Short Bed Ext. Cab vs Long Bed Four Door

[svt440]

Hey everyone. I have a 30' fifth wheel that weighs in around 8400lbs dry. Currently towing it with a 2003 2500HD Silverado Duramax. Truck is an extended cab, short bed (the shortest truck you can get aside from a two door short bed). I felt it get a little squirmy a few times at 65mph that made me nervous enough to back off the gas. Did it a couple times in a couple of hours. One thought I've had, is buying a newer four door, long bed, 3500 srw. My thoughts are, with the longer wheel base and the heavier suspension, I will be over trucked (at least for an 8500-9000lb setup) and not feel like I'm the minor like I do in my current truck. I know a dually would most likely eliminate that possibility all together (I see these things with the hammer down running 70+mph on the freeway with tri-axle fifth wheels!) but I'm really preferring a srw and given the fact that I have a lighter fifth wheel, I feel like a 3500 srw should be more than enough truck.

Question is, will I notice much difference between the combination of a greater wheel base, and the heavier suspension, or will it not change much? I know the HD series trucks are similar to a 1 ton, (or so I read), so I'm wondering if my only gain in this situation will be the longer wheel base. Any thoughts or experience? <- preferred! Thanks guys!

[jerem0621]

You could also inspect the trailers suspension and ensure that the leaf spring bushings and equalizer look good. Tight bolts...etc. also, check the trailers tires.

Thanks!

Jeremiah

[Bedlam]

If moving weight does not change the behavior of your snowmachine trailer, I suspect your axles are not tracking straight or the hitch frame is not square. Do you get any strange tire wear patterns (may be hard to tell if you do low mileage)? After replacing my enclosed trailer tires, I could see which ones were out of balance but it tracks straight and uses no sway control devices.

[Grit_dog]

I think you're still well with in the limits of your current truck. Yes, by default a brand new, tight, much longer wheelbase truck will be better, on most all fronts, but unless you're looking into an excuse to upgrade, just figure out the problem at hand with your current truck.
Longer rig by itself won't be night and day difference.
Example, my bumper pull snomachine trailer is about 34' long overall.
I've pulled it with a F150, new F250, and also the Dodge in my sig. So every vehicle from at the max ((150)) to completely overkill (the Mega cab). It tows the same. Pulls straight, no sway, etc. But that long trailer has just a little wiggle to it at speeds over 65 mph. Doesn't get any worse doing 80 and doesn't matter loaded, empty, nose heavy or not.
Takes about 30min to get used to it after not towing for a while. It doesn't push the truck around, it's just enough to notice and if you try to correct it, you end up looking like a drucnk driver! Hold the wheel n go works best.

[rhagfo]

I will restate don't think running max air in the TV rear tires is necessary. The rear tires have a capacity between 6,084# to 6,830# depending on size. Assume 6,084#, if empty TV weighs 3,000# on rear axle empty plus 1,640# pin is only 4,640# on the rear axle. So even with the weakest tire max pressure his over inflated and riding on the center.

On Edit: it would be nice if the OP posted some scale weights and tire sizes and capacitys.

[rhagfo]

Bedlam wrote:

mkirsch wrote:
You don't "need" a specific pin weight with a fifth wheel. Unless something is really really wrong with it, it should tow fine with almost no pin weight at all.

It's just that in an RV configuration, it is nearly impossible to do that. The axles tend to be closer to the rear of the trailer, and living space up over the hitch. 20-25 percent of the trailer's weight just tends to naturally end up on the pin due to design limitations.

Insufficient pin weight can cause fore/aft pitching in the truck and greater chance of jackknifing. At some point, acceleration and deceleration traction is also affected. I don't see any balanced teeter totter fifth wheels...

X2
That is the most irrational statement I have seen in a while!

Having near zero pin weight will lead to all kinds of ride issues, this is one reason I travel with a full FW tank! Increase my pin weight.

[Bedlam]

mkirsch wrote:
You don't "need" a specific pin weight with a fifth wheel. Unless something is really really wrong with it, it should tow fine with almost no pin weight at all.

It's just that in an RV configuration, it is nearly impossible to do that. The axles tend to be closer to the rear of the trailer, and living space up over the hitch. 20-25 percent of the trailer's weight just tends to naturally end up on the pin due to design limitations.

Insufficient pin weight can cause fore/aft pitching in the truck and greater chance of jackknifing. At some point, acceleration and deceleration traction is also affected. I don't see any balanced teeter totter fifth wheels...

[Dave_H_M]

Bedlam X2

[mkirsch]

You don't "need" a specific pin weight with a fifth wheel. Unless something is really really wrong with it, it should tow fine with almost no pin weight at all.

It's just that in an RV configuration, it is nearly impossible to do that. The axles tend to be closer to the rear of the trailer, and living space up over the hitch. 20-25 percent of the trailer's weight just tends to naturally end up on the pin due to design limitations.

[svt440]

Bedlam wrote:
I suggested maximum pressure in the rear truck tires to eliminate side wall flex as a factor. If you find this helps, you can reduce pressure to closer to suggested inflation tables and see if squirm returns.

