Robochallenge wheels

Hi all,

Im using some brand new robochallenge wheels and when mounted, they are ever so slightly off centre meaning the bot bumps along. I was wondering if anyone had worked out a good way to sand/ grind the bumps out by rotating the wheel so it runs true?

Cheers

Dan

Hi Dan

We have had the same problem with them: http://www.youtube.com/watch?v=UxdVSLEXazg

We did get another one made but it was similarly as wobbly, however we have found that it doesn't affect the drive at all!

I'd imagine that by driving the robot around on a Tarmac floor it should wear the wheels down so they are less off centre. Failing that just get a 3/8" unf bolt and screw the wheels into that, stick the bolt in a centre lathe and turn a bit off the wheels so theta re perfectly round.
But to be honest I doubt it will be a huge problem if the wheels are a bit off centre.

i've never had the problem before but a couple of motors have failed since ive had new wheels and i dont whether the completely rigid nature of my bot plus the off centre wheels is the cause of the failures? i tried driving around on tarmac thinking that exact thing but thats where one of the motors failed, another failed in the arena.

I'd love to get anywhere near a centre lathe to sort the problem but finding access to one is proving difficult.

i straiten my wheels by using a long 3/8 unf bolt and a soldering iron i warm the nut up and then use the bolt for leverage, it doesn't get them 100% but it gets them close enough

that sounds like the kinda thing i would totally screw up! lol.

You could just hold a cordless drill in the vice with the bolt with the wheel attached in the chuck and spin it round holding a coarse file against it? Or if you have one stick it in the chuck of a pillar drill like Ellis did in his video of how to make wheels

cordless drill against tarmac! cheers for the idea!

Has anyone contacted robochallenge about this? It could be worth a look into.

not too sure, i havent. To be honest, all the wheels ive got from robochallenge have been like it and ive just accepted it as i thought it was the norm.

It is the norm. We took a lot of care in trying to press the nut as centered as possible and the wheels all came out wonky anyway. Just a limitation of this attachment method.

That said, good luck in getting them more centered, if you find a method that works that doesn't require a lathe, do share!

I have a couple to go back to robochallenge as they look buckled when running. I was gonna try and straighten them but didn't want to damage them further. I wondered if it was anything to do with the new red wheel as I have had loads of blue over the years and never had the wobble like these.

I sent one back to RC and they just sent me another one... with exactly the same problem!
But like Eliss and I have already said, quite a few people have a case of "wobbly wheel" and it doesn't significantly affect the drive of the robot.