Replacing an Axle - leading arm to trailing arm, plus adding brakes (long post) Options

[Raya L.]

Andrew,

Oh, interesting - I hadn't thought about counting tongue weight as "unsprung" weight along with the running gear itself (axle, rims, tires, brakes).

Now I see even more how the earlier trailers could use a 1200# axle (although it may have been a bit light - and they did switch to 1600# - now it's not as crazy as it first sounded). Thinking out loud:

If the rig weighs 1600# loaded, you could now subtract
Tongue weight of 200# (12.5%)
Running gear weight of 200#
So your "sprung" axle weight is ...1200# exactly.

Still a bit close, and certainly not what I would purchase now, but not as crazily low as I had been thinking. Subtracting the tongue weight makes a big difference.

But... are we sure that's correct? What if one is going up a hill and/or over bumps? Do you still "get" to subtract the tongue weight?

Raya

[james kent]

Raya
That's like asking, "How much does a pound of cement weigh if your flying at a thousand feet?"

So the answer is ....YUP.

[Alf S.]

Hi: All... Trailer weights are subjective... Like the age old question "Whats a Greecian urn"??? I always look for the Gross Weight rating for the axle and work backwards from there!!! I seem to do best working BACKWARDS!!!
Alf S. North shore of Lake Erie

[Raya L.]

James,

I just wasn't sure if, say, you were driving up a steep, bumpy hill, that some of the tongue weight would not be shifted to the trailer axle. It still seems to me like it would, but I'll accept that it must be one of those things that seems to be true but isn't.

So that does take that 10% - 15% off the weight that must be applied to the axle's rating then (along with the unsprung weight of the running gear itself).

Good to know.

Raya

[Pete Dumbleton]

I would expect the axle's rating to include the normal use of up/down hills and in turns where the weight is shifted to one side or the other. They specify a static weight because that's the easiest to measure and is understood by all.

[Raya L.]

Pete,

I wasn't very clear above, I realize.

What I was asking about wasn't the (original) axle's rating, but about factors to consider when getting a new axle and deciding how much weight to have it "rubbered" for. I was musing on whether or not tongue weight would "shift" back onto the axle at any time - say if one was going up a steep, bumpy hill.

I had thought that it might (and one would thus want to add it to the overall "sprung" weight in making calculations), but apparently it does not.

Just one of those "physics-al" illusions, I guess

Raya

This post has been edited by Raya L.: Apr 8 2009, 08:40 PM

[jeff isaacson]

hey Roy, got to tell ya' this info. is invaluable..you could market it! As you know my 1970 ECO is very similar in all aspects to the early Bolers. And yes it is exhibiting all the classic signs of axle fatigue. One I most enjoy is the low-rider effect, and with My age getting in and out is very EZ! Non the less its time to replace, I've been putting this off for some 16 years now. I have to admit the little bugger rides well and hasn't gotten considerably worse since I purchased it. Yes there is some uneven tire wear, and as with all trailers you have to fasten and batten while traveling. The most notable items that bounced around are the Coleman stove grates, used to fly right off ! You get used to it. What else can I say? But its time. And for YourS !

[Roy in TO]

One I most enjoy is the low-rider effect, and with My age getting in and out is very EZ!

You are welcome Jeff,

If you hold off a bit, someone here may be following my work with a 22.5 degree up. That should be a few inches lower than mine. Switching to the Carlisle mounted ST145R12 lowered me about an inch too. Tinker around enough and you might be able to keep that low rider look.

BTW your ECO may be a lot closer to the bolers than you think. I noticed you have it listed as a 1970+. I have not been able to track down all the info yet, but I postulate the ECO was supposed to be one of the boler American plants in 1972. I've read your bit about hot tubs in the boler history thread. From what I've gathered the boler American people tracked down companies that were alreading working with fiberglass to make trailers for them.

[JenPB]

Wow...that's a LOT more involved than my simple leaf replacement completed this evening. Still, I'm proud to have managed. Someday, I'll be brave enough to tackle welding...maybe.

[Roy in TO]

We just picked up the trailer today from winter storage. The Kanadiann May "Two Four" weekend being the unofficial start of summer, camping and working on the trailer.

I was asked earlier about final heights. Hope These Help:

Height to step at door 10"
To bottom of frame 14"
(Add 3" for hitch = 17")
Road clearance to bottom of axle 8"

[Roy in TO]

I just compared these to the original specs in the brochure.

Height was listed at 6' 11"
Head room 6' 1"
That leaves 10" exactly the height of the step to my floor.

Looks like my mod flipping the axle restored the height back to the original specs!

This post has been edited by Roy in TO: May 17 2009, 11:01 AM

[DannyH]

Thanks for all the information roy. When you said earlier that your final tire is a ST 145/R12, is this the tire that you are currently using? If so, isn't this a 12" tire, not the typical 13" size?

[Roy in TO]

you said earlier that your final tire is a ST 145/R12, is this the tire that you are currently using? If so, isn't this a 12" tire, not the typical 13" size?

Thanks Danny,

The final and current tire is a stock Carlisle ST 145/R12 premounted on a 5 x 4.5 bolt pattern rim. They were on sale at Princess Auto for under a $100 CDN ea.

It is a 12" tire, but total outside diameter was slightly smaller than original 6.00x13. The next closest Trailer tire on a 13" rim was just a little too big for my liking and cost as much for the tire alone even more if you include mounting etc.

The size difference between all 3 tires are shown standing on end below. The final ST 145/R12 is in the forground, the original 6.00-13 in the middle and its recommended replacement the ST175/80R13 is in the rear. A tape measure is shown for comparison purposes.

 tire_diff.JPG ( 280.85K ) Number of downloads: 33


This post has been edited by Roy in TO: May 20 2009, 03:29 PM

[Phillip]

3 thoughts come to mind.
Since the kitchen floor is 3" lower than the bottom of the frame you would have to raise the trailer a little too high to get everything to work under the trailer with a straight axle.
If you used a "drop" axle (the spindles are higher than the axle), ground clearance would be in the 4-6" range.
3rd reason is that the frame ends at the door. One may not have enough room for shackles unless you are using really short springs.

1 question Roy.. Is there a reason you didnt have bolt on brackets welded onto the trailer for mounting the new axle, instead of welding it back ??

I'm having a #9 w/brakes put on my Casita next week, But in addition I'm planning on having brackets that can be welded on then the axle can be bolted on so that if for some reason it needs a axle it would be much easier for a do it yourself job...is my line of thinking

[Roy in TO]

1 question Roy.. Is there a reason you didnt have bolt on brackets welded onto the trailer for mounting the new axle, instead of welding it back ??

I did have the bolt on brackets welded onto the trailer. If you order a new axle with the bracket option, the brackets are bolted onto the axle at the factory. If you look closely at the pictures in post # 5 of this thread, you can see them. It helps to know what you are looking for because they are all black like everything else.

As far as I am concerned the brackets are good insurance if one ever has to replace an axle again, or worse yet, the frame.