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Unread 11-01-2016, 10:21
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Nathan Streeter Nathan Streeter is offline
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FRC #1519 (Mechanical MAYHEM)
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Re: Andymark pneumatic wheel diameter?

Quote:
Originally Posted by Kellen Hill View Post
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.
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Student: 2006-2010 (#1519)
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