Thinking out load

[laserjock]

Thinking out loud

Thinking out loud not load...


So, I tripped over my dually adapters yesterday while I was cleaning up around the blast cabinet and I started thinking. Wouldn't it be nice to be able to bolt on duallies when I was going on a road trip. You get the benefit of the extra stability. Yeah, I know the argument about putting more strain on the bearings but, it's probably not going to tow really heavy. If I run stock 215 tires on the dually rims that would bump my gear ratio down a bit. Haven't done the math but with the 3.55's, that might be a bonus. I could pick up a set of fender flares and make myself a set of fenders to pin on in place of the flare. I think there would be plenty of room with the shorter tires that I don't think I would have to cut the fenders. A set of highway tires on the dually rims wouldn't break the bank. I'd have a little rougher tire for normal use.

So what do you think? Is it worth the effort if I were going on a cross country road trip with the camper or car hauler to bolt the duallies on?

 

[Waystro]

Sounds kinda dangerous to me but what do I know. Anything can be done but is it safe probably not. I wouldn't want to share the road with the setup your thinking about especially towing a camper.No Flame Just My 2 cents.

 

[IDIoit]

i dont know enough about the adapters,
if you didnt have the correct fenders, i would be steering clear of "this guy"
i know, 10 years ago i bought a dualie with SRW's on the back,
i wondered why everyone would get out of my way

thankfully i only drove it a week until my 29 x 18 tires came in!

on another note. im in the planning stages of putting my 01 F250 on a F350 dualie frame.
correct fenders are a must.
however mine will be kinda custom.... the front half of the fender will be bolted to the rear door

 

[laserjock]

They are the arrowcraft adapters so really no safety issues with them. If I were going to do this, I'd build a set of steel dually fenders that would bolt on in place of the fender flares. I'd just use the flare as a pattern so the same holes would be used. Ron (Dsl dog catcher or treat depending on what version of his user name is up) I believe has been running these for quite a while I think.

Just kicking things around at this point. I've got work to do on the bed anyway so now would be the time.

 

[79jasper]

I think it's diesel dog treat now. Lol


Sent from my SAMSUNG-SM-G890A using Tapatalk

 

[Thewespaul]

If you wanted a more comfortable pulling experience I would consider the F450 chassis swap in my sig. truck pulls like a dream and I'm not going through ball joints on my rough driveway

We have a 2003 and a half 6.0 (I don't say that with any pride) that is a dually but I would prefer to pull with my truck any day, doesn't walk on the road and a lot less of the "white knuckle" effect

 

[fsmyth]

Well, I wouldn't be afraid to drive beside him. Probably prefer it, actually.
Lose a tire and keep going.
Would not have any qualms about adding the 2cd set of tires to ANY decent
floating rear.

 

[catbird7]

Laser, I've actually consider the same thing you're suggesting. It makes perfect sense to me. Towing or hauling heavy with and without dual rear is night & day however you will pay the price at the pump. DRW will have a slight negative impact on MPG. I put DRW on my 74 highboy then built a dump /flatbed for it. Arrowcraft adapters on the front only. It's very stable when hauling heavy (up to 2tons in the bed). This was built in 1999, hauled many many loads and I've never had a problem. Having the ability to convert from single to dual rear would be nice when it comes time to haul.

 

[riotwarrior]

As the adapters do not increase capapcjty I feel if you add them and stay within limitz the added safety of duals and the ztability it provides would be great.

 

[jaluhn83]

Question I have is how much of the added stability of a dually is from simply having 4 rear tires and how much is from the stiffer springs? Adding a pair of tires will make the wheelbase wider, but woln't change anything else - might help a bit but it's more of a band aid fix than anything else, and I'm not sure it would make enough difference to be worth much effort.

