Upsizing axles...

[JRTJH]

I agree, the scale is the only objective way to know what the trailer weighs. Unfortunately, the CAT scale capabilities do not allow for individual wheel weights, the best you can get is individual axle weights and that's a "tricky proposition" because you have to park the trailer with one axle on each scale pad. With your spread axle configuration, it's easier to do, but without a spotter standing between the scale pads, it's "hit and miss at best"... DO NOT BACK UP ON A CAT SCALE !!!!! The weighmaster will definitely inform you that it's a violation of their rules !!! Actually, what it does, as I understand it, is interfere with the reliability of the scale settings and mess up the calibration.

The best way to determine if you have a "flat spring" is to actually measure the arch in the springs.. Do that by crawling under the trailer, tie a string between the shackle bolts (that hold the spring to the shackle and the spring to the hanger) then use a ruler to measure the distance from the spring to the top of the axle beam. You won't have "identical measurements" on all 4 springs. The weight differences from wheel to wheel will cause the springs to carry different amounts and bend differently, but you can use the measurement to determine if you have "one spring that is significantly different from the rest".. If so, then I'd be suspicious of issues with that single spring pack.

From the looks of your photos, you do not have the "mono-spring system" on your trailer. That's a "blessing in itself" since that "single leaf spring" has been problematic for a number of people. It's much less reliable than the multi-leaf springs commonly used in heavier trailers.

[jasin1]

Originally Posted by JRTJH

I ran into a "roadblock" at a local RV dealership last fall. I am changing my 5200 pound axles (derated to 4400 pounds) and installing 6000 pound axles. Both have the same size axle beam, same size 15" hubs, same size brakes and use the same size tires and wheels with the same hub 6 lug pattern. That dealer, a Keystone dealership, could not get Dexter axles in a timely manner, so they contacted Keystone to have them ship the axles (which are sitting outside every fifth wheel plant in Goshen)... Keystone refused to ship the axles to an "authorized dealership" for installation on a trailer not designated for that size axles. In other words, the factory would not approve installing upgraded axles on my Cougar model and would not ship the axles to the dealership....

Your trailer, with 3500 pound axles likely has 5 lug 15" wheels. I don't believe that hub configuration is available on the next larger size axle rating, which is the 5200 pound axle.

So, not only might you run into the same resistance from Keystone, you may also have problems trying to upgrade to the larger 5200 pound axle beams unless you also change out your 5 lug hubs, 5 lug wheels as well.

Do some homework, but realize that Keystone is likely going to be the same "roadblock" to your axle upgrade as they were for mine.... So, I ordered my axles from an independent supplier, had them built to my spindle width, spring hanger perch measurements and I'm installing them myself. You may have to find an "independent axle shop" to do the work and it likely won't be associated with any "approved warranty".....

I hope you have better luck than I did, but don't hold your breath.....

ADDED: I don't believe 3500 pound axles are available with 6 lug hubs (so your wheels are 5 lug wheels) and I don't believe 5200 pound axles are available with 5 lug hubs (all of them are 6 lug configuration), so I don't believe your current wheels will fit any "upgraded axle" heavier than your current 3500 pound 5 lug configuration. You're going to be faced with more than an "axle upgrade" since you'll also need new wheels and most installers probably won't install the OEM LRC tires, but will require you to also buy Load Range E tires so the tire capacity matches the axle rating. 5200 pound axle and 2830 pound tire rating (5660 for both tires on the axle beam)

John can you explain the 5200 axles derated to 4400?

I have the 5200 axles on 12390 gvw fifth wheel …I guess I’m the bare minimum also

Could I possibly have 6k axles derated?

[Javi]

The only difference between 5200 lb axles and 6000 lb axles is the bend to correct camber.

[CWtheMan]

RV trailer manufacturer minimum tire requirement: The tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label.

Anything above the GAWR requirements is known as "load capacity reserves".

[jasin1]

Originally Posted by Javi

The only difference between 5200 lb axles and 6000 lb axles is the bend to correct camber.

Ok thanks. I don’t know anything about axle ratings. I appreciate

[jasin1]

Originally Posted by Javi

The only difference between 5200 lb axles and 6000 lb axles is the bend to correct camber.

Originally Posted by CWtheMan

RV trailer manufacturer minimum tire requirement: The tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label.

Anything above the GAWR requirements is known as "load capacity reserves".

