very high lifts where there aren't really other options.

First a bit of history. The GM factory service manual gives suspension height specs that measure from the actual positions of the parts, not the wheelwell. They are for an empty van of the various load capacities and the preferred alignment specs are based on those heights.

Stock Roadtreks are mostly at about 2" lower than the midpoint spec for a 3500 van do to all the weight they carry all the time. This puts the suspension at a compromised very low position and messes with it's geometry and the springs ability to support the weight without hitting the bumpstops. Unless the springs are changed, the bad geometry stays in place or may get worse or better by some in a knuckle lift.

A 3" lift at the wheelwells is only 1" above the factory spec at the suspension in terms of road clearance.

A spring lift on the front can give you 2-2.5" of lift or maybe a bit more sometimes and will put the steering parts at the high end of factory spec, well of the bumpstops and with enough springrate to support the van without porpoising. The geometry does not get altered like with a knuckle lift so offset and alignment specs stay the same. IMO the ride quality and handling of a spring lift will better better than with a knuckle lift.

For the rear you can do the same as the Weldtec with new rear springs but the ride may get worse or better depending on how low you were sitting before the change. I prefer adding properly height mounted 5000# aribags to rear to get an adjustable and matching lift as a spring lift in the front.

Knuckle lifts are all the rage right now for may vehicles and have their place as in 6" lifted pickups with huge tire on wheels with big negative offset to clear things. But, again my opinion is for a 5 ton van that is 9" tall and will driven all day, in high winds often, I will always chose the setup that drives the easiest and and rides the best.

Everybody gets to make their own choices on stuff like this, but I would recommend reading at least some of the past discussions and results of various tries.

We have had a spring lift and airbags for nearly 15 years now and I do all the driving. A few years ago we had to do a fast dash home do the an emergency there, and we were in eastern Oregon about 1200 miles from home. We left late one afternoon and drove until dark, and the next day I drove 850 miles with only gas stops in 20-30mph winds across the high plateaus. We averaged over72mph including stops. The worst part for me was sitting that long, not controlling the van.

 

[solidsnake]

Smart move to do that check if they are that far away.

Be aware that the 3" lift from Weldtec is a knuckly lift so you will have the front wheels pushed outboard and the steering geometry altered. The +28 wheels may or may not be best for that geometry. Please note that the wheels that Weldtec recommends are not +28mm offset, the last time I looked.

We have had a lot discussions here on the benefit vs detriment of knuckle lifts, and I am plainly on the side of not using them for anything but very high lifts where there aren't really other options.

First a bit of history. The GM factory service manual gives suspension height specs that measure from the actual positions of the parts, not the wheelwell. They are for an empty van of the various load capacities and the preferred alignment specs are based on those heights.

Stock Roadtreks are mostly at about 2" lower than the midpoint spec for a 3500 van do to all the weight they carry all the time. This puts the suspension at a compromised very low position and messes with it's geometry and the springs ability to support the weight without hitting the bumpstops. Unless the springs are changed, the bad geometry stays in place or may get worse or better by some in a knuckle lift.

A 3" lift at the wheelwells is only 1" above the factory spec at the suspension in terms of road clearance.

A spring lift on the front can give you 2-2.5" of lift or maybe a bit more sometimes and will put the steering parts at the high end of factory spec, well of the bumpstops and with enough springrate to support the van without porpoising. The geometry does not get altered like with a knuckle lift so offset and alignment specs stay the same. IMO the ride quality and handling of a spring lift will better better than with a knuckle lift.

For the rear you can do the same as the Weldtec with new rear springs but the ride may get worse or better depending on how low you were sitting before the change. I prefer adding properly height mounted 5000# aribags to rear to get an adjustable and matching lift as a spring lift in the front.

Knuckle lifts are all the rage right now for may vehicles and have their place as in 6" lifted pickups with huge tire on wheels with big negative offset to clear things. But, again my opinion is for a 5 ton van that is 9" tall and will driven all day, in high winds often, I will always chose the setup that drives the easiest and and rides the best.

Everybody gets to make their own choices on stuff like this, but I would recommend reading at least some of the past discussions and results of various tries.

We have had a spring lift and airbags for nearly 15 years now and I do all the driving. A few years ago we had to do a fast dash home do the an emergency there, and we were in eastern Oregon about 1200 miles from home. We left late one afternoon and drove until dark, and the next day I drove 850 miles with only gas stops in 20-30mph winds across the high plateaus. We averaged over72mph including stops. The worst part for me was sitting that long, not controlling the van.

I had assumed a knuckle lift maintains the stock steering geometry, at least that’s what I’ve seen via google and what weldech mentions on the lift. Surprisingly the ride quality of my stock 210 Roadtrek is good so only reason I’d want to increase ride height is to accommodate the larger tire size. I am concerned if my ride quality degrades with knuckle or even a spring lift. I did see a thread where the op got a 245/75R17 for their 210 max capacity for tire is 3,195, I might go this tire size if going bigger requires a lift which I’m still hesitant on doing

 

[booster]

I had assumed a knuckle lift maintains the stock steering geometry, at least that’s what I’ve seen via google and what weldech mentions on the lift. Surprisingly the ride quality of my stock 210 Roadtrek is good so only reason I’d want to increase ride height is to accommodate the larger tire size. I am concerned if my ride quality degrades with knuckle or even a spring lift. I did see a thread where the op got a 245/75R17 for their 210 max capacity for tire is 3,195, I might go this tire size if going bigger requires a lift which I’m still hesitant on doing

I saw the statements about no change in steering geometry also on the Weldtec site and other places.

