trying to modify my beach cart; how can I extend/enlarge axle?

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  #1  
Old 07-31-17, 12:00 PM
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trying to modify my beach cart; how can I extend/enlarge axle?

The cart currently has a 5/16" rod as an axle for its ineffective plastic wheels, and I'm looking at some wheels with pneumatic tires that have a 5/8" hub bearing. Wheels are 3-1/2" wide so I'm thinking a 4" long tube/pipe with an OD of 5/8" and an ID of 5/16" on each side would be a start but where does one find such a tube?
 
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Old 07-31-17, 12:03 PM
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A 5/16" rod, even modified by extension, is just too small. Adding an extension will most likely cause it to bend.

It would be better to change the entire axle to what you need.
 
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Old 07-31-17, 12:19 PM
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the 5/16" rod has always supported the load sufficiently, and that won't change. that rod goes through other parts of the cart, and they won't support a 5/8" rod.
 
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Old 07-31-17, 01:20 PM
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Wont find, 5/8 od pipe will have somewhere around a 1/2" id.

Probably going to have to stay with the smaller plastic wheels!
 
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Old 07-31-17, 05:41 PM
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The problem when you extend the axles to put on wider/larger tires is you are also extending the overhung load. So with the same weight in the cart your axle will experience more bending force. The 5/16" is currently working because the wheel is so narrow and close to the frame. If you extend it out it likely will bend.

Going to a 5/8" axle all the way through is the best option. If you can't drill out the holes in the frame then consider attaching the axle to the bottom of the cart frame with U bolts or even hose clamps. To save on weight you can use tubing but it's much more difficult to find but it can be found on Ebay and from industrial steel suppliers.

If you want to try your tubing extension over the axle you can try. Best would be to find .150 wall tubing which would leave the inner diameter slightly larger than 5/16" but that is a very rare material so you'll have a hard time finding any. Unfortunately the closest commonly available tubing size has a .120 wall thickness which will leave a good bit of slop over your 5/16" axles. Solid 5/8" diameter rod will be much cheaper though.
 
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Old 08-01-17, 11:38 AM
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A 5/16" rod, even modified by extension, is just too small. Adding an extension will most likely cause it to bend.
The problem when you extend the axles to put on wider/larger tires is you are also extending the overhung load. So with the same weight in the cart your axle will experience more bending force. The 5/16" is currently working because the wheel is so narrow and close to the frame. If you extend it out it likely will bend.
I'll defer to your knowledge - I did ask for your advice after all - but I fail to see how such a small extension could matter. The current plastic wheels are 2-1/2" wide and the wheels I propose are 3-1/2" wide:

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Wont find, 5/8 od pipe will have somewhere around a 1/2" id.
I found couplings, but they're only an inch long with my OD/ID.

[ATTACH=CONFIG]83719[/ATTACH]

I could put 2 on each side and cheat an extra half inch onto each side but I'd still need a way to keep the wheels on. Perhaps a rivet with a shaft long enough to reach the outer coupling set screw and a head larger than 5/8" that would work like a hubcap!!

[ATTACH=CONFIG]83720[/ATTACH]
 
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Old 08-01-17, 12:55 PM
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Your axle or extension must extend beyond the hub of your wheel. The outer bearing of the wheel rides on the axle so you can't "cheat" it.

If you want extensions seek out a local machine shop or metal fabricator that has a lathe. They could turn a piece of 5/8" material for you and put a 5/16" bore down the center. Don't forget that you'll need some way to hold your extension onto the existing axle so see if they can drill and tap for a couple set screws at one end. And, don't forget that they need to make the extension long enough so it protrudes beyond your wheel. Have them also put in a hole in the outer end for a cotter pin to hold the wheel on the axle extension.

Wheels are commonly available with centered and 2 1/4" offset hubs and the offset style would be best for what you are trying. If you get a centered hub your axle exteion will need to be longer and you'll need a spacer to prevent the wheel from rubbing on your cart.

Or, get a longer piece of 5/16" material and two more wheels like are on your cart now and put two wheels per side. Tandem tires like a truck.
 
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Old 08-01-17, 04:34 PM
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You found a solution, nothing wrong is going to happen!

From the picture I'm not sure what that cart is, is it worth the effort??

Only you can answer that! I get a kick out of fixing items, hate the throw it away mentality today, tell us how it works out!
 
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Old 08-03-17, 01:55 PM
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Wheels are commonly available with centered and 2 1/4" offset hubs and the offset style would be best for what you are trying.
That offset advice made me realize I'm measuring the wheel width wrong! 2-1/4"-2-3/8" is all I need so I don't have to "extend" the axle at all, just find a way to "beef up" that last 2+ inches with something 5/8" OD/ 5/16" ID.....
 
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Old 08-05-17, 07:43 AM
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...currently looking at tube/hose couplers in plastic/nylon. maybe even in 1/4" so I can force it on tightly.
 
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Old 08-13-17, 05:42 AM
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Success!!

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I used spiral cut tubing intended for cable management and feed-through bushings. Test drive at the beach today!
 
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