Thanks. Will cross the bridge of upsizing axles down the road if I have issues

[JRTJH]

This is the way I understand "how axles are built" so if my "uneducated understanding" is not correct, hopefully someone with more knowledge will also check in:

First, the 3500 pound axle only comes with 5 lug hubs, designed for 14" wheels. It has a 2 3/8" beam diameter and 10" brakes so the 14" wheels will fit on the hub. 14" wheels won't fit on a 5200 or 6000 pound axle because of the 12" hubs/brakes.

The axle beam/spindles on a 5200 pound and a 6000 pound axle both use a 3" axle beam diameter. There is a "HD 3" beam" available that is a thicker wall tube (used on 7K axle beams), but that is not typically used on either the 5200 or 6000 axle beam.

The spindles are the same on both 5200/6000 axle ratings.

The difference comes with the hub configuration (both 6 lug) in how they hubs are machined for the outer bearing races. The 5200 pound hub/spindle use a smaller race ID and smaller outer bearing. The 6000 pound hub/spinndle use a larger race ID and a larger outer bearing. The inner race/bearings are identical on both hubs/spindles.

You can't get 8 lug hubs until you go to the 7000 pound axle or heavier.

Here's the list of 5200 pound bearing/race components followed by the 6000 pound kit components:

5200 Specs:
Double Lip Grease Seal-010-036-00 3.376 O.D 2.250 I.D
Inner Race-25520 3.265 O.D.
Inner Bearing-25580 1.750 I.D.
Outer Race-LM67010 2.328 O.D
Outer Bearing-LM67048 1.250 I.D.


6000 Specs:
Double Lip Grease Seal-010-036-00 3.376 O.D 2.250 I.D
Inner Race-25520 3.265 O.D.
Inner Bearing-25580 1.750 I.D.
Outer Race-15245 2.441 O.D
Outer Bearing-15123 1.250 I.D.

As you can see, the seal and inner bearing/race are the same, but the outer race on the 6000 hub is larger which allows for a larger bearing thickness.

Now, as I understand the "axle math game" that manufacturers play (or use to their advantage) is that starting with the axle, each component moving out must be stronger....

So, you can't put 225 75R15 LRD tires (2540 rating) on a 5200 pound axle. That would be 5080 tire rating which is smaller than the axle 5200 rating...

So, the manufacturers "derate the axle" to allow for lighter tires and include the tongue/pin weight to "offset the GVWR"... It's a "math game" that complies with federal regulations, allowing them to "play the numbers game" and put lighter tires/wheels on heavier axles, so they can get "more capacity but not be required to install heavier tires/wheels, saving money by "derating" a heavier component so they can use lighter accessories...

Where we, the customers, get caught up in the numbers is when we try to improve the weight margins and we find that there's no option to install stronger components on the existing equipment. As an example, you can't find 6 lug hubs for a 3500 pound axle beam with 10" brakes and you can't find 8 lug hubs for a 5200 pound axle beam (the bearings and races won't fit)...

That's how I understand it, that people get "into trouble" trying to add improvements and "overbuild the tires/wheels moving the weakest link higher up the assembly". Sort of like making the axles/tires/wheels "bulletproof" but making the frame subject to twisting which can't be repaired or making the springs/shackles subject to damage from axles that no longer "give before the springs/shackles reach their limit"...

[jasin1]

Thanks for that detailed response John. I appreciate it

[Northofu1]

This is a straightened spring.
The matching spring snapped in half.

[Javi]

Originally Posted by JRTJH

The spindles are the same on both 5200/6000 axle ratings.

The difference comes with the hub configuration (both 6 lug) in how they hubs are machined for the outer bearing races. The 5200 pound hub/spindle use a smaller race ID and smaller outer bearing. The 6000 pound hub/spindle use a larger race ID and a larger outer bearing. The inner race/bearings are identical on both hubs/spindles.

Here's the list of 5200 pound bearing/race components followed by the 6000 pound kit components:

5200 Specs:
Double Lip Grease Seal-010-036-00 3.376 O.D 2.250 I.D
Inner Race-25520 3.265 O.D.
Inner Bearing-25580 1.750 I.D.
Outer Race-LM67010 2.328 O.D
Outer Bearing-LM67048 1.250 I.D.


6000 Specs:
Double Lip Grease Seal-010-036-00 3.376 O.D 2.250 I.D
Inner Race-25520 3.265 O.D.
Inner Bearing-25580 1.750 I.D.
Outer Race-15245 2.441 O.D
Outer Bearing-15123 1.250 I.D.

