Attaching casters

[vcrt]

I read over the posts on the topic of replacing the triangular drag bars with casters from a few years ago. Very informative, but I have another idea I'd like to bounce off you guys. I see that there is a gap between my frame rails and the undercovering which may provide enough room to slip a u-bolt through. I see square style u-bolts in my RV catalog that have 5-3/8" legs with 2-1/16" space between them. My frame rails are 2"x4" square tubing, so I'd like to use the u-bolts to go over the frame rails and then slip them through the holes in the caster plate to secure with nuts. Does anyone have any thoughts on this way of attaching the casters?
Thanks,
Rich

[JohnB]

Hi Rich

Your method sounds good but a few questions and things to think through

In this case a picture of your frame helps as I cannot exactly tell what you have or what your caster you selected looks like.

So here goes some generic questions/comments.


If I understand it right you want to go up and over the top of the frame with the U bolt. Good thought the only issue I see without seeing what you have is how to get the U bolt over the top of the frame? On my prior 04 T2499 it was channel iron but still the V area was under the camper floor. Did you find a spot where you can wiggle the U bolt up over the top of the frame and under the Dacro membrane? If your past this then great problem 1 solved.

Next is the holding power of the caster to the frame. Not knowing the caster you are looking at and how thick the mounting foot is. 1/8”, 3/16” or maybe ¼”. If you have one of the thinner feet that might be an area to deal with. I’m envisioning the foot hanging off each side of your 2” wide frame and the U bolt going through it. The thinner mounting foot would tend to bend up trying to hold it on. If that is the case then getting a piece of ¼” plate as a heavy backer plate to pull on would help. Just drill 4 holes in the plate to match the caster and U bolt holes and put it on top of the caster before mounting. Then the caster edge hanging off will not twist up so easy when you try and tighten it as the washer plate creates a stiffer connection when tightening.

If you make it past those 2 areas then you have a fairly simple mount and no drilling or welding on the camper.

Those square U bolts they sell them in many other place then RV stores. Trailer shops, NAPA and others. It may take a hunt to find the longer lengths.

http://www.easternmarine.com/index.cfm?fuseaction=catalog.search

OR the old stand by McMaster Carr. They have a 2” by 6 5/8” long 3/8” one and cut off the excess

http://www.mcmaster.com/#u-bolts/=ch2qi5

http://www.mcmaster.com/#=ch2psy

Hope this helps

John


If the links do not fire, search on u bolt or U-bolt on those sites. My Pc is acting up

[kanyonkitty]

One other thing to think about is that once you "add" the casters, you have now also reduced your clearance and the rear of your rig will contact the ground even more than before. I personally did "not" like the rear of the 2499 dragging, I DID not like the idea of adding casters (as that takes away clearance inches), so I have my trailer lifted 4 inches. SOLVED the dragging problem
My concern with dragging the frame was "frame damage", and I didn't think that the casters would eliminate the possibility of frame damage.
So there ya have it, a second option for what it's worth.

Kitty

[mainah]

If the casters are the same hight as the skids it should not matter I like the caster ideal I think I would rather roll over a bump then skid over one. That said I really did not see any marks on my 90 T1700 skids.

[Steve Collins]

The flimsy Sunline skids on my 2453 hung down 6". When I replaced them with casters, they also hung down 6" and generally made contact with badly shaped driveways, etc. in exactly the same points. The big difference was that the casters take the weight and roll across the surface. The skids dragged, creating friction, and eventually folded in on themselves rendering them useless. Since the skids were in the same location, I can only deduce that Sunline felt that it was a good location to take some weight pushing up on the frame.

The key here is that 99.9% of all skid or caster contact will generally be at very slow speeds. My worst problem was backing into my own badly sloped driveway or entering/exiting from gas stations with terribly located rain gutters along the mouth of their entrances. That slow speed generally means that weight is transferred on and off the casters in a reasonably "gentle" fashion, at least compared to hitting a New York State pothole at 55 MPH.

