Dexter Axle Questions

[Hummer]

OK as I understand it Dexter is now the official manufacturer for AS axles.

On my 31' 76 Sovereign the mountingholes through the frame and through the axle mounting plate are 9.300" C-C best I can tell with my Mitutoyo digital caliper.

The Dexter No 10 mounting plate calls for 8.0" C-C for 2300-3500 lb axles which obviously is not going to work unless a new rear hole is drilled in mounting plate.

The Dexter No 11 mounting plate calls for 9.5" C-C for 4000-6000 lb axles which obviously means one of the holes needs to be elongated horizontally about .200"

Thus begging the question does Dexter make a special AS mounting bracket for the up to 3500 lb axle or are the new AS axle mounting holes 9.5" C-C?

I realize the heavier 4000-6000 lb axle is going to have a larger diameter tube thusly the inverted U is going to have to be elongated to get in into the cut out area which would not be a big problem with a 9" side grinder and this inverted U is not a load bearing surface unless the mounting bolts come loose and it starts to get vertical movement and elongate the holes in that direction to the point the axle shaft contacts the mounting plate.

I am extremely hesitant to elongate the mounting holes ! ! ! ! !

Background: About 2002 I got a single 8000 axle for a heavy utility trailer I have that the mobile home axles were shot it came equipped with. It was a conventional top mount bracket and I had questions about how and where to locate a single axle and was directed to a guy who had been building trailers about 40 years and he gave me precise instructions of how to locate the axle as he warned if the axle is not at right angle to the tow line the trailer will jerk back and forth going down the road which we have all had pass us over the years.

I followed his directions and remeasured his critical dimensions about three times each and drilled the trailer frame and mounted Grade 8 Bolts and that trailer pulls as true as my military M100 Jeep Trailer made by Strick Corp in 1950. i.e. no side to side movement at any speed.

Based on this I am extremely hesitant to elongate any holes.

I have identified an axle that has a standard side hole dimension of 9.300 which appears it would be an exact match for AS factory hole location.

So bottom line does Dexter make a 9.300 C-C side plate for AS mounting?

[crispyboy]

You have a good question about the Dexter axle brackets but I doubt Dexter is going to make a special bracket for new Airstreams. I'm sure they will just drill the new trailer frame to fit whatever bracket Dexter sends with the axle.

I wouldn't worry too much about elongating the holes. Only the 2 rear holes on the axle bracket need to be elongated. If this worries you then have the 2 rear holes welded shut and drill the bracket to match what is on the trailer. The 2 front holes should line up perfectly with the axle bracket and the location of the frame cutout for the axle tube.
If the new axle has a larger tube then you can still use the front holes for alignment and cut away just enough of the frame to slide the tube into place.

[Inland RV Center, In]

Originally Posted by Hummer

On my 31' 76 Sovereign the mountingholes through the frame and through the axle mounting plate are 9.300" C-C best I can tell with my Mitutoyo digital caliper.

The Dexter No 11 mounting plate calls for 9.5" C-C for 4000-6000 lb axles which obviously means one of the holes needs to be elongated horizontally about .200"

Thus begging the question does Dexter make a special AS mounting bracket for the up to 3500 lb axle or are the new AS axle mounting holes 9.5" C-C?

I am extremely hesitant to elongate the mounting holes ! ! ! ! !

Based on this I am extremely hesitant to elongate any holes.

So bottom line does Dexter make a 9.300 C-C side plate for AS mounting?

No they do not, and will not.

Drilling a new hole or elongating one hole, does not hurt anything.

The key is to have the bolts tight.

Using grade "8" hardware allows that to happen, without any other issues.

Hummer, use the KISS program, and enjoy another beer.

Andy

[M2HB]

Before you start elongating a hole, make sure the factory holes are square with the frame. If they aren't, this will give you the opportunity to correct a problem. Don't assume that they are correct because they came from the factory that way.
Also, check to make sure the axle mounting brackets are square to the axle. They should be real close, but it pays to make sure.

