Announcement

**bellis** · 05-06-2024, 05:50 PM

The difference between the one from e-trailer and lippert (links re-posted below) are 50 pounds of additional capacity on the lippert (curt) but at an additional $86.77 before taxes and shipping.

https://www.lippert.com/adjustable-r...mes-2020102702
https://www.etrailer.com/dept-pg-RV_...unt_Hitch.aspx

I haven't weight things, but if the bike carrier I have is 50 pounds and if I added 4 bikes at 50 pounds each = 250 pounds - which is well below the 300 or 350 limit. 50 pounds a bike is overly generous as well....they are probably half that.

Not yet sure what direction I will take. Due to overwork, I may pay my mechanic to do it for me or a fabricator to weld it on for me.

**ScottK** · 05-06-2024, 06:01 PM

bellis I would just get the UltraFab and weld it on. What really helps with a bike rack (or any rack) is a stabilizer like this one: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
This prevents rocking and bouncing of the rack, thus reducing stress by tons. I don't think you've mentioned what you want to do with the receiver?

**bellis** · 05-06-2024, 06:15 PM

Originally posted by ScottK View Post

bellis I would just get the UltraFab and weld it on. What really helps with a bike rack (or any rack) is a stabilizer like this one: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
This prevents rocking and bouncing of the rack, thus reducing stress by tons. I don't think you've mentioned what you want to do with the receiver?

That stabilizer is golden. Will definitely grab one when I do this.

I am definitely leaning towards the Ultra Fab and welding it on. I don't plan on welding myself....so I need to investigate fabricator weld cost.

When you previously said to disconnect batteries before welding. Do you mean to throw the positive master battery switch to off OR do you mean I need to physically disconnect my frame ground connection from the negative busbar? When welding - what happens? Surges rush through frame?

**Cate&Rob** · 05-06-2024, 07:27 PM

As long as the hitch bolts to the web of the frame and not the lower flange, I would go with the bolted design. The strength of an I beam is in the flanges and I wouldn’t bolt (or weld) to the flanges, if there is another choice. The bolted design is easier to self install and doesn’t require finding a suitably qualified welder.

Rob

**ScottK** · 05-06-2024, 07:30 PM

Originally posted by bellis View Post

When you previously said to disconnect batteries before welding. Do you mean to throw the positive master battery switch to off OR do you mean I need to physically disconnect my frame ground connection from the negative busbar? When welding - what happens? Surges rush through frame?

bellis What I know about it is from a YouTube video where Grand Design fixed someone's frame, welding all kinds of extra steel onto it, and ruined the BattleBorn batteries, Victron equipment, TV, microwave, and anything else that was plugged in. I don't want to tell you the exact course of action, but as a welder, I know you don't want all that current flowing through your electronics. It depends on how your rig is wired. There is not going to be a lot of welding for that hitch, and if the ground is connected nearby, there should not be any problem if you simply disconnect the negative terminal of the battery bank. We're talking about the back of the trailer where there are no electronics anyway. So as long as the welder ground is connected in that area, I would be comfortable on my own rig, just disconnecting the battery bank, by switch or otherwise. That's all I did and no damage was done. But might as well unplug the TV if the plug is accessible. You know what - just thought of it - turn off the main breaker in your circuit panel, along with the battery. Then you will be totally safe. I'm a dumbass I guess since I forgot about that when I did it. Arghhh

**Country Campers** · 05-06-2024, 07:50 PM

I agree with Rob, Cate&Rob, bolting to the web is better than welding, no bolts or weld on the lower or upper flange. Etrailer has the same Curt hitch Adjustable Width Trailer Hitch Receiver for RVs, 22" to 72" Wide CURT RV and Camper Hitch 13703 (etrailer.com) for a better price than Lippert, funny that Lippert owns Curt now. I like this hitch better than the Ultra Fab because of the mounting of the hitch. More money but I really think the mounting will make the difference.

Brian

**Jlawles2** · 05-06-2024, 10:26 PM

When they say disconnect the batteries, physically remove both leads from the batteries and insulate the positive one(s).

Unfortunately if you have not installed a true disconnect switch the GD installed on only disconnects certain "NON SAFETY ITEMS". The jacks, gas monitor and a few other things are powered at all times.

Any stray current can cause major issues with both sensitive electronics and other printers circuit board items along with thing that you might consider robust like lights (led's don't like stray current or voltage).

**bellis** · 05-06-2024, 11:21 PM

Originally posted by Jlawles2 View Post

When they say disconnect the batteries, physically remove both leads from the batteries and insulate the positive one(s).

Unfortunately if you have not installed a true disconnect switch the GD installed on only disconnects certain "NON SAFETY ITEMS". The jacks, gas monitor and a few other things are powered at all times.

