Andymark pneumatic wheel diameter?

[Nathan Streeter]

Originally Posted by Kellen Hill

For teams having used pneumatic tires before in a 6wd, what do you typically use as the drop for the center wheels?

I understand you can play around with tire pressures to adjust this as well, but I am curious about the drop that is initially designed in.

We've usually needed a far-bigger drop for Pneumatic tires... the fact that they compress under load and are usually very grippy require it.

Usually rigid-ish wheels need 1/8" of drop or less... expect 1/4" or more for pneumatic tires. Inflation pressure, robot weight, and I suspect 6WD vs 8WD will all impact turning dynamics. Honestly, I wouldn't shy away from 3/8" of drop for pneumatics... I'd prefer to have it turn a little to freely and adjust pressure to minimize than have it hop and draw high current and need to adjust.

As a side-note, also expect shockingly low tire pressure for pneumatic tires... most of them have a huge contact patch (particularly when you have 6 or 8 wheels on the robot) and FRC robots aren't all that heavy for the size of that contact patch. I'd say expect 10-15psi, but I could see the center wheel on a 6WD being a moderate bit higher. When the tire is off the robot it'll feel very soft.

[Monochron]

Originally Posted by Nathan Streeter

We've usually needed a far-bigger drop for Pneumatic tires... the fact that they compress under load and are usually very grippy require it.

Usually rigid-ish wheels need 1/8" of drop or less... expect 1/4" or more for pneumatic tires. Inflation pressure, robot weight, and I suspect 6WD vs 8WD will all impact turning dynamics. Honestly, I wouldn't shy away from 3/8" of drop for pneumatics... I'd prefer to have it turn a little to freely and adjust pressure to minimize than have it hop and draw high current and need to adjust.

Thanks for this info, it's good to hear from someone with experience . Considering that the KOP drivebase kind of locks you in to a 1/8" center drop, do you have any recommendations to mitigate this? I don't really see a way to increase the drop with the holes currently in the side plates, but 1/8" sounds like it would have serious issues turning....

[Peyton Yeung]

Originally Posted by Monochron

Thanks for this info, it's good to hear from someone with experience . Considering that the KOP drivebase kind of locks you in to a 1/8" center drop, do you have any recommendations to mitigate this? I don't really see a way to increase the drop with the holes currently in the side plates, but 1/8" sounds like it would have serious issues turning....

I saw a bot in 2012 using pneumatic wheels with about an 1/8th inch drop and they used duct tape over the front set of wheels to help it turn.

[Mr V]

For the Team [Redacted] Ri3D robot we used the pneumatic wheel kit provided to us by AndyMark and do not have any problems turning. Note however that the robot is very light (sorry haven't weighed it yet) and we assembled it using the belts included in the AM14U3 chassis kit that are for the "square" configuration and did not use the belts that come with the pneumatic wheel kit that are designed for a longer configuration. I believe that is what 'Snow Problem did with their AM14U3 and pneumatic wheel kit.


Unfortunately we don't have any video up at this point of the robot turning. I believe we will have some in our reveal video which should post today.