[Distantdrummer]

What exactly does 4000-6000 lb. axle mean?
Why does it not have an exact capacity?
Do you divide it by 2 and that gives the carry capacity of each hub or what?

Is the actual torsion bar larger for the bigger tube? And therefore using the same size rubbers?
or
is the torsion bar the same size as the smaller capacity axle and larger rubbers used to fill the difference?

I did not find dimensions on either the Torsion bar nor the Torque Rubbers on Dexter's site.

[M2HB]

Originally Posted by Distantdrummer

What exactly does 4000-6000 lb. axle mean?
Why does it not have an exact capacity?
Do you divide it by 2 and that gives the carry capacity of each hub or what?

Is the actual torsion bar larger for the bigger tube? And therefore using the same size rubbers?
or
is the torsion bar the same size as the smaller capacity axle and larger rubbers used to fill the difference?

I did not find dimensions on either the Torsion bar nor the Torque Rubbers on Dexter's site.

I think what they mean is that the axles within that weight range use the same mounting bracket. The axles are rated for what the maximum load that they are designed to carry. An example would be that a 4,000#, or a 5,000# or a 6,000# axle would have the same mounting bracket.

[Inland RV Center, In]

Originally Posted by M2HB

I think what they mean is that the axles within that weight range use the same mounting bracket. The axles are rated for what the maximum load that they are designed to carry. An example would be that a 4,000#, or a 5,000# or a 6,000# axle would have the same mounting bracket.

Not so.

The axle mounting bracket is the same, regardless of axle rating.

What is different, starting at 4000 pounds, is the size of the square tube, which becomes 3 inches.

The square tube from 3900 pounds and lower, is 2 5/8 inches.

Andy

[M2HB]

On the Flexiride axles, the mounts do change after a certain weight rating. The tube size also varies with the weight rating. The other thing that changes with weight is the amount that the axle can cantilever past the mount to the spindle. An example would be that the 5,200# axle can cantilever out further than the 7,000# axle. I would have to look it up, but I think that they have two different mount sizes that I know about. What exact weight rating is used for each mount, I would have to check. I know that the 5,200# mount is the same as the 7,000# but that is only because I have used them quite a bit. My last 3,500# axle I bought had a different mount than the larger axles, so I know that they are different. The tube size is also different for the mounts. Note: I am not familiar with AS axles, since I've never worked on them. The principle of how the axles work is the same, but mounting is different. All the torsion axles that I have used don't have shocks, but I like to try new things. I like the Flexiride axles because you can get them custom made with a lot less hassle than other manufacturers. When buying these custom made axles, the measurements that they are concerned with is the outside dimension of the frame (this sets the mount location), the hub face to face dimension , and the angle of the torsion arm. The nice part about the Flexiride axles is that the angle can be changed by just removing one large bolt, pulling the torsion arm off the splines and relocating it.
Keep in mind, from what I notice the AS frames use a vertical mount instead of the horizontal mount that is bolted or welded to the bottom of the frame. For those who are interested, there is another issue to welding the mounts on a torsion axle, to the frame. They only get welded in the same basic location as to where the bolt holes are. (not in the holes) They don't get welded across the entire mount. The reason for this is to allow for the axle to flex with the weight.

[saburkha]

I think the problem with Flexiride axles is the length of the torsion arm. They are only 4" long. So you'd have to move your axles back about 3 inches or your tires would be moved forward in relation to the wheel well. At least this was the case with the 3500# axles.

[Hummer]

http://l.b5z.net/i/u/6149609/f/Torfl...ation_4-04.pdf

Open the above Dexter site and you will start to see axles rated for different weight ranges and scroll down till you see "BRACKET DIMENSIONS" and look at dimension "C"
and you will see the No 8 bracket is 8 inches C-C for the side mounting holes which is how they mount on a 76 31ft. Sovereign.

Keep on scrolling down and you will see #9 and #10 "Bracket Dimensions" are the same spacing and these go up to 3500 lbs weight.