As you can see, the seal and inner bearing/race are the same, but the outer race on the 6000 hub is larger which allows for a larger bearing thickness.

Now, as I understand the "axle math game" that manufacturers play (or use to their advantage) is that starting with the axle, each component moving out must be stronger....

That's what I found when I had my 333MKS Cougar so I swapped out the hubs and bearings for a stronger setup..

Note that I wasn't trying to work the system and gain anything but a little piece of mind that my setup was as strong as I could make it with little real effort.

I did basically the same thing this time... when I converted to disc brakes and replaced the bearings and hubs with 8K hardware on the 313RS

[gearhead]

I'm trying to remember when I had 5200# axles under the Montana HC. Don't take this to the bank but I think there was a change on the grease seal. There seemed to be an old and a new spec. Just be aware if you're diving deep into it.

[Canadian Sue]

I have a Passport195RB. In 10 years we have just put our 4th set of tires on it. Recently while in Palm Springs my husband noticed about 8 different cracks in the frame which we then spent a lot of money getting a questionable weld done. Back home our local dealer says the keystone axels are bent and possibly underrated. Thats what has caused the flex and crack in the frame and the inside of our tires to keep wearing. We are replacing with a heavy duty set of axles and a custom weld job. We have other friends with keystones and they have axle and frame issues. Poor product in my opinion. I would definitely recommend new axles that are more heavy duty

[goodellj]

I also had an issue with one of my axles being slightly bent, which put stress on the RL wheel and resulted in excessive wear on that tire and the RR tire. I opted to get both axles replaced and moved up to a heavier axle, same wheels, new heavy duty wet bolts, new equalizer and new springs. All done at my RV repair shop.

I wish now that I had gone to a trailer repair shop or chassis shop. The repair and replacement was done and all seemed good but I was still putting a lot of wear on the RL tire. In the meantime I moved to Texas. I went to a real trailer repair shop and they said one of my springs was bent and the brakes had grease in the drums. So they cleaned out the drums, replaced the springs, did what they could, but said they still didn't think it was 100% right. But I found that it is about 90% better, as measured by the fact that the tires are now wearing normally.

My advice is to take it to a real axle and suspension repair shop. You may have to do some searching. If you need some RV equipment repaired, use the RV shop. Tires should be bought and serviced from a tire shop. And axle repairs should be done by an appropriate shop.

[CWtheMan]

Originally Posted by Canadian Sue

I have a Passport195RB. In 10 years, we have just put our 4th set of tires on it. Recently while in Palm Springs my husband noticed about 8 different cracks in the frame which we then spent a lot of money getting a questionable weld done. Back home our local dealer says the keystone axels are bent and possibly underrated. Thats what has caused the flex and crack in the frame and the inside of our tries to keep wearing. We are replacing with a heavy duty set of axles and a custom weld job. We have other friends with keystones, and they have axle and frame issues. Poor product in my opinion. I would definitely recommend new axles that are more heavy duty

What is an underrated RV trailer axle???

It is actually against the law for RV trailer manufacturers to fit axles that do not meet the minimum safety standards.

[wegone]

Well going on two weeks and no return on calls or email.

I knew the supervisor was away for a few days, he shared that, but the trailer was left in an unresolved status awaiting confirmation from extended warranty input.

I inquired about out-of-pocket upgrades, and nothing replied.

I am leaving early AM to go to another state.

I will share this too, with you all.

It's the first time in 20 years of sobriety I am "stepping out" and have been invited to share with others still under the grip of addictions.

These are really special folks, they are military, law enforcement, fire and rescue first responders, who have helped others in their lives, and now need a little help themselves.

I can listen, share, and give back.

When I return in a week, I will just go get my trailer and take it to an independent repair shop, if not resolved by the dealer.

My wife will be livid.

[Rocketsled]

You’re dealing with other limiting factors than what I encountered (you do NOT want the wheels/lugs to be the weakest link)…In my experience, I came down off a bad road patch inWyoming, going too fast, in the dark. It removed the camber on the back axle (dual Dexter 7000 axles) and caused the tires to wear prematurely, and the change in alignment made the trailer bounce and hop all over the place.

Merril Automotive in Denver has a reputation for being ‘where all the RV dealerships go’ and so I took it there. They have a recipe for fixing these things that include upgraded shackles, wet bolts, CRE-3000 equalizers and adding an extra spring to the spring pack. That plus a new axle ran a little over $3k.