The issue with bearing load isn't from the drive torque, ie how much you're towing, it's from the vertical load on the rear axle - towing heavy or not, if you have enough weight to be needing the dual you have enough to worried about bearings. The concern is that the extra length of the tire sticking out put a significant lever arm for the load on that tire, which is taken through the bearings - in other words having the same load on the bolt on dually setup means the wheel bearings are probably under something like 50% greater load than doing the same thing with a single tire. (even if the load is evenly distributed over both tires) A true dually sets the hub more or less centered over both tires, so they balance each other and it only take the vertical load. (roughly speaking)

 

[freebird01]

the adapters are designed for the loads... i see no issue with using them...or with your logic...

but to me personally i would pick either or and not both. seems like a major pain in the male member to have to go through all that work before a roadtrip only to do it again later. my CCLB 4x4 dually gets around 12-13mpg on the highway... my ext cab f250 4x4 LB got around 16-17. the F250 handled all my hauling needs..the crew cab is just more convenient for family.

 

[laserjock]

As the adapters do not increase capapcjty I feel if you add them and stay within limitz the added safety of duals and the ztability it provides would be great.

This was exactly my thinking. Not looking to triple my load or anything, just thinking out loud about how to handle the "acceptable" load better/safer.


So here are my thoughts. Most of the time I probably wouldn't bother. I am strongly considering a 5'er next year though and it seems like although, the pin weight would be well under the carrying capacity, the duals would provide more stability albeit as pointed out with additional load on the bearings. As it is, the axle under the truck has a leaky seal so I may be replacing bearings all around anyway.

The other added advantage like I mentioned is going down in tire size to run the duals would bring my gear ratio down a bit. Right now I've got 3.55's and I have 285 70 16's to run on the truck which work out to stock height down to 2 decimal places. Dropping to the factory size dual which is 215 85 16 works out to be about 4.3% difference so the effective gear ratio would also drop to about 3.69 which is close to the magic 3.73 we talk about as being a pretty good compromise. This of course assumes I did all my math right... a hefty assumption... but it feels right.

As for having to bolt them on and off, I can say I don't think it would be much harder than rotating tires. For the once or twice a year (maybe) I don't think that's a concern. I want to get to the point of taking some long road trips with the camper in tow so I'd trade some stability and handling for a couple hours swapping tires.

Anyway, just mental ************ right now. Feel free to continue the discussion. I'll update when I get there.


Edit: The other possibility this opens up is letting me run Load range D tires with the SRW for a better ride of course while staying within the limits of the weight ratings. But realistically the load range D tires go to like 2600lb each so that's probably 2 ton in the bed. I don't think I'll be doing that too often.

 

[riotwarrior]

Loqd on axle bearjng remains pretty constant due to DUAL tyres...yes if you ran ONLY the outer dual you would see a significant change in how bearing load takes place due to leaverage on hub. However having the INNER tyre in place ounters the outter leverage to balance the laod more or less across the bearings.

The REAL dually axle might have a wider bearing placemwnt I don know for sure inner to outter vs srw axke but that difference will not be huge.

If the OP stays within the confines of the srw weight capacity he has the load spread out over 4 tyres thus a greater balance due to width for cornering.

Maybe I am mastermentalbating too kuch too

 

[laserjock]

The strain on the bearings is a real thing but realistically we are talking about a 2.5" spacer I think (have to measure). I can do the math on it but, I suspect it's actually actually not a huge percent difference. All that being said, though, I don't really think I'd be pushing the limits of axle.

To me it's about being smart and not push the limits. I want reliability. I want to better utilize what I have not abuse what I have.

 

[jaluhn83]

My gut feeling is it will be a significant difference.

The load will be distributed across both tires since they will both flex until it's more or less even. This load will essentially act through the center of the tire(s) - in the SRW version this center is roughly where the center section of the rim is, and hence slightly outboard of the inner bearing, so the inner bearing sees most of the load and the outer sees a smaller amount.

With a dual setup this center shifts to between the 2 tires. On a DRW axle, this is again just outboard of the larger (inner) bearing. With a spacer on a SRW axle however, this center is now right around the outer bearing which means that the majority of the load now acts on this bearing. Normally this bearing would see ~25% (guess) of the load.... now it's seeing close to 100% or possibly even more (if the center of the wheel assembly is outboard of the outer bearing it will have leverage and apply more than 100% to that outer bearing)

Now, chances are the bearings will still live ok, but I would expect a significant reduction in the life of the outer bearing possibly with catastrophic consequences if it's not caught soon enough.

Yes, it's only a few inches, but the bearings are only a few inches apart to begin with - doesn't take much to shift the bearing loads around.