6K Axle Tube Strength verses Tube Thickness

[powerscol]

I am in the process of special ordering replacement axles for my Reflection 220RK. Stock axles are 3" LW tube 4400 lb axles. Tube thickness is 0.16" I bent both on my Alaska trip - trailer was not overloaded, just very rough roads.

So I am upgrading to 6K axles and hubs. However most of the 6K axles on our GD rigs have the same 3" LW tube be leave it or not. The difference is in the spindle and hub and larger brakes

Axle tube wall thickness information is hard to track down. I have talked to several Dexter distributors (from thier web page https://www.dexteraxle.com/)

I can get a custom 6K axle with a 3" HW 0.25" tube, ($965 each) but that just gets me about 10% more strength I think. Please correct me if I am wrong.

Or I can order a custom 6K axle with an optional 3.5" HW 0.5" tube ($1836 each), but that gets me into ordering special tie plates and U bolts for a 1.75" wide spring pack. Not a big issue. This is what I would like to do, but pricy.

Axles come fully assembled without springs.

Speaking of springs I am going with Dexter/Rockwell USA made with USA/Canadian steel - part number 4362-33 6 leaf 3200 lb, to help gain some lift - I need about 1" overall to get thing perfect with the truck. The initial compression rate is the same as the 4 leaf springs I have, so ride difference should be minimal.

Now the above prices are direct from Dexter - excluding shipping. I was told I could save going through an authorized retailer, but there are none in my immediate area. So if you have ordered Dexter axles and springs before, any information on who to shop with would be very helpful.

So any thoughts on my choices or places too order from?

Thanks

[Hoopy Frood]

I guess a lot of it may depend on whether you have another trip to Alaska on the horizon. The roads may be bad in places in the lower 48, but one doesn't hear frequently about bent axles.

[dryfly]

I cannot speak to axles or springs, but I found prices direct from Dexter on brake assemblies and hubs were more expensive than many internet sources. When recently replacing these parts I found using specific Dexter part numbers and searching the internet will provide many sources with different pricing. Of course with axles shipping costs will be an issue and must be considered, but I would definitely do some shopping.

[Pap and Mimi]

I don't see a 220RK in the GD line-up, but here are some numbers for a 226RK, which is listed as having 9,995 GVWR (I will round off to 10,000) and a calculated pin weight of .2 x GVWR or 2,000.
10,000 GVWR minus 2,000 pin weight leaves 8,000 to be supported by the axles.

1. Stock 4.4k axles have 8,800 capacity minus 8,000 load leaves 800 "safety margin" which isn't very much and why the "very rough roads" gave you the need to be shopping for axles.
2. The "standard" 6K axles have 12,000 capacity minus the 8,000 load leaves 4,000 "safety margin" which is a huge improvement.

The thicker wall tubes would definitely be stronger, but it doesn't look like they would be necessary as you are increasing your '"safety margin" by a factor of 4 (3200 lbs) with the standard 6K.

[geotex1]

No space to make this a structural engineering review, but D44 and D60 light duty would be the same axle tube. It's the D60 HDs that are run on the heavier GD's, discernable by the different hub bolt pattern. The HD also has forged spindles.

If you "upgrade" to D60 light duty to preserve your bolt pattern It's no upgrade at all if your axle failure from Alaska was loss of the camber of the axle. If you bent at the spindles, then you're upgrading. Stiffness of the springs have huge bearing here as static load capacities are nice, but are only indicators of stiffness to guesstimate performance under dynamic (impact for Alaskan roads) loading.

Direct from Dexter is too expensive. It's steeply more cost effective from an outfit that deals with them. Call local trailer shops of any type. Remember, small guys deal with distributors.

[Najataagihe]

I just did this with my 2950RL with the 4400# axles, for the same reasons.

I called Dexter and they fixed me up with 5200# THICK TUBE axles.

This serves two purposes.

One, it allows you to use the same brakes and hubs.

Two, it is far easier to get parts for 5200# axles than it is for 6000# axles.

Since either higher-rated axle is an improvement, the ready availability of parts becomes a consideration.


According to Dexter, those tubes come in three thicknesses.

Manufacturers use the thinnest tubes that will do the job.


Supposedly, the engineers design for an average 200 mile round trip and 5-6000 miles over the life of a camper.

Birmingham to Seattle, once, exceeded those design parameters by several thousand miles in one trip, much less the subsequent trips.


Bent the stock axles TWICE, before replacing them.

The view from the back of the trailer was like looking at a post-1968 VW Beetle!


Total of 26,000 miles with NO bent axles, after replacement.


Dexter had to build them from scratch, but had them at my repair shop in less than two weeks.

Outstanding service!

[powerscol]

I talked with Dexter Warranty today and found out there is a third option - a 5/16" HW 3" tube. So folks know the 3" Dexter tubes are available in three wall thickness LW - 0.16 MW 0.25 (std) and HW 5/16". The also gave me a number to order from - one plant that does all of thier warranty replacements in Missouri. Ill be calling tomorrow Meanwhile I have check around locally - not much response from anyone. However Spring Works in CA did respond - anyone work with them?
Thanks

[markandkim]

Most of the time it is a bent spindle not the tube.

[powerscol]

Most of the time it is a bent spindle not the tube.

Not in my case The Light Wall tube is only 0.16 thick and I had it inspected by a good frame and axle shop. The tubes bent on both axles. If you look at the photo you can see the camber is gone, especially outboard of the last U-bolt.

[powerscol]

An update. I went with the 3.5" tube 0.5 thick wall axle with the 6K hub fixings to fit my 6 on 5.5 rims Springs are the matching 3500lb. The initial compression rate is the same as the springs I have.