Gravity Vehicle C

[iwonder]

Hmm... I guess the threadlocker doesn't like whatever plastic it is... just for the bearing though, what's the play between the bearing and the threaded rod? Also, do you have bearings with an extended inner race? It's possible that you could just run two nuts up on either side of the bearing to hold the rod in, thought without a wider inner race it might rub against the rest of the bearing.

[mrsteven]

thread lock just isnt meant for the amount of punishment and side ways torques the wheels see on my car

there is some play, but i glued them in so that there is now NO play. Since its glued in, nuts arent needed

lol, I'm saying these things in current tense but the car is dead, so I guess I should say that the next car will also have these features?

[iwonder]

Good point about the larger amount of torque... Last thought, have you tried putting a roll pin/cotter pin through it? Just another thought, not for the bearing, obviously

[mrsteven]

Good point about the larger amount of torque... Last thought, have you tried putting a roll pin/cotter pin through it? Just another thought, not for the bearing, obviously

good thoughts, i have thought about those and went against it for the sole reason that I know a glue (evidently I didnt pick the right one) will hold, without fail.
When you add pins, with vibrations etc i worried about it being a permanent option

[2346273454]

If you want to understand the factors that will get you to lower friction, Google "ball bearings friction"
Smaller diameter = lower rolling friction.
Especially with the ramp height scoring this year, every little bit of friction reduction pays off big-time.
The Bones skateboard bearings are 8mm i.d.; that's 0.31496 inches. That's a lot bigger than you need.
Also means some sort of sleeving to fit inch-sized axle (e.g. 1/4, 1/8th, etc.).
ABEC ratings do not reflect/correlate to rolling friction.
Also, shielded bearings, like this have slightly higher friction than open ones.
Lubrication actually also increases friction.
We're running 1/8th i.d/1/4 o.d., open- see discussion from last year.

Would a dry, graphite based lubricant still increase friction? I can't imagine why it would.

[Balsa Man]

Theoretically?, yes. As a practical/measurable matter?, probably not, or at least not much.

[_HenryHscioly_]

my ramp is about 48.8cm wide, and my axles stick out of the ramp's vertical plane
my axle is 49.6cm

In your opinion, should i make it shorter?
i have enough extra axle length to shorten it about 1cm...

When i put on the wheels, it is kinda hard to measure how long it is..I myself wasn't sure if it was under 50.cm until i took off the wheels to measure the length.
I dont want to risk get a construction parameter...but i am having a hard time cutting/filing/sanding.
It's 1/4" stainless steel all-thread, i have a saw, i thnk it's meant for metal, but it took me more than half an hour the first time to cut through enough to break of the extra piece.
I also have cold chisels that were really cheap...and I used it with a hammer my dad just bought..and it chipped the hammer head + smushed the axle's thread a bit + dented the chisel

my violin teacher lent me this rotating grinding thingy...really loud
tried it just now, i put a paper towel soaked in water near the end where i was grinding, and i stopped after about 5 seconds cuz it was really loud....
i move the papertowel over, and it sizzled for one second....
measured again; 49.7cm ._.

[mrsteven]

bestbestbestbest way:
Bolt cutters, if you don't have them, someone on your team/technology department at school will, try the autoshop.
Takes less than 5 seconds, super easy. But how you make sure that you can still use the threads is before you cut them, put 2 nuts on the axle. Cut it, then try to twist them off. It will be difficult but when you get them off, it reforms the threads so you can use them again

[olympiaddict]

or if someone you know has a dremel tool (your tech teacher most likely has one...) that's what I would do- very very minimal thread damage (but still use the nuts like mrsteven said), and I would be afraid I'd damage the vehicle using the boltcutters, dremel is very precise. but either way should work.

[mrsteven]

or if someone you know has a dremel tool (your tech teacher most likely has one...) that's what I would do- very very minimal thread damage (but still use the nuts like mrsteven said), and I would be afraid I'd damage the vehicle using the boltcutters, dremel is very precise. but either way should work.

thats good too,
I used bolt cutters without any issue on my car (now 4 times... just about finishing up the second rebuild)