Next you will see Bracket Dimensions #11 and the C dimension is 9.50 and this range is 4000 to 6000 lbs. Same spacing for #12 and #12V brackets and now you are up to 7200 lbs.

Bracket 13 gets you into 8000 lb range which is 10.56 C-C spacing which is what I have on my utility trailer.

I agree elongating one hole would be acceptable and the rear would be my choice to elongate.

I am satisfied my hole locations are on the money as I have not rotated my wheels in over 5000 miles of actual trailer towing and if I didn't have the wheels placed so I knew which was front or back I could not visibly tell a difference as there appears to be equal wear on all of them and in sharp turns the front tires get a side drag.

Then again I am not running AS wheels and original tires but 225X75X16 10 ply light truck tires with 80 lbs in them and 3040 lb steel rims. For kicks when I go to remount them I will check tread depth with my digital caliper and see if there is a difference.

On the original AS wheels in a tight turn on a black top lot I could hear the front tires protesting and see the scuff marks on them.

The Dexter data shows how much movement is experienced as they rotate as well and it would appear the vertical movement is about 5.85 to 6" with full load depending on the down angle.

What I have not been able to determine is if in the first 22.5 deg of deflection does the vertical movement correlate evenly throughout the range. For instance if you have a 6000 lb rated axle and apply 6000 lbs it should move about 6" vertical. It would be nice to know if the 6000 lb axle only deflects 2" with 2000 lbs, 3" with 3000 and 4" with 4000 lb load.

I guess I need to measure my 8000 axle utility trailer before and after I offload my tractor when I go pick it up. The tractor is 3000 lbs and trailer is about 1100 lbs.(frame/body weight) Obviously it goes down some when tractor is on board but it is not real visible and the ride is great with no shocks. Of course empty it will tend to bounce around but with 1/2 the axle rated load on it it is a very nice ride.

I detect no bounce and it recovers quickly from bumps with tractor loaded. It appears to deflect maybe 1 1/2" down on bump, comes up and on second downward movement maybe 1/2" and then nothing visible in mirrors?????

Empty on hitting a good bump it there is definite visible movement than can be felt in tow vehicle giving a rougher ride as the tongue weight changes. I estimate the tongue weight to be about 200 lbs as I can just pick it up and place it on hitch ball myself.

I will make sure to re-torque the 5/8" mounting bolts down well and will also apply Loctite 202 to the threads for extra security. By the way does anyone know what the torque load is supposed to be on these? I have a 1/2" drive Snap On Torqueometer so I can do it by the book if someone knows for sure.

[Ganglin]

see page 14 of their Applications Manual:

[Lance M]

It depends on what type of 5/8 bolts and nuts you use. A 5/8-18 plated grade 8 bolt standard torque is 180ft/lb. 5/8-11 plated grade 8 is 159.

Tightening Torque Guide

[Frank's Trailer Works]

It took you longer to write about it than it would have taken to zap two elongated holes with a step bit. Just saying It is really easy and makes no loss of integrity. The frame actually sits on top of the bracket, so the bolt is just causing the bracket to not fall out on an extreme bump. Just zap the new holes and drink a second beer as Andy suggested...

[M2HB]

Originally Posted by saburkha

I think the problem with Flexiride axles is the length of the torsion arm. They are only 4" long. So you'd have to move your axles back about 3 inches or your tires would be moved forward in relation to the wheel well. At least this was the case with the 3500# axles.

You are right. The arms on the Flexiride are 4.5" long, center to center.
http://www.ucfamerica.com/FlexirideT...ll%20Sizes.jpg

They do have two different mounting brackets. The hole centers are 8" on the lighter axles and 9" centers on the larger axles. If they don't match an AS trailer, it isn't worth trying to make them work. The reason I use them almost exclusively, when I'm building trailers with rubber torsion axles, is because they are the most adaptable axle out there, that I know of. It is easier to get several builders to make the Flexiride axle components with a much faster turn around time than you get from the other major manufacturers.