34 replies to this topic

[EYEMLOST]

On my set up; I weighed the rig right after mounting the FWC Granby.

 

The results;

Steer axle: 2,560lbs (factory GAWR: 2,800lbs)

 

Drive axle: 3,360lbs (swapped in Sterling 10.25/GAWR: 8,250lbs)

 

 

My questions;

1) How common is it for TC's front axle to lose weight as mine has?

2) How concerned should a TC be with said weight loss of said front axle?

3) IYO; what percentage of TC go about their business with a lighter front axle weight(shift)?

[eyemgh]

On my set up; I weighed the rig right after mounting the FWC Granby.

 

The results;

Steer axle: 2,560lbs (factory GAWR: 2,800lbs)

 

Drive axle: 3,360lbs (swapped in Sterling 10.25/GAWR: 8,250lbs)

 

 

My questions;

1) How common is it for TC's front axle to lose weight as mine has?

2) How concerned should a TC be with said weight loss of said front axle?

3) IYO; what percentage of TC go about their business with a lighter front axle weight(shift)?

 

What makes you say it lost weight? The GAWR F and R aren't what they do weight, but the most they should weigh. Also, where did you weigh? They seem low for a truck with the capacity to carry a Granby and the camper itself. 

[Vic Harder]

The OP has noted that putting the Grandby on his short wheel base truck actually made the front axle lighter than it was before putting the camper on.  He is also posting the GAWR so we know that he is not exceeding those ratings.

 

FWC and truck manufacturers recommend that the center of gravity of the payload be ON or in front of the rear axle.  If that happens, then the front axle weight will increase too, not just the rear.  I believe this recommendation is because having the weight too far back is dangerous and decreases the handling/stability of the rig.

 

I noted that on my 3500, the front wheel arch went down 1/2" to 1" while the rear went down 2" when I added the camper.  Have not weighed it, but that shows that the front is carrying weight, not just the rear.  I'd not drive a rig where the front lifted when I added the payload.

[eyemgh]

The OP has noted that putting the Grandby on his short wheel base truck actually made the front axle lighter than it was before putting the camper on.  He is also posting the GAWR so we know that he is not exceeding those ratings.

 

FWC and truck manufacturers recommend that the center of gravity of the payload be ON or in front of the rear axle.  If that happens, then the front axle weight will increase too, not just the rear.  I believe this recommendation is because having the weight too far back is dangerous and decreases the handling/stability of the rig.

 

I noted that on my 3500, the front wheel arch went down 1/2" to 1" while the rear went down 2" when I added the camper.  Have not weighed it, but that shows that the front is carrying weight, not just the rear.  I'd not drive a rig where the front lifted when I added the payload.

 

Got it. Yea, I wouldn't want a truck prone to popping a wheelie either.

[EYEMLOST]

What makes you say it lost weight? The GAWR F and R aren't what they do weight, but the most they should weigh. Also, where did you weigh? They seem low for a truck with the capacity to carry a Granby and the camper itself. 

A CAT scale.

 

 

The CofG for the Granby is 11" behind the rear axle.

 

Of the 8ft footprint; 5ft is within the bed, and 3ft is beyond the taillights.

 

 

With 1ton rear leaf springs/1ton dually rear axle/HMMWV tires combo, I barely know the camper is on.

 

 

It wasn't until I weighed the Bronco/camper set up that I realized the front axle was 240lbs lighter, and that the steering did feel 'a little' lighter.

 

 

I attached the carrier rack on the front hitch receiver and put 4 5gal water jerry cans on, and then weighed set up again:

 

Steering axle: 2,820lbs <---Back to factory GAWR

 

Drive axle: 3,360lbs <---40% of GAWR

[EYEMLOST]

1) The OP has noted that putting the Grandby on his short wheel base truck actually made the front axle lighter than it was before putting the camper on.  He is also posting the GAWR so we know that he is not exceeding those ratings.

 

2) FWC and truck manufacturers recommend that the center of gravity of the payload be ON or in front of the rear axle.  If that happens, then the front axle weight will increase too, not just the rear.  I believe this recommendation is because having the weight too far back is dangerous and decreases the handling/stability of the rig.

 

3) I noted that on my 3500, the front wheel arch went down 1/2" to 1" while the rear went down 2" when I added the camper.  Have not weighed it, but that shows that the front is carrying weight, not just the rear.  I'd not drive a rig where the front lifted when I added the payload.

1) All correct. 

 

2) Exactly

 

3) You bring up a good point that I asked about (question #3).