Any stray current can cause major issues with both sensitive electronics and other printers circuit board items along with thing that you might consider robust like lights (led's don't like stray current or voltage).

and
ScottK

I have my negative bus bar wired to a bolt that goes into the frame of the trailer. I did wire in a master battery switch in addition to the Grand Design switch.

Hmmn...per the comments - starting to lean the other way. Lower price of the same item helped.

https://www.etrailer.com/RV-and-Camp...URT/13703.html

**Scott'n'Wendy** · 05-07-2024, 06:05 AM

I'm confused?....Bolt to the web? It's the weakest in the web. Everything is either bolted or welded to the flanges as far as I can tell. My factory hitch is welded to the bottom flange and doesn't touch the web.
I don't really know how the walls are attached but I figure they must be bolted to the upper flange?

**Cate&Rob** · 05-07-2024, 06:45 AM

In an I beam, the strength of the beam is in the flanges. One in tension (usually the lower) and one in compression (usually the upper). The web serves to hold the flanges apart (an over simplification) and stresses in the steel are at the lowest on the centerline of the web. Minimizing damage or holes in the flanges is important. Welding to the edge of a flange is OK but there will be a heat affected zone adjacent to the weld that weakens the flange to some degree. Relatively small holes drilled at or close to the vertical centre of the web would have the least affect on beam strength. Easily strong enough to carry the 350 lb design load.

Have you ever noticed cargo trailer I beams with large lightening openings cut in the web or wondered why anything attached to building I beam structure is clamped rather than welded to the flanges?

Rob

**Jkwilson** · 05-07-2024, 11:27 AM

Originally posted by Cate&Rob View Post

In an I beam, the strength of the beam is in the flanges. One in tension (usually the lower) and one in compression (usually the upper). The web serves to hold the flanges apart (an over simplification) and stresses in the steel are at the lowest on the centerline of the web. Minimizing damage or holes in the flanges is important. Welding to the edge of a flange is OK but there will be a heat affected zone adjacent to the weld that weakens the flange to some degree. Relatively small holes drilled at or close to the vertical centre of the web would have the least affect on beam strength. Easily strong enough to carry the 350 lb design load.

Have you ever noticed cargo trailer I beams with large lightening openings cut in the web or wondered why anything attached to building I beam structure is clamped rather than welded to the flanges?

Rob

I can remember an exercise in school where we analyzed the forces in a rectangular steel bar under load. Most of the stress was near the top surface and bottom surface, and you could just start cutting away the sides of the beam with very little effect on the load-bearing capacity until you tried to take some off the flange area. Weight saving without capacity reduction is kind of a civil/mechanical engineering dream

**Scott'n'Wendy** · 05-07-2024, 01:03 PM

Originally posted by Cate&Rob View Post

Have you ever noticed cargo trailer I beams with large lightening openings cut in the web or wondered why anything attached to building I beam structure is clamped rather than welded to the flanges?

Rob

I have not.....I'm an electrician...needs to have wires on it to get my attention..lol

Do you happen to know how the walls are attached to the frame in an RV?

**Country Campers** · 05-07-2024, 06:33 PM

Originally posted by Scott'n'Wendy View Post

I have not.....I'm an electrician...needs to have wires on it to get my attention..lol

Do you happen to know how the walls are attached to the frame in an RV?

The walls actually sit on the floor which is attached to the frame. The frame has outriggers that support the outer edges of the floor and the walls. Take a peak under your rig and you will see.

Brian

**Jlawles2** · 05-09-2024, 05:45 PM

Originally posted by Cate&Rob View Post

In an I beam, the strength of the beam is in the flanges. One in tension (usually the lower) and one in compression (usually the upper). The web serves to hold the flanges apart (an over simplification) and stresses in the steel are at the lowest on the centerline of the web. Minimizing damage or holes in the flanges is important. Welding to the edge of a flange is OK but there will be a heat affected zone adjacent to the weld that weakens the flange to some degree. Relatively small holes drilled at or close to the vertical centre of the web would have the least affect on beam strength. Easily strong enough to carry the 350 lb design load.

Have you ever noticed cargo trailer I beams with large lightening openings cut in the web or wondered why anything attached to building I beam structure is clamped rather than welded to the flanges?

Rob

As rob stated, NORMALLY a beam is supported on the ends with load across it which puts the top flange in compression and the bottom in tension. In trailers though, between the tongue and the wheels top is compression bottom tension, at the axles, this changes and the overhang causes the bottom to be in compression and top in tension.

Look around at seemingly normal things in buildings. Those with exposed roof joist (like Walmarts, home depots, Lowes, etc) and notice that the roof is held up by 4 pcs of angle iron spaced apart with tiny bent bars.

Announcement

Bumper weight - adding a receiver

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment