Upgrading Axels, Wheels, Suspension & tires

[Big-Foot]

Hi gang,
Well I've read until I was cross-eyed many nights here and still have a bunch of questions that I have not been successful in answering via the search..

We're looking at an apparent orphan fifth wheel toyhauler (yes, I have been to the toyhauler section - but this is relevant to all fifth wheels - please bear with me..)... It's a triple axle mid-2000 McKenzie Dune Chaser.

The place that has it tells me that it has 5050# axels (yes, the numbers are right) and 225/75R15 Load Range D tires.

I like the rig itself and I am told that McKenzie made quality units (would like to hear your take on that) but I am suspect of the Axel and tire loading and would like to figure out what my alternatives are with this.

Upgrading Axles to 6-7,000#
Upgrading springs to match axel capacity (if necessary)
Upgrading from 15" to 16" wheels and tires

There appears to be enough room between the tires to support tires that were 1" to 1-1/2" larger in diameter and still have a couple inches to spare. The bodywork on the coach also looks to have sufficient clearance.

I've only found 1 15" load range E tire out there that is the same size as the original and it has some pretty bad reviews as being a member of the China-Tire bomb family..

I'm not looking to carry more weight than the factory rated maximums, but I am looking for a wider comfort zone between that maximum capacity and the rated capacity of the axles and tires..

I am an accomplished fabricator and have my own welders and machine-shop tools, so doing the work to install is sweat only on my brow. As you can probably guess, I am biased toward the "overkill" side..

Has anyone done an upgrade such as this?
Any help and pointers are appreciated..

Thank you...

[Kurmudgeon]

Never heard of McKenzie trailers, so I can't comment on that. But I am a big fan of 16 inch tires. You will have a whole lot more choices in size and load range in 16s. Even if you're using the heaviest duty 15, you may have trouble finding a replacement on short notice.

When it comes to overkill, you and I are in the same club. I have 17 trailers of various types and sizes, and I spend a lot of time towing. I always use tires that are rated significantly above what they will be carrying. I've been told more than once that I don't NEED such a heavy tire. Well, I have NEVER had a tire failure on the road.

The only tire failure I've ever had was a U.S. made Goodyear Marathon that literally came apart while the trailer was parked. It hadn't moved in at least 6 months. So much for the highly rated GY Marathons.

[Gordon Dewald]

Dont overdo the springs too much. Even with a triple axle the back end of the trailer will be very rough and will fling your toys around. I was told to keep the axles and springs near the maximum load you are expecting to carry otherwise it will be more likely to bounce. Best thing is to replace the springs with torsion axles if you can. They ride way smoother.

[wingnut60]

15k available axle rating may be plenty--the axles only see the actual weight less the pin weight. You definitely need to upsize to 16" tires/wheels.
What is the GVWR on the trailer?
Joe

[Big-Foot]

Originally Posted by Kurmudgeon

Never heard of McKenzie trailers, so I can't comment on that. But I am a big fan of 16 inch tires. You will have a whole lot more choices in size and load range in 16s. Even if you're using the heaviest duty 15, you may have trouble finding a replacement on short notice.

When it comes to overkill, you and I are in the same club. I have 17 trailers of various types and sizes, and I spend a lot of time towing. I always use tires that are rated significantly above what they will be carrying. I've been told more than once that I don't NEED such a heavy tire. Well, I have NEVER had a tire failure on the road.

The only tire failure I've ever had was a U.S. made Goodyear Marathon that literally came apart while the trailer was parked. It hadn't moved in at least 6 months. So much for the highly rated GY Marathons.

Here's the last Goodyear Marathon that went on me... Luckily it did not blow while I reached in with a valve core remover.. I have more pictures than this, but you get the idea.. BTW, these tires were only about 6 months old..

Originally Posted by Gordon Dewald

Dont overdo the springs too much. Even with a triple axle the back end of the trailer will be very rough and will fling your toys around. I was told to keep the axles and springs near the maximum load you are expecting to carry otherwise it will be more likely to bounce. Best thing is to replace the springs with torsion axles if you can. They ride way smoother.

Hello again Gordon...
I like torsion axles too, but to replace leaf springs with them, it's going to take a fair amount of structural work as the entire load of a torsion axle is located all within about 10" of frame where the torsion tube bolts into the frame. Plus, the trailer would sit much lower unless I welded up a dropped carriage to bolt the axles to.



What about wheels? Aluminum vs. steel certainly the alloys look better, but at a substantial price delta. The steel wheels I have seen have relatively flat disc centers. Would there be any concern about side loading and these wheels not being up to the task?

Tires.. So I'm pretty certain that I won't be using ST's but LT's..

Is there any chart that will get me tires that are maybe 1 to 1-1/2" larger in diameter than ST225/75R15?

Would love to hear from folks that have already done this themselves..

Thanks

[Big-Foot]

Originally Posted by wingnut60

15k available axle rating may be plenty--the axles only see the actual weight less the pin weight. You definitely need to upsize to 16" tires/wheels.
What is the GVWR on the trailer?
Joe

Hi Joe,
This is what I have on it:
According to the advertised weights on this rig, it can have a GVWR of 16,950 and 2,910 on the hitch.
This leaves 14,040 on the tires.

[Kurmudgeon]

Originally Posted by Big-Foot

Is there any chart that will get me tires that are maybe 1 to 1-1/2" larger in diameter than ST225/75R15?

This should tell you what you want to know. A 225/75R16 would give you an inch.

http://www.tirerack.com/tires/tirete....jsp?techid=53






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[Big-Foot]

Originally Posted by Kurmudgeon

This should tell you what you want to know. A 225/75R16 would give you an inch.

http://www.tirerack.com/tires/tirete....jsp?techid=53
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*PERFECT*

Thanks Jim!