Snapping off any 3/4" axles???

[madprofessor]

Considering store-bought spindle and bracket setup (from MFG) for scratch-build kart, $23.99 each. Heaviest they carry is 3/4" in 3 lengths, would get the longest (6" axle) and bush it down to minimum I need. Getting bolts and bushings and not having to drill the 4 holes for the bolts sounds good to me.
Question: Anybody ever snap off a 3/4" spindle axle before? This kart will be doing wheelies, and if I have to go homemade for enough over-the-top strength to keep from snapping axles, so be it. Just want to know the normal sizing for strength, if 3/4" is wheelie-strength enough or not.

 

[950speed]

If they are not extra long it should be fine. If it is longer then the leverage and force applied to them coming down would bend or snap it, I would make sure the wheel is as close to the inside as possible so that the force is applied evenly and not way on the outside.

 

[itsid]

well you can buy racing kart spindles
there are 25mm ones available

like p.e.:
https://righettiridolfi.com/en/product/search/spindles/25mm-1/3-kz-107

But really the most important bit is the 'suspension' not the spindle really
a nice tall tyre sidewall (or in fact a coilover)
should keep even a 5/8" spindle alive.

Oh and the SHORTEST spindle is the one you want..
the longer the lever (spindle shaft) the sooner it's going to give on impact.

'sid

 

[madprofessor]

Leverage physics part is easy......

Appreciate the input. The fancy racing spindles are beyond me, not even comfortable with "store-boughts" at $24 each, strains the "scratch-built" phrasing.
The leverage is just physics, longer the lever, less force to snap it. Just unknown what 6" steel split rim with 3/4" bearing and 4.10x3.50x6 tire will look like, ie; distance from inside to outside of bearing (minimum axle length required), and how far out I'll want the inside of the wheel to be from the spindle steering arm (clearance with very sharp turning radius I'll be building into it). Will be trailing spindles instead of leading though, will help.
Suspension will have a crazy amount of travel in boonies mode, but only about 2" travel in track mode. That's the mode that worries me, big stop in little distance.
Figuring that the max 6" one will allow for scooting wheel in far as final objective allows, and not fall short by a couple threads if it turns out needing more axle than I'm hoping for. Do want to reduce leverage as much as possible by scooting in far as possible, and don't mind sleeving excess with 3/4" I.D. bushing stock out to the axle nut.
Encouraging to hear that even 5/8" can take a good beating if done right. Believe I'll go ahead with the store-bought 3/4", and beef them up with sisters and weld if they make me feel uneasy at first sight of it all.