I do know there is something wrong with your match up and you need to make one change at a time to figure out the cure. If you still want a newer truck, don't let this stop you but that is a different issue.

Great point! Weak sidewalls caused some major problems back when I had a travel trailer, so I totally see where you're coming from. I'll definitely try the things you suggested, and as you suggested. Thanks!!

[Bedlam]

I suggested maximum pressure in the rear truck tires to eliminate side wall flex as a factor. If you find this helps, you can reduce pressure to closer to suggested inflation tables and see if squirm returns.

I do know there is something wrong with your match up and you need to make one change at a time to figure out the cure. If you still want a newer truck, don't let this stop you but that is a different issue.

[svt440]

rhagfo wrote:

svt440 wrote:
Hey everyone. I have a 30' fifth wheel that weighs in around 8400lbs dry. Currently towing it with a 2003 2500HD Silverado Duramax. Truck is an extended cab, short bed (the shortest truck you can get aside from a two door short bed). I felt it get a little squirmy a few times at 65mph that made me nervous enough to back off the gas. Did it a couple times in a couple of hours. One thought I've had, is buying a newer four door, long bed, 3500 srw. My thoughts are, with the longer wheel base and the heavier suspension, I will be over trucked (at least for an 8500-9000lb setup) and not feel like I'm the minor like I do in my current truck. I know a dually would most likely eliminate that possibility all together (I see these things with the hammer down running 70+mph on the freeway with tri-axle fifth wheels!) but I'm really preferring a srw and given the fact that I have a lighter fifth wheel, I feel like a 3500 srw should be more than enough truck.

Question is, will I notice much difference between the combination of a greater wheel base, and the heavier suspension, or will it not change much? I know the HD series trucks are similar to a 1 ton, (or so I read), so I'm wondering if my only gain in this situation will be the longer wheel base. Any thoughts or experience? <- preferred! Thanks guys!

Bedlam wrote:
I would look at the following:
1. Actual pin weight verses actual loaded trailer weight
2. Verify your tow vehicle is leveled under load with sufficient front axle weight
3. Verify the trailer is level or slightly nose down when hitched
4. Run your rear trucks tires at maximum PSI
5. Allow your overloads to take some of the load if you use air bags for leveling

I agree with most of what Bedlam states, but will add a bit of personal experience.

Under Bedlam's #2, make sure your pin is over the rear axle, with a short bed some move the hitch back and put the pin slightly behind the axle and unload the front axle.

I do disagree with Bedlam's #4, my 5er is heaver than yours and I run my rear tires at 70 psi (265/75-16E 3,415# ea.) 70 psi gives plenty of capacity with 5,500# on the rear axle. Max air pressure and not near max load you will be over inflated and riding on the center of the tread only. You might try the check or tape test across the tread to check best inflation.

So to the personal experience, we have a 2001 RAM 2500 CTD Quad Cab Long bed with Camper Package, so do have stronger springs, and the 265/75-16E tires. I would assume that you have at least 245/75-16E tires.
When our current 5er presented itself and we needed to move on it, I had just identified that the lower ball joints on our TV were worn. They were not at the point of failure, but noticeably worn. Well we needed to pull the new 5er 250 miles home, and I had a couple of lane changes where I got a noticeable wiggle that was uncomfortable. Once I replaced the ball joints the next week, the 5er has been a dream to tow. The only additional enhancement to the suspension has been a full set of Bilstein 5100 shocks.

I would suggest you have your front end checked out.

Just as a point of reference, our 5er is 9,820# dry and a 12,360 GVWR, towed at about 11,000#.

More interesting things to think about. Thank you! I just had it in a shop to be aligned and they commented on a driver side lower ball joint being bad. I took it to another shop (because (no offense to young mechanics) it was a young kid who said it was bad and I just put Moog ball joints in 4000 miles ago) and the other shop said they were fine. This is a more reputable shop with more experienced mechanics. They said a wheel bearing has a little play, but isnt of any concern yet. Maybe the kid was on to something?

[svt440]

JIMNLIN wrote:
Something with the combo isn't right. A new longer wheelbase truck may or may not fix the "squirmy" feeling.
Your extended cab short bed has a 140" wheel base and should have no problems handling a 8500 lb dry/ 10k wet weight 5th wheel trailer.
Other things I look for causing "squirmy" feeling pulling a GN/5th wheel trailer is;

Too much tire pressure in the front and rear truck tires...causes the tire to roll on the center of the tread and will wonder all over the road.

Aggressive all terrain tires and mud terrain tires with those large lugs and voids can exhibit tread roll..... feels like the tires are half flat.

New tires on the truck can have a bit of tread roll also before their broke in.

Truck and or trailers suspension not aligned properly.... the truck/trailer simply will not track each other.

Bias ply tires on the trailer also may not track the truck with radial tires.

The trailers tires has too much air pressure .....tires rolling on the center of the tread won't track the truck.

The truck wheels too narrow for tires like a LT265/75 or 285/75 on a std 6.5" GM wheel can roll on the center of the tires tread.....causing handling/tracking issues. Many GM owners myself included have had this happen.

