We are ready to attach our treads to AndyMark Performance wheels…what is the very best way to attach them so they will hold up to the rigors of competition?
Also, is it normal that our treads are about 3/4 inch shorter than the circumference of the wheels?
We use thick, slow cure, cyano glue. Surface preparation is the key.
We carefully sand the back of the tread material (using a belt sander) to get just into the black rubber surface below the first cloth layer that does not glue well at all. We then sand blast the aluminum surface and scrub all the dust off with soap, water, and a stiff brush. The final cleaning of both the tread material and the aluminum is done with a clean rag with some MEK on it.
We then slather both the tread and the rim with the slow cure cyano glue using an acid brush, and clamp the tread on the wheel with the moral equivalent of a giant hose clamp actuated with a pair of long jaw vice grips. Needle nose vice grips can be used to pin down any spots that lift under the clamp. The glue is then zip kicked by applying the zip kicker with an acid brush.
After zip kicking, the glue will cure to the point of being able to take the clamp off in about 30 minutes or so. The glue fumes are quite irritating, doing this outside or under a fume hood is a good idea.
Glued properly with good surface prep, the black rubber will be left on the wheel if you peel the tread off, and you really can’t do much better than that. If the tread comes off and looks like it was sprayed with aluminum paint, you did not get the wheel scrubbed well enough. If the glue separates from the aluminum without leaving black rubber on the wheel, you did not get the surface clean enough. Rivets are optional. Use them if you think they will help.
I would like to note that cyano glue sticks to the black polycarbonate the kit wheels are made of really well.
Ideally, your treads should be cut so that the ends of the tread just meet when they are clamped on the wheel, without puckering. If your treads do not do that, you risk peeling getting started at the gap between the ends of the tread. If the treads that come from Andy Mark are too short, you can buy wedgetop belting from McMaster and cut your own to fit properly.
Have fun,
Eugene
we have been using two-part epoxy and hose clamps. let it cure overnight. it has been working fine with no problems.
Why not follow AndyMark’s method of using aluminum rivets for the tread? Keep in mind that all of the previously mentioned methods are somewhat permanent.
Another permanent solution is to use a SEM product. plastic bumper repair material works well, as well as the quick set 50.
We all remember how fun that was. Our treads started falling off in the semifinals at Davis, and we were pretty much useless for the next three elimination rounds.
If you choose to use rivits, I would suggest that you drill a few holes in additinon to the ones that come on the wheels so that you can stick in more rivets. This seemed to do a good job of fixing our tread loss problems.
Our treads are about 1/8 too short to wrap completely around the wheels.
Is this normal?
Depends on the tread, we used the big wedge in previous years. this year, idk. But we lathed the wheels 1/4" and then took screws and drove them in, deep. They dont come out, and the screws dont touch the ground if screwed in correctly. Now sometimes, depending on the wheel, the screw will come out the plastic, just file the end of the screw so it wont hurt anyone when touching, you know like almost everything on your robots. lol.
We’ve used rivets with success, but they are kind of a pain in the $@#$@#$@#; so far, however, they’ve been the best option we’ve found.
IFI tread shipped with extra-wide-head rivets this year, so that should alleviate some of the tread tearing for many teams.
-Dillon
EDIT: Removed incorrect statement regarding glue/epoxy. I was misinformed, taking another team-member at their word regarding illegality and not verifying it in the rules. My apologies to anyone who took my statement as fact!
Oh really? Would you mind citing that rule?
Read <R35> thoroughly. Notice that it says “Adhesive backed tapes are NOT allowed except as follows:…” Glue is not an adhesive backed tape.
[quote=<R35>]Adhesive backed tapes are NOT allowed except as follows:
?? Velcro tape, any hook and loop tape or double-sided sticky foam may be used for attaching
components to the ROBOT.
?? Reflective tape may be used with optical sensors in small amounts.
?? Adhesive backed tape and labels may be used for labeling purposes on wires, cables,
pneumatic lines, etc.
?? Electrical tape may be used as an electrical insulator.
[/quote]
Glues are DEFINITELY legal. Last year we used epoxy, JB weld, etc.
We lost our IFI treads on their traction wheels a bunch of times at the Philly regional last year. We wound up having to drill more holes for rivets to keep the suckers on.
For anyone having trouble cutting the treads in any effective or accurate fashion, a fine blade bandsaw does the trick nicely.