A call to Dexter and they said the extra springs would not invalidate the geometry.

The end result was a trailer that’s massively improved, though it rides better when it’s loaded down…it’s a little hoppy when taking it to storage with everything out of it for the winter. Put some kayaks in back and fill the fresh tank and it’s a great towing experience.

I guess what I’m trying to say is: It’s entirely possible the axles are undersized for the load your applying to it, and it’s entirely possible for the axle and springs to be overwhelmed during use.

[apachewolf]

Originally Posted by Island Eddie

My trailer has been sitting 3 weeks at CW regarding my axles.
Last I heard was that it needed new axles and other stuff.

Sorry, don't mean to be vague, the conversation was hurried, and answers were not readily available from the tech, I was talking to a supervisor, who was looking into the matter, and our extended warranty, etc.

It's been frustrating to say the least.

My gut feeling is I think best case scenario is they replace it, and I am thinking I'll be saddled again with the same minimal axles, that failed already.

My questions guys is should I just go get my trailer and take it to a private trailer repair shop, and have a better axle installed?

I have 3500's on there now, and that just seems to be too small, if you tally everything up, and take into account the bumping strain roads can have by adding more stress.

This is my trailer, and the data, etc.

https://www.rvusa.com/rv-guide/2019-...5rbiwe-tr38196

I have thought about going a little smaller, but we love this floor plan and opposing slides, it really gives us room, and overall, we want to keep it.

Since I will be paying for it out of my pocket, what might I expect to pay, anybody have any idea?

I need to decide this week, we have half a dozen trips already booked.


THANKS guys

Years ago I had a LANCE trailer that also had axle problems. I got the axles shipped to a local trailer store and they installed them for me. Cost was about $ 700.00 axles included. Took a few hours to do it and I was very happy with it.

Happy camping.

[JRTJH]

Originally Posted by Canadian Sue

I have a Passport195RB. In 10 years we have just put our 4th set of tires on it. Recently while in Palm Springs my husband noticed about 8 different cracks in the frame which we then spent a lot of money getting a questionable weld done. Back home our local dealer says the keystone axels are bent and possibly underrated. Thats what has caused the flex and crack in the frame and the inside of our tires to keep wearing. We are replacing with a heavy duty set of axles and a custom weld job. We have other friends with keystones and they have axle and frame issues. Poor product in my opinion. I would definitely recommend new axles that are more heavy duty

Obviously I'm not there and have not seen your trailer frame or your axle/tire issues, so this is a "generalized comment" not a "don't believe your dealer" comment.....

I don't see how it's possible for a 'too small axle" to induce frame flex in a trailer. There's something else going on with your frame. If you "think about it logically" the springs induce "flex in the suspension" and regardless of the size of the axles, there is going to be "flex/movement" from the axles and springs. Your trailer is built on a BAL NOCO "huck type frame"... It is not a welded frame and is designed to use "thinner steel, state of the art fasteners and engineering trickery" (bends and angles) to create a lighter frame for ultra-lite trailers. It's the "huck fasteners" and the "frame material" that are inducing the flexing and metal fatigue in your frame, not the "too small axles"...

Granted, the axles are "minimally adequate" for your trailer weight and ought to be upgraded to larger axles to prevent the "loss of camber that is causing your tire wear issues"...

BUT: The axles are not what's inducing frame flex in your frame "main beam rails"....

[sourdough]

Piggybacking on what John said; we've seen several instances of the Norco huck bolt frames cracking on this forum and I'm sure there are others on other forums. They are not robust. One of the issues very well may be loading. Have you scaled the trailer, compared axle to axle and better yet, tire to tire (if you can find a place to do that). With those lightweight frames and then penetrated by those bolts (making it weaker IMO) I would think any hint of getting overweight, or taking rough roads with the trailer loaded, would flex the heck out of the frame and lead to cracks.

As far as the axles I figure they aren't "underrated" as in illegal but heavier ones would benefit you. Most of the manufacturers use a range of RV models on a particular rated axle. If you own one of the RVs on the lighter end of the scale you will probably have more than enough axle. If you own an RV that is at the top of the weight range they will use with that axle you are then probably on the edge.

[Jerry S]

Originally Posted by Island Eddie

Not a good picture, and the ground was a little uneven, but I took this shot under the trailer after a guy first called my attention to the issue while towing to the campground.

Does that leaf spring look flat?

If all the weight is on the axles those leaf springs are not even close to flat.