[Steve Collins]

Originally Posted by mainah

If the casters are the same height as the skids it should not matter I like the caster ideal I think I would rather roll over a bump then skid over one. That said I really did not see any marks on my 90 T1700 skids.

The general rule seems to be that the shorter the TT, the less the possibility of the skids touching down for any reason. In that, your T1700 is very lucky.

That is due to a simple matter of geometry: angles vs. length. The longer the distance from the wheels to the rear bumper, the shorter the distance for said rear end to scrape on even minor variations in road surface height.

Only one thing will alter that - flip the axles and raise the TT 3"-5".

[vcrt]

Thanks everyone for the replies. Yes John, there is some clearance above the frame rails since the subfloor rests on 2"x2" wood joists.
But, I've been thinking about this modification and since I'd like to locate the casters which are 1200# rated (They look identical to the ones in Hutch's pix), in the same place as the skid bars, there is one problem. The skid bars extend down 5-1/2" and the total height of the casters is 6-1/2" (approximately). I don't want the back of the trailer making contact with the ground any sooner than it already does, so I'm rethinking my plan.
Instead of using the u-bolts, I'm thinking of using a piece of square tubing (or two pcs.) to mount between the frame rails. I would weld plates to the ends so I could regulate the height of these pieces of tubing to where the casters would then match the extension of the skid bars. So, instead of mounting them directly under the frame rails, they would mount directly inboard of them with the tubing going all the way across to the other frame rail for strength. I think angle iron at the ends would be stronger than flat plates since it would then catch under the rails. The only part I'm not sure of is the size and wall thickness of the square tubing, but 3/16" wall thickness on 2" tubing might do it.
Any thoughts on this?
Thanks,
Rich

[mainah]

Weld some on that have replaceable wheels.

[Jim-Bev-2363]

Since the castors swivel letting the rear shift sideways if not pushing the ramp straight on had anyone tried fixed castors?

Also, with the swivel castor, if the bearings in the swivel become frozen, damaged or wornout, wouldn't welding them on cause another problem?

jim

[Steve Collins]

Originally Posted by Jim-Bev-2363

Since the castors swivel letting the rear shift sideways if not pushing the ramp straight on had anyone tried fixed castors?

Also, with the swivel castor, if the bearings in the swivel become frozen, damaged or wornout, wouldn't welding them on cause another problem?

jim

The swivel casters work better when making a turn of any kind. The fixed casters are only effective when the unit is moving straight forward or backward. Most of the time when my trailer bottoms out, it is in the middle of some kind of turn where the rear end was definitely moving to left or right. Swivel casters are much preferred, IMHO.

If one were to opt to weld to the frame, it should be a mounting plate, not the caster itself. The caster is then bolted to the mounting plate. Problem solved.

Part of the issue is that the base of the caster may not be strong enough by itself for the intended purpose we are using them for even though the caster is rated at 1,000#. Backing it with a thick mounting plate, whether bolted or welded to the frame, solves both problems.

If you look at my caster, you can see that the mounting holes for the caster don't match up (dimension wise) with the frame so using a mounting plate actually solves a third issue as well.




And, here is the reason that replacing the skids is a good idea:

[Jim-Bev-2363]

Makes sense to me.

[vcrt]

Looking it over today, I've decided to go back to the original idea with a twist. Instead of using u-bolts which, in the area I want to mount the casters, I would be working between two joists that are spaced to close together to get the rear u=bolt into place. So, instead, I'm going to use 1/4" plates on top of the frame (the old skid bars cut down will work perfectly) that I can easily slip into place, then long bolts to go into threaded holes I will incorporate into them. If it ever fails to live up to expectations, I can always make mods.
I'll post pix when I do it.
Rich

[vcrt]

I have one in place, the only thing I will do differently on the other side is to weld the nuts to the plates so I don't have to bother with a second wrench to hold them.