They do leave the actual stock steering parts in place, including the control arms, stock spring, stock shock length and I think that is being referred to for "stock geometry". I think where some things get lost is that those parts stay "stock geometry" to the body and frame of the van, but they don't stay in the same geometry to the wheel or the ground because the wheel attachment point has move down 3" on the steering knuckle and also the wheel has moved about .7" outboard away from the balljoints. (The .7" I think is correct but it wasn't from the Weldtec site) and both of those difference change some suspension geometries even with all the physical control arms, etc still in the stock position. The scrub radius is probably the thing that get changed the most and could have largest effect on road feel in terms of effort, bump kickback, directional stability type stuff. Knuckle lifts can mess it up because they often get into clearance issues with balljoints or tie rods and have to offset the wheels outboard to clear them. Here is a screenshot of a Chevy with the 3" lift and 265-70-17 tires on it. They didn't give the offset of the wheels they used but they are very close to tire rod end. They also stick out of the wheelwell quite a ways so it looks like a lot more the .7" outboard from stock. This van appears to be empty based on the spring compression so would be nearly 4000# lighter than a Roadtrek and sit about 2" higher before the lift than a Roadtrek.

Since a stock Roadtrek is sitting two inches lower than a stock van in front in most cases, if you do a 2" spring lift it puts right where the factory spec center point is for ride height (trim height in the service manual specs). We very rarely here of anyone saying the handling got worse a 2" spring lift, and usually the say better. That is what we found also. The ride smoothness is where some people didn't like the spring lift and said it got to harsh or porpoised. Stock Roadtreks are nearly sitting on the bump stops in the front and the stock springs are just plain too low a spring rate for a fully loaded van. The soft springs will make it feel smoother on small bumps, but larger bumps will make it slam into the bump stop and kind of pitch back up off it, while with the higher rate springs that don't hit the bump stop, it flips that around. Small bumps may feel more pronounced, but large bumps will be smoother and with less steering disruption. Getting the right shocks can also alter this balance of large and small. Many of us have Bilsteins and like them. I find them a bit smoother on small bumps and more controlling on big bumps myself. Fox also makes so pricey, but very nice variable rate shocks to smooth out the small bumps and better control the big ones.

With a spring lift you use stock offset wheels like the GMC wheels on ours and that you were looking at and the 265-70-17 tires should fit well. Anytime you go bigger tire or different offset, the rear tire carrier would need modification. Even the Roadtrek 16" aluminum wheels that are the wrong offset won't fit on the carrier, only the steel 16" ones.

 

[solidsnake]

Almost all the larger tire swaps are also lifted, plus 210s ride really low to the ground, but you should be OK with perhaps for minor trimming on the corners of the ground effects around the front wheels. You will have stock offset wheels and that helps a lot because they won't move as far front to rear as they turn compared to the -6 or zero offset wheels. Every van is also a bit different, especially ours on our 190 because the right front wheel sat 5/8" of an inch to the rear when compared to the left side. It was visually very easy to see it was way off center of the wheel. Even lifted we came very close to touching the rear of the wheelwell and ground effects because of it. Now that I fixed the location of the lower control arm on that side we have plenty of room with a just under 2" lift.

On the carrier modification, you might be time and money ahead to go to a custom trailer hitch place and ask them. They probably have short pieces of the tubing lying around because it a used in lots of heavy duty hitch work. They would have no problem, cutting the upright and adding an inch or two by welding in a small piece. You also would have it welded by somebody that would make sure it looked OK and was safe. Once that is done all you need are a bunch of big washers to space out the wheel a bit at the lug nut studs in the carrier.

Be sure to check the wheels over closely, as it is Facebook where some bad stuff can happen. They will have GM logo, no weight limit marked, GM part numbers and probably "made in Hungary" on them. Take them to you tire place before putting on the tires and have them spin them to look for damage or runout.

If they have the center cover, a big bonus especially if they are chrome ones, not painted silver, and are in good shape. They sell for almost as much as the wheels a lot of the time for the GMC version.

Finally got the 17x7.5 aluminum GMC rims, I think they are legit. It has the GM logo, part number, it does say USA under the part number. The rims came with 265 70 size tires which is good so I can do a test fit. The tires themselves aren't rated as high as I would like so I can't use them so I will try to sell once I decide on the final tire size.

 

[booster]

Finally got the 17x7.5 aluminum GMC rims, I think they are legit. It has the GM logo, part number, it does say USA under the part number. The rims came with 265 70 size tires which is good so I can do a test fit. The tires themselves aren't rated as high as I would like so I can't use them so I will try to sell once I decide on the final tire size.

Those certainly look legit. They must be pretty early production to be USA, as all the ones I have seen said Hungary. Do they have a date code anywhere on them?

Did they come with center caps?

I see it in the pic 86th day of 07, which isn't all that early in the use years.

 

[solidsnake]

Those certainly look legit. They must be pretty early production to be USA, as all the ones I have seen said Hungary. Do they have a date code anywhere on them?

Did they come with center caps?

I see it in the pic 86th day of 07, which isn't all that early in the use years.

I wasn’t even aware those numbers were the manufacturer date, there are other numbers on the rim but I’m not sure what they mean.

It came with 3 gmc center caps, not the best condition. I already bought some Chevy center caps instead .