Now if the truck is squirmy cause it makes a great story to tell the wife so she will want you to get the new truck ....then heck yeah go for it :B

Haha I love the last comment! And I don't have to convince her unfortunately, I have to convince myself! It means the 700hp Coyote Mustang goes bye-bye, and that will be a sad day for me. You pointed out alot. I'm wondering if its tires. I've actually got BF Goodrich All-Terrain tires that have less than 1000 miles on them, and are a 265/75 on the stock GM wheel. I thought maybe it was a 7 or 8" wheel, but it must be the 6.5" you referred to! I know I have 65psi in the front, and 80psi in the rear, but the other points you pointed out might be worth looking into! I'm going to make another trip in a couple of weeks and might try to pickup a little tongue weight too. My tongue is barely 15% of the overall weight (1274 tongue, 8408 dry), and loaded might be less than 15%. Dont I need to be between like 15%-25% with a fifth wheel or something? I forget where I read that, I just read its more than a bumper pull.

[rhagfo]

svt440 wrote:
Hey everyone. I have a 30' fifth wheel that weighs in around 8400lbs dry. Currently towing it with a 2003 2500HD Silverado Duramax. Truck is an extended cab, short bed (the shortest truck you can get aside from a two door short bed). I felt it get a little squirmy a few times at 65mph that made me nervous enough to back off the gas. Did it a couple times in a couple of hours. One thought I've had, is buying a newer four door, long bed, 3500 srw. My thoughts are, with the longer wheel base and the heavier suspension, I will be over trucked (at least for an 8500-9000lb setup) and not feel like I'm the minor like I do in my current truck. I know a dually would most likely eliminate that possibility all together (I see these things with the hammer down running 70+mph on the freeway with tri-axle fifth wheels!) but I'm really preferring a srw and given the fact that I have a lighter fifth wheel, I feel like a 3500 srw should be more than enough truck.

Question is, will I notice much difference between the combination of a greater wheel base, and the heavier suspension, or will it not change much? I know the HD series trucks are similar to a 1 ton, (or so I read), so I'm wondering if my only gain in this situation will be the longer wheel base. Any thoughts or experience? <- preferred! Thanks guys!

Bedlam wrote:
I would look at the following:
1. Actual pin weight verses actual loaded trailer weight
2. Verify your tow vehicle is leveled under load with sufficient front axle weight
3. Verify the trailer is level or slightly nose down when hitched
4. Run your rear trucks tires at maximum PSI
5. Allow your overloads to take some of the load if you use air bags for leveling

I agree with most of what Bedlam states, but will add a bit of personal experience.

Under Bedlam's #2, make sure your pin is over the rear axle, with a short bed some move the hitch back and put the pin slightly behind the axle and unload the front axle.

I do disagree with Bedlam's #4, my 5er is heaver than yours and I run my rear tires at 70 psi (265/75-16E 3,415# ea.) 70 psi gives plenty of capacity with 5,500# on the rear axle. Max air pressure and not near max load you will be over inflated and riding on the center of the tread only. You might try the check or tape test across the tread to check best inflation.

So to the personal experience, we have a 2001 RAM 2500 CTD Quad Cab Long bed with Camper Package, so do have stronger springs, and the 265/75-16E tires. I would assume that you have at least 245/75-16E tires.
When our current 5er presented itself and we needed to move on it, I had just identified that the lower ball joints on our TV were worn. They were not at the point of failure, but noticeably worn. Well we needed to pull the new 5er 250 miles home, and I had a couple of lane changes where I got a noticeable wiggle that was uncomfortable. Once I replaced the ball joints the next week, the 5er has been a dream to tow. The only additional enhancement to the suspension has been a full set of Bilstein 5100 shocks.

I would suggest you have your front end checked out.

Just as a point of reference, our 5er is 9,820# dry and a 12,360 GVWR, towed at about 11,000#.

[JIMNLIN]

Something with the combo isn't right. A new longer wheelbase truck may or may not fix the "squirmy" feeling.
Your extended cab short bed has a 140" wheel base and should have no problems handling a 8500 lb dry/ 10k wet weight 5th wheel trailer.
Other things I look for causing "squirmy" feeling pulling a GN/5th wheel trailer is;

Too much tire pressure in the front and rear truck tires...causes the tire to roll on the center of the tread and will wonder all over the road.

Aggressive all terrain tires and mud terrain tires with those large lugs and voids can exhibit tread roll..... feels like the tires are half flat.

New tires on the truck can have a bit of tread roll also before their broke in.

Truck and or trailers suspension not aligned properly.... the truck/trailer simply will not track each other.

Bias ply tires on the trailer also may not track the truck with radial tires.

The trailers tires has too much air pressure .....tires rolling on the center of the tread won't track the truck.

The truck wheels too narrow for tires like a LT265/75 or 285/75 on a std 6.5" GM wheel can roll on the center of the tires tread.....causing handling/tracking issues. Many GM owners myself included have had this happen.

Now if the truck is squirmy cause it makes a great story to tell the wife so she will want you to get the new truck ....then heck yeah go for it :B