 

Like the common practice of exceeding the GVWR with a loaded TC; how many campers drive/travel with a lighter front axle?

 

 

FOR THE RECORD:

I've used my FWC while it was on a HMMWV trailer for the 15yrs I've owned it.

 

With mounting the Granby in the bed of the Bronco; I plan on camping the next 5yrs that way (a TC).

 

 

I will be making a big investment decision at the end of said 5yrs as to whether I want another TC or TT (maybe even both!).

 

 

The plan is to go fulltime RV'ing at the 6th+ year. 

[rubberlegs]

All the weight of our fleet is on the rear axle of our Tacoma. Be careful about accessories on the back, which pivot weight off the front and thus add even more to the rear.

[eyemgh]

All the weight of our fleet is on the rear axle of our Tacoma. Be careful about accessories on the back, which pivot weight off the front and thus add even more to the rear.

 

It's super balanced, 3650/3750 loaded for the absolute worst case (2 spares, 4 wheel chains, all safety gear, lots of water, etc.) and 3400/3450 mostly unloaded. That's with both of us in the rig. 

[Wallowa]

A CAT scale.

 

 

The CofG for the Granby is 11" behind the rear axle.

 

Of the 8ft footprint; 5ft is within the bed, and 3ft is beyond the taillights.

 

 

With 1ton rear leaf springs/1ton dually rear axle/HMMWV tires combo, I barely know the camper is on.

 

 

It wasn't until I weighed the Bronco/camper set up that I realized the front axle was 240lbs lighter, and that the steering did feel 'a little' lighter.

 

 

I attached the carrier rack on the front hitch receiver and put 4 5gal water jerry cans on, and then weighed set up again:

 

Steering axle: 2,820lbs <---Back to factory GAWR

 

Drive axle: 3,360lbs <---40% of GAWR

 

Look this is way out of my league...but what Vic said seems to me to be not only true but a huge red flag concerning your design...any weight aft of the rear axle creates lift forward of the rear axle...including the front axle/steering...the further the distance the load rear of the rear axle the longer the lever arm and the more leverage/affect that weight will create in lifting the front of the vehicle...

 

I could be entirely wrong in my assumptions but 16% [2,820 vs 3,360...don't see 240 lb difference] less weight on front sounds like asking for trouble and any vertical movement of the load aft of the rear axle will magnify this disparity and future lift/unweight the front end..hit a bump, up comes front end and down goes back end as weight is transferred aft, but back end will rebound and pick up speed coming down the backside of the bump to future lift the front...nasty pogoing could be set up...don't limit your analysis to static conditions but dynamic on the road conditions...but I could be wrong..

 

Phil

Edited by Wallowa, 09 August 2021 - 10:41 PM.

[EYEMLOST]

Look this is way out of my league...but what Vic said seems to me to be not only true but a huge red flag concerning your design...any weight aft of the rear axle creates lift forward of the rear axle...including the front axle/steering...the further the distance the load rear of the rear axle the longer the lever arm and the more leverage/affect that weight will create in lifting the front of the vehicle...

 

I could be entirely wrong in my assumptions but 16% [2,820 vs 3,360...don't see 240 lb difference] less weight on front sounds like asking for trouble and any vertical movement of the load aft of the rear axle will magnify this disparity and future lift/unweight the front end..hit a bump, up comes front end and down goes back end as weight is transferred aft, but back end will rebound and pick up speed coming down the backside of the bump to future lift the front...nasty pogoing could be set up...don't limit your analysis to static conditions but dynamic on the road conditions...but I could be wrong..

 

Phil

 

When I 1st put the camper on and weighed everything, Bronco/camper, The result was;

 

Steer axle: 2,560lbs (factory GAWR - 2,800lbs)

 

Drive axle: 3,360lbs (swapped in Sterling 10.25 GAWR - 8,250lbs)

 

 

Continuing experimenting with weight, I put 4 water-filled jerry cans on the front carrier rack and weighed again;

 

Steer axle: 2,820lbs <----FACTORY GAWR (+ 20lbs!)

 

Drive axle: 3,360lbs

 

 

So I got the front end back to factory weight. 

 

 

What I would like to know is the weight distribution on those class-As and class-Cs with the loooong chassis with at least 25+% of it's entire chassis length BEHIND the rear axle, and I'm talking about single rear axle RVs.

 

IMHO; I'm no worse than those RVs.

 

 

Finally; I've been asking this question that no one seems to want to answer:

 

Like the common practice of exceeding the GVWR with a loaded TC; how many campers drive/travel with a lighter front axle?