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What material and size axles do you guys use? I've heard of people using carbon threaded axles, titanium axles, stainless steel-what are your opinions on those? I've also seen reports of 1/8" diameter axles bending. Currently using a 1/8" stainless steel axle.

pumptato-cat wrote: ↑December 29th, 2022, 11:47 am What material and size axles do you guys use? I've heard of people using carbon threaded axles, titanium axles, stainless steel-what are your opinions on those? I've also seen reports of 1/8" diameter axles bending. Currently using a 1/8" stainless steel axle.

Hiii
I personally think cf threaded rods are overkill, the mass you lose from that upgrade shouldn't really be a huge help. If you really want to lose weight I'd focus on other parts like chassis I guess :)) Also, they are super expensive :O
Same thing with titanium
1/8" diameter should work if you reinforce it enough around the rod, only reason I'd imagine it would bend would be because of mishandling/braking with a lot of force. If your braking is warping the rod, you should try to slow down the braking !

Hm yeah, I was mostly going for strength increase rather than weight deduction. I used the 1/8", it's holding up okay so far. My chassis weighs around 70-80g so far, so I don't think I need to cut more weight. Thanks!

pumptato-cat wrote: ↑January 24th, 2023, 3:16 pm Hm yeah, I was mostly going for strength increase rather than weight deduction. I used the 1/8", it's holding up okay so far. My chassis weighs around 70-80g so far, so I don't think I need to cut more weight. Thanks!

I'm thinking of replacing our current (steel) axle with a composite threaded rod. I'm deciding between nylon, fiberglass, PVC, and acetal. Does anyone know which one would have the highest stiffness/warp resistance?

I'm back around 2 months later, after lots of testing. My car has a bent front axle and it's so bad you can tell when you rotate it. But then again, the front is quite wide... so 1/8" stainless steel seems to be okay.
Someone correct me if I'm wrong, but in 4 years of building cars, I've never had an issue with a warped axle ASSUMING all 4 wheels touch the ground. Generally, it seems like warped axles should be okay as long as your design is good(mine allows the frame to flex slightly so all 4 wheels touch the ground, no matter how warped the axle is(reasonably)).
I would work on other aspects of your design instead of focusing on axles, because the only issue that a stiff axle seems to help with is the 4 wheels problem. If you're relying on straight axles for good contact between wheels and the ground, it's more of a design flaw than an issue with the material used.
EDIT: I'm rereading this and I've managed to confuse myself with my long ramble so here's my actual answer: bent axles don't really matter as long as your axle isn't TOO long. I don't think axle material matters much, I used this crusty 2-year-old 1/8" threaded rod(bent. Oops.) and it's working fine!