Which flex wheels have the most traction? How can I test for traction?
I don’t know which has the most traction, but you can easily solve for it by finding the coefficient of friction each wheel has. You can solve for the coefficient of friction by putting weight on the wheel and pull it with the force sensor, the one with the highest amount of force has the highest friction and thus the highest traction
(Edit: make sure the wheel can’t turn, if it can turn you will find the coefficient of friction for the axel and not the wheel)
(Edit2: don’t put so much weight that it starts compressing the wheel, just enough to keep it in the surface)
Check the individual durometers listed on the VEX website
the durometers are 30A, 40A, and 60A. I’m familiar with that but isn’t that more how much the wheel stretches and compresses and the firmness of the wheel? How does that apply to traction
Is there a correlation between firmness and traction?
Perhaps one should test this and record the results in their engineering notebook…
Yes that’s why I asked on how to test, but I’m too stupid to do this -
I believe that if you put the wheel on a surface ( do a vex foam tile on a piece of wood or something) and tilt the surface up, the angle that the wheel starts to slide off is the coefficient of friction between the wheel and the tile. In this case, the one that you have to tilt it up the highest to is the grippiest wheel.
I would do that, but I don’t have access to all of them. I’m going to have my school place an order for these as soon as I find out which have the most traction because I need the most traction to serve my purpose
Out of curiosity, what is your purpose?
making modified traction wheels, I want to see which flex wheels would work best for it
My guess is that 30A would work best for these, as those will squish and compress the most and have the best grip on the foam tiles.
If you need to order some, I’d say you could order all 3 types if your budget etc permits it, but if not just go with 30A. That seems to be what everyone else who has made custom traction wheels has used.
I don’t know which ones are best, but I am using flex wheels for my bot. I used the middle color (b maybe) but the darker grey. The results are very effective, so while I am not sure which ones work the best, I know these do work. If you want to check out how I did it we made a video on it: GOLD! RoboVlog - Turret Intake, Flex Wheel Tire, Dimension Motor - Vex Spin-up Ep10 - YouTube
Here is my work for a similar problem I had in AP Physics I last year. While the problem is different than what you described, the work should be similar to what needs to be done to solve your problem.
If you have access to them, the new V2 traction wheels have a ton of traction both forwards and backwards and sideways. Would definitely recommend over doing custom flex wheel traction tires.
Yeah would probably be the better/easier solution. I did the flex wheel thing because 1) we didn’t have any of those traction wheels on hand and 2) the 4in omnis are slightly bigger than 4in and the flex wheels could stretch out. But yeah if the other ones work then that’s prolly a good solution
While I would agree on this in general circumstances,1) I don’t think they have more traction than flex wheels, and 2) if you make the modified wheels slightly larger than the rest of the wheels (3.35 vs 3.25) they dig into the mat of the field because the weight of the bot pushes it down and if you have the outer wheels be 3.25 and the middle be 3.35 it provides a lot of traction, and lastly 3) the traction wheels have bumps that only makes it so they have contact with the ground 50% of the time (in the words of the great Xenon) and better traction could be provided
Yes there’s a hassle, but I think it’s worth it
this fact is true about the old 3.25" traction wheels, which were pretty bad.
I’ve heard good things about the new traction wheels though, I can’t speak from experience but it sounds like they might be an acceptable alternative to flex wheels. I can’t imagine they are quite as grippy, but if you don’t want to spend a lot of time on custom wheels they might be good enough.
My team got some of the new anti-static traction wheels recently and from the small amount of testing we have done they seem super grippy, as the “tire” bit is the same material as the rollers on the anti-static omni wheels. I can’t vouch for whether they are better then custom traction wheels though, because we don’t have any of those to test against.
@Sylvie I know you have used both custom wheels and this season(so far) are useing the new traction wheels. Whats your take?