Robochallenge wheels

[Danjr1]

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

[SamO]

Hi Dan

We have had the same problem with them:

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!

[Max]

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.

[Danjr1]

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.

[plargen]

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

[Danjr1]

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

[Max]

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

[Danjr1]

cordless drill against tarmac! cheers for the idea!

[Shakey]

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

[Danjr1]

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.

[Ellis]

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!

[ady]

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.